1 /* @(#)s_modf.c 5.1 93/09/24 */ 2 /* 3 * ==================================================== 4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 5 * 6 * Developed at SunPro, a Sun Microsystems, Inc. business. 7 * Permission to use, copy, modify, and distribute this 8 * software is freely granted, provided that this notice 9 * is preserved. 10 * ==================================================== 11 */ 12 13 /* 14 * modfl(long double x, long double *iptr) 15 * return fraction part of x, and return x's integral part in *iptr. 16 * Method: 17 * Bit twiddling. 18 * 19 * Exception: 20 * No exception. 21 */ 22 23 #include <math.h> 24 25 #include "math_private.h" 26 27 static const long double one = 1.0; 28 29 long double 30 modfl(long double x, long double *iptr) 31 { 32 int32_t i0,i1,jj0; 33 u_int32_t i,se; 34 GET_LDOUBLE_WORDS(se,i0,i1,x); 35 jj0 = (se&0x7fff)-0x3fff; /* exponent of x */ 36 if(jj0<32) { /* integer part in high x */ 37 if(jj0<0) { /* |x|<1 */ 38 SET_LDOUBLE_WORDS(*iptr,se&0x8000,0,0); /* *iptr = +-0 */ 39 return x; 40 } else { 41 i = (0x7fffffff)>>jj0; 42 if(((i0&i)|i1)==0) { /* x is integral */ 43 *iptr = x; 44 SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ 45 return x; 46 } else { 47 SET_LDOUBLE_WORDS(*iptr,se,i0&(~i),0); 48 return x - *iptr; 49 } 50 } 51 } else if (jj0>63) { /* no fraction part */ 52 *iptr = x*one; 53 /* We must handle NaNs separately. */ 54 if (jj0 == 0x4000 && ((i0 & 0x7fffffff) | i1)) 55 return x*one; 56 SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ 57 return x; 58 } else { /* fraction part in low x */ 59 i = ((u_int32_t)(0x7fffffff))>>(jj0-32); 60 if((i1&i)==0) { /* x is integral */ 61 *iptr = x; 62 SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ 63 return x; 64 } else { 65 SET_LDOUBLE_WORDS(*iptr,se,i0,i1&(~i)); 66 return x - *iptr; 67 } 68 } 69 } 70