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Diffstat (limited to 'libgcc/config/libbid/bid128_mul.c')
-rw-r--r--libgcc/config/libbid/bid128_mul.c2088
1 files changed, 356 insertions, 1732 deletions
diff --git a/libgcc/config/libbid/bid128_mul.c b/libgcc/config/libbid/bid128_mul.c
index f5fe5e86871..5a60aed98be 100644
--- a/libgcc/config/libbid/bid128_mul.c
+++ b/libgcc/config/libbid/bid128_mul.c
@@ -30,1775 +30,399 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
#if DECIMAL_CALL_BY_REFERENCE
void
-__bid128_mul (UINT128 * pres, UINT128 * px,
- UINT128 *
- py _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
- _EXC_INFO_PARAM) {
- UINT128 x = *px, y = *py;
-
+bid64dq_mul (UINT64 * pres, UINT64 * px, UINT128 * py
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+ UINT64 x = *px;
#if !DECIMAL_GLOBAL_ROUNDING
unsigned int rnd_mode = *prnd_mode;
-
#endif
#else
-UINT128
-__bid128_mul (UINT128 x,
- UINT128 y _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
- _EXC_INFO_PARAM) {
-
+UINT64
+bid64dq_mul (UINT64 x, UINT128 y
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
#endif
- UINT128 res;
- UINT64 x_sign, y_sign, sign;
- UINT64 x_exp, y_exp;
-
- // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64)
- // Note: C2.w[1], C2.w[0] represent y_signif_hi, y_signif_lo (all are UINT64)
- UINT64 tmp64, tmp64A;
- BID_UI64DOUBLE tmp1, tmp2;
- int x_nr_bits, y_nr_bits;
- int q1, q2, ind, shift;
- UINT128 C1, C2;
- UINT128 Cstar; // C* represents up to 34 decimal digits ~ 113 bits
- UINT384 fstar;
- int q;
- UINT128 P128, R128; // for underflow path
- UINT192 P192, R192; // for underflow path
- UINT256 C, P256, R256;
- UINT384 P384;
- UINT512 P512;
- int incr_exp = 0; // for underflow path
- int incr_exp1 = 0; // for underflow path
- int tmp_fpa = 0; // if possible underflow and q>=34, use to undo the rounding
- UINT64 C1_hi, C2_hi;
- UINT64 C1_lo, C2_lo;
- int is_inexact = 0;
- int is_midpoint_lt_even = 0, is_midpoint_gt_even = 0;
- int is_inexact_lt_midpoint = 0, is_inexact_gt_midpoint = 0;
- int is_midpoint_lt_even1 = 0, is_midpoint_gt_even1 = 0;
- int is_inexact_lt_midpoint1 = 0, is_inexact_gt_midpoint1 = 0;
- int is_overflow = 0;
- int no_underflow = 0;
+ UINT64 res = 0xbaddbaddbaddbaddull;
+ UINT128 x1;
- // unpack the arguments
- // unpack x
- x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative
- x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bit positions
- C1_hi = x.w[1] & MASK_COEFF;
- C1_lo = x.w[0];
-
- // unpack y
- y_sign = y.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative
- y_exp = y.w[1] & MASK_EXP; // biased and shifted left 49 bit positions
- C2_hi = y.w[1] & MASK_COEFF;
- C2_lo = y.w[0];
- sign = x_sign ^ y_sign;
-
- // check for NaN or Infinity
- if (((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL)
- || ((y.w[1] & MASK_SPECIAL) == MASK_SPECIAL)) {
+#if DECIMAL_CALL_BY_REFERENCE
+ bid64_to_bid128 (&x1, &x _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ bid64qq_mul (&res, &x1, py
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#else
+ x1 = bid64_to_bid128 (x _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ res = bid64qq_mul (x1, y
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#endif
+ BID_RETURN (res);
+}
- // x is special or y is special
- if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN
- if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN
- // set invalid flag
- *pfpsf |= INVALID_EXCEPTION;
- // return quiet (x)
- res.w[1] = x.w[1] & 0xfdffffffffffffffull;
- res.w[0] = x.w[0];
- } else { // x is QNaN
- if ((y.w[1] & MASK_SNAN) == MASK_SNAN) { // y is SNAN
- // set invalid flag
- *pfpsf |= INVALID_EXCEPTION;
- }
- // return x
- res.w[1] = x.w[1];
- res.w[0] = x.w[0];
- }
- BID_RETURN (res);
- } else if ((y.w[1] & MASK_NAN) == MASK_NAN) { // y is NAN
- if ((y.w[1] & MASK_SNAN) == MASK_SNAN) { // y is SNAN
- // set invalid flag
- *pfpsf |= INVALID_EXCEPTION;
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid64qd_mul (UINT64 * pres, UINT128 * px, UINT64 * py
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+ UINT64 y = *py;
+#if !DECIMAL_GLOBAL_ROUNDING
+ unsigned int rnd_mode = *prnd_mode;
+#endif
+#else
+UINT64
+bid64qd_mul (UINT128 x, UINT64 y
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+#endif
+ UINT64 res = 0xbaddbaddbaddbaddull;
+ UINT128 y1;
- // return quiet (y)
- res.w[1] = y.w[1] & 0xfdffffffffffffffull;
- res.w[0] = y.w[0];
- } else { // y is QNaN
- // return y
- res.w[1] = y.w[1];
- res.w[0] = y.w[0];
- }
- BID_RETURN (res);
- } else { // neither x nor y is NaN; at least one is infinity
- if ((x.w[1] & MASK_ANY_INF) == MASK_INF) { // x is infinity
- if (((y.w[1] & MASK_ANY_INF) == MASK_INF) || (C2_hi != 0x0ull)
- || (C2_lo != 0x0ull)) {
+#if DECIMAL_CALL_BY_REFERENCE
+ bid64_to_bid128 (&y1, &y _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ bid64qq_mul (&res, px, &y1
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#else
+ y1 = bid64_to_bid128 (y _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ res = bid64qq_mul (x, y1
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#endif
+ BID_RETURN (res);
+}
- // y is infinity OR y is finite
- // if same sign, return +inf otherwise return -inf
- if (!sign) {
- res.w[1] = 0x7800000000000000ull; // +inf
- res.w[0] = 0x0000000000000000ull;
- } else { // x and y are infinities of opposite signs
- res.w[1] = 0xf800000000000000ull; // -inf
- res.w[0] = 0x0000000000000000ull;
- }
- } else { // if y is 0
- // set invalid flag
- *pfpsf |= INVALID_EXCEPTION;
- // return QNaN Indefinite
- res.w[1] = 0x7c00000000000000ull;
- res.w[0] = 0x0000000000000000ull;
- }
- } else { // x is not NaN or infinity, so y must be infinity
- if ((C1_hi != 0x0ull) || (C1_lo != 0x0ull)) {
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid64qq_mul (UINT64 * pres, UINT128 * px, UINT128 * py
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+ UINT128 x = *px, y = *py;
+#if !DECIMAL_GLOBAL_ROUNDING
+ unsigned int rnd_mode = *prnd_mode;
+#endif
+#else
+UINT64
+bid64qq_mul (UINT128 x, UINT128 y
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+#endif
- // x is finite
- // if same sign, return +inf otherwise return -inf
- if (!sign) {
- res.w[1] = 0x7800000000000000ull; // +inf
- res.w[0] = 0x0000000000000000ull;
- } else { // y and x are of opposite signs
- res.w[1] = 0xf800000000000000ull; // -inf
- res.w[0] = 0x0000000000000000ull;
- }
- } else { // if x is 0
- // set invalid flag
- *pfpsf |= INVALID_EXCEPTION;
+ UINT128 z = { {0x0000000000000000ull, 0x5ffe000000000000ull}
+ };
+ UINT64 res = 0xbaddbaddbaddbaddull;
+ UINT64 x_sign, y_sign, p_sign;
+ UINT64 x_exp, y_exp, p_exp;
+ int true_p_exp;
+ UINT128 C1, C2;
- // return QNaN Indefinite
- res.w[1] = 0x7c00000000000000ull;
- res.w[0] = 0x0000000000000000ull;
- }
+ BID_SWAP128 (z);
+ // skip cases where at least one operand is NaN or infinity
+ if (!(((x.w[HIGH_128W] & MASK_NAN) == MASK_NAN) ||
+ ((y.w[HIGH_128W] & MASK_NAN) == MASK_NAN) ||
+ ((x.w[HIGH_128W] & MASK_ANY_INF) == MASK_INF) ||
+ ((y.w[HIGH_128W] & MASK_ANY_INF) == MASK_INF))) {
+ // x, y are 0 or f but not inf or NaN => unpack the arguments and check
+ // for non-canonical values
+
+ x_sign = x.w[HIGH_128W] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative
+ C1.w[1] = x.w[HIGH_128W] & MASK_COEFF;
+ C1.w[0] = x.w[LOW_128W];
+ // check for non-canonical values - treated as zero
+ if ((x.w[HIGH_128W] & 0x6000000000000000ull) ==
+ 0x6000000000000000ull) {
+ // G0_G1=11 => non-canonical
+ x_exp = (x.w[HIGH_128W] << 2) & MASK_EXP; // biased and shifted left 49 bits
+ C1.w[1] = 0; // significand high
+ C1.w[0] = 0; // significand low
+ } else { // G0_G1 != 11
+ x_exp = x.w[HIGH_128W] & MASK_EXP; // biased and shifted left 49 bits
+ if (C1.w[1] > 0x0001ed09bead87c0ull ||
+ (C1.w[1] == 0x0001ed09bead87c0ull &&
+ C1.w[0] > 0x378d8e63ffffffffull)) {
+ // x is non-canonical if coefficient is larger than 10^34 -1
+ C1.w[1] = 0;
+ C1.w[0] = 0;
+ } else { // canonical
+ ;
}
- BID_RETURN (res);
- }
- }
- // test for non-canonical values:
- // - values whose encoding begins with x00, x01, or x10 and whose
- // coefficient is larger than 10^34 -1, or
- // - values whose encoding begins with x1100, x1101, x1110 (if NaNs
- // and infinitis were eliminated already this test is reduced to
- // checking for x10x)
-
- // test for non-canonical values of the argument x
- if ((((C1_hi > 0x0001ed09bead87c0ull) ||
- ((C1_hi == 0x0001ed09bead87c0ull) && (C1_lo > 0x378d8e63ffffffffull))) &&
- ((x.w[1] & 0x6000000000000000ull) != 0x6000000000000000ull)) ||
- ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) {
- // check for the case where the exponent is shifted right by 2 bits!
- if ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull) {
- x_exp = (x.w[1] << 2) & MASK_EXP; // same position as for G[0]G[1] != 11
}
- x.w[1] = x.w[1] & 0x8000000000000000ull; // preserve the sign bit
- x.w[0] = 0;
- C1_hi = 0;
- C1_lo = 0;
- }
- // test for non-canonical values of the argument y
- if ((((C2_hi > 0x0001ed09bead87c0ull)
- || ((C2_hi == 0x0001ed09bead87c0ull)
- && (C2_lo > 0x378d8e63ffffffffull)))
- && ((y.w[1] & 0x6000000000000000ull) != 0x6000000000000000ull))
- || ((y.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) {
-
- // check for the case where the exponent is shifted right by 2 bits!
- if ((y.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull) {
- y_exp = (y.w[1] << 2) & MASK_EXP; // same position as for G[0]G[1] != 11
- }
- y.w[1] = y.w[1] & 0x8000000000000000ull; // preserve the sign bit
- y.w[0] = 0;
- C2_hi = 0;
- C2_lo = 0;
- }
- if (((C1_hi == 0x0ull) && (C1_lo == 0x0ull)) || ((C2_hi == 0x0ull)
- && (C2_lo == 0x0ull))) {
-
- // x is 0 and y is not special OR y is 0 and x is not special
- // if same sign, return +0 otherwise return -0
- ind = (x_exp >> 49) + (y_exp >> 49) - 6176;
- if (ind < 0)
- ind = 0;
- if (ind > 0x2fff)
- ind = 0x2fff; // 6111 + 6176
- if ((x.w[1] & MASK_SIGN) == (y.w[1] & MASK_SIGN)) {
- res.w[1] = 0x0000000000000000ull | ((UINT64) ind << 49); // +0.0
- res.w[0] = 0x0000000000000000ull;
- } else { // opposite signs
- res.w[1] = 0x8000000000000000ull | ((UINT64) ind << 49); // -0.0
- res.w[0] = 0x0000000000000000ull;
- }
- BID_RETURN (res);
- } else { // x and y are not special and are not zero
- // unpack x
- C1.w[1] = C1_hi;
- C1.w[0] = C1_lo;
-
- // q1 = nr. of decimal digits in x
- // determine first the nr. of bits in x
- if (C1.w[1] == 0) {
- if (C1.w[0] >= 0x0020000000000000ull) { // x >= 2^53
- // split the 64-bit value in two 32-bit halves to avoid rounding errors
- if (C1.w[0] >= 0x0000000100000000ull) { // x >= 2^32
- tmp1.d = (double) (C1.w[0] >> 32); // exact conversion
- x_nr_bits =
- 33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff);
- } else { // x < 2^32
- tmp1.d = (double) (C1.w[0]); // exact conversion
- x_nr_bits =
- 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff);
- }} else { // if x < 2^53
- tmp1.d = (double) C1.w[0]; // exact conversion
- x_nr_bits =
- 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff);
- }} else { // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1])
- tmp1.d = (double) C1.w[1]; // exact conversion
- x_nr_bits =
- 65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff);
- } q1 = __bid_nr_digits[x_nr_bits - 1].digits;
- if (q1 == 0) {
- q1 = __bid_nr_digits[x_nr_bits - 1].digits1;
- if (C1.w[1] > __bid_nr_digits[x_nr_bits - 1].threshold_hi
- || (C1.w[1] == __bid_nr_digits[x_nr_bits - 1].threshold_hi
- && C1.w[0] >= __bid_nr_digits[x_nr_bits - 1].threshold_lo))
- q1++;
- }
- C2.w[1] = C2_hi;
- C2.w[0] = C2_lo;
- if (C2.w[1] == 0) {
- if (C2.w[0] >= 0x0020000000000000ull) { // y >= 2^53
- // split the 64-bit value in two 32-bit halves to avoid rounding errors
- if (C2.w[0] >= 0x0000000100000000ull) { // y >= 2^32
- tmp2.d = (double) (C2.w[0] >> 32); // exact conversion
- y_nr_bits =
- 32 + ((((unsigned int) (tmp2.ui64 >> 52)) & 0x7ff) - 0x3ff);
- } else { // y < 2^32
- tmp2.d = (double) C2.w[0]; // exact conversion
- y_nr_bits =
- ((((unsigned int) (tmp2.ui64 >> 52)) & 0x7ff) - 0x3ff);
- }} else { // if y < 2^53
- tmp2.d = (double) C2.w[0]; // exact conversion
- y_nr_bits =
- ((((unsigned int) (tmp2.ui64 >> 52)) & 0x7ff) - 0x3ff);
- }} else { // C2.w[1] != 0 => nr. bits = 64 + nr_bits (C2.w[1])
- tmp2.d = (double) C2.w[1]; // exact conversion
- y_nr_bits =
- 64 + ((((unsigned int) (tmp2.ui64 >> 52)) & 0x7ff) - 0x3ff);
- } q2 = __bid_nr_digits[y_nr_bits].digits;
- if (q2 == 0) {
- q2 = __bid_nr_digits[y_nr_bits].digits1;
- if (C2.w[1] > __bid_nr_digits[y_nr_bits].threshold_hi
- || (C2.w[1] == __bid_nr_digits[y_nr_bits].threshold_hi
- && C2.w[0] >= __bid_nr_digits[y_nr_bits].threshold_lo))
- q2++;
- }
- // the exact product has either q1 + q2 - 1 or q1 + q2 decimal digits
- // where 2 <= q1 + q2 <= 68
- // calculate C' = C1 * C2 and determine q
- C.w[3] = C.w[2] = C.w[1] = C.w[0] = 0;
- if (q1 + q2 <= 19) { // if 2 <= q1 + q2 <= 19, C' = C1 * C2 fits in 64 bits
- C.w[0] = C1.w[0] * C2.w[0];
-
- // if C' < 10^(q1+q2-1) then q = q1 + q2 - 1 else q = q1 + q2
- if (C.w[0] < __bid_ten2k64[q1 + q2 - 1])
- q = q1 + q2 - 1; // q in [1, 18]
- else
- q = q1 + q2; // q in [2, 19]
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 64;
- } else if (q1 + q2 == 20) { // C' = C1 * C2 fits in 64 or 128 bits
- // q1 <= 19 and q2 <= 19 so both C1 and C2 fit in 64 bits
- __mul_64x64_to_128MACH (C, C1.w[0], C2.w[0]);
-
- // if C' < 10^(q1+q2-1) = 10^19 then q = q1+q2-1 = 19 else q = q1+q2 = 20
- if (C.w[1] == 0 && C.w[0] < __bid_ten2k64[19]) { // 19 = q1+q2-1
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 64;
- q = 19; // 19 = q1 + q2 - 1
- } else {
-
- // if (C.w[1] == 0)
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 64;
- // else
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 128;
- q = 20; // 20 = q1 + q2
- }
- } else if (q1 + q2 <= 38) { // 21 <= q1 + q2 <= 38
- // C' = C1 * C2 fits in 64 or 128 bits
- // (64 bits possibly, but only when q1 + q2 = 21 and C' has 20 digits)
- // at least one of C1, C2 has at most 19 decimal digits & fits in 64 bits
- if (q1 <= 19) {
- __mul_128x64_to_128 (C, C1.w[0], C2);
- } else { // q2 <= 19
- __mul_128x64_to_128 (C, C2.w[0], C1);
- }
-
- // if C' < 10^(q1+q2-1) then q = q1 + q2 - 1 else q = q1 + q2
- if (C.w[1] < __bid_ten2k128[q1 + q2 - 21].w[1]
- || (C.w[1] == __bid_ten2k128[q1 + q2 - 21].w[1]
- && C.w[0] < __bid_ten2k128[q1 + q2 - 21].w[0])) {
-
- // if (C.w[1] == 0) // q = 20, necessarily
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 64;
- // else
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 128;
- q = q1 + q2 - 1; // q in [20, 37]
- } else {
-
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 128;
- q = q1 + q2; // q in [21, 38]
- }
- } else if (q1 + q2 == 39) { // C' = C1 * C2 fits in 128 or 192 bits
- // both C1 and C2 fit in 128 bits (actually in 113 bits)
- // may replace this by 128x128_to192
- __mul_128x128_to_256 (C, C1, C2); // C.w[3] is 0
- // if C' < 10^(q1+q2-1) = 10^38 then q = q1+q2-1 = 38 else q = q1+q2 = 39
- if (C.w[2] == 0 && (C.w[1] < __bid_ten2k128[18].w[1] ||
- (C.w[1] == __bid_ten2k128[18].w[1] && C.w[0] < __bid_ten2k128[18].w[0]))) {
- // 18 = 38 - 20 = q1+q2-1 - 20
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 128;
- q = 38; // 38 = q1 + q2 - 1
- } else {
-
- // if (C.w[2] == 0)
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 128;
- // else
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 192;
- q = 39; // 39 = q1 + q2
- }
- } else if (q1 + q2 <= 57) { // 40 <= q1 + q2 <= 57
- // C' = C1 * C2 fits in 128 or 192 bits
- // (128 bits possibly, but only when q1 + q2 = 40 and C' has 39 digits)
- // both C1 and C2 fit in 128 bits (actually in 113 bits); at most one
- // may fit in 64 bits
- if (C1.w[1] == 0) { // C1 fits in 64 bits
- // __mul_64x128_full (REShi64, RESlo128, A64, B128)
- __mul_64x128_full (C.w[2], C, C1.w[0], C2);
- } else if (C2.w[1] == 0) { // C2 fits in 64 bits
- // __mul_64x128_full (REShi64, RESlo128, A64, B128)
- __mul_64x128_full (C.w[2], C, C2.w[0], C1);
- } else { // both C1 and C2 require 128 bits
- // may use __mul_128x128_to_192 (C.w[2], C.w[0], C2.w[0], C1);
- __mul_128x128_to_256 (C, C1, C2); // C.w[3] = 0
- }
-
- // if C' < 10^(q1+q2-1) then q = q1 + q2 - 1 else q = q1 + q2
- if (C.w[2] < __bid_ten2k256[q1 + q2 - 40].w[2]
- || (C.w[2] == __bid_ten2k256[q1 + q2 - 40].w[2]
- && (C.w[1] < __bid_ten2k256[q1 + q2 - 40].w[1]
- || (C.w[1] == __bid_ten2k256[q1 + q2 - 40].w[1]
- && C.w[0] < __bid_ten2k256[q1 + q2 - 40].w[0])))) {
-
- // if (C.w[2] == 0) // q = 39, necessarily
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 128;
- // else
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 192;
- q = q1 + q2 - 1; // q in [39, 56]
- } else {
-
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 192;
- q = q1 + q2; // q in [40, 57]
- }
- } else if (q1 + q2 == 58) { // C' = C1 * C2 fits in 192 or 256 bits
- // both C1 and C2 fit in 128 bits (actually in 113 bits); at most one
- // may fit in 64 bits
- if (C1.w[1] == 0) { // C1 * C2 will fit in 192 bits
- __mul_64x128_full (C.w[2], C, C1.w[0], C2); // may use 64x128_to_192
- } else if (C2.w[1] == 0) { // C1 * C2 will fit in 192 bits
- __mul_64x128_full (C.w[2], C, C2.w[0], C1); // may use 64x128_to_192
- } else { // C1 * C2 will fit in 192 bits or in 256 bits
- __mul_128x128_to_256 (C, C1, C2);
- }
-
- // if C' < 10^(q1+q2-1) = 10^57 then q = q1+q2-1 = 57 else q = q1+q2 = 58
- if (C.w[3] == 0 && (C.w[2] < __bid_ten2k256[18].w[2] ||
- (C.w[2] == __bid_ten2k256[18].w[2] && (C.w[1] < __bid_ten2k256[18].w[1] ||
- (C.w[1] == __bid_ten2k256[18].w[1] && C.w[0] < __bid_ten2k256[18].w[0]))))) {
- // 18 = 57 - 39 = q1+q2-1 - 39
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 192;
- q = 57; // 57 = q1 + q2 - 1
- } else {
-
- // if (C.w[3] == 0)
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 192;
- // else
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 256;
- q = 58; // 58 = q1 + q2
- }
- } else { // if 59 <= q1 + q2 <= 68
- // C' = C1 * C2 fits in 192 or 256 bits
- // (192 bits possibly, but only when q1 + q2 = 59 and C' has 58 digits)
- // both C1 and C2 fit in 128 bits (actually in 113 bits); none fits in
- // 64 bits
- // may use __mul_128x128_to_192 (C.w[2], C.w[0], C2.w[0], C1);
- __mul_128x128_to_256 (C, C1, C2); // C.w[3] = 0
- // if C' < 10^(q1+q2-1) then q = q1 + q2 - 1 else q = q1 + q2
- if (C.w[3] < __bid_ten2k256[q1 + q2 - 40].w[3]
- || (C.w[3] == __bid_ten2k256[q1 + q2 - 40].w[3]
- && (C.w[2] < __bid_ten2k256[q1 + q2 - 40].w[2]
- || (C.w[2] == __bid_ten2k256[q1 + q2 - 40].w[2]
- && (C.w[1] < __bid_ten2k256[q1 + q2 - 40].w[1]
- || (C.w[1] == __bid_ten2k256[q1 + q2 - 40].w[1]
- && C.w[0] < __bid_ten2k256[q1 + q2 - 40].w[0])))))) {
-
- // if (C.w[3] == 0) // q = 58, necessarily
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 192;
- // else
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 256;
- q = q1 + q2 - 1; // q in [58, 67]
- } else {
-
- // length of C1 * C2 rounded up to a multiple of 64 bits is len = 256;
- q = q1 + q2; // q in [59, 68]
+ y_sign = y.w[HIGH_128W] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative
+ C2.w[1] = y.w[HIGH_128W] & MASK_COEFF;
+ C2.w[0] = y.w[LOW_128W];
+ // check for non-canonical values - treated as zero
+ if ((y.w[HIGH_128W] & 0x6000000000000000ull) ==
+ 0x6000000000000000ull) {
+ // G0_G1=11 => non-canonical
+ y_exp = (y.w[HIGH_128W] << 2) & MASK_EXP; // biased and shifted left 49 bits
+ C2.w[1] = 0; // significand high
+ C2.w[0] = 0; // significand low
+ } else { // G0_G1 != 11
+ y_exp = y.w[HIGH_128W] & MASK_EXP; // biased and shifted left 49 bits
+ if (C2.w[1] > 0x0001ed09bead87c0ull ||
+ (C2.w[1] == 0x0001ed09bead87c0ull &&
+ C2.w[0] > 0x378d8e63ffffffffull)) {
+ // y is non-canonical if coefficient is larger than 10^34 -1
+ C2.w[1] = 0;
+ C2.w[0] = 0;
+ } else { // canonical
+ ;
}
}
- if (((UINT64) q << 49) + x_exp + y_exp <
- ((UINT64) P34 << 49) + EXP_MIN + BIN_EXP_BIAS) {
-
- // possible underflow
- // q + ex + ey < P34 + EMIN <=> q - P34 < EMIN - ex - ey <=> q - P34 < ind
- goto _underflow_path;
- }
- if (q <= 34) { // 2 <= q <= 34 the result is exact, and fits in 113 bits
- tmp64 = x_exp + y_exp;
- if (tmp64 > EXP_MAX + BIN_EXP_BIAS) { // possible overflow
- ind = (tmp64 - EXP_MAX - BIN_EXP_BIAS) >> 49;
- if (ind > 34 - q) { // overflow in all rounding modes
- // |res| >= 10^p * 10^emax = 10^(p-1) * 10^(emax+1)
- // assemble the result
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY) {
- res.w[1] = sign | 0x7800000000000000ull;
- res.w[0] = 0x0ull;
- } else if (rnd_mode == ROUNDING_DOWN) {
- if (sign) { // res = -inf
- res.w[1] = 0xf800000000000000ull;
- res.w[0] = 0x0ull;
- } else { // res = +MAXFP
- res.w[1] = 0x5fffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull;
- }
- } else if (rnd_mode == ROUNDING_UP) {
- if (sign) { // res = -MAXFP
- res.w[1] = 0xdfffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull;
- } else { // res = +inf
- res.w[1] = 0x7800000000000000ull;
- res.w[0] = 0x0ull;
- }
- } else { // if (rnd_mode == ROUNDING_TO_ZERO)
- // |res| = (10^34 - 1) * 10^6111 = +MAXFP
- res.w[1] = sign | 0x5fffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull;
- }
-
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
-
- // set the overflow flag
- *pfpsf |= OVERFLOW_EXCEPTION;
-
- // is_overflow = 1;
- BID_RETURN (res);
- } else { // tmp64 > EXP_MAX + BIN_EXP_BIAS but
- // ind = ((tmp64-EXP_MAX-BIN_EXP_BIAS)>>49) <= 34 - q
- // the exponent will be the maximum exponent
- // multiply C by 10^ind; the result fits in 34 digits
- if (ind <= 19) { // multiply by __bid_ten2k64[ind]
- if (q <= 19) { // 64x64 -> 128
- __mul_64x64_to_128MACH (C, C.w[0], __bid_ten2k64[ind]);
- } else { // 128 x 64 -> 128
- // may optimize to multiply 64 x 128 -> 128
- __mul_64x128_full (tmp64, C, __bid_ten2k64[ind], C);
- }
- } else { // if 20 <= ind <= 32 multiply by __bid_ten2k128[ind - 20]
- // it must be that C.w[1] = 0, as C < 10^14
- // may optimize to multiply 64 x 128 -> 128
- __mul_64x128_full (tmp64, C, C.w[0], __bid_ten2k128[ind - 20]);
- }
- res.w[0] = C.w[0];
- res.w[1] = C.w[1];
- res.w[1] |= EXP_MAX; // EXP MAX
- }
- } else {
- res.w[0] = C.w[0];
- res.w[1] = C.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- res.w[1] |= sign;
- } else if (q <= 38) { // 35 <= q <= 38; exact coefficient fits in 128 bits
- // C = C + 1/2 * 10^x where the result C fits in 127 bits
- ind = q - 35;
- tmp64 = C.w[0];
- C.w[0] = C.w[0] + __bid_midpoint64[ind];
- if (C.w[0] < tmp64)
- C.w[1]++;
-
- // x = q - p = q - 34, 1 <= x <= 4
- // kx = 10^(-x) = __bid_ten2mk128M[ind]
- // C* = (C + 1/2 * 10^x) * 10^(-x)
- // the approximation of 10^(-x) was rounded up to 128 bits
- __mul_128x128_to_256 (P256, C, __bid_ten2mk128M[ind]);
- Cstar.w[1] = P256.w[3];
- Cstar.w[0] = P256.w[2];
- fstar.w[2] = Cstar.w[0] & __bid_maskhigh128M[ind]; // fstar.w[3|4|5]=0
- fstar.w[1] = P256.w[1];
- fstar.w[0] = P256.w[0];
-
- // calculate C* and f*
- // C* is actually floor(C*) in this case
- // C* and f* need shifting and masking, as shown by
- // __bid_shiftright128M[] and __bid_maskhigh128M[]
- // the top Ex bits of 10^(-x) are T* = __bid_ten2mk128truncM[ind], e.g.
- // if x=1, T*=__bid_ten2mk128truncM[0]=0xcccccccccccccccccccccccccccccccc
- // if (0 < f* < 10^(-x)) then the result is a midpoint
- // if floor(C*) is even then C* = floor(C*) - logical right
- // shift; C* has p decimal digits, correct by Prop. 1)
- // else if floor(C*) is odd C* = floor(C*)-1 (logical right
- // shift; C* has p decimal digits, correct by Pr. 1)
- // else
- // C* = floor(C*) (logical right shift; C has p decimal digits,
- // correct by Property 1)
- // n = C* * 10^(e+x)
-
- // shift right C* by Ex-128 = __bid_shiftright128M[ind]
- shift = __bid_shiftright128M[ind]; // 3 <= shift <= 13
- Cstar.w[0] = (Cstar.w[0] >> shift) | (Cstar.w[1] << (64 - shift));
- Cstar.w[1] = (Cstar.w[1] >> shift);
-
- // determine inexactness of the rounding of C*
- // if (0 < f* - 1/2 < 10^(-x)) then
- // the result is exact
- // else // if (f* - 1/2 > T*) then
- // the result is inexact
- if (fstar.w[2] > __bid_one_half128M[ind]
- || (fstar.w[2] == __bid_one_half128M[ind]
- && (fstar.w[1] || fstar.w[0]))) {
-
- // f* > 1/2 and the result may be exact
- // Calculate f* - 1/2
- tmp64 = fstar.w[2] - __bid_one_half128M[ind];
- if (tmp64 || fstar.w[1] > __bid_ten2mk128truncM[ind].w[1] ||
- (fstar.w[1] == __bid_ten2mk128truncM[ind].w[1] &&
- fstar.w[0] > __bid_ten2mk128truncM[ind].w[0])) { // f* - 1/2 > 10^(-x)
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
- is_inexact_lt_midpoint = 1;
- } // else the result is exact
- } else { // the result is inexact; f2* <= 1/2
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
- tmp_fpa = 1;
- is_inexact_gt_midpoint = 1;
- }
-
- // check for midpoints (could do this before determining inexactness)
- if ((fstar.w[2] == 0) && (fstar.w[1] || fstar.w[0])
- && (fstar.w[1] < __bid_ten2mk128truncM[ind].w[1]
- || (fstar.w[1] == __bid_ten2mk128truncM[ind].w[1]
- && fstar.w[0] <= __bid_ten2mk128truncM[ind].w[0]))) {
-
- // the result is a midpoint
- if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD]
- // if floor(C*) is odd C = floor(C*) - 1; the result may be 0
- Cstar.w[0]--; // Cstar.w[0] is now even
- if (tmp_fpa == 1)
- tmp_fpa = 0;
- is_midpoint_gt_even = 1;
- is_inexact_lt_midpoint = 0;
- is_inexact_gt_midpoint = 0;
- } else { // else MP in [ODD, EVEN]
- is_midpoint_lt_even = 1;
- is_inexact_lt_midpoint = 0;
- is_inexact_gt_midpoint = 0;
- }
- }
- // check for rounding overflow
- if (Cstar.w[1] == 0x0001ed09bead87c0ull &&
- Cstar.w[0] == 0x378d8e6400000000ull) { // if Cstar = 10^34
- tmp64 = x_exp + y_exp + ((UINT64) (ind + 2) << 49);
- Cstar.w[1] = 0x0000314dc6448d93ull; // Cstar = 10^33
- Cstar.w[0] = 0x38c15b0a00000000ull;
-
- // if rounding overflow made the exponent equal to emin, set underflow
- if (tmp64 == EXP_MIN + BIN_EXP_BIAS)
- *pfpsf |= UNDERFLOW_EXCEPTION;
- } else { // 10^33 <= Cstar <= 10^34 - 1
- tmp64 = x_exp + y_exp + ((UINT64) (ind + 1) << 49); // ind+1 = q-34
- }
- if (tmp64 >= EXP_MAX + BIN_EXP_BIAS) { // possibble overflow
- // exp >= emax for the result rounded to nearest even
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY) {
- if (tmp64 > EXP_MAX + BIN_EXP_BIAS) {
-
- // |res| >= 10^(p-1) * 10^(emax+1) <=> exp >= emax+1
- res.w[1] = sign | 0x7800000000000000ull; // +/-inf
- res.w[0] = 0x0ull;
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- } else if (rnd_mode == ROUNDING_DOWN) {
- if (!sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
-
- // res = +MAXFP
- res.w[1] = 0x5fffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // (10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else if (sign && ((tmp64 > EXP_MAX + BIN_EXP_BIAS) ||
- ((tmp64 == EXP_MAX + BIN_EXP_BIAS) &&
- Cstar.w[1] == 0x0001ed09bead87c0ull &&
- Cstar.w[0] == 0x378d8e63ffffffffull && // (10^34-1) * 10^emax
- is_inexact_lt_midpoint))) {
- res.w[1] = 0xf800000000000000ull; // -inf
- res.w[0] = 0x0ull;
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- } else if (rnd_mode == ROUNDING_UP) {
- if (sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
- // res = -MAXFP
- res.w[1] = 0xdfffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // -(10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else if (!sign && ((tmp64 > EXP_MAX + BIN_EXP_BIAS) ||
- ((tmp64 == EXP_MAX + BIN_EXP_BIAS) &&
- Cstar.w[1] == 0x0001ed09bead87c0ull &&
- Cstar.w[0] == 0x378d8e63ffffffffull && // (10^34-1) * 10^emax
- is_inexact_lt_midpoint))) {
- res.w[1] = 0x7800000000000000ull; // inf
- res.w[0] = 0x0ull;
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- } else { // if (rnd_mode == ROUNDING_TO_ZERO)
- if (!sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
- // res = +MAXFP
- res.w[1] = 0x5fffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // (10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else if (sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
- // res = -MAXFP
- res.w[1] = 0xdfffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // -(10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- }
- if (is_overflow) { // return for overflow
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
-
- // set the overflow flag
- *pfpsf |= OVERFLOW_EXCEPTION;
-
- // is_overflow = 1;
- BID_RETURN (res);
- }
- } else {
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- res.w[1] |= sign;
- } else if (q <= 57) { // 39 <= q <= 57; exact coefficient takes 128-192 bits
- // C = C + 1/2 * 10^x where the result C fits in 190 bits
- // (10^57 - 1 + 1/2 * 10^23 can be represented with 190 bits)
- // x = q - p = q - 34, 5 <= x <= 23
- // kx = 10^(-x) = __bid_ten2mk192M[ind]
- // C* = (C + 1/2 * 10^x) * 10^(-x)
- // the approximation of 10^(-x) was rounded up to 192 bits
- ind = q - 39; // 0 <= ind <= 18
- tmp64 = C.w[0];
- tmp64A = C.w[1];
-
- // Note:
- // if 5 <= x <= 19 <=> 0 <= ind <= 14 then
- // f* has 256 bits
- // else // if 20 <= x <= 23 <=> 15 <= ind <= 18 then
- // f* has 320 bits
- if (ind <= 14) { // x - 1 = q - 35 = ind + 4 <= 18
- // add one 64-bit word
- C.w[0] = C.w[0] + __bid_midpoint64[ind + 4];
- if (C.w[0] < tmp64)
- C.w[1]++;
- if (C.w[1] < tmp64A)
- C.w[2]++;
- __mul_192x192_to_384 (P384, C, __bid_ten2mk192M[ind])
- // calculate C* and f*; C* is actually floor(C*) in this case
- // C* and f* need shifting and masking, as shown by
- // __bid_shiftright192M[] and __bid_maskhigh192M[]
- // C* has 128 bits; P384.w[5], P384.w[4], P384.w[3] need to be
- // shifted right by Ex-192 = __bid_shiftright192M[ind]
- shift = __bid_shiftright192M[ind]; // 16 <= shift <= 63
- Cstar.w[0] = (P384.w[3] >> shift) | (P384.w[4] << (64 - shift));
- Cstar.w[1] = (P384.w[4] >> shift) | (P384.w[5] << (64 - shift));
-
- // f* has 256 bits
- fstar.w[3] = P384.w[3] & __bid_maskhigh192M[ind];
- fstar.w[2] = P384.w[2];
- fstar.w[1] = P384.w[1];
- fstar.w[0] = P384.w[0];
-
- // the top Ex bits of 10^(-x) are T* = __bid_ten2mk192truncM[ind], e.g.
- // if x=5, T* = __bid_ten2mk192truncM[0] =
- // 0xa7c5ac471b4784230fcf80dc33721d53cddd6e04c0592103
- // if (0 < f* < 10^(-x)) then the result is a midpoint
- // if floor(C*) is even then C* = floor(C*) - logical right
- // shift; C* has p decimal digits, correct by Prop. 1)
- // else if floor(C*) is odd C* = floor(C*)-1 (logical right
- // shift; C* has p decimal digits, correct by Pr. 1)
- // else
- // C* = floor(C*) (logical right shift; C has p decimal digits,
- // correct by Property 1)
- // n = C* * 10^(e+x)
-
- // determine inexactness of the rounding of C*
- // if (0 < f* - 1/2 < T* ~= 10^(-x)) then
- // the result is exact
- // else // if (f* - 1/2 >= T*) then
- // the result is inexact
- if (fstar.w[3] > __bid_one_half192M[ind]
- || (fstar.w[3] == __bid_one_half192M[ind]
- && (fstar.w[2] || fstar.w[1] || fstar.w[0]))) {
-
- // f* > 1/2 and the result may be exact
- // Calculate f* - 1/2
- tmp64 = fstar.w[3] - __bid_one_half192M[ind];
- if (tmp64 || fstar.w[2] > __bid_ten2mk192truncM[ind].w[2] ||
- (fstar.w[2] == __bid_ten2mk192truncM[ind].w[2] &&
- fstar.w[1] > __bid_ten2mk192truncM[ind].w[1]) ||
- (fstar.w[2] == __bid_ten2mk192truncM[ind].w[2] &&
- fstar.w[1] == __bid_ten2mk192truncM[ind].w[1] &&
- fstar.w[0] > __bid_ten2mk192truncM[ind].w[0])) { // f* - 1/2 > 10^(-x)
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
- is_inexact_lt_midpoint = 1;
- } // else the result is exact
- } else { // the result is inexact; f2* <= 1/2
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
- tmp_fpa = 1;
- is_inexact_gt_midpoint = 1;
- }
-
- // check for midpoints (could do this before determining inexactness)
- if ((fstar.w[3] == 0)
- && (fstar.w[2] || fstar.w[1] || fstar.w[0])
- && (fstar.w[2] < __bid_ten2mk192truncM[ind].w[2]
- || (fstar.w[2] == __bid_ten2mk192truncM[ind].w[2]
- && fstar.w[1] < __bid_ten2mk192truncM[ind].w[1])
- || (fstar.w[2] == __bid_ten2mk192truncM[ind].w[2]
- && fstar.w[1] == __bid_ten2mk192truncM[ind].w[1]
- && fstar.w[0] <= __bid_ten2mk192truncM[ind].w[0]))) {
-
- // the result is a midpoint
- if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD]
- // if floor(C*) is odd C = floor(C*) - 1; the result may be 0
- Cstar.w[0]--; // Cstar.w[0] is now even
- if (tmp_fpa == 1)
- tmp_fpa = 0;
- is_midpoint_gt_even = 1;
- is_inexact_lt_midpoint = 0;
- is_inexact_gt_midpoint = 0;
- } else { // else MP in [ODD, EVEN]
- is_midpoint_lt_even = 1;
- is_inexact_lt_midpoint = 0;
- is_inexact_gt_midpoint = 0;
- }
- }
- } else { // if ind >= 15 <=> x - 1 = q - 35 = ind + 4 >= 19
- // add two 64-bit words
- C.w[0] = C.w[0] + __bid_midpoint128[ind - 15].w[0];
- C.w[1] = C.w[1] + __bid_midpoint128[ind - 15].w[1];
- if (C.w[0] < tmp64)
- C.w[1]++;
- if (C.w[1] < tmp64A)
- C.w[2]++;
- __mul_192x192_to_384 (P384, C, __bid_ten2mk192M[ind])
- // calculate C* and f*; C* is actually floor(C*) in this case
- // C* and f* need shifting and masking, as shown by
- // __bid_shiftright192M[] and __bid_maskhigh192M[]
- // C* has 128 bits; P384.w[5], P384.w[4], need to be
- // shifted right by Ex-256 = __bid_shiftright192M[ind]
- shift = __bid_shiftright192M[ind]; // 2 <= shift <= 12
- Cstar.w[0] = (P384.w[4] >> shift) | (P384.w[5] << (64 - shift));
- Cstar.w[1] = (P384.w[5] >> shift);
-
- // f* has 320 bits
- fstar.w[4] = P384.w[4] & __bid_maskhigh192M[ind];
- fstar.w[3] = P384.w[3];
- fstar.w[2] = P384.w[2];
- fstar.w[1] = P384.w[1];
- fstar.w[0] = P384.w[0];
-
- // the top Ex bits of 10^(-x) are T* = __bid_ten2mk192truncM[ind], e.g.
- // if x=23, T* = __bid_ten2mk192truncM[18] =
- // 0xc16d9a0095928a2775b7053c0f1782938d6f439b43088650
- // if (0 < f* < 10^(-x)) then the result is a midpoint
- // if floor(C*) is even then C* = floor(C*) - logical right
- // shift; C* has p decimal digits, correct by Prop. 1)
- // else if floor(C*) is odd C* = floor(C*)-1 (logical right
- // shift; C* has p decimal digits, correct by Pr. 1)
- // else
- // C* = floor(C*) (logical right shift; C has p decimal digits,
- // correct by Property 1)
- // n = C* * 10^(e+x)
-
- // determine inexactness of the rounding of C*
- // if (0 < f* - 1/2 < T* ~= 10^(-x)) then
- // the result is exact
- // else // if (f* - 1/2 >= T*) then
- // the result is inexact
- if (fstar.w[4] > __bid_one_half192M[ind]
- || (fstar.w[4] == __bid_one_half192M[ind]
- && (fstar.w[3] || fstar.w[2] || fstar.w[1] || fstar.w[0]))) {
-
- // f* > 1/2 and the result may be exact
- // Calculate f* - 1/2
- tmp64 = fstar.w[4] - __bid_one_half192M[ind];
- if (tmp64 || fstar.w[3] || fstar.w[2] > __bid_ten2mk192truncM[ind].w[2] ||
- (fstar.w[2] == __bid_ten2mk192truncM[ind].w[2] &&
- fstar.w[1] > __bid_ten2mk192truncM[ind].w[1]) ||
- (fstar.w[2] == __bid_ten2mk192truncM[ind].w[2] &&
- fstar.w[1] == __bid_ten2mk192truncM[ind].w[1] &&
- fstar.w[0] > __bid_ten2mk192truncM[ind].w[0])) { // f* - 1/2 > 10^(-x)
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
- is_inexact_lt_midpoint = 1;
- } // else the result is exact
- } else { // the result is inexact; f2* <= 1/2
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
- tmp_fpa = 1;
- is_inexact_gt_midpoint = 1;
- }
+ p_sign = x_sign ^ y_sign; // sign of the product
+
+ true_p_exp = (x_exp >> 49) - 6176 + (y_exp >> 49) - 6176;
+ // true_p_exp, p_exp are used only for 0 * 0, 0 * f, or f * 0
+ if (true_p_exp < -398)
+ p_exp = 0; // cannot be less than EXP_MIN
+ else if (true_p_exp > 369)
+ p_exp = (UINT64) (369 + 398) << 53; // cannot be more than EXP_MAX
+ else
+ p_exp = (UINT64) (true_p_exp + 398) << 53;
+
+ if ((C1.w[1] == 0x0 && C1.w[0] == 0x0) ||
+ (C2.w[1] == 0x0 && C2.w[0] == 0x0)) {
+ // x = 0 or y = 0
+ // the result is 0
+ res = p_sign | p_exp; // preferred exponent in [EXP_MIN, EXP_MAX]
+ BID_RETURN (res)
+ } // else continue
+ }
+ // swap x and y - ensure that a NaN in x has 'higher precedence' than one in y
+#if DECIMAL_CALL_BY_REFERENCE
+ bid64qqq_fma (&res, &y, &x, &z
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#else
+ res = bid64qqq_fma (y, x, z
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#endif
+ BID_RETURN (res);
+}
- // check for midpoints (could do this before determining inexactness)
- if ((fstar.w[4] == 0) && (fstar.w[3] == 0)
- && (fstar.w[2] || fstar.w[1] || fstar.w[0])
- && (fstar.w[2] < __bid_ten2mk192truncM[ind].w[2]
- || (fstar.w[2] == __bid_ten2mk192truncM[ind].w[2]
- && fstar.w[1] < __bid_ten2mk192truncM[ind].w[1])
- || (fstar.w[2] == __bid_ten2mk192truncM[ind].w[2]
- && fstar.w[1] == __bid_ten2mk192truncM[ind].w[1]
- && fstar.w[0] <= __bid_ten2mk192truncM[ind].w[0]))) {
- // the result is a midpoint
- if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD]
- // if floor(C*) is odd C = floor(C*) - 1; the result may be 0
- Cstar.w[0]--; // Cstar.w[0] is now even
- if (tmp_fpa == 1)
- tmp_fpa = 0;
- is_midpoint_gt_even = 1;
- is_inexact_lt_midpoint = 0;
- is_inexact_gt_midpoint = 0;
- } else { // else MP in [ODD, EVEN]
- is_midpoint_lt_even = 1;
- is_inexact_lt_midpoint = 0;
- is_inexact_gt_midpoint = 0;
- }
- }
- }
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid128dd_mul (UINT128 * pres, UINT64 * px, UINT64 * py
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+ UINT64 x = *px, y = *py;
+#if !DECIMAL_GLOBAL_ROUNDING
+ unsigned int rnd_mode = *prnd_mode;
+#endif
+#else
+UINT128
+bid128dd_mul (UINT64 x, UINT64 y
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+#endif
+ UINT128 res = { {0xbaddbaddbaddbaddull, 0xbaddbaddbaddbaddull}
+ };
+ UINT128 x1, y1;
- // check for rounding overflow
- if (Cstar.w[1] == 0x0001ed09bead87c0ull &&
- Cstar.w[0] == 0x378d8e6400000000ull) { // if Cstar = 10^34
- tmp64 = x_exp + y_exp + ((UINT64) (ind + 6) << 49);
- Cstar.w[1] = 0x0000314dc6448d93ull; // Cstar = 10^33
- Cstar.w[0] = 0x38c15b0a00000000ull;
- } else { // 10^33 <= Cstar <= 10^34 - 1
- tmp64 = x_exp + y_exp + ((UINT64) (ind + 5) << 49); // ind+5 = q-34
- }
- if (tmp64 >= EXP_MAX + BIN_EXP_BIAS) { // possibble overflow
- // exp >= emax for the result rounded to nearest even
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY) {
- if (tmp64 > EXP_MAX + BIN_EXP_BIAS) {
+#if DECIMAL_CALL_BY_REFERENCE
+ bid64_to_bid128 (&x1, &x _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ bid64_to_bid128 (&y1, &y _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ bid128_mul (&res, &x1, &y1
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#else
+ x1 = bid64_to_bid128 (x _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ y1 = bid64_to_bid128 (y _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ res = bid128_mul (x1, y1
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#endif
+ BID_RETURN (res);
+}
- // |res| >= 10^(p-1) * 10^(emax+1) <=> exp >= emax+1
- res.w[1] = sign | 0x7800000000000000ull; // +/-inf
- res.w[0] = 0x0ull;
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- } else if (rnd_mode == ROUNDING_DOWN) {
- if (!sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
- // res = +MAXFP
- res.w[1] = 0x5fffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // (10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else if (sign && ((tmp64 > EXP_MAX + BIN_EXP_BIAS) ||
- ((tmp64 == EXP_MAX + BIN_EXP_BIAS) &&
- Cstar.w[1] == 0x0001ed09bead87c0ull &&
- Cstar.w[0] == 0x378d8e63ffffffffull && // (10^34-1) * 10^emax
- is_inexact_lt_midpoint))) {
- res.w[1] = 0xf800000000000000ull; // -inf
- res.w[0] = 0x0ull;
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- } else if (rnd_mode == ROUNDING_UP) {
- if (sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
- // res = -MAXFP
- res.w[1] = 0xdfffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // -(10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else if (!sign && ((tmp64 > EXP_MAX + BIN_EXP_BIAS) ||
- ((tmp64 == EXP_MAX + BIN_EXP_BIAS) &&
- Cstar.w[1] == 0x0001ed09bead87c0ull &&
- Cstar.w[0] == 0x378d8e63ffffffffull && // (10^34-1) * 10^emax
- is_inexact_lt_midpoint))) {
- res.w[1] = 0x7800000000000000ull; // inf
- res.w[0] = 0x0ull;
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- } else { // if (rnd_mode == ROUNDING_TO_ZERO)
- if (!sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
- // res = +MAXFP
- res.w[1] = 0x5fffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // (10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else if (sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
- // res = -MAXFP
- res.w[1] = 0xdfffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // -(10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- }
- if (is_overflow) { // return for overflow
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
- // set the overflow flag
- *pfpsf |= OVERFLOW_EXCEPTION;
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid128dq_mul (UINT128 * pres, UINT64 * px, UINT128 * py
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+ UINT64 x = *px;
+#if !DECIMAL_GLOBAL_ROUNDING
+ unsigned int rnd_mode = *prnd_mode;
+#endif
+#else
+UINT128
+bid128dq_mul (UINT64 x, UINT128 y
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+#endif
+ UINT128 res = { {0xbaddbaddbaddbaddull, 0xbaddbaddbaddbaddull}
+ };
+ UINT128 x1;
- // is_overflow = 1;
- BID_RETURN (res)}
- } else {
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- res.w[1] |= sign;
- } else { // if (58 <= q <= 68) exact coefficient takes 192-226 bits
- // C = C + 1/2 * 10^x where the result C fits in 226 bits
- // (10^68 - 1 + 1/2 * 10^34 can be represented with 226 bits)
- // x = q - p = q - 34, 24 <= x <= 34
- // kx = 10^(-x) = __bid_ten2mk256M[ind]
- // C* = (C + 1/2 * 10^x) * 10^(-x)
- // the approximation of 10^(-x) was rounded up to 256 bits
- ind = q - 58; // 0 <= ind <= 10
- tmp64 = C.w[0];
- tmp64A = C.w[1];
+#if DECIMAL_CALL_BY_REFERENCE
+ bid64_to_bid128 (&x1, &x _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ bid128_mul (&res, &x1, py
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#else
+ x1 = bid64_to_bid128 (x _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ res = bid128_mul (x1, y
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#endif
+ BID_RETURN (res);
+}
- // Note:
- // f* has 384 bits (more than 320 bits)
- // x - 1 = q - 35 = ind + 23
- // add two 64-bit words; e.g. for ind=0 <=> q=58, add 1/2*10^24
- C.w[0] = C.w[0] + __bid_midpoint128[ind + 4].w[0];
- C.w[1] = C.w[1] + __bid_midpoint128[ind + 4].w[1];
- if (C.w[0] < tmp64)
- C.w[1]++;
- if (C.w[1] < tmp64A)
- C.w[2]++;
- if (C.w[2] == 0)
- C.w[3]++;
- __mul_256x256_to_512 (P512, C, __bid_ten2mk256M[ind])
- // calculate C* and f*; C* is actually floor(C*) in this case
- // C* and f* need shifting and masking, as shown by
- // __bid_shiftright256M[] and __bid_maskhigh256M[]
- // C* has 128 bits; P512.w[7], P512.w[6], P512.w[5] need to be
- // shifted right by Ex-320 = __bid_shiftright256M[ind]
- shift = __bid_shiftright256M[ind]; // 15 <= shift <= 48
- if (shift == 32) {
- Cstar.w[0] =
- ((P512.w[5] >> 31) >> 1) | ((P512.w[6] << 31) << 1);
- Cstar.w[1] =
- ((P512.w[6] >> 31) >> 1) | ((P512.w[7] << 31) << 1);
- } else {
- Cstar.w[0] = (P512.w[5] >> shift) | (P512.w[6] << (64 - shift));
- Cstar.w[1] = (P512.w[6] >> shift) | (P512.w[7] << (64 - shift));
- }
- // f* has 384 bits
- fstar.w[5] = P512.w[5] & __bid_maskhigh256M[ind];
- fstar.w[4] = P512.w[4];
- fstar.w[3] = P512.w[3];
- fstar.w[2] = P512.w[2];
- fstar.w[1] = P512.w[1];
- fstar.w[0] = P512.w[0];
- // the top Ex bits of 10^(-x) are T* = __bid_ten2mk256truncM[ind], e.g.
- // if x=24, T* = __bid_ten2mk256truncM[0] =
- // 0x9abe14cd44753b52c4926a9672793542d78c3615cf3a050cf23472530ce6e3ec =~
- // 10^(-24) * 2^335
- // if (0 < f* < 10^(-x)) then the result is a midpoint
- // if floor(C*) is even then C* = floor(C*) - logical right
- // shift; C* has p decimal digits, correct by Prop. 1)
- // else if floor(C*) is odd C* = floor(C*)-1 (logical right
- // shift; C* has p decimal digits, correct by Pr. 1)
- // else
- // C* = floor(C*) (logical right shift; C has p decimal digits,
- // correct by Property 1)
- // n = C* * 10^(e+x)
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid128qd_mul (UINT128 * pres, UINT128 * px, UINT64 * py
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+ UINT64 y = *py;
+#if !DECIMAL_GLOBAL_ROUNDING
+ unsigned int rnd_mode = *prnd_mode;
+#endif
+#else
+UINT128
+bid128qd_mul (UINT128 x, UINT64 y
+ _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+#endif
+ UINT128 res = { {0xbaddbaddbaddbaddull, 0xbaddbaddbaddbaddull}
+ };
+ UINT128 y1;
- // determine inexactness of the rounding of C*
- // if (0 < f* - 1/2 < T* ~= 10^(-x)) then
- // the result is exact
- // else // if (f* - 1/2 >= T*) then
- // the result is inexact
- if (fstar.w[5] > __bid_one_half256M[ind]
- || (fstar.w[5] == __bid_one_half256M[ind]
- && (fstar.w[4] || fstar.w[3] || fstar.w[2] || fstar.w[1]
- || fstar.w[0]))) {
+#if DECIMAL_CALL_BY_REFERENCE
+ bid64_to_bid128 (&y1, &y _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ bid128_mul (&res, px, &y1
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#else
+ y1 = bid64_to_bid128 (y _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
+ res = bid128_mul (x, y1
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#endif
+ BID_RETURN (res);
+}
- // f* > 1/2 and the result may be exact
- // Calculate f* - 1/2
- tmp64 = fstar.w[5] - __bid_one_half256M[ind]; // tmp64 >= 0
- if (tmp64 || fstar.w[4] || fstar.w[3] > __bid_ten2mk256truncM[ind].w[3] ||
- (fstar.w[3] == __bid_ten2mk256truncM[ind].w[3] &&
- fstar.w[2] > __bid_ten2mk256truncM[ind].w[2]) ||
- (fstar.w[3] == __bid_ten2mk256truncM[ind].w[3] &&
- fstar.w[2] == __bid_ten2mk256truncM[ind].w[2] &&
- fstar.w[1] > __bid_ten2mk256truncM[ind].w[1]) ||
- (fstar.w[3] == __bid_ten2mk256truncM[ind].w[3] &&
- fstar.w[2] == __bid_ten2mk256truncM[ind].w[2] &&
- fstar.w[1] == __bid_ten2mk256truncM[ind].w[1] &&
- fstar.w[0] > __bid_ten2mk256truncM[ind].w[0])) { // f* - 1/2 > 10^(-x)
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
- is_inexact_lt_midpoint = 1;
- } // else the result is exact
- } else { // the result is inexact; f2* <= 1/2
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
- tmp_fpa = 1;
- is_inexact_gt_midpoint = 1;
- }
- // check for midpoints (could do this before determining inexactness)
- if ((fstar.w[5] == 0) && (fstar.w[4] == 0)
- && (fstar.w[3] || fstar.w[2] || fstar.w[1] || fstar.w[0])
- && (fstar.w[3] < __bid_ten2mk256truncM[ind].w[3]
- || (fstar.w[3] == __bid_ten2mk256truncM[ind].w[3]
- && fstar.w[2] < __bid_ten2mk256truncM[ind].w[2])
- || (fstar.w[3] == __bid_ten2mk256truncM[ind].w[3]
- && fstar.w[2] == __bid_ten2mk256truncM[ind].w[2]
- && fstar.w[1] < __bid_ten2mk256truncM[ind].w[1])
- || (fstar.w[3] == __bid_ten2mk256truncM[ind].w[3]
- && fstar.w[2] == __bid_ten2mk256truncM[ind].w[2]
- && fstar.w[1] == __bid_ten2mk256truncM[ind].w[1]
- && fstar.w[0] <= __bid_ten2mk256truncM[ind].w[1]))) {
+// bid128_mul stands for bid128qq_mul
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid128_mul (UINT128 * pres, UINT128 * px,
+ UINT128 *
+ py _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
+ UINT128 x = *px, y = *py;
- // the result is a midpoint
- if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD]
- // if floor(C*) is odd C = floor(C*) - 1; the result may be 0
- Cstar.w[0]--; // Cstar.w[0] is now even
- if (tmp_fpa == 1)
- tmp_fpa = 0;
- is_midpoint_gt_even = 1;
- is_inexact_lt_midpoint = 0;
- is_inexact_gt_midpoint = 0;
- } else { // else MP in [ODD, EVEN]
- is_midpoint_lt_even = 1;
- is_inexact_lt_midpoint = 0;
- is_inexact_gt_midpoint = 0;
- }
- }
- // check for rounding overflow
- if (Cstar.w[1] == 0x0001ed09bead87c0ull &&
- Cstar.w[0] == 0x378d8e6400000000ull) { // if Cstar = 10^34
- tmp64 = x_exp + y_exp + ((UINT64) (ind + 25) << 49);
- Cstar.w[1] = 0x0000314dc6448d93ull; // Cstar = 10^33
- Cstar.w[0] = 0x38c15b0a00000000ull;
- } else { // 10^33 <= Cstar <= 10^34 - 1
- tmp64 = x_exp + y_exp + ((UINT64) (ind + 24) << 49); // ind+24 = q-34
- }
- if (tmp64 >= EXP_MAX + BIN_EXP_BIAS) { // possibble overflow
- // exp >= emax for the result rounded to nearest even
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY) {
- if (tmp64 > EXP_MAX + BIN_EXP_BIAS) {
+#if !DECIMAL_GLOBAL_ROUNDING
+ unsigned int rnd_mode = *prnd_mode;
- // |res| >= 10^(p-1) * 10^(emax+1) <=> exp >= emax+1
- res.w[1] = sign | 0x7800000000000000ull; // +/-inf
- res.w[0] = 0x0ull;
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- } else if (rnd_mode == ROUNDING_DOWN) {
- if (!sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
- // res = +MAXFP
- res.w[1] = 0x5fffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // (10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else if (sign && ((tmp64 > EXP_MAX + BIN_EXP_BIAS) ||
- ((tmp64 == EXP_MAX + BIN_EXP_BIAS) &&
- Cstar.w[1] == 0x0001ed09bead87c0ull &&
- Cstar.w[0] == 0x378d8e63ffffffffull && // (10^34-1) * 10^emax
- is_inexact_lt_midpoint))) {
- res.w[1] = 0xf800000000000000ull; // -inf
- res.w[0] = 0x0ull;
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- } else if (rnd_mode == ROUNDING_UP) {
- if (sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
- // res = -MAXFP
- res.w[1] = 0xdfffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // -(10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else if (!sign && ((tmp64 > EXP_MAX + BIN_EXP_BIAS) ||
- ((tmp64 == EXP_MAX + BIN_EXP_BIAS) &&
- Cstar.w[1] == 0x0001ed09bead87c0ull &&
- Cstar.w[0] == 0x378d8e63ffffffffull && // (10^34-1) * 10^emax
- is_inexact_lt_midpoint))) {
- res.w[1] = 0x7800000000000000ull; // inf
- res.w[0] = 0x0ull;
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- } else { // if (rnd_mode == ROUNDING_TO_ZERO)
- if (!sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
- // res = +MAXFP
- res.w[1] = 0x5fffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // (10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else if (sign && (tmp64 > EXP_MAX + BIN_EXP_BIAS) &&
- !(tmp64 == EXP_MAX + BIN_EXP_BIAS + EXP_P1 &&
- Cstar.w[1] == 0x0000314dc6448d93ull &&
- Cstar.w[0] == 0x38c15b0a00000000ull && // 10^33 * 10^(emax+1)
- (is_midpoint_lt_even || is_inexact_gt_midpoint))) {
- // res = -MAXFP
- res.w[1] = 0xdfffed09bead87c0ull;
- res.w[0] = 0x378d8e63ffffffffull; // -(10^34-1) * 10^emax
- *pfpsf |= INEXACT_EXCEPTION; // set the inexact flag
- *pfpsf |= OVERFLOW_EXCEPTION; // set the overflow flag
- is_overflow = 1;
- } else { // not overflow
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
- }
- }
- if (is_overflow) { // return for overflow
- // set the inexact flag
- *pfpsf |= INEXACT_EXCEPTION;
+#endif
+#else
+UINT128
+bid128_mul (UINT128 x,
+ UINT128 y _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+ _EXC_INFO_PARAM) {
- // set the overflow flag
- *pfpsf |= OVERFLOW_EXCEPTION;
+#endif
+ UINT128 z = { {0x0000000000000000ull, 0x5ffe000000000000ull}
+ };
+ UINT128 res = { {0xbaddbaddbaddbaddull, 0xbaddbaddbaddbaddull}
+ };
+ UINT64 x_sign, y_sign, p_sign;
+ UINT64 x_exp, y_exp, p_exp;
+ int true_p_exp;
+ UINT128 C1, C2;
- // is_overflow = 1;
- BID_RETURN (res);
- }
- } else {
- res.w[0] = Cstar.w[0];
- res.w[1] = Cstar.w[1];
- res.w[1] |= (tmp64 - BIN_EXP_BIAS);
+ BID_SWAP128 (x);
+ BID_SWAP128 (y);
+ // skip cases where at least one operand is NaN or infinity
+ if (!(((x.w[1] & MASK_NAN) == MASK_NAN) ||
+ ((y.w[1] & MASK_NAN) == MASK_NAN) ||
+ ((x.w[1] & MASK_ANY_INF) == MASK_INF) ||
+ ((y.w[1] & MASK_ANY_INF) == MASK_INF))) {
+ // x, y are 0 or f but not inf or NaN => unpack the arguments and check
+ // for non-canonical values
+
+ x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative
+ C1.w[1] = x.w[1] & MASK_COEFF;
+ C1.w[0] = x.w[0];
+ // check for non-canonical values - treated as zero
+ if ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull) {
+ // G0_G1=11 => non-canonical
+ x_exp = (x.w[1] << 2) & MASK_EXP; // biased and shifted left 49 bits
+ C1.w[1] = 0; // significand high
+ C1.w[0] = 0; // significand low
+ } else { // G0_G1 != 11
+ x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bits
+ if (C1.w[1] > 0x0001ed09bead87c0ull ||
+ (C1.w[1] == 0x0001ed09bead87c0ull &&
+ C1.w[0] > 0x378d8e63ffffffffull)) {
+ // x is non-canonical if coefficient is larger than 10^34 -1
+ C1.w[1] = 0;
+ C1.w[0] = 0;
+ } else { // canonical
+ ;
}
- res.w[1] |= sign;
}
-
- // general correction from RN to RA, RM, RP, RZ
- if (rnd_mode != ROUNDING_TO_NEAREST && !is_overflow) { // overflow is solved
- x_exp = res.w[1] & MASK_EXP; // biased and shifted left 49 bit positions
- C1_hi = res.w[1] & MASK_COEFF;
- C1_lo = res.w[0];
- if ((!sign && ((rnd_mode == ROUNDING_UP && is_inexact_lt_midpoint) ||
- ((rnd_mode == ROUNDING_TIES_AWAY || rnd_mode == ROUNDING_UP) &&
- is_midpoint_gt_even))) ||
- (sign && ((rnd_mode == ROUNDING_DOWN && is_inexact_lt_midpoint) ||
- ((rnd_mode == ROUNDING_TIES_AWAY || rnd_mode == ROUNDING_DOWN) &&
- is_midpoint_gt_even)))) {
-
- // C1 = C1 + 1
- C1_lo = C1_lo + 1;
- if (C1_lo == 0) { // rounding overflow in the low 64 bits
- C1_hi = C1_hi + 1;
- if (C1_hi == 0x0001ed09bead87c0ull
- && C1_lo == 0x378d8e6400000000ull) {
-
- // C1 = 10^34 => rounding overflow
- C1_hi = 0x0000314dc6448d93ull;
- C1_lo = 0x38c15b0a00000000ull; // 10^33
- x_exp = x_exp + EXP_P1;
- }
- }
- } else if ((is_midpoint_lt_even || is_inexact_gt_midpoint)
- && ((sign && (rnd_mode == ROUNDING_UP ||
- rnd_mode == ROUNDING_TO_ZERO)) ||
- (!sign && (rnd_mode == ROUNDING_DOWN ||
- rnd_mode == ROUNDING_TO_ZERO)))) {
-
- // C1 = C1 - 1
- C1_lo = C1_lo - 1;
- if (C1_lo == 0xffffffffffffffffull)
- C1_hi--;
-
- // check if we crossed into the lower decade
- if (C1_hi == 0x0000314dc6448d93ull && C1_lo == 0x38c15b09ffffffffull) {
- // 10^33 - 1
- C1_hi = 0x0001ed09bead87c0ull; // 10^34 - 1
- C1_lo = 0x378d8e63ffffffffull;
- x_exp = x_exp - EXP_P1; // no underflow (TO CHECK)
- }
- } else {
- ; // exact, the result is already correct
+ y_sign = y.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative
+ C2.w[1] = y.w[1] & MASK_COEFF;
+ C2.w[0] = y.w[0];
+ // check for non-canonical values - treated as zero
+ if ((y.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull) {
+ // G0_G1=11 => non-canonical
+ y_exp = (y.w[1] << 2) & MASK_EXP; // biased and shifted left 49 bits
+ C2.w[1] = 0; // significand high
+ C2.w[0] = 0; // significand low
+ } else { // G0_G1 != 11
+ y_exp = y.w[1] & MASK_EXP; // biased and shifted left 49 bits
+ if (C2.w[1] > 0x0001ed09bead87c0ull ||
+ (C2.w[1] == 0x0001ed09bead87c0ull &&
+ C2.w[0] > 0x378d8e63ffffffffull)) {
+ // y is non-canonical if coefficient is larger than 10^34 -1
+ C2.w[1] = 0;
+ C2.w[0] = 0;
+ } else { // canonical
+ ;
}
-
- // assemble the result
- res.w[1] = x_exp | C1_hi;
- res.w[0] = C1_lo;
}
- res.w[1] |= sign;
- BID_RETURN (res);
+ p_sign = x_sign ^ y_sign; // sign of the product
+
+ true_p_exp = (x_exp >> 49) - 6176 + (y_exp >> 49) - 6176;
+ // true_p_exp, p_exp are used only for 0 * 0, 0 * f, or f * 0
+ if (true_p_exp < -6176)
+ p_exp = 0; // cannot be less than EXP_MIN
+ else if (true_p_exp > 6111)
+ p_exp = (UINT64) (6111 + 6176) << 49; // cannot be more than EXP_MAX
+ else
+ p_exp = (UINT64) (true_p_exp + 6176) << 49;
+
+ if ((C1.w[1] == 0x0 && C1.w[0] == 0x0) ||
+ (C2.w[1] == 0x0 && C2.w[0] == 0x0)) {
+ // x = 0 or y = 0
+ // the result is 0
+ res.w[1] = p_sign | p_exp; // preferred exponent in [EXP_MIN, EXP_MAX]
+ res.w[0] = 0x0;
+ BID_SWAP128 (res);
+ BID_RETURN (res)
+ } // else continue
}
-_underflow_path:
- // got here because q - P34 < ind where ind = EMIN - ex - ey
- // q is the number of digits in C; ind is the [positive] exponent of the
- // negative power of 10 that must multiply C in order to make the result's
- // exponent equal to e_min - P34 + 1 = -6176
- ind =
- (int) (((SINT64) EXP_MIN + (SINT64) BIN_EXP_BIAS - (SINT64) x_exp -
- (SINT64) y_exp) >> 49);
-
- // q - P34 < ind => -P34 + 1 < ind => -P34 + 2 <= ind
- // ind = EMIN - ex - ey < -6176 + 6176 + 6176 = 6176
- if (q < ind) { // q - ind < 0; result rounds to 0 when rounding to nearest
- // set the inexact and underflow flags
- *pfpsf |= (INEXACT_EXCEPTION | UNDERFLOW_EXCEPTION);
- res.w[1] = EXP_MIN; // EXP_MIN = 0x0
- res.w[0] = 0x0;
- if (rnd_mode != ROUNDING_TO_NEAREST) {
- if ((rnd_mode == ROUNDING_DOWN && sign) ||
- (rnd_mode == ROUNDING_UP && !sign))
- res.w[0] = 0x0000000000000001ull;
- }
- } else if (q == ind) { // q - ind = 0; result rounds to 0 or +/-1*10^EMIN
- // set the inexact and underflow flags
- *pfpsf |= (INEXACT_EXCEPTION | UNDERFLOW_EXCEPTION);
-
- // if C <= 5*10^(q-1) then C = 0 else C = 1
- if (q <= 19) {
- if (C.w[0] == __bid_midpoint64[q - 1]) { // C = 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST || (rnd_mode == ROUNDING_DOWN
- && !sign) || (rnd_mode == ROUNDING_UP && sign)
- || rnd_mode == ROUNDING_TO_ZERO) {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- }
- } else if (C.w[0] < __bid_midpoint64[q - 1]) { // C < 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY
- || (rnd_mode == ROUNDING_DOWN && !sign)
- || (rnd_mode == ROUNDING_UP && sign)
- || rnd_mode == ROUNDING_TO_ZERO) {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- }
- } else { // C > 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY
- || (rnd_mode == ROUNDING_DOWN && sign)
- || (rnd_mode == ROUNDING_UP && !sign)) {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- }
- }
- } else if (q <= 38) { // 20 <= q <= 38
- // if q <= P34 = 34 the exact result rounded to P34 digits with unbounded
- // exponent will have an exponent smaller than e_min; otherwise if
- // 35 <= q <= 38, it depends
- if (C.w[1] == __bid_midpoint128[q - 20].w[1] &&
- C.w[0] == __bid_midpoint128[q - 20].w[0]) { // C = 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST || (rnd_mode == ROUNDING_DOWN
- && !sign) || (rnd_mode == ROUNDING_UP && sign)
- || rnd_mode == ROUNDING_TO_ZERO) {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- }
- } else if (C.w[1] < __bid_midpoint128[q - 20].w[1] ||
- (C.w[1] == __bid_midpoint128[q - 20].w[1] &&
- C.w[0] < __bid_midpoint128[q - 20].w[0])) { // C < 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY
- || (rnd_mode == ROUNDING_DOWN && !sign)
- || (rnd_mode == ROUNDING_UP && sign)
- || rnd_mode == ROUNDING_TO_ZERO) {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- }
- } else { // C > 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY
- || (rnd_mode == ROUNDING_DOWN && sign)
- || (rnd_mode == ROUNDING_UP && !sign)) {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- }
- }
- } else if (q <= 58) { // 39 <= q <= 58
- // Note: for q = 58 C may take 256 bits, so need to test C.w[3]
- if (C.w[3] == 0x0 && C.w[2] == __bid_midpoint192[q - 39].w[2] &&
- C.w[1] == __bid_midpoint192[q - 39].w[1] &&
- C.w[0] == __bid_midpoint192[q - 39].w[0]) { // C = 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST || (rnd_mode == ROUNDING_DOWN
- && !sign) || (rnd_mode == ROUNDING_UP && sign)
- || rnd_mode == ROUNDING_TO_ZERO) {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- }
- } else if ((C.w[3] == 0x0 && C.w[2] < __bid_midpoint192[q - 39].w[2]) ||
- (C.w[3] == 0x0 && C.w[2] == __bid_midpoint192[q - 39].w[2] &&
- C.w[1] < __bid_midpoint192[q - 39].w[1]) || (C.w[3] == 0x0 &&
- C.w[2] == __bid_midpoint192[q - 39].w[2] &&
- C.w[1] == __bid_midpoint192[q - 39].w[1] &&
- C.w[0] < __bid_midpoint192[q - 39].w[0])) { // C < 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY
- || (rnd_mode == ROUNDING_DOWN && !sign)
- || (rnd_mode == ROUNDING_UP && sign)
- || rnd_mode == ROUNDING_TO_ZERO) {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- }
- } else { // C > 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY
- || (rnd_mode == ROUNDING_DOWN && sign)
- || (rnd_mode == ROUNDING_UP && !sign)) {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- }
- }
- } else { // if (q <= 68), i.e. 59 <= q <= 68
- if (C.w[3] == __bid_midpoint256[q - 59].w[3] &&
- C.w[2] == __bid_midpoint256[q - 59].w[2] &&
- C.w[1] == __bid_midpoint256[q - 59].w[1] &&
- C.w[0] == __bid_midpoint256[q - 59].w[0]) { // C = 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST || (rnd_mode == ROUNDING_DOWN
- && !sign) || (rnd_mode == ROUNDING_UP && sign)
- || rnd_mode == ROUNDING_TO_ZERO) {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- }
- } else if (C.w[3] < __bid_midpoint256[q - 59].w[3] ||
- (C.w[3] == __bid_midpoint256[q - 59].w[3] &&
- C.w[2] < __bid_midpoint256[q - 59].w[2]) ||
- (C.w[3] == __bid_midpoint256[q - 59].w[3] &&
- C.w[2] == __bid_midpoint256[q - 59].w[2] &&
- C.w[1] < __bid_midpoint256[q - 59].w[1]) ||
- (C.w[3] == __bid_midpoint256[q - 59].w[3] &&
- C.w[2] == __bid_midpoint256[q - 59].w[2] &&
- C.w[1] == __bid_midpoint256[q - 59].w[1] &&
- C.w[0] < __bid_midpoint256[q - 59].w[0])) { // C < 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY
- || (rnd_mode == ROUNDING_DOWN && !sign)
- || (rnd_mode == ROUNDING_UP && sign)
- || rnd_mode == ROUNDING_TO_ZERO) {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- }
- } else { // C > 0.5 * 10^emin
- if (rnd_mode == ROUNDING_TO_NEAREST
- || rnd_mode == ROUNDING_TIES_AWAY
- || (rnd_mode == ROUNDING_DOWN && sign)
- || (rnd_mode == ROUNDING_UP && !sign)) {
- res.w[1] = EXP_MIN;
- res.w[0] = 1;
- } else {
- res.w[1] = EXP_MIN;
- res.w[0] = 0;
- }
- }
- }
- } else { // if 0 < q - ind < P34 <=> 1 <= q - ind <= P34 - 1 = 33
- // In general -P34 + 2 <= ind <= 6176 => -P34 + 2 <= ind < q =>
- // -P34 + 2 <= ind <= q - 1
- if (rnd_mode != ROUNDING_TO_NEAREST) {
- is_inexact_lt_midpoint = 0;
- is_inexact_gt_midpoint = 0;
- is_midpoint_lt_even = 0;
- is_midpoint_gt_even = 0;
- }
- if (ind <= 0) { // 0 <= -ind
- // the result is exact
- res.w[1] = (x_exp + y_exp - BIN_EXP_BIAS) | C.w[1];
- res.w[0] = C.w[0];
-
- // because the result is exact the U and I status flags are not set
- } else {
-
- // if ind > 0 <=> 1 <= ind <= q - 1; must remove ind digits
- // from C, which may have up to 68 digits; note that q >= ind + 1 >= 2
- // Note: there is no underflow in some cases when the coefficient of
- // the result is 10^33 or 10^33 - 1
- if (q <= 18) { // 2 <= q <= 18
- __bid_round64_2_18 (q, ind, C.w[0], &res.w[0], &incr_exp,
- &is_midpoint_lt_even, &is_midpoint_gt_even,
- &is_inexact_lt_midpoint, &is_inexact_gt_midpoint);
- if (incr_exp) {
-
- // multiply by 10; this cannot be 10^33
- __mul_64x64_to_128MACH (res, res.w[0], __bid_ten2k64[1]);
- res.w[1] |= (UINT64) EXP_MIN;
- } else { // underflow
- res.w[1] = (UINT64) EXP_MIN;
- }
- if (is_midpoint_lt_even || is_midpoint_gt_even
- || is_inexact_lt_midpoint || is_inexact_gt_midpoint) {
-
- // set the inexact and underflow flags
- *pfpsf |= (INEXACT_EXCEPTION | UNDERFLOW_EXCEPTION);
- }
- } else if (q <= 38) { // 19 <= q <= 38
- P128.w[1] = C.w[1];
- P128.w[0] = C.w[0];
- __bid_round128_19_38 (q, ind, P128, &res, &incr_exp,
- &is_midpoint_lt_even, &is_midpoint_gt_even,
- &is_inexact_lt_midpoint,
- &is_inexact_gt_midpoint);
- if (incr_exp) {
-
- // multiply by 10 and check is this is 10^33, because in that case
- // it is possible that this is not underflow
- if (q - ind <= 19) {
- __mul_64x64_to_128MACH (res, res.w[0], __bid_ten2k64[1]);
- } else { // if 20 <= q - ind
- __mul_128x64_to_128 (res, __bid_ten2k64[1], res);
- }
- if ((q - ind + 1) == P34) { // the result is 10^(P34-1)
- // if the result rounded directly to P34 digits is the same, then
- // there is no underflow
- __bid_round128_19_38 (q, ind - 1, P128, &R128, &incr_exp1,
- &is_midpoint_lt_even1,
- &is_midpoint_gt_even1,
- &is_inexact_lt_midpoint1,
- &is_inexact_gt_midpoint1);
- if (res.w[1] == R128.w[1] && res.w[0] == R128.w[0]) {
- no_underflow = 1;
- }
- }
- // res.w[1] |= (UINT64)EXP_MIN; // redundant
- } else { // underflow
- // res.w[1] = (UINT64)EXP_MIN | res.w[1]; // redundant
- }
- if (is_midpoint_lt_even || is_midpoint_gt_even
- || is_inexact_lt_midpoint || is_inexact_gt_midpoint) {
-
- // set the inexact and underflow flags
- *pfpsf |= INEXACT_EXCEPTION;
- is_inexact = 1;
- if (!no_underflow)
- *pfpsf |= UNDERFLOW_EXCEPTION;
- }
- } else if (q <= 57) { // 39 <= q <= 57
- P192.w[2] = C.w[2];
- P192.w[1] = C.w[1];
- P192.w[0] = C.w[0];
- __bid_round192_39_57 (q, ind, P192, &R192, &incr_exp,
- &is_midpoint_lt_even, &is_midpoint_gt_even,
- &is_inexact_lt_midpoint,
- &is_inexact_gt_midpoint);
- if (incr_exp) {
-
- // multiply by 10 and check is this is 10^33, because in that case
- // it is possible that this is not underflow
- res.w[1] = R192.w[1]; // res has q - ind digits
- res.w[0] = R192.w[0];
- if (q - ind <= 19) {
- __mul_64x64_to_128MACH (res, res.w[0], __bid_ten2k64[1]);
- } else { // if 20 <= q - ind
- __mul_128x64_to_128 (res, __bid_ten2k64[1], res);
- }
- if ((q - ind + 1) == P34) { // the result is 10^(P34-1)
- // if the result rounded directly to P34 digits is the same, then
- // there is no underflow
- __bid_round192_39_57 (q, ind - 1, P192, &R192, &incr_exp1,
- &is_midpoint_lt_even1,
- &is_midpoint_gt_even1,
- &is_inexact_lt_midpoint1,
- &is_inexact_gt_midpoint1);
- if (res.w[1] == R192.w[1] && res.w[0] == R192.w[0]) {
- no_underflow = 1;
- }
- }
- // res.w[1] |= (UINT64)EXP_MIN; // redundant
- } else { // underflow
- res.w[1] = (UINT64) EXP_MIN | R192.w[1];
- res.w[0] = R192.w[0];
- }
- if (is_midpoint_lt_even || is_midpoint_gt_even
- || is_inexact_lt_midpoint || is_inexact_gt_midpoint) {
-
- // set the inexact and underflow flags
- *pfpsf |= INEXACT_EXCEPTION;
- is_inexact = 1;
- if (!no_underflow)
- *pfpsf |= UNDERFLOW_EXCEPTION;
- }
- } else if (q <= 76) { // 58 <= q <= 76 (actually 58 <= q <= 68)
- P256.w[3] = C.w[3];
- P256.w[2] = C.w[2];
- P256.w[1] = C.w[1];
- P256.w[0] = C.w[0];
- __bid_round256_58_76 (q, ind, P256, &R256, &incr_exp,
- &is_midpoint_lt_even, &is_midpoint_gt_even,
- &is_inexact_lt_midpoint,
- &is_inexact_gt_midpoint);
- if (incr_exp) {
-
- // multiply by 10 and check is this is 10^33, because in that case
- // it is possible that this is not underflow
- res.w[1] = R256.w[1]; // res has q - ind digits
- res.w[0] = R256.w[0];
- if (q - ind <= 19) {
- __mul_64x64_to_128MACH (res, res.w[0], __bid_ten2k64[1]);
- } else { // if 20 <= q - ind
- __mul_128x64_to_128 (res, __bid_ten2k64[1], res);
- }
- if ((q - ind + 1) == P34) { // the result is 10^(P34-1)
- // if the result rounded directly to P34 digits is the same, then
- // there is no underflow
- __bid_round256_58_76 (q, ind - 1, P256, &R256, &incr_exp1,
- &is_midpoint_lt_even1,
- &is_midpoint_gt_even1,
- &is_inexact_lt_midpoint1,
- &is_inexact_gt_midpoint1);
- if (res.w[1] == R256.w[1] && res.w[0] == R256.w[0]) {
- no_underflow = 1;
- }
- }
- // res.w[1] |= (UINT64)EXP_MIN; // redundant
- } else { // underflow
- res.w[1] = (UINT64) EXP_MIN | R256.w[1];
- res.w[0] = R256.w[0];
- }
- if (is_midpoint_lt_even || is_midpoint_gt_even
- || is_inexact_lt_midpoint || is_inexact_gt_midpoint) {
-
- // set the inexact and underflow flags
- *pfpsf |= INEXACT_EXCEPTION;
- is_inexact = 1;
- if (!no_underflow)
- *pfpsf |= UNDERFLOW_EXCEPTION;
- }
- }
- }
- // general correction from RN to RA, RM, RP, RZ
- if (rnd_mode != ROUNDING_TO_NEAREST) {
- x_exp = res.w[1] & MASK_EXP; // biased and shifted left 49 bit positions
- // this must be e_min
- C1_hi = res.w[1] & MASK_COEFF;
- C1_lo = res.w[0];
- if ((!sign && ((rnd_mode == ROUNDING_UP && is_inexact_lt_midpoint) ||
- ((rnd_mode == ROUNDING_TIES_AWAY || rnd_mode == ROUNDING_UP) &&
- is_midpoint_gt_even))) ||
- (sign && ((rnd_mode == ROUNDING_DOWN && is_inexact_lt_midpoint) ||
- ((rnd_mode == ROUNDING_TIES_AWAY || rnd_mode == ROUNDING_DOWN) &&
- is_midpoint_gt_even)))) {
-
- // C1 = C1 + 1
- C1_lo = C1_lo + 1;
- if (C1_lo == 0) { // rounding overflow in the low 64 bits
- C1_hi = C1_hi + 1;
- if (C1_hi == 0x0001ed09bead87c0ull
- && C1_lo == 0x378d8e6400000000ull) {
-
- // C1 = 10^34 => rounding overflow (not possible) TO CHECK
- C1_hi = 0x0000314dc6448d93ull;
- C1_lo = 0x38c15b0a00000000ull; // 10^33
- x_exp = x_exp + EXP_P1; // this must be e_min
- }
- }
- } else if ((is_midpoint_lt_even || is_inexact_gt_midpoint) &&
- ((sign &&
- (rnd_mode == ROUNDING_UP || rnd_mode == ROUNDING_TO_ZERO)) ||
- (!sign &&
- (rnd_mode == ROUNDING_DOWN || rnd_mode == ROUNDING_TO_ZERO)))) {
-
- // C1 = C1 - 1 (the exponent is emin already)
- C1_lo = C1_lo - 1;
- if (C1_lo == 0xffffffffffffffffull)
- C1_hi--;
-
- // cannot cross into the lower decade anymore, but the result can be 0
- } else {
- ; // exact, the result is already correct
- }
-
- // no overflow is possible
- // assemble the result
- res.w[1] = x_exp | C1_hi;
- res.w[0] = C1_lo;
-
- // Now fix the case where the general rounding routine returned a non-tiny
- // result, but after the correction for rounding modes other than to
- // nearest, the result is less in magnitude than 100...0[34] * 10^(-6176)
- // (this is due to the fact that the general rounding routine works only
- // with rounding to nearest)
- if (is_inexact && (x_exp == EXP_MIN)
- && (C1_hi < 0x0000314dc6448d93ull
- || (C1_hi == 0x0000314dc6448d93ull
- && C1_lo < 0x38c15b0a00000000ull))) {
- *pfpsf |= UNDERFLOW_EXCEPTION;
- }
- }
- }
- res.w[1] |= sign;
+ BID_SWAP128 (x);
+ BID_SWAP128 (y);
+ BID_SWAP128 (z);
+ // swap x and y - ensure that a NaN in x has 'higher precedence' than one in y
+#if DECIMAL_CALL_BY_REFERENCE
+ bid128_fma (&res, &y, &x, &z
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#else
+ res = bid128_fma (y, x, z
+ _RND_MODE_ARG _EXC_FLAGS_ARG _EXC_MASKS_ARG
+ _EXC_INFO_ARG);
+#endif
BID_RETURN (res);
}
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