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Diffstat (limited to 'src/math/s_remquo.c')
| -rw-r--r-- | src/math/s_remquo.c | 149 |
1 files changed, 0 insertions, 149 deletions
diff --git a/src/math/s_remquo.c b/src/math/s_remquo.c deleted file mode 100644 index 1a2992d6..00000000 --- a/src/math/s_remquo.c +++ /dev/null @@ -1,149 +0,0 @@ -/* @(#)e_fmod.c 1.3 95/01/18 */ -/*- - * ==================================================== - * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. - * - * Developed at SunSoft, a Sun Microsystems, Inc. business. - * Permission to use, copy, modify, and distribute this - * software is freely granted, provided that this notice - * is preserved. - * ==================================================== - */ - -#include <math.h> -#include "math_private.h" - -static const double Zero[] = {0.0, -0.0,}; - -/* - * Return the IEEE remainder and set *quo to the last n bits of the - * quotient, rounded to the nearest integer. We choose n=31 because - * we wind up computing all the integer bits of the quotient anyway as - * a side-effect of computing the remainder by the shift and subtract - * method. In practice, this is far more bits than are needed to use - * remquo in reduction algorithms. - */ -double -remquo(double x, double y, int *quo) -{ - int32_t n,hx,hy,hz,ix,iy,sx,i; - uint32_t lx,ly,lz,q,sxy; - - EXTRACT_WORDS(hx,lx,x); - EXTRACT_WORDS(hy,ly,y); - sxy = (hx ^ hy) & 0x80000000; - sx = hx&0x80000000; /* sign of x */ - hx ^=sx; /* |x| */ - hy &= 0x7fffffff; /* |y| */ - - /* purge off exception values */ - if((hy|ly)==0||(hx>=0x7ff00000)|| /* y=0,or x not finite */ - ((hy|((ly|-ly)>>31))>0x7ff00000)) /* or y is NaN */ - return (x*y)/(x*y); - if(hx<=hy) { - if((hx<hy)||(lx<ly)) { - q = 0; - goto fixup; /* |x|<|y| return x or x-y */ - } - if(lx==ly) { - *quo = 1; - return Zero[(uint32_t)sx>>31]; /* |x|=|y| return x*0*/ - } - } - - /* determine ix = ilogb(x) */ - if(hx<0x00100000) { /* subnormal x */ - if(hx==0) { - for (ix = -1043, i=lx; i>0; i<<=1) ix -=1; - } else { - for (ix = -1022,i=(hx<<11); i>0; i<<=1) ix -=1; - } - } else ix = (hx>>20)-1023; - - /* determine iy = ilogb(y) */ - if(hy<0x00100000) { /* subnormal y */ - if(hy==0) { - for (iy = -1043, i=ly; i>0; i<<=1) iy -=1; - } else { - for (iy = -1022,i=(hy<<11); i>0; i<<=1) iy -=1; - } - } else iy = (hy>>20)-1023; - - /* set up {hx,lx}, {hy,ly} and align y to x */ - if(ix >= -1022) - hx = 0x00100000|(0x000fffff&hx); - else { /* subnormal x, shift x to normal */ - n = -1022-ix; - if(n<=31) { - hx = (hx<<n)|(lx>>(32-n)); - lx <<= n; - } else { - hx = lx<<(n-32); - lx = 0; - } - } - if(iy >= -1022) - hy = 0x00100000|(0x000fffff&hy); - else { /* subnormal y, shift y to normal */ - n = -1022-iy; - if(n<=31) { - hy = (hy<<n)|(ly>>(32-n)); - ly <<= n; - } else { - hy = ly<<(n-32); - ly = 0; - } - } - - /* fix point fmod */ - n = ix - iy; - q = 0; - while(n--) { - hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1; - if(hz<0){hx = hx+hx+(lx>>31); lx = lx+lx;} - else {hx = hz+hz+(lz>>31); lx = lz+lz; q++;} - q <<= 1; - } - hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1; - if(hz>=0) {hx=hz;lx=lz;q++;} - - /* convert back to floating value and restore the sign */ - if((hx|lx)==0) { /* return sign(x)*0 */ - *quo = (sxy ? -q : q); - return Zero[(uint32_t)sx>>31]; - } - while(hx<0x00100000) { /* normalize x */ - hx = hx+hx+(lx>>31); lx = lx+lx; - iy -= 1; - } - if(iy>= -1022) { /* normalize output */ - hx = ((hx-0x00100000)|((iy+1023)<<20)); - } else { /* subnormal output */ - n = -1022 - iy; - if(n<=20) { - lx = (lx>>n)|((uint32_t)hx<<(32-n)); - hx >>= n; - } else if (n<=31) { - lx = (hx<<(32-n))|(lx>>n); hx = sx; - } else { - lx = hx>>(n-32); hx = sx; - } - } -fixup: - INSERT_WORDS(x,hx,lx); - y = fabs(y); - if (y < 0x1p-1021) { - if (x+x>y || (x+x==y && (q & 1))) { - q++; - x-=y; - } - } else if (x>0.5*y || (x==0.5*y && (q & 1))) { - q++; - x-=y; - } - GET_HIGH_WORD(hx,x); - SET_HIGH_WORD(x,hx^sx); - q &= 0x7fffffff; - *quo = (sxy ? -q : q); - return x; -} |