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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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+
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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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+
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+#include "math_libm.h"
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+#include "math_private.h"
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+
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+static const double one = 1.0, Zero[] = {0.0, -0.0,};
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+
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+double attribute_hidden __ieee754_fmod(double x, double y)
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+{
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+ int32_t n,hx,hy,hz,ix,iy,sx,i;
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+ u_int32_t lx,ly,lz;
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+
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+ EXTRACT_WORDS(hx,lx,x);
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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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+
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+ /* purge off exception values */
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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<hy)||(lx<ly)) return x; /* |x|<|y| return x */
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+ if(lx==ly)
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+ return Zero[(u_int32_t)sx>>31]; /* |x|=|y| return x*0*/
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+ }
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+
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+ /* determine ix = ilogb(x) */
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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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+
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+ /* determine iy = ilogb(y) */
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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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+
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+ /* set up {hx,lx}, {hy,ly} and align y to x */
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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<<n)|(lx>>(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<<n)|(ly>>(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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+
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+ /* fix point fmod */
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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<ly) hz -= 1;
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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[(u_int32_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<ly) hz -= 1;
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+ if(hz>=0) {hx=hz;lx=lz;}
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+
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+ /* convert back to floating value and restore the sign */
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+ if((hx|lx)==0) /* return sign(x)*0 */
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+ return Zero[(u_int32_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)|((u_int32_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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+
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+/*
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+ * wrapper fmod(x,y)
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+ */
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+#ifndef _IEEE_LIBM
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+double fmod(double x, double y)
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+{
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+ double z = __ieee754_fmod(x, y);
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+ if (_LIB_VERSION == _IEEE_ || isnan(y) || isnan(x))
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+ return z;
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+ if (y == 0.0)
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+ return __kernel_standard(x, y, 27); /* fmod(x,0) */
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+ return z;
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+}
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+#else
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+strong_alias(__ieee754_fmod, fmod)
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+#endif
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+libm_hidden_def(fmod)
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