| 1 | /* s_frexpl.c -- long double version of s_frexp.c. |
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| 2 | */ |
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| 3 | |
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| 4 | /* |
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| 5 | * ==================================================== |
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| 6 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 7 | * |
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| 8 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 9 | * Permission to use, copy, modify, and distribute this |
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| 10 | * software is freely granted, provided that this notice |
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| 11 | * is preserved. |
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| 12 | * ==================================================== |
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| 13 | */ |
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| 14 | |
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| 15 | #if defined(LIBM_SCCS) && !defined(lint) |
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| 16 | static char rcsid[] = "$NetBSD: $" ; |
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| 17 | #endif |
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| 18 | |
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| 19 | /* |
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| 20 | * for non-zero x |
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| 21 | * x = frexpl(arg,&exp); |
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| 22 | * return a long double fp quantity x such that 0.5 <= |x| <1.0 |
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| 23 | * and the corresponding binary exponent "exp". That is |
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| 24 | * arg = x*2^exp. |
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| 25 | * If arg is inf, 0.0, or NaN, then frexpl(arg,&exp) returns arg |
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| 26 | * with *exp=0. |
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| 27 | */ |
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| 28 | |
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| 29 | #include <float.h> |
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| 30 | #include <math.h> |
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| 31 | #include <math_private.h> |
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| 32 | #include <libm-alias-ldouble.h> |
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| 33 | |
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| 34 | static const long double |
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| 35 | #if LDBL_MANT_DIG == 64 |
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| 36 | two65 = 3.68934881474191032320e+19L; /* 0x4040, 0x80000000, 0x00000000 */ |
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| 37 | #else |
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| 38 | # error "Cannot handle this MANT_DIG" |
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| 39 | #endif |
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| 40 | |
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| 41 | |
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| 42 | long double __frexpl(long double x, int *eptr) |
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| 43 | { |
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| 44 | uint32_t se, hx, ix, lx; |
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| 45 | GET_LDOUBLE_WORDS(se,hx,lx,x); |
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| 46 | ix = 0x7fff&se; |
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| 47 | *eptr = 0; |
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| 48 | if(ix==0x7fff||((ix|hx|lx)==0)) return x + x; /* 0,inf,nan */ |
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| 49 | if (ix==0x0000) { /* subnormal */ |
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| 50 | x *= two65; |
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| 51 | GET_LDOUBLE_EXP(se,x); |
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| 52 | ix = se&0x7fff; |
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| 53 | *eptr = -65; |
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| 54 | } |
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| 55 | *eptr += ix-16382; |
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| 56 | se = (se & 0x8000) | 0x3ffe; |
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| 57 | SET_LDOUBLE_EXP(x,se); |
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| 58 | return x; |
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| 59 | } |
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| 60 | libm_alias_ldouble (__frexp, frexp) |
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| 61 | |
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