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/* |
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* ==================================================== |
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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* |
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* Developed at SunPro, a Sun Microsystems, Inc. business. |
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* Permission to use, copy, modify, and distribute this |
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* software is freely granted, provided that this notice |
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* is preserved. |
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* ==================================================== |
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*/ |
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* __ieee754_fmod(x,y) |
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* Return x mod y in exact arithmetic |
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* Method: shift and subtract |
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*/ |
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static const double one = 1.0, Zero[] = {0.0, -0.0,}; |
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#else |
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static double one = 1.0, Zero[] = {0.0, -0.0,}; |
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#endif |
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double __ieee754_fmod(double x, double y) |
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#else |
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double __ieee754_fmod(x,y) |
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double x,y ; |
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#endif |
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{ |
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__int32_t n,hx,hy,hz,ix,iy,sx,i; |
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__uint32_t lx,ly,lz; |
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EXTRACT_WORDS(hy,ly,y); |
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sx = hx&0x80000000; /* sign of x */ |
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hx ^=sx; /* |x| */ |
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hy &= 0x7fffffff; /* |y| */ |
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if((hy|ly)==0||(hx>=0x7ff00000)|| /* y=0,or x not finite */ |
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((hy|((ly|-ly)>>31))>0x7ff00000)) /* or y is NaN */ |
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return (x*y)/(x*y); |
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if(hx<=hy) { |
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if((hx |
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if(lx==ly) |
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return Zero[(__uint32_t)sx>>31]; /* |x|=|y| return x*0*/ |
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} |
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if(hx<0x00100000) { /* subnormal x */ |
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if(hx==0) { |
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for (ix = -1043, i=lx; i>0; i<<=1) ix -=1; |
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} else { |
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for (ix = -1022,i=(hx<<11); i>0; i<<=1) ix -=1; |
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} |
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} else ix = (hx>>20)-1023; |
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if(hy<0x00100000) { /* subnormal y */ |
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if(hy==0) { |
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for (iy = -1043, i=ly; i>0; i<<=1) iy -=1; |
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} else { |
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for (iy = -1022,i=(hy<<11); i>0; i<<=1) iy -=1; |
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} |
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} else iy = (hy>>20)-1023; |
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if(ix >= -1022) |
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hx = 0x00100000|(0x000fffff&hx); |
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else { /* subnormal x, shift x to normal */ |
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n = -1022-ix; |
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if(n<=31) { |
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hx = (hx<>(32-n)); |
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lx <<= n; |
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} else { |
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hx = lx<<(n-32); |
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lx = 0; |
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} |
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} |
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if(iy >= -1022) |
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hy = 0x00100000|(0x000fffff&hy); |
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else { /* subnormal y, shift y to normal */ |
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n = -1022-iy; |
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if(n<=31) { |
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hy = (hy<>(32-n)); |
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ly <<= n; |
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} else { |
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hy = ly<<(n-32); |
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ly = 0; |
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} |
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} |
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n = ix - iy; |
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while(n--) { |
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hz=hx-hy;lz=lx-ly; if(lx |
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if(hz<0){hx = hx+hx+(lx>>31); lx = lx+lx;} |
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else { |
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if((hz|lz)==0) /* return sign(x)*0 */ |
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return Zero[(__uint32_t)sx>>31]; |
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hx = hz+hz+(lz>>31); lx = lz+lz; |
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} |
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} |
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hz=hx-hy;lz=lx-ly; if(lx |
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if(hz>=0) {hx=hz;lx=lz;} |
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if((hx|lx)==0) /* return sign(x)*0 */ |
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return Zero[(__uint32_t)sx>>31]; |
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while(hx<0x00100000) { /* normalize x */ |
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hx = hx+hx+(lx>>31); lx = lx+lx; |
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iy -= 1; |
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} |
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if(iy>= -1022) { /* normalize output */ |
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hx = ((hx-0x00100000)|((iy+1023)<<20)); |
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INSERT_WORDS(x,hx|sx,lx); |
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} else { /* subnormal output */ |
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n = -1022 - iy; |
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if(n<=20) { |
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lx = (lx>>n)|((__uint32_t)hx<<(32-n)); |
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hx >>= n; |
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} else if (n<=31) { |
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lx = (hx<<(32-n))|(lx>>n); hx = sx; |
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} else { |
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lx = hx>>(n-32); hx = sx; |
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} |
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INSERT_WORDS(x,hx|sx,lx); |
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x *= one; /* create necessary signal */ |
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} |
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return x; /* exact output */ |
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} |
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> |