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30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
106 lines
2.9 KiB
C
106 lines
2.9 KiB
C
/*
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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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* __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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#include <math.h>
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#include <math_private.h>
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#include <stdint.h>
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#include <libm-alias-finite.h>
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static const double one = 1.0, Zero[] = {0.0, -0.0,};
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double
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__ieee754_fmod (double x, double y)
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{
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int32_t n,ix,iy;
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int64_t hx,hy,hz,sx,i;
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EXTRACT_WORDS64(hx,x);
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EXTRACT_WORDS64(hy,y);
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sx = hx&UINT64_C(0x8000000000000000); /* sign of x */
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hx ^=sx; /* |x| */
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hy &= UINT64_C(0x7fffffffffffffff); /* |y| */
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/* purge off exception values */
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if(__builtin_expect(hy==0
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|| hx >= UINT64_C(0x7ff0000000000000)
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|| hy > UINT64_C(0x7ff0000000000000), 0))
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/* y=0,or x not finite or y is NaN */
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return (x*y)/(x*y);
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if(__builtin_expect(hx<=hy, 0)) {
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if(hx<hy) return x; /* |x|<|y| return x */
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return Zero[(uint64_t)sx>>63]; /* |x|=|y| return x*0*/
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}
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/* determine ix = ilogb(x) */
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if(__builtin_expect(hx<UINT64_C(0x0010000000000000), 0)) {
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/* subnormal x */
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for (ix = -1022,i=(hx<<11); i>0; i<<=1) ix -=1;
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} else ix = (hx>>52)-1023;
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/* determine iy = ilogb(y) */
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if(__builtin_expect(hy<UINT64_C(0x0010000000000000), 0)) { /* subnormal y */
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for (iy = -1022,i=(hy<<11); i>0; i<<=1) iy -=1;
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} else iy = (hy>>52)-1023;
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/* set up hx, hy and align y to x */
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if(__builtin_expect(ix >= -1022, 1))
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hx = UINT64_C(0x0010000000000000)|(UINT64_C(0x000fffffffffffff)&hx);
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else { /* subnormal x, shift x to normal */
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n = -1022-ix;
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hx<<=n;
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}
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if(__builtin_expect(iy >= -1022, 1))
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hy = UINT64_C(0x0010000000000000)|(UINT64_C(0x000fffffffffffff)&hy);
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else { /* subnormal y, shift y to normal */
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n = -1022-iy;
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hy<<=n;
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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;
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if(hz<0){hx = hx+hx;}
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else {
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if(hz==0) /* return sign(x)*0 */
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return Zero[(uint64_t)sx>>63];
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hx = hz+hz;
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}
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}
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hz=hx-hy;
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if(hz>=0) {hx=hz;}
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/* convert back to floating value and restore the sign */
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if(hx==0) /* return sign(x)*0 */
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return Zero[(uint64_t)sx>>63];
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while(hx<UINT64_C(0x0010000000000000)) { /* normalize x */
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hx = hx+hx;
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iy -= 1;
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}
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if(__builtin_expect(iy>= -1022, 1)) { /* normalize output */
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hx = ((hx-UINT64_C(0x0010000000000000))|((uint64_t)(iy+1023)<<52));
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INSERT_WORDS64(x,hx|sx);
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} else { /* subnormal output */
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n = -1022 - iy;
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hx>>=n;
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INSERT_WORDS64(x,hx|sx);
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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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libm_alias_finite (__ieee754_fmod, __fmod)
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