diff options
Diffstat (limited to 'lib/libm/remquol.c')
| -rw-r--r-- | lib/libm/remquol.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/lib/libm/remquol.c b/lib/libm/remquol.c new file mode 100644 index 00000000..23c88487 --- /dev/null +++ b/lib/libm/remquol.c @@ -0,0 +1,128 @@ +#include "libm.h" + +#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024 +long double remquol(long double x, long double y, int *quo) +{ + return remquo(x, y, quo); +} +#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384 +long double remquol(long double x, long double y, int *quo) +{ + union ldshape ux = { x }, uy = { y }; + int ex = ux.i.se & 0x7fff; + int ey = uy.i.se & 0x7fff; + int sx = ux.i.se >> 15; + int sy = uy.i.se >> 15; + uint32_t q; + + *quo = 0; + if (y == 0 || isnan(y) || ex == 0x7fff) + return (x * y) / (x * y); + if (x == 0) + return x; + + /* normalize x and y */ + if (!ex) { + ux.i.se = ex; + ux.f *= 0x1p120f; + ex = ux.i.se - 120; + } + if (!ey) { + uy.i.se = ey; + uy.f *= 0x1p120f; + ey = uy.i.se - 120; + } + + q = 0; + if (ex >= ey) { + /* x mod y */ +#if LDBL_MANT_DIG == 64 + uint64_t i, mx, my; + mx = ux.i.m; + my = uy.i.m; + for (; ex > ey; ex--) { + i = mx - my; + if (mx >= my) { + mx = 2 * i; + q++; + q <<= 1; + } else if (2 * mx < mx) { + mx = 2 * mx - my; + q <<= 1; + q++; + } else { + mx = 2 * mx; + q <<= 1; + } + } + i = mx - my; + if (mx >= my) { + mx = i; + q++; + } + if (mx == 0) + ex = -120; + else + for (; mx >> 63 == 0; mx *= 2, ex--) + ; + ux.i.m = mx; +#elif LDBL_MANT_DIG == 113 + uint64_t hi, lo, xhi, xlo, yhi, ylo; + xhi = (ux.i2.hi & -1ULL >> 16) | 1ULL << 48; + yhi = (uy.i2.hi & -1ULL >> 16) | 1ULL << 48; + xlo = ux.i2.lo; + ylo = ux.i2.lo; + for (; ex > ey; ex--) { + hi = xhi - yhi; + lo = xlo - ylo; + if (xlo < ylo) + hi -= 1; + if (hi >> 63 == 0) { + xhi = 2 * hi + (lo >> 63); + xlo = 2 * lo; + q++; + } else { + xhi = 2 * xhi + (xlo >> 63); + xlo = 2 * xlo; + } + q <<= 1; + } + hi = xhi - yhi; + lo = xlo - ylo; + if (xlo < ylo) + hi -= 1; + if (hi >> 63 == 0) { + xhi = hi; + xlo = lo; + q++; + } + if ((xhi | xlo) == 0) + ex = -120; + else + for (; xhi >> 48 == 0; + xhi = 2 * xhi + (xlo >> 63), xlo = 2 * xlo, ex--) + ; + ux.i2.hi = xhi; + ux.i2.lo = xlo; +#endif + } + + /* scale result and decide between |x| and |x|-|y| */ + if (ex <= 0) { + ux.i.se = ex + 120; + ux.f *= 0x1p-120f; + } else + ux.i.se = ex; + x = ux.f; + if (sy) + y = -y; + if (ex == ey || + (ex + 1 == ey && (2 * x > y || (2 * x == y && q % 2)))) { + x -= y; + q++; + } + q &= 0x7fffffff; + *quo = sx ^ sy ? -(int)q : (int)q; + return sx ? -x : x; +} +#endif |
