| /* Rewritten for 64-bit machines by Ulrich Drepper <drepper@gmail.com>. */ |
| /* |
| * ==================================================== |
| * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Developed at SunPro, a Sun Microsystems, Inc. business. |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| */ |
| |
| /* |
| * __ieee754_fmod(x,y) |
| * Return x mod y in exact arithmetic |
| * Method: shift and subtract |
| */ |
| |
| #include <math.h> |
| #include <math_private.h> |
| #include <stdint.h> |
| |
| static const double one = 1.0, Zero[] = {0.0, -0.0,}; |
| |
| double |
| __ieee754_fmod (double x, double y) |
| { |
| int32_t n,ix,iy; |
| int64_t hx,hy,hz,sx,i; |
| |
| EXTRACT_WORDS64(hx,x); |
| EXTRACT_WORDS64(hy,y); |
| sx = hx&UINT64_C(0x8000000000000000); /* sign of x */ |
| hx ^=sx; /* |x| */ |
| hy &= UINT64_C(0x7fffffffffffffff); /* |y| */ |
| |
| /* purge off exception values */ |
| if(__builtin_expect(hy==0 |
| || hx >= UINT64_C(0x7ff0000000000000) |
| || hy > UINT64_C(0x7ff0000000000000), 0)) |
| /* y=0,or x not finite or y is NaN */ |
| return (x*y)/(x*y); |
| if(__builtin_expect(hx<=hy, 0)) { |
| if(hx<hy) return x; /* |x|<|y| return x */ |
| return Zero[(uint64_t)sx>>63]; /* |x|=|y| return x*0*/ |
| } |
| |
| /* determine ix = ilogb(x) */ |
| if(__builtin_expect(hx<UINT64_C(0x0010000000000000), 0)) { |
| /* subnormal x */ |
| for (ix = -1022,i=(hx<<11); i>0; i<<=1) ix -=1; |
| } else ix = (hx>>52)-1023; |
| |
| /* determine iy = ilogb(y) */ |
| if(__builtin_expect(hy<UINT64_C(0x0010000000000000), 0)) { /* subnormal y */ |
| for (iy = -1022,i=(hy<<11); i>0; i<<=1) iy -=1; |
| } else iy = (hy>>52)-1023; |
| |
| /* set up hx, hy and align y to x */ |
| if(__builtin_expect(ix >= -1022, 1)) |
| hx = UINT64_C(0x0010000000000000)|(UINT64_C(0x000fffffffffffff)&hx); |
| else { /* subnormal x, shift x to normal */ |
| n = -1022-ix; |
| hx<<=n; |
| } |
| if(__builtin_expect(iy >= -1022, 1)) |
| hy = UINT64_C(0x0010000000000000)|(UINT64_C(0x000fffffffffffff)&hy); |
| else { /* subnormal y, shift y to normal */ |
| n = -1022-iy; |
| hy<<=n; |
| } |
| |
| /* fix point fmod */ |
| n = ix - iy; |
| while(n--) { |
| hz=hx-hy; |
| if(hz<0){hx = hx+hx;} |
| else { |
| if(hz==0) /* return sign(x)*0 */ |
| return Zero[(uint64_t)sx>>63]; |
| hx = hz+hz; |
| } |
| } |
| hz=hx-hy; |
| if(hz>=0) {hx=hz;} |
| |
| /* convert back to floating value and restore the sign */ |
| if(hx==0) /* return sign(x)*0 */ |
| return Zero[(uint64_t)sx>>63]; |
| while(hx<UINT64_C(0x0010000000000000)) { /* normalize x */ |
| hx = hx+hx; |
| iy -= 1; |
| } |
| if(__builtin_expect(iy>= -1022, 1)) { /* normalize output */ |
| hx = ((hx-UINT64_C(0x0010000000000000))|((uint64_t)(iy+1023)<<52)); |
| INSERT_WORDS64(x,hx|sx); |
| } else { /* subnormal output */ |
| n = -1022 - iy; |
| hx>>=n; |
| INSERT_WORDS64(x,hx|sx); |
| x *= one; /* create necessary signal */ |
| } |
| return x; /* exact output */ |
| } |
| strong_alias (__ieee754_fmod, __fmod_finite) |
