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FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
Current File : //compat/linux/proc/self/root/usr/src/lib/msun/src/e_fmodf.c |
/* e_fmodf.c -- float version of e_fmod.c. * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.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. * ==================================================== */ #include <sys/cdefs.h> __FBSDID("$FreeBSD: release/9.1.0/lib/msun/src/e_fmodf.c 176451 2008-02-22 02:30:36Z das $"); /* * __ieee754_fmodf(x,y) * Return x mod y in exact arithmetic * Method: shift and subtract */ #include "math.h" #include "math_private.h" static const float one = 1.0, Zero[] = {0.0, -0.0,}; float __ieee754_fmodf(float x, float y) { int32_t n,hx,hy,hz,ix,iy,sx,i; GET_FLOAT_WORD(hx,x); GET_FLOAT_WORD(hy,y); sx = hx&0x80000000; /* sign of x */ hx ^=sx; /* |x| */ hy &= 0x7fffffff; /* |y| */ /* purge off exception values */ if(hy==0||(hx>=0x7f800000)|| /* y=0,or x not finite */ (hy>0x7f800000)) /* or y is NaN */ return (x*y)/(x*y); if(hx<hy) return x; /* |x|<|y| return x */ if(hx==hy) return Zero[(u_int32_t)sx>>31]; /* |x|=|y| return x*0*/ /* determine ix = ilogb(x) */ if(hx<0x00800000) { /* subnormal x */ for (ix = -126,i=(hx<<8); i>0; i<<=1) ix -=1; } else ix = (hx>>23)-127; /* determine iy = ilogb(y) */ if(hy<0x00800000) { /* subnormal y */ for (iy = -126,i=(hy<<8); i>=0; i<<=1) iy -=1; } else iy = (hy>>23)-127; /* set up {hx,lx}, {hy,ly} and align y to x */ if(ix >= -126) hx = 0x00800000|(0x007fffff&hx); else { /* subnormal x, shift x to normal */ n = -126-ix; hx = hx<<n; } if(iy >= -126) hy = 0x00800000|(0x007fffff&hy); else { /* subnormal y, shift y to normal */ n = -126-iy; hy = 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[(u_int32_t)sx>>31]; 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[(u_int32_t)sx>>31]; while(hx<0x00800000) { /* normalize x */ hx = hx+hx; iy -= 1; } if(iy>= -126) { /* normalize output */ hx = ((hx-0x00800000)|((iy+127)<<23)); SET_FLOAT_WORD(x,hx|sx); } else { /* subnormal output */ n = -126 - iy; hx >>= n; SET_FLOAT_WORD(x,hx|sx); x *= one; /* create necessary signal */ } return x; /* exact output */ }