| /* s_modfl.c -- long double version of s_modf.c. |
| * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz. |
| */ |
| |
| /* |
| * ==================================================== |
| * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Developed at SunPro, a Sun Microsystems, Inc. business. |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| */ |
| |
| #if defined(LIBM_SCCS) && !defined(lint) |
| static char rcsid[] = "$NetBSD: $"; |
| #endif |
| |
| /* |
| * modfl(long double x, long double *iptr) |
| * return fraction part of x, and return x's integral part in *iptr. |
| * Method: |
| * Bit twiddling. |
| * |
| * Exception: |
| * No exception. |
| */ |
| |
| #include <math.h> |
| #include <math_private.h> |
| #include <math_ldbl_opt.h> |
| |
| static const long double one = 1.0; |
| |
| long double __modfl(long double x, long double *iptr) |
| { |
| int64_t i0,i1,j0; |
| u_int64_t i; |
| double xhi, xlo; |
| |
| ldbl_unpack (x, &xhi, &xlo); |
| EXTRACT_WORDS64 (i0, xhi); |
| EXTRACT_WORDS64 (i1, xlo); |
| i1 &= 0x000fffffffffffffLL; |
| j0 = ((i0>>52)&0x7ff)-0x3ff; /* exponent of x */ |
| if(j0<52) { /* integer part in high x */ |
| if(j0<0) { /* |x|<1 */ |
| /* *iptr = +-0 */ |
| INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL); |
| *iptr = xhi; |
| return x; |
| } else { |
| i = (0x000fffffffffffffLL)>>j0; |
| if(((i0&i)|(i1&0x7fffffffffffffffLL))==0) { /* x is integral */ |
| *iptr = x; |
| /* return +-0 */ |
| INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL); |
| x = xhi; |
| return x; |
| } else { |
| INSERT_WORDS64 (xhi, i0&(~i)); |
| *iptr = xhi; |
| return x - *iptr; |
| } |
| } |
| } else if (j0>103) { /* no fraction part */ |
| *iptr = x*one; |
| /* We must handle NaNs separately. */ |
| if ((i0 & 0x7fffffffffffffffLL) > 0x7ff0000000000000LL) |
| return x*one; |
| /* return +-0 */ |
| INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL); |
| x = xhi; |
| return x; |
| } else { /* fraction part in low x */ |
| i = -1ULL>>(j0-52); |
| if((i1&i)==0) { /* x is integral */ |
| *iptr = x; |
| /* return +-0 */ |
| INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL); |
| x = xhi; |
| return x; |
| } else { |
| INSERT_WORDS64 (xhi, i0); |
| INSERT_WORDS64 (xlo, i1&(~i)); |
| *iptr = ldbl_pack (xhi, xlo); |
| return x - *iptr; |
| } |
| } |
| } |
| #ifdef IS_IN_libm |
| long_double_symbol (libm, __modfl, modfl); |
| #else |
| long_double_symbol (libc, __modfl, modfl); |
| #endif |
