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On s390 feraiseexcept (FE_OVERFLOW|FE_UNDERFLOW) sets FE_INEXACT, too. This patch uses z196 zarch load rounded instruction which can suppress FE_INEXACT exception if gcc has z196 support in used configuration. Otherwise FE_INEXACT flag is set as before. The gcc support is tested in a new configure-check. A comment in fsetexcptflg.c is corrected as new exceptions are not executed with the next floating-point instruction if fpc is set with _FPU_SETCW macro. It seems the comment was copied e.g. from sysdeps/x86_64/fpu/fsetexcptflg.c file. ChangeLog: * config.h.in (HAVE_S390_MIN_Z196_ZARCH_ASM_SUPPORT): New undefine. * sysdeps/s390/configure.ac: Add test for z196 zarch support. * sysdeps/s390/configure: Regenerated. * sysdeps/s390/fpu/fraiseexcpt.c (__feraiseexcept): Use ledbra instruction for raising over-/underflow if z196 zarch is supported by default. * sysdeps/s390/fpu/fsetexcptflg.c (fesetexceptflag): Correct comment.
54 lines
2.0 KiB
C
54 lines
2.0 KiB
C
/* Set floating-point environment exception handling.
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Copyright (C) 2000-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Denis Joseph Barrow (djbarrow@de.ibm.com).
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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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#include <fenv_libc.h>
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#include <math.h>
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#include <fpu_control.h>
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int
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fesetexceptflag (const fexcept_t *flagp, int excepts)
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{
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fexcept_t temp, newexcepts;
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/* Get the current environment. We have to do this since we cannot
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separately set the status word. */
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_FPU_GETCW (temp);
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/* Install the new exception bits in the Accrued Exception Byte. */
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excepts = excepts & FE_ALL_EXCEPT;
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newexcepts = excepts << FPC_FLAGS_SHIFT;
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temp &= ~newexcepts;
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if ((temp & FPC_NOT_FPU_EXCEPTION) == 0)
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/* Bits 6, 7 of dxc-byte are zero,
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thus bits 0-5 of dxc-byte correspond to the flag-bits.
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Clear given exceptions in dxc-field. */
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temp &= ~(excepts << FPC_DXC_SHIFT);
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/* Integrate dxc-byte of flagp into flags. The dxc-byte of flagp contains
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either an ieee-exception or 0 (see fegetexceptflag). */
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temp |= (*flagp | ((*flagp >> FPC_DXC_SHIFT) << FPC_FLAGS_SHIFT))
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& newexcepts;
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/* Store the new status word (along with the rest of the environment.
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Possibly new exceptions are set but they won't get executed. */
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_FPU_SETCW (temp);
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/* Success. */
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return 0;
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}
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