| /* | |
| * ==================================================== | |
| * 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_fmodf(x,y) | |
| * Return x mod y in exact arithmetic | |
| * Method: shift and subtract | |
| */ | |
| #include "bsd_privatef.h" | |
| float bsd__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 */ | |
| } |