diff options
Diffstat (limited to 'src/cmp2.c')
| -rw-r--r-- | src/cmp2.c | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/src/cmp2.c b/src/cmp2.c index c4eee67f7..9c649b822 100644 --- a/src/cmp2.c +++ b/src/cmp2.c @@ -38,6 +38,7 @@ mpfr_cmp2 (mpfr_srcptr b, mpfr_srcptr c, mpfr_prec_t *cancel) { mp_limb_t *bp, *cp, bb, cc = 0, lastc = 0, dif, high_dif = 0; mp_size_t bn, cn; + mpfr_exp_t sdiff_exp; mpfr_uexp_t diff_exp; mpfr_prec_t res = 0; int sign; @@ -48,13 +49,21 @@ mpfr_cmp2 (mpfr_srcptr b, mpfr_srcptr c, mpfr_prec_t *cancel) /* the cases b=0 or c=0 are also treated apart in agm and sub (which calls sub1) */ - MPFR_ASSERTD (MPFR_IS_PURE_FP(b)); - MPFR_ASSERTD (MPFR_IS_PURE_FP(c)); + MPFR_ASSERTD (MPFR_IS_PURE_UBF (b)); + MPFR_ASSERTD (MPFR_IS_PURE_UBF (c)); - if (MPFR_GET_EXP (b) >= MPFR_GET_EXP (c)) + sdiff_exp = MPFR_UNLIKELY (MPFR_IS_UBF (b) || MPFR_IS_UBF (c)) ? + mpfr_ubf_diff_exp (b, c) : MPFR_GET_EXP (b) - MPFR_GET_EXP (c); + + /* The returned result is restricted to [MPFR_EXP_MIN,MPFR_EXP_MAX], + which is the range of the mpfr_exp_t type. But under the condition + below, the value of cancel will not be affected. */ + MPFR_STAT_STATIC_ASSERT (MPFR_EXP_MAX > MPFR_PREC_MAX); + + if (sdiff_exp >= 0) { sign = 1; - diff_exp = (mpfr_uexp_t) MPFR_GET_EXP (b) - MPFR_GET_EXP (c); + diff_exp = sdiff_exp; bp = MPFR_MANT(b); cp = MPFR_MANT(c); @@ -85,7 +94,7 @@ mpfr_cmp2 (mpfr_srcptr b, mpfr_srcptr c, mpfr_prec_t *cancel) if (MPFR_UNLIKELY (cn < 0)) /* c discards exactly the upper part of b */ { - unsigned int z; + int z; MPFR_ASSERTD (bn >= 0); @@ -96,7 +105,7 @@ mpfr_cmp2 (mpfr_srcptr b, mpfr_srcptr c, mpfr_prec_t *cancel) res += GMP_NUMB_BITS; } - count_leading_zeros(z, bp[bn]); /* bp[bn] <> 0 */ + count_leading_zeros (z, bp[bn]); /* bp[bn] <> 0 */ *cancel = res + z; return sign; } @@ -118,7 +127,7 @@ mpfr_cmp2 (mpfr_srcptr b, mpfr_srcptr c, mpfr_prec_t *cancel) else /* MPFR_EXP(b) < MPFR_EXP(c) */ { sign = -1; - diff_exp = (mpfr_uexp_t) MPFR_GET_EXP (c) - MPFR_GET_EXP (b); + diff_exp = - (mpfr_uexp_t) sdiff_exp; bp = MPFR_MANT(c); cp = MPFR_MANT(b); @@ -152,6 +161,7 @@ mpfr_cmp2 (mpfr_srcptr b, mpfr_srcptr c, mpfr_prec_t *cancel) while (MPFR_UNLIKELY ((cn >= 0 || lastc != 0) && (high_dif == 0) && (dif == 1))) { /* dif=1 implies diff_exp = 0 or 1 */ + MPFR_ASSERTD (diff_exp <= 1); bb = (bn >= 0) ? bp[bn] : 0; cc = lastc; if (cn >= 0) @@ -160,8 +170,9 @@ mpfr_cmp2 (mpfr_srcptr b, mpfr_srcptr c, mpfr_prec_t *cancel) { cc += cp[cn]; } - else /* diff_exp = 1 */ + else { + MPFR_ASSERTD (diff_exp == 1); cc += cp[cn] >> 1; lastc = cp[cn] << (GMP_NUMB_BITS - 1); } @@ -188,9 +199,9 @@ mpfr_cmp2 (mpfr_srcptr b, mpfr_srcptr c, mpfr_prec_t *cancel) } else /* high_dif == 0 */ { - unsigned int z; + int z; - count_leading_zeros(z, dif); /* dif > 1 here */ + count_leading_zeros (z, dif); /* dif > 1 here */ res += z; if (MPFR_LIKELY(dif != (MPFR_LIMB_ONE << (GMP_NUMB_BITS - z - 1)))) { /* dif is not a power of two */ |