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-rw-r--r--mul_ui.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/mul_ui.c b/mul_ui.c
new file mode 100644
index 000000000..5976a4633
--- /dev/null
+++ b/mul_ui.c
@@ -0,0 +1,42 @@
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+#include "mpfr.h"
+
+void
+mpfr_mul_ui(mpfr_ptr y, mpfr_ptr x, unsigned long u, char RND_MODE)
+ /* on suppose SIZ(y)=SIZ(x) */
+{
+ mp_limb_t carry = 0, *my, *old_my; unsigned long c;
+ unsigned long xsize, ysize, cnt;
+
+ my = MANT(y);
+ ysize = ABSSIZE(y); xsize = ABSSIZE(x);
+
+ /*
+ if (ysize < xsize)
+ {
+ old_my = my;
+ my = _mp_allocate_func(xsize*BYTES_PER_MP_LIMB);
+ _mp_free_func(old_my, ysize*BYTES_PER_MP_LIMB);
+ }
+ */
+ carry = mpn_mul_1(my, MANT(x), xsize, u);
+ count_leading_zeros(cnt, carry);
+
+ c = mpfr_round_raw(my, my, RND_MODE, ysize, PREC(y)-BITS_PER_MP_LIMB+cnt);
+
+ /* If cnt = 1111111111111 and c = 1 we shall get depressed */
+ if (c && (carry == (1UL << (BITS_PER_MP_LIMB - cnt)) - 1))
+ {
+ cnt--;
+ mpn_rshift(my, my, ysize, BITS_PER_MP_LIMB - cnt);
+ my[ysize - 1] |= 1 << (BITS_PER_MP_LIMB - 1);
+ }
+ else
+ {
+ mpn_rshift(my, my, ysize, BITS_PER_MP_LIMB - cnt);
+ my[ysize - 1] |= (carry << cnt);
+ }
+ EXP(y) = EXP(x) + BITS_PER_MP_LIMB - cnt;
+}