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Diffstat (limited to 'newlib/libm/common/s_remquo.c')
| -rw-r--r-- | newlib/libm/common/s_remquo.c | 208 |
1 files changed, 0 insertions, 208 deletions
diff --git a/newlib/libm/common/s_remquo.c b/newlib/libm/common/s_remquo.c deleted file mode 100644 index 8ae287575..000000000 --- a/newlib/libm/common/s_remquo.c +++ /dev/null @@ -1,208 +0,0 @@ -/* Adapted for Newlib, 2009. (Allow for int < 32 bits; return *quo=0 during - * errors to make test scripts easier.) */ -/* @(#)e_fmod.c 1.3 95/01/18 */ -/*- - * ==================================================== - * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. - * - * Developed at SunSoft, a Sun Microsystems, Inc. business. - * Permission to use, copy, modify, and distribute this - * software is freely granted, provided that this notice - * is preserved. - * ==================================================== - */ -/* -FUNCTION -<<remquo>>, <<remquof>>--remainder and part of quotient -INDEX - remquo -INDEX - remquof - -ANSI_SYNOPSIS - #include <math.h> - double remquo(double <[x]>, double <[y]>, int *<[quo]>); - float remquof(float <[x]>, float <[y]>, int *<[quo]>); - -DESCRIPTION -The <<remquo>> functions compute the same remainder as the <<remainder>> -functions; this value is in the range -<[y]>/2 ... +<[y]>/2. In the object -pointed to by <<quo>> they store a value whose sign is the sign of <<x>>/<<y>> -and whose magnitude is congruent modulo 2**n to the magnitude of the integral -quotient of <<x>>/<<y>>. (That is, <<quo>> is given the n lsbs of the -quotient, not counting the sign.) This implementation uses n=31 if int is 32 -bits or more, otherwise, n is 1 less than the width of int. - -For example: -. remquo(-29.0, 3.0, &<[quo]>) -returns -1.0 and sets <[quo]>=10, and -. remquo(-98307.0, 3.0, &<[quo]>) -returns -0.0 and sets <[quo]>=-32769, although for 16-bit int, <[quo]>=-1. In -the latter case, the actual quotient of -(32769=0x8001) is reduced to -1 -because of the 15-bit limitation for the quotient. - -RETURNS -When either argument is NaN, NaN is returned. If <[y]> is 0 or <[x]> is -infinite (and neither is NaN), a domain error occurs (i.e. the "invalid" -floating point exception is raised or errno is set to EDOM), and NaN is -returned. -Otherwise, the <<remquo>> functions return <[x]> REM <[y]>. - -BUGS -IEEE754-2008 calls for <<remquo>>(subnormal, inf) to cause the "underflow" -floating-point exception. This implementation does not. - -PORTABILITY -C99, POSIX. - -*/ - -#include <limits.h> -#include <math.h> -#include "fdlibm.h" - -/* For quotient, return either all 31 bits that can from calculation (using - * int32_t), or as many as can fit into an int that is smaller than 32 bits. */ -#if INT_MAX > 0x7FFFFFFFL - #define QUO_MASK 0x7FFFFFFF -# else - #define QUO_MASK INT_MAX -#endif - -static const double Zero[] = {0.0, -0.0,}; - -/* - * Return the IEEE remainder and set *quo to the last n bits of the - * quotient, rounded to the nearest integer. We choose n=31--if that many fit-- - * because we wind up computing all the integer bits of the quotient anyway as - * a side-effect of computing the remainder by the shift and subtract - * method. In practice, this is far more bits than are needed to use - * remquo in reduction algorithms. - */ -double -remquo(double x, double y, int *quo) -{ - __int32_t n,hx,hy,hz,ix,iy,sx,i; - __uint32_t lx,ly,lz,q,sxy; - - EXTRACT_WORDS(hx,lx,x); - EXTRACT_WORDS(hy,ly,y); - sxy = (hx ^ hy) & 0x80000000; - sx = hx&0x80000000; /* sign of x */ - hx ^=sx; /* |x| */ - hy &= 0x7fffffff; /* |y| */ - - /* purge off exception values */ - if((hy|ly)==0||(hx>=0x7ff00000)|| /* y=0,or x not finite */ - ((hy|((ly|-ly)>>31))>0x7ff00000)) { /* or y is NaN */ - *quo = 0; /* Not necessary, but return consistent value */ - return (x*y)/(x*y); - } - if(hx<=hy) { - if((hx<hy)||(lx<ly)) { - q = 0; - goto fixup; /* |x|<|y| return x or x-y */ - } - if(lx==ly) { - *quo = (sxy ? -1 : 1); - return Zero[(__uint32_t)sx>>31]; /* |x|=|y| return x*0 */ - } - } - - /* determine ix = ilogb(x) */ - if(hx<0x00100000) { /* subnormal x */ - if(hx==0) { - for (ix = -1043, i=lx; i>0; i<<=1) ix -=1; - } else { - for (ix = -1022,i=(hx<<11); i>0; i<<=1) ix -=1; - } - } else ix = (hx>>20)-1023; - - /* determine iy = ilogb(y) */ - if(hy<0x00100000) { /* subnormal y */ - if(hy==0) { - for (iy = -1043, i=ly; i>0; i<<=1) iy -=1; - } else { - for (iy = -1022,i=(hy<<11); i>0; i<<=1) iy -=1; - } - } else iy = (hy>>20)-1023; - - /* set up {hx,lx}, {hy,ly} and align y to x */ - if(ix >= -1022) - hx = 0x00100000|(0x000fffff&hx); - else { /* subnormal x, shift x to normal */ - n = -1022-ix; - if(n<=31) { - hx = (hx<<n)|(lx>>(32-n)); - lx <<= n; - } else { - hx = lx<<(n-32); - lx = 0; - } - } - if(iy >= -1022) - hy = 0x00100000|(0x000fffff&hy); - else { /* subnormal y, shift y to normal */ - n = -1022-iy; - if(n<=31) { - hy = (hy<<n)|(ly>>(32-n)); - ly <<= n; - } else { - hy = ly<<(n-32); - ly = 0; - } - } - - /* fix point fmod */ - n = ix - iy; - q = 0; - while(n--) { - hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1; - if(hz<0){hx = hx+hx+(lx>>31); lx = lx+lx;} - else {hx = hz+hz+(lz>>31); lx = lz+lz; q++;} - q <<= 1; - } - hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1; - if(hz>=0) {hx=hz;lx=lz;q++;} - - /* convert back to floating value and restore the sign */ - if((hx|lx)==0) { /* return sign(x)*0 */ - q &= QUO_MASK; - *quo = (sxy ? -q : q); - return Zero[(__uint32_t)sx>>31]; - } - while(hx<0x00100000) { /* normalize x */ - hx = hx+hx+(lx>>31); lx = lx+lx; - iy -= 1; - } - if(iy>= -1022) { /* normalize output */ - hx = ((hx-0x00100000)|((iy+1023)<<20)); - } else { /* subnormal output */ - n = -1022 - iy; - if(n<=20) { - lx = (lx>>n)|((__uint32_t)hx<<(32-n)); - hx >>= n; - } else if (n<=31) { - lx = (hx<<(32-n))|(lx>>n); hx = sx; - } else { - lx = hx>>(n-32); hx = sx; - } - } -fixup: - INSERT_WORDS(x,hx,lx); - y = fabs(y); - if (y < 0x1p-1021) { - if (x+x>y || (x+x==y && (q & 1))) { - q++; - x-=y; - } - } else if (x>0.5*y || (x==0.5*y && (q & 1))) { - q++; - x-=y; - } - GET_HIGH_WORD(hx,x); - SET_HIGH_WORD(x,hx^sx); - q &= QUO_MASK; - *quo = (sxy ? -q : q); - return x; -} |