1/* fmodq.c -- __float128 version of e_fmod.c. 2 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz. 3 */ 4/* 5 * ==================================================== 6 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 7 * 8 * Developed at SunPro, a Sun Microsystems, Inc. business. 9 * Permission to use, copy, modify, and distribute this 10 * software is freely granted, provided that this notice 11 * is preserved. 12 * ==================================================== 13 */ 14 15/* remainderq(x,p) 16 * Return : 17 * returns x REM p = x - [x/p]*p as if in infinite 18 * precise arithmetic, where [x/p] is the (infinite bit) 19 * integer nearest x/p (in half way case choose the even one). 20 * Method : 21 * Based on fmodq() return x-[x/p]chopped*p exactlp. 22 */ 23 24#include "quadmath-imp.h" 25 26static const __float128 zero = 0.0Q; 27 28__float128 29remainderq (__float128 x, __float128 p) 30{ 31 int64_t hx,hp; 32 uint64_t sx,lx,lp; 33 __float128 p_half; 34 35 GET_FLT128_WORDS64(hx,lx,x); 36 GET_FLT128_WORDS64(hp,lp,p); 37 sx = hx&0x8000000000000000ULL; 38 hp &= 0x7fffffffffffffffLL; 39 hx &= 0x7fffffffffffffffLL; 40 41 /* purge off exception values */ 42 if((hp|lp)==0) return (x*p)/(x*p); /* p = 0 */ 43 if((hx>=0x7fff000000000000LL)|| /* x not finite */ 44 ((hp>=0x7fff000000000000LL)&& /* p is NaN */ 45 (((hp-0x7fff000000000000LL)|lp)!=0))) 46 return (x*p)/(x*p); 47 48 if (hp<=0x7ffdffffffffffffLL) x = fmodq (x,p+p); /* now x < 2p */ 49 if (((hx-hp)|(lx-lp))==0) return zero*x; 50 x = fabsq(x); 51 p = fabsq(p); 52 if (hp<0x0002000000000000LL) { 53 if(x+x>p) { 54 x-=p; 55 if(x+x>=p) x -= p; 56 } 57 } else { 58 p_half = 0.5Q*p; 59 if(x>p_half) { 60 x-=p; 61 if(x>=p_half) x -= p; 62 } 63 } 64 GET_FLT128_MSW64(hx,x); 65 SET_FLT128_MSW64(x,hx^sx); 66 return x; 67} 68