11dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 21dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* @(#)e_fmod.c 1.3 95/01/18 */ 31dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* 41dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ==================================================== 51dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 61dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 71dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Developed at SunSoft, a Sun Microsystems, Inc. business. 81dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Permission to use, copy, modify, and distribute this 91dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * software is freely granted, provided that this notice 101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * is preserved. 111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ==================================================== 121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#ifndef lint 151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic char rcsid[] = "$FreeBSD: src/lib/msun/src/e_fmod.c,v 1.9 2005/02/04 18:26:05 das Exp $"; 161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#endif 171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* 191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * __ieee754_fmod(x,y) 201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Return x mod y in exact arithmetic 211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Method: shift and subtract 221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include "math.h" 251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include "math_private.h" 261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic const double one = 1.0, Zero[] = {0.0, -0.0,}; 281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectdouble 301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project__ieee754_fmod(double x, double y) 311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int32_t n,hx,hy,hz,ix,iy,sx,i; 331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project u_int32_t lx,ly,lz; 341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project EXTRACT_WORDS(hx,lx,x); 361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project EXTRACT_WORDS(hy,ly,y); 371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project sx = hx&0x80000000; /* sign of x */ 381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hx ^=sx; /* |x| */ 391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hy &= 0x7fffffff; /* |y| */ 401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* purge off exception values */ 421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if((hy|ly)==0||(hx>=0x7ff00000)|| /* y=0,or x not finite */ 431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ((hy|((ly|-ly)>>31))>0x7ff00000)) /* or y is NaN */ 441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return (x*y)/(x*y); 451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(hx<=hy) { 461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if((hx<hy)||(lx<ly)) return x; /* |x|<|y| return x */ 471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(lx==ly) 481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return Zero[(u_int32_t)sx>>31]; /* |x|=|y| return x*0*/ 491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* determine ix = ilogb(x) */ 521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(hx<0x00100000) { /* subnormal x */ 531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(hx==0) { 541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (ix = -1043, i=lx; i>0; i<<=1) ix -=1; 551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } else { 561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (ix = -1022,i=(hx<<11); i>0; i<<=1) ix -=1; 571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } else ix = (hx>>20)-1023; 591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* determine iy = ilogb(y) */ 611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(hy<0x00100000) { /* subnormal y */ 621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(hy==0) { 631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (iy = -1043, i=ly; i>0; i<<=1) iy -=1; 641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } else { 651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (iy = -1022,i=(hy<<11); i>0; i<<=1) iy -=1; 661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } else iy = (hy>>20)-1023; 681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* set up {hx,lx}, {hy,ly} and align y to x */ 701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(ix >= -1022) 711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hx = 0x00100000|(0x000fffff&hx); 721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project else { /* subnormal x, shift x to normal */ 731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project n = -1022-ix; 741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(n<=31) { 751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hx = (hx<<n)|(lx>>(32-n)); 761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project lx <<= n; 771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } else { 781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hx = lx<<(n-32); 791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project lx = 0; 801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(iy >= -1022) 831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hy = 0x00100000|(0x000fffff&hy); 841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project else { /* subnormal y, shift y to normal */ 851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project n = -1022-iy; 861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(n<=31) { 871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hy = (hy<<n)|(ly>>(32-n)); 881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ly <<= n; 891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } else { 901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hy = ly<<(n-32); 911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ly = 0; 921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* fix point fmod */ 961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project n = ix - iy; 971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project while(n--) { 981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1; 991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(hz<0){hx = hx+hx+(lx>>31); lx = lx+lx;} 1001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project else { 1011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if((hz|lz)==0) /* return sign(x)*0 */ 1021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return Zero[(u_int32_t)sx>>31]; 1031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hx = hz+hz+(lz>>31); lx = lz+lz; 1041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 1051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 1061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hz=hx-hy;lz=lx-ly; if(lx<ly) hz -= 1; 1071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(hz>=0) {hx=hz;lx=lz;} 1081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* convert back to floating value and restore the sign */ 1101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if((hx|lx)==0) /* return sign(x)*0 */ 1111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return Zero[(u_int32_t)sx>>31]; 1121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project while(hx<0x00100000) { /* normalize x */ 1131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hx = hx+hx+(lx>>31); lx = lx+lx; 1141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project iy -= 1; 1151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 1161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(iy>= -1022) { /* normalize output */ 1171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hx = ((hx-0x00100000)|((iy+1023)<<20)); 1181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project INSERT_WORDS(x,hx|sx,lx); 1191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } else { /* subnormal output */ 1201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project n = -1022 - iy; 1211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(n<=20) { 1221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project lx = (lx>>n)|((u_int32_t)hx<<(32-n)); 1231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hx >>= n; 1241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } else if (n<=31) { 1251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project lx = (hx<<(32-n))|(lx>>n); hx = sx; 1261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } else { 1271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project lx = hx>>(n-32); hx = sx; 1281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 1291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project INSERT_WORDS(x,hx|sx,lx); 1301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project x *= one; /* create necessary signal */ 1311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 1321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return x; /* exact output */ 1331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 134