diff options
Diffstat (limited to 'Build/source/libs/mpfr/mpfr-src/src/rec_sqrt.c')
-rw-r--r-- | Build/source/libs/mpfr/mpfr-src/src/rec_sqrt.c | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/Build/source/libs/mpfr/mpfr-src/src/rec_sqrt.c b/Build/source/libs/mpfr/mpfr-src/src/rec_sqrt.c index 3e5bb571d88..a95d3caa548 100644 --- a/Build/source/libs/mpfr/mpfr-src/src/rec_sqrt.c +++ b/Build/source/libs/mpfr/mpfr-src/src/rec_sqrt.c @@ -1,6 +1,6 @@ /* mpfr_rec_sqrt -- inverse square root -Copyright 2008-2019 Free Software Foundation, Inc. +Copyright 2008-2020 Free Software Foundation, Inc. Contributed by the AriC and Caramba projects, INRIA. This file is part of the GNU MPFR Library. @@ -165,7 +165,7 @@ mpfr_mpn_rec_sqrt (mpfr_limb_ptr x, mpfr_prec_t p, MPFR_ASSERTD((a[an - 1] & MPFR_LIMB_HIGHBIT) != 0); /* We should have enough bits in one limb and GMP_NUMB_BITS should be even. Since that does not depend on MPFR, we always check this. */ - MPFR_STAT_STATIC_ASSERT (GMP_NUMB_BITS >= 12 && (GMP_NUMB_BITS & 1) == 0); + MPFR_STAT_STATIC_ASSERT ((GMP_NUMB_BITS & 1) == 0); /* {a, an} and {x, n} should not overlap */ MPFR_ASSERTD((a + an <= x) || (x + n <= a)); MPFR_ASSERTD(p >= 11); @@ -179,15 +179,34 @@ mpfr_mpn_rec_sqrt (mpfr_limb_ptr x, mpfr_prec_t p, if (p == 11) /* should happen only from recursive calls */ { unsigned long i, ab, ac; - mp_limb_t t; + unsigned int t; /* take the 12+as most significant bits of A */ +#if GMP_NUMB_BITS >= 16 i = a[an - 1] >> (GMP_NUMB_BITS - (12 + as)); +#else + MPFR_STAT_STATIC_ASSERT (GMP_NUMB_BITS == 8); + { + unsigned int a12 = a[an - 1] << 8; + if (an >= 2) + a12 |= a[an - 2]; + MPFR_ASSERTN(GMP_NUMB_BITS >= 4 + as); + i = a12 >> (GMP_NUMB_BITS - (4 + as)); + } +#endif /* if one wants faithful rounding for p=11, replace #if 0 by #if 1 */ ab = i >> 4; ac = (ab & 0x3F0) | (i & 0x0F); - t = (mp_limb_t) T1[ab - 0x80] + (mp_limb_t) T2[ac - 0x80]; - x[0] = t << (GMP_NUMB_BITS - p); + t = T1[ab - 0x80] + T2[ac - 0x80]; /* fits on 16 bits */ +#if GMP_NUMB_BITS >= 16 + /* x has only one limb */ + x[0] = (mp_limb_t) t << (GMP_NUMB_BITS - p); +#else + MPFR_STAT_STATIC_ASSERT (GMP_NUMB_BITS == 8); + MPFR_ASSERTD (1024 <= t && t <= 2047); + x[1] = t >> 3; /* 128 <= x[1] <= 255 */ + x[0] = MPFR_LIMB_LSHIFT(t, 5); +#endif } else /* p >= 12 */ { @@ -225,7 +244,7 @@ mpfr_mpn_rec_sqrt (mpfr_limb_ptr x, mpfr_prec_t p, /* we need h+1+as bits of a */ ahn = LIMB_SIZE(h + 1 + as); /* number of high limbs of A - needed for the recursive call*/ + needed for the recursive call */ if (MPFR_UNLIKELY(ahn > an)) ahn = an; mpfr_mpn_rec_sqrt (x + ln, h, a + an - ahn, ahn * GMP_NUMB_BITS, as); @@ -373,9 +392,10 @@ mpfr_mpn_rec_sqrt (mpfr_limb_ptr x, mpfr_prec_t p, thus we round u to nearest at bit pl-1 of u[0] */ if (pl > 0) { - cu = mpn_add_1 (u, u, un, u[0] & (MPFR_LIMB_ONE << (pl - 1))); + cu = mpn_add_1 (u, u, un, + u[0] & MPFR_LIMB_LSHIFT(MPFR_LIMB_ONE, pl - 1)); /* mask bits 0..pl-1 of u[0] */ - u[0] &= ~MPFR_LIMB_MASK(pl); + u[0] &= MPFR_LIMB(~MPFR_LIMB_MASK(pl)); } else /* round bit is in u[-1] */ cu = mpn_add_1 (u, u, un, u[-1] >> (GMP_NUMB_BITS - 1)); |