diff options
Diffstat (limited to 'lib/mlibc/options/ansi/musl-generic-math/fma.c')
| -rw-r--r-- | lib/mlibc/options/ansi/musl-generic-math/fma.c | 194 |
1 files changed, 0 insertions, 194 deletions
diff --git a/lib/mlibc/options/ansi/musl-generic-math/fma.c b/lib/mlibc/options/ansi/musl-generic-math/fma.c deleted file mode 100644 index f65eab7..0000000 --- a/lib/mlibc/options/ansi/musl-generic-math/fma.c +++ /dev/null @@ -1,194 +0,0 @@ -#include <stdint.h> -#include <float.h> -#include <math.h> - -static inline int a_clz_64(uint64_t x) -{ - uint32_t y; - int r; - if (x>>32) y=x>>32, r=0; else y=x, r=32; - if (y>>16) y>>=16; else r |= 16; - if (y>>8) y>>=8; else r |= 8; - if (y>>4) y>>=4; else r |= 4; - if (y>>2) y>>=2; else r |= 2; - return r | !(y>>1); -} - -#define ASUINT64(x) ((union {double f; uint64_t i;}){x}).i -#define ZEROINFNAN (0x7ff-0x3ff-52-1) - -struct num { uint64_t m; int e; int sign; }; - -static struct num normalize(double x) -{ - uint64_t ix = ASUINT64(x); - int e = ix>>52; - int sign = e & 0x800; - e &= 0x7ff; - if (!e) { - ix = ASUINT64(x*0x1p63); - e = ix>>52 & 0x7ff; - e = e ? e-63 : 0x800; - } - ix &= (1ull<<52)-1; - ix |= 1ull<<52; - ix <<= 1; - e -= 0x3ff + 52 + 1; - return (struct num){ix,e,sign}; -} - -static void mul(uint64_t *hi, uint64_t *lo, uint64_t x, uint64_t y) -{ - uint64_t t1,t2,t3; - uint64_t xlo = (uint32_t)x, xhi = x>>32; - uint64_t ylo = (uint32_t)y, yhi = y>>32; - - t1 = xlo*ylo; - t2 = xlo*yhi + xhi*ylo; - t3 = xhi*yhi; - *lo = t1 + (t2<<32); - *hi = t3 + (t2>>32) + (t1 > *lo); -} - -double fma(double x, double y, double z) -{ - #pragma STDC FENV_ACCESS ON - - /* normalize so top 10bits and last bit are 0 */ - struct num nx, ny, nz; - nx = normalize(x); - ny = normalize(y); - nz = normalize(z); - - if (nx.e >= ZEROINFNAN || ny.e >= ZEROINFNAN) - return x*y + z; - if (nz.e >= ZEROINFNAN) { - if (nz.e > ZEROINFNAN) /* z==0 */ - return x*y + z; - return z; - } - - /* mul: r = x*y */ - uint64_t rhi, rlo, zhi, zlo; - mul(&rhi, &rlo, nx.m, ny.m); - /* either top 20 or 21 bits of rhi and last 2 bits of rlo are 0 */ - - /* align exponents */ - int e = nx.e + ny.e; - int d = nz.e - e; - /* shift bits z<<=kz, r>>=kr, so kz+kr == d, set e = e+kr (== ez-kz) */ - if (d > 0) { - if (d < 64) { - zlo = nz.m<<d; - zhi = nz.m>>64-d; - } else { - zlo = 0; - zhi = nz.m; - e = nz.e - 64; - d -= 64; - if (d == 0) { - } else if (d < 64) { - rlo = rhi<<64-d | rlo>>d | !!(rlo<<64-d); - rhi = rhi>>d; - } else { - rlo = 1; - rhi = 0; - } - } - } else { - zhi = 0; - d = -d; - if (d == 0) { - zlo = nz.m; - } else if (d < 64) { - zlo = nz.m>>d | !!(nz.m<<64-d); - } else { - zlo = 1; - } - } - - /* add */ - int sign = nx.sign^ny.sign; - int samesign = !(sign^nz.sign); - int nonzero = 1; - if (samesign) { - /* r += z */ - rlo += zlo; - rhi += zhi + (rlo < zlo); - } else { - /* r -= z */ - uint64_t t = rlo; - rlo -= zlo; - rhi = rhi - zhi - (t < rlo); - if (rhi>>63) { - rlo = -rlo; - rhi = -rhi-!!rlo; - sign = !sign; - } - nonzero = !!rhi; - } - - /* set rhi to top 63bit of the result (last bit is sticky) */ - if (nonzero) { - e += 64; - d = a_clz_64(rhi)-1; - /* note: d > 0 */ - rhi = rhi<<d | rlo>>64-d | !!(rlo<<d); - } else if (rlo) { - d = a_clz_64(rlo)-1; - if (d < 0) - rhi = rlo>>1 | (rlo&1); - else - rhi = rlo<<d; - } else { - /* exact +-0 */ - return x*y + z; - } - e -= d; - - /* convert to double */ - int64_t i = rhi; /* i is in [1<<62,(1<<63)-1] */ - if (sign) - i = -i; - double r = i; /* |r| is in [0x1p62,0x1p63] */ - - if (e < -1022-62) { - /* result is subnormal before rounding */ - if (e == -1022-63) { - double c = 0x1p63; - if (sign) - c = -c; - if (r == c) { - /* min normal after rounding, underflow depends - on arch behaviour which can be imitated by - a double to float conversion */ - float fltmin = 0x0.ffffff8p-63*FLT_MIN * r; - return DBL_MIN/FLT_MIN * fltmin; - } - /* one bit is lost when scaled, add another top bit to - only round once at conversion if it is inexact */ - if (rhi << 53) { - i = rhi>>1 | (rhi&1) | 1ull<<62; - if (sign) - i = -i; - r = i; - r = 2*r - c; /* remove top bit */ - - /* raise underflow portably, such that it - cannot be optimized away */ - { - double_t tiny = DBL_MIN/FLT_MIN * r; - r += (double)(tiny*tiny) * (r-r); - } - } - } else { - /* only round once when scaled */ - d = 10; - i = ( rhi>>d | !!(rhi<<64-d) ) << d; - if (sign) - i = -i; - r = i; - } - } - return scalbn(r, e); -} |