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876c5bd30c
C99 and C11 allow but do not require ceil, floor, round and trunc to raise the "inexact" exception for noninteger arguments. TS 18661-1 requires that this exception not be raised by these functions. This aligns them with general IEEE semantics, where "inexact" is only raised if the final step of rounding the infinite-precision result to the result type is inexact; for these functions, the infinite-precision integer result is always representable in the result type, so "inexact" should never be raised. The generic implementations of ceil, floor and round functions contain code to force "inexact" to be raised. This patch removes it for floor functions to align them with TS 18661-1 in this regard. Note that some architecture-specific versions may still raise "inexact", so the tests are not updated and the bug is not yet fixed. Tested for x86_64, x86 and mips64. [BZ #15479] * sysdeps/ieee754/dbl-64/s_floor.c: Do not mention "inexact" exception in comment. (huge): Remove variable. (__floor): Do not force "inexact" exception. * sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c: Do not mention "inexact" exception in comment. (huge): Remove variable. (__floor): Do not force "inexact" exception. * sysdeps/ieee754/flt-32/s_floorf.c: Do not mention "inexact" exception in comment. (huge): Remove variable. (__floorf): Do not force "inexact" exception. * sysdeps/ieee754/ldbl-128/s_floorl.c: Do not mention "inexact" exception in comment. (huge): Remove variable. (__floorl): Do not force "inexact" exception.
90 lines
1.8 KiB
C
90 lines
1.8 KiB
C
/* @(#)s_floor.c 5.1 93/09/24 */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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/*
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* floor(x)
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* Return x rounded toward -inf to integral value
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* Method:
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* Bit twiddling.
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*/
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#include <math.h>
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#include <math_private.h>
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double
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__floor (double x)
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{
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int32_t i0, i1, j0;
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u_int32_t i, j;
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EXTRACT_WORDS (i0, i1, x);
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j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
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if (j0 < 20)
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{
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if (j0 < 0)
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{
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/* return 0*sign(x) if |x|<1 */
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if (i0 >= 0)
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{
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i0 = i1 = 0;
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}
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else if (((i0 & 0x7fffffff) | i1) != 0)
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{
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i0 = 0xbff00000; i1 = 0;
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}
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}
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else
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{
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i = (0x000fffff) >> j0;
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if (((i0 & i) | i1) == 0)
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return x; /* x is integral */
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if (i0 < 0)
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i0 += (0x00100000) >> j0;
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i0 &= (~i); i1 = 0;
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}
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}
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else if (j0 > 51)
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{
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if (j0 == 0x400)
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return x + x; /* inf or NaN */
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else
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return x; /* x is integral */
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}
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else
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{
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i = ((u_int32_t) (0xffffffff)) >> (j0 - 20);
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if ((i1 & i) == 0)
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return x; /* x is integral */
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if (i0 < 0)
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{
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if (j0 == 20)
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i0 += 1;
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else
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{
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j = i1 + (1 << (52 - j0));
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if (j < i1)
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i0 += 1; /* got a carry */
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i1 = j;
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}
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}
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i1 &= (~i);
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}
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INSERT_WORDS (x, i0, i1);
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return x;
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}
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#ifndef __floor
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weak_alias (__floor, floor)
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# ifdef NO_LONG_DOUBLE
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strong_alias (__floor, __floorl)
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weak_alias (__floor, floorl)
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# endif
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#endif
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