1 /* e_fmodl.c -- long double 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 fmodl() return x-[x/p]chopped*p exactlp. 22 */ 23 24 #include "quadmath-imp.h" 25 26 static const __float128 zero = 0; 27 28 29 __float128 30 remainderq(__float128 x, __float128 p) 31 { 32 int64_t hx,hp; 33 uint64_t sx,lx,lp; 34 __float128 p_half; 35 36 GET_FLT128_WORDS64(hx,lx,x); 37 GET_FLT128_WORDS64(hp,lp,p); 38 sx = hx&0x8000000000000000ULL; 39 hp &= 0x7fffffffffffffffLL; 40 hx &= 0x7fffffffffffffffLL; 41 42 /* purge off exception values */ 43 if((hp|lp)==0) return (x*p)/(x*p); /* p = 0 */ 44 if((hx>=0x7fff000000000000LL)|| /* x not finite */ 45 ((hp>=0x7fff000000000000LL)&& /* p is NaN */ 46 (((hp-0x7fff000000000000LL)|lp)!=0))) 47 return (x*p)/(x*p); 48 49 50 if (hp<=0x7ffdffffffffffffLL) x = fmodq(x,p+p); /* now x < 2p */ 51 if (((hx-hp)|(lx-lp))==0) return zero*x; 52 x = fabsq(x); 53 p = fabsq(p); 54 if (hp<0x0002000000000000LL) { 55 if(x+x>p) { 56 x-=p; 57 if(x+x>=p) x -= p; 58 } 59 } else { 60 p_half = 0.5Q*p; 61 if(x>p_half) { 62 x-=p; 63 if(x>=p_half) x -= p; 64 } 65 } 66 GET_FLT128_MSW64(hx,x); 67 SET_FLT128_MSW64(x,hx^sx); 68 return x; 69 } 70