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| author | 3gg <3gg@shellblade.net> | 2025-12-27 12:03:39 -0800 |
|---|---|---|
| committer | 3gg <3gg@shellblade.net> | 2025-12-27 12:03:39 -0800 |
| commit | 5a079a2d114f96d4847d1ee305d5b7c16eeec50e (patch) | |
| tree | 8926ab44f168acf787d8e19608857b3af0f82758 /contrib/SDL-3.2.8/src/libm/e_fmod.c | |
Initial commit
Diffstat (limited to 'contrib/SDL-3.2.8/src/libm/e_fmod.c')
| -rw-r--r-- | contrib/SDL-3.2.8/src/libm/e_fmod.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/contrib/SDL-3.2.8/src/libm/e_fmod.c b/contrib/SDL-3.2.8/src/libm/e_fmod.c new file mode 100644 index 0000000..32c0249 --- /dev/null +++ b/contrib/SDL-3.2.8/src/libm/e_fmod.c | |||
| @@ -0,0 +1,145 @@ | |||
| 1 | #include "SDL_internal.h" | ||
| 2 | /* | ||
| 3 | * ==================================================== | ||
| 4 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. | ||
| 5 | * | ||
| 6 | * Developed at SunPro, a Sun Microsystems, Inc. business. | ||
| 7 | * Permission to use, copy, modify, and distribute this | ||
| 8 | * software is freely granted, provided that this notice | ||
| 9 | * is preserved. | ||
| 10 | * ==================================================== | ||
| 11 | */ | ||
| 12 | |||
| 13 | /* | ||
| 14 | * __ieee754_fmod(x,y) | ||
| 15 | * Return x mod y in exact arithmetic | ||
| 16 | * Method: shift and subtract | ||
| 17 | */ | ||
| 18 | |||
| 19 | #include "math_libm.h" | ||
| 20 | #include "math_private.h" | ||
| 21 | |||
| 22 | static const double one = 1.0, Zero[] = {0.0, -0.0,}; | ||
| 23 | |||
| 24 | double attribute_hidden __ieee754_fmod(double x, double y) | ||
| 25 | { | ||
| 26 | int32_t n,hx,hy,hz,ix,iy,sx,i; | ||
| 27 | u_int32_t lx,ly,lz; | ||
| 28 | |||
| 29 | EXTRACT_WORDS(hx,lx,x); | ||
| 30 | EXTRACT_WORDS(hy,ly,y); | ||
| 31 | sx = hx&0x80000000; /* sign of x */ | ||
| 32 | hx ^=sx; /* |x| */ | ||
| 33 | hy &= 0x7fffffff; /* |y| */ | ||
| 34 | |||
| 35 | /* purge off exception values */ | ||
| 36 | if((hy|ly)==0||(hx>=0x7ff00000)|| /* y=0,or x not finite */ | ||
| 37 | ((hy|((ly|-(int32_t)ly)>>31))>0x7ff00000)) /* or y is NaN */ | ||
| 38 | return (x*y)/(x*y); | ||
| 39 | if(hx<=hy) { | ||
| 40 | if((hx<hy)||(lx<ly)) return x; /* |x|<|y| return x */ | ||
| 41 | if(lx==ly) | ||
| 42 | return Zero[(u_int32_t)sx>>31]; /* |x|=|y| return x*0*/ | ||
| 43 | } | ||
| 44 | |||
| 45 | /* determine ix = ilogb(x) */ | ||
| 46 | if(hx<0x00100000) { /* subnormal x */ | ||
| 47 | if(hx==0) { | ||
| 48 | for (ix = -1043, i=lx; i>0; i<<=1) ix -=1; | ||
| 49 | } else { | ||
| 50 | for (ix = -1022,i=(hx<<11); i>0; i<<=1) ix -=1; | ||
| 51 | } | ||
| 52 | } else ix = (hx>>20)-1023; | ||
| 53 | |||
| 54 | /* determine iy = ilogb(y) */ | ||
| 55 | if(hy<0x00100000) { /* subnormal y */ | ||
| 56 | if(hy==0) { | ||
| 57 | for (iy = -1043, i=ly; i>0; i<<=1) iy -=1; | ||
| 58 | } else { | ||
| 59 | for (iy = -1022,i=(hy<<11); i>0; i<<=1) iy -=1; | ||
| 60 | } | ||
| 61 | } else iy = (hy>>20)-1023; | ||
| 62 | |||
| 63 | /* set up {hx,lx}, {hy,ly} and align y to x */ | ||
| 64 | if(ix >= -1022) | ||
| 65 | hx = 0x00100000|(0x000fffff&hx); | ||
| 66 | else { /* subnormal x, shift x to normal */ | ||
| 67 | n = -1022-ix; | ||
| 68 | if(n<=31) { | ||
| 69 | hx = (hx<<n)|(lx>>(32-n)); | ||
| 70 | lx <<= n; | ||
| 71 | } else { | ||
| 72 | hx = lx<<(n-32); | ||
| 73 | lx = 0; | ||
| 74 | } | ||
| 75 | } | ||
| 76 | if(iy >= -1022) | ||
| 77 | hy = 0x00100000|(0x000fffff&hy); | ||
| 78 | else { /* subnormal y, shift y to normal */ | ||
| 79 | n = -1022-iy; | ||
| 80 | if(n<=31) { | ||
| 81 | hy = (hy<<n)|(ly>>(32-n)); | ||
| 82 | ly <<= n; | ||
| 83 | } else { | ||
| 84 | hy = ly<<(n-32); | ||
| 85 | ly = 0; | ||
| 86 | } | ||
| 87 | } | ||
| 88 | |||
| 89 | /* fix point fmod */ | ||
| 90 | n = ix - iy; | ||
| 91 | while(n--) { | ||
| 92 | hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1; | ||
| 93 | if(hz<0){hx = hx+hx+(lx>>31); lx = lx+lx;} | ||
| 94 | else { | ||
| 95 | if((hz|lz)==0) /* return sign(x)*0 */ | ||
| 96 | return Zero[(u_int32_t)sx>>31]; | ||
| 97 | hx = hz+hz+(lz>>31); lx = lz+lz; | ||
| 98 | } | ||
| 99 | } | ||
| 100 | hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1; | ||
| 101 | if(hz>=0) {hx=hz;lx=lz;} | ||
| 102 | |||
| 103 | /* convert back to floating value and restore the sign */ | ||
| 104 | if((hx|lx)==0) /* return sign(x)*0 */ | ||
| 105 | return Zero[(u_int32_t)sx>>31]; | ||
| 106 | while(hx<0x00100000) { /* normalize x */ | ||
| 107 | hx = hx+hx+(lx>>31); lx = lx+lx; | ||
| 108 | iy -= 1; | ||
| 109 | } | ||
| 110 | if(iy>= -1022) { /* normalize output */ | ||
| 111 | hx = ((hx-0x00100000)|((iy+1023)<<20)); | ||
| 112 | INSERT_WORDS(x,hx|sx,lx); | ||
| 113 | } else { /* subnormal output */ | ||
| 114 | n = -1022 - iy; | ||
| 115 | if(n<=20) { | ||
| 116 | lx = (lx>>n)|((u_int32_t)hx<<(32-n)); | ||
| 117 | hx >>= n; | ||
| 118 | } else if (n<=31) { | ||
| 119 | lx = (hx<<(32-n))|(lx>>n); hx = sx; | ||
| 120 | } else { | ||
| 121 | lx = hx>>(n-32); hx = sx; | ||
| 122 | } | ||
| 123 | INSERT_WORDS(x,hx|sx,lx); | ||
| 124 | x *= one; /* create necessary signal */ | ||
| 125 | } | ||
| 126 | return x; /* exact output */ | ||
| 127 | } | ||
| 128 | |||
| 129 | /* | ||
| 130 | * wrapper fmod(x,y) | ||
| 131 | */ | ||
| 132 | #ifndef _IEEE_LIBM | ||
| 133 | double fmod(double x, double y) | ||
| 134 | { | ||
| 135 | double z = __ieee754_fmod(x, y); | ||
| 136 | if (_LIB_VERSION == _IEEE_ || isnan(y) || isnan(x)) | ||
| 137 | return z; | ||
| 138 | if (y == 0.0) | ||
| 139 | return __kernel_standard(x, y, 27); /* fmod(x,0) */ | ||
| 140 | return z; | ||
| 141 | } | ||
| 142 | #else | ||
| 143 | strong_alias(__ieee754_fmod, fmod) | ||
| 144 | #endif | ||
| 145 | libm_hidden_def(fmod) | ||
