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Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/e_fmodl.c')
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diff --git a/sysdeps/ieee754/ldbl-128ibm/e_fmodl.c b/sysdeps/ieee754/ldbl-128ibm/e_fmodl.c
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+++ b/sysdeps/ieee754/ldbl-128ibm/e_fmodl.c
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+/* e_fmodl.c -- long double version of e_fmod.c.
+ * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
+ */
+/*
+ * ====================================================
+ * 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_fmodl(x,y)
+ * Return x mod y in exact arithmetic
+ * Method: shift and subtract
+ */
+
+#include "math.h"
+#include "math_private.h"
+#include <ieee754.h>
+
+#ifdef __STDC__
+static const long double one = 1.0, Zero[] = {0.0, -0.0,};
+#else
+static long double one = 1.0, Zero[] = {0.0, -0.0,};
+#endif
+
+#ifdef __STDC__
+ long double __ieee754_fmodl(long double x, long double y)
+#else
+ long double __ieee754_fmodl(x,y)
+ long double x,y;
+#endif
+{
+ int64_t n,hx,hy,hz,ix,iy,sx,i;
+ u_int64_t lx,ly,lz;
+ int temp;
+
+ GET_LDOUBLE_WORDS64(hx,lx,x);
+ GET_LDOUBLE_WORDS64(hy,ly,y);
+ sx = hx&0x8000000000000000ULL; /* sign of x */
+ hx ^=sx; /* |x| */
+ hy &= 0x7fffffffffffffffLL; /* |y| */
+
+ /* purge off exception values */
+ if((hy|(ly&0x7fffffffffffffff))==0||(hx>=0x7ff0000000000000LL)|| /* y=0,or x not finite */
+ (hy>0x7ff0000000000000LL)) /* or y is NaN */
+ return (x*y)/(x*y);
+ if(hx<=hy) {
+ if((hx<hy)||(lx<ly)) return x; /* |x|<|y| return x */
+ if(lx==ly)
+ return Zero[(u_int64_t)sx>>63]; /* |x|=|y| return x*0*/
+ }
+
+ /* determine ix = ilogb(x) */
+ if(hx<0x0010000000000000LL) { /* subnormal x */
+ if(hx==0) {
+ for (ix = -1043, i=lx; i>0; i<<=1) ix -=1;
+ } else {
+ for (ix = -1022, i=hx<<19; i>0; i<<=1) ix -=1;
+ }
+ } else ix = (hx>>52)-0x3ff;
+
+ /* determine iy = ilogb(y) */
+ if(hy<0x0010000000000000LL) { /* subnormal y */
+ if(hy==0) {
+ for (iy = -1043, i=ly; i>0; i<<=1) iy -=1;
+ } else {
+ for (iy = -1022, i=hy<<19; i>0; i<<=1) iy -=1;
+ }
+ } else iy = (hy>>52)-0x3ff;
+
+ /* Make the IBM extended format 105 bit mantissa look like the ieee854 112
+ bit mantissa so the following operatations will give the correct
+ result. */
+ ldbl_extract_mantissa(&hx, &lx, &temp, x);
+ ldbl_extract_mantissa(&hy, &ly, &temp, y);
+
+ /* set up {hx,lx}, {hy,ly} and align y to x */
+ if(ix >= -1022)
+ hx = 0x0001000000000000LL|(0x0000ffffffffffffLL&hx);
+ else { /* subnormal x, shift x to normal */
+ n = -1022-ix;
+ if(n<=63) {
+ hx = (hx<<n)|(lx>>(64-n));
+ lx <<= n;
+ } else {
+ hx = lx<<(n-64);
+ lx = 0;
+ }
+ }
+ if(iy >= -1022)
+ hy = 0x0001000000000000LL|(0x0000ffffffffffffLL&hy);
+ else { /* subnormal y, shift y to normal */
+ n = -1022-iy;
+ if(n<=63) {
+ hy = (hy<<n)|(ly>>(64-n));
+ ly <<= n;
+ } else {
+ hy = ly<<(n-64);
+ ly = 0;
+ }
+ }
+
+ /* fix point fmod */
+ n = ix - iy;
+ while(n--) {
+ hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
+ if(hz<0){hx = hx+hx+(lx>>63); lx = lx+lx;}
+ else {
+ if((hz|(lz&0x7fffffffffffffff))==0) /* return sign(x)*0 */
+ return Zero[(u_int64_t)sx>>63];
+ hx = hz+hz+(lz>>63); lx = lz+lz;
+ }
+ }
+ hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1;
+ if(hz>=0) {hx=hz;lx=lz;}
+
+ /* convert back to floating value and restore the sign */
+ if((hx|(lx&0x7fffffffffffffff))==0) /* return sign(x)*0 */
+ return Zero[(u_int64_t)sx>>63];
+ while(hx<0x0001000000000000LL) { /* normalize x */
+ hx = hx+hx+(lx>>63); lx = lx+lx;
+ iy -= 1;
+ }
+ if(iy>= -1022) { /* normalize output */
+ x = ldbl_insert_mantissa((sx>>63), iy, hx, lx);
+ } else { /* subnormal output */
+ n = -1022 - iy;
+ if(n<=48) {
+ lx = (lx>>n)|((u_int64_t)hx<<(64-n));
+ hx >>= n;
+ } else if (n<=63) {
+ lx = (hx<<(64-n))|(lx>>n); hx = sx;
+ } else {
+ lx = hx>>(n-64); hx = sx;
+ }
+ x = ldbl_insert_mantissa((sx>>63), iy, hx, lx);
+ x *= one; /* create necessary signal */
+ }
+ return x; /* exact output */
+}