1 /* s_modfl.c -- long double version of s_modf.c. 2 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz. 3 */ 4 5 /* 6 * ==================================================== 7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 8 * 9 * Developed at SunPro, a Sun Microsystems, Inc. business. 10 * Permission to use, copy, modify, and distribute this 11 * software is freely granted, provided that this notice 12 * is preserved. 13 * ==================================================== 14 */ 15 16 #if defined(LIBM_SCCS) && !defined(lint) 17 static char rcsid[] = "NetBSD: "; 18 #endif 19 20 /* 21 * modfq(long double x, long double *iptr) 22 * return fraction part of x, and return x's integral part in *iptr. 23 * Method: 24 * Bit twiddling. 25 * 26 * Exception: 27 * No exception. 28 */ 29 30 #include "quadmath-imp.h" 31 32 static const __float128 one = 1.0; 33 34 __float128 modfq(__float128 x, __float128 *iptr) 35 { 36 int64_t i0,i1,j0; 37 uint64_t i; 38 GET_FLT128_WORDS64(i0,i1,x); 39 j0 = ((i0>>48)&0x7fff)-0x3fff; /* exponent of x */ 40 if(j0<48) { /* integer part in high x */ 41 if(j0<0) { /* |x|<1 */ 42 /* *iptr = +-0 */ 43 SET_FLT128_WORDS64(*iptr,i0&0x8000000000000000ULL,0); 44 return x; 45 } else { 46 i = (0x0000ffffffffffffLL)>>j0; 47 if(((i0&i)|i1)==0) { /* x is integral */ 48 *iptr = x; 49 /* return +-0 */ 50 SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0); 51 return x; 52 } else { 53 SET_FLT128_WORDS64(*iptr,i0&(~i),0); 54 return x - *iptr; 55 } 56 } 57 } else if (j0>111) { /* no fraction part */ 58 *iptr = x*one; 59 /* We must handle NaNs separately. */ 60 if (j0 == 0x4000 && ((i0 & 0x0000ffffffffffffLL) | i1)) 61 return x*one; 62 /* return +-0 */ 63 SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0); 64 return x; 65 } else { /* fraction part in low x */ 66 i = -1ULL>>(j0-48); 67 if((i1&i)==0) { /* x is integral */ 68 *iptr = x; 69 /* return +-0 */ 70 SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0); 71 return x; 72 } else { 73 SET_FLT128_WORDS64(*iptr,i0,i1&(~i)); 74 return x - *iptr; 75 } 76 } 77 } 78