diff options
Diffstat (limited to 'src/sqr.c')
| -rw-r--r-- | src/sqr.c | 13 |
1 files changed, 2 insertions, 11 deletions
@@ -45,16 +45,7 @@ mpfr_sqr_1 (mpfr_ptr a, mpfr_srcptr b, mpfr_rnd_t rnd_mode, mpfr_prec_t p) */ ax = MPFR_GET_EXP(b) * 2; umul_ppmm (a0, sb, b0, b0); - /* Instead of comparing a0 to MPFR_LIMB_HIGHBIT, we compare b0 to the - smallest value giving a0 >= MPFR_LIMB_HIGHBIT. This should be more - efficient since we don't have to wait the result of umul_ppmm to know - which branch to take. */ -#if GMP_NUMB_BITS == 32 -#define MAGIC 3037000500UL /* ceil(sqrt(2^63)) */ -#else /* GMP_NUMB_BITS = 64 */ -#define MAGIC 13043817825332782213UL /* ceil(sqrt(2^127)) */ -#endif - if (b0 < MAGIC) /* equivalent to a0 < MPFR_LIMB_HIGHBIT */ + if (a0 < MPFR_LIMB_HIGHBIT) { ax --; a0 = (a0 << 1) | (sb >> (GMP_NUMB_BITS - 1)); @@ -147,7 +138,7 @@ mpfr_sqr_1n (mpfr_ptr a, mpfr_srcptr b, mpfr_rnd_t rnd_mode) ax = MPFR_GET_EXP(b) * 2; umul_ppmm (a0, sb, b0, b0); - if (b0 < MAGIC) /* equivalent to a0 < MPFR_LIMB_HIGHBIT */ + if (a0 < MPFR_LIMB_HIGHBIT) { ax --; a0 = (a0 << 1) | (sb >> (GMP_NUMB_BITS - 1)); |