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As noted in bug 6803, scalbn fails to set errno on overflow and underflow. This patch fixes this by making scalbn an alias of ldexp, which has exactly the same semantics (for floating-point types with radix 2) and already has wrappers that deal with setting errno, instead of an alias of the internal __scalbn (which ldexp calls). Notes: * Where compat symbols were defined for scalbn functions, I didn't change what they point to (to keep the patch minimal), so such compat symbols continue to go directly to the non-errno-setting functions. * Mike, I didn't do anything with the IA64 versions of these functions, where I think both the ldexp and scalbn functions already deal with setting errno. As a cleanup (not needed to fix this bug) however you might want to make those functions into aliases for IA64; there is no need for them to be separate function implementations at all. * This concludes the fix for bug 6803 since the scalb and scalbln cases of that bug were fixed some time ago. Tested for x86_64, x86, mips64 and powerpc. [BZ #6803] * math/s_ldexp.c (scalbn): Define as weak alias of __ldexp. [NO_LONG_DOUBLE] (scalbnl): Define as weak alias of __ldexp. * math/s_ldexpf.c (scalbnf): Define as weak alias of __ldexpf. * math/s_ldexpl.c (scalbnl): Define as weak alias of __ldexpl. * sysdeps/i386/fpu/s_scalbn.S (scalbn): Remove alias. * sysdeps/i386/fpu/s_scalbnf.S (scalbnf): Likewise. * sysdeps/i386/fpu/s_scalbnl.S (scalbnl): Likewise. * sysdeps/ieee754/dbl-64/s_scalbn.c (scalbn): Likewise. [NO_LONG_DOUBLE] (scalbnl): Likewise. * sysdeps/ieee754/dbl-64/wordsize-64/s_scalbn.c (scalbn): Likewise. [NO_LONG_DOUBLE] (scalbnl): Likewise. * sysdeps/ieee754/flt-32/s_scalbnf.c (scalbnf): Likewise. * sysdeps/ieee754/ldbl-128/s_scalbnl.c (scalbnl): Likewise. * sysdeps/ieee754/ldbl-128ibm/s_scalbnl.c (scalbnl): Remove long_double_symbol calls. * sysdeps/ieee754/ldbl-64-128/s_scalbnl.c (scalbnl): Likewise. * sysdeps/ieee754/ldbl-opt/s_ldexpl.c (__ldexpl_2): Define as strong alias of __ldexpl. (scalbnl): Define using long_double_symbol. * sysdeps/m68k/m680x0/fpu/s_scalbn.c (__CONCATX(scalbn,suffix)): Remove alias. * sysdeps/sparc/sparc64/soft-fp/s_scalbnl.c (scalbnl): Likewise. * sysdeps/x86_64/fpu/s_scalbnl.S (scalbnl): Likewise. * math/libm-test.inc (scalbn_test_data): Add errno expectations. (scalbln_test_data): Add more errno expectations.
53 lines
1.4 KiB
C
53 lines
1.4 KiB
C
/* Software floating-point emulation.
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scalbnl(x, exp)
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Copyright (C) 1999-2015 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Jakub Jelinek (jj@ultra.linux.cz).
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/*
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* scalbnl (long double x, int n)
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* scalbnl(x,n) returns x* 2**n computed by exponent
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* manipulation rather than by actually performing an
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* exponentiation or a multiplication.
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*/
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#include "soft-fp.h"
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#include "quad.h"
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long double __scalbnl(long double arg, int exp)
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{
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FP_DECL_EX;
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FP_DECL_Q(A);
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long double r;
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FP_UNPACK_Q(A, arg);
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switch (A_c)
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{
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case FP_CLS_ZERO:
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return arg;
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case FP_CLS_NAN:
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case FP_CLS_INF:
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FP_HANDLE_EXCEPTIONS;
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return arg;
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}
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A_e += exp;
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FP_PACK_Q(r, A);
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FP_HANDLE_EXCEPTIONS;
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return r;
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}
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