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On s390, the DXC(data-exception-code)-byte in FPC(floating-point-control)-
register contains a code of the last occured exception.
If bits 6 and 7 of DXC-byte are zero, the bits 0-5 correspond to the
ieee-exception flag bits.
The current implementation always uses these bits as ieee-exception flag bits.
fetestexcept() reports any exception after the first usage of a
vector-instruction in a process, because it raises an "vector instruction
exception" with DXC-code 0xFE.
This patch fixes the handling of the DXC-byte. The DXC-Byte is only handled
if bits 6 and 7 are zero.
The #define _FPU_RESERVED is extended by the DXC-Byte.
Otherwise the tests math/test-fpucw-static and math/test-fpucw-ieee-static
fails, because DXC-Byte contains the vector instruction exception when reaching
main(). This exception was triggered by strrchr() call in __init_misc().
__init_misc() is called after __setfpucw () in __libc_init_first().
The field __ieee_instruction_pointer in struct fenv_t is renamed to __unused
because it is a relict from commit "Remove PTRACE_PEEKUSER"
(87b9b50f0d) and isn´t used anymore.
ChangeLog:
[BZ #18610]
* sysdeps/s390/fpu/bits/fenv.h (fenv_t): Rename
__ieee_instruction_pointer to __unused.
* sysdeps/s390/fpu/fesetenv.c (__fesetenv): Remove usage of
__ieee_instruction_pointer.
* sysdeps/s390/fpu/fclrexcpt.c (feclearexcept): Fix dxc-field handling.
* sysdeps/s390/fpu/fgetexcptflg.c (fegetexceptflag): Likewise.
* sysdeps/s390/fpu/fsetexcptflg.c (fesetexceptflag): Likewise.
* sysdeps/s390/fpu/ftestexcept.c (fetestexcept): Likewise.
* sysdeps/s390/fpu/fpu_control.h (_FPU_RESERVED):
Mark dxc-field as reserved.
44 lines
1.6 KiB
C
44 lines
1.6 KiB
C
/* FPU control word definitions. Stub version.
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Copyright (C) 2000-2015 Free Software Foundation, Inc.
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Contributed by Denis Joseph Barrow (djbarrow@de.ibm.com) and
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Martin Schwidefsky (schwidefsky@de.ibm.com).
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This file is part of the GNU C Library.
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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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#ifndef _FPU_CONTROL_H
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#define _FPU_CONTROL_H
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#include <features.h>
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/* These bits are reserved are not changed. */
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#define _FPU_RESERVED 0x0707FFFC
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/* The fdlibm code requires no interrupts for exceptions. Don't
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change the rounding mode, it would break long double I/O! */
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#define _FPU_DEFAULT 0x00000000 /* Default value. */
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/* Type of the control word. */
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typedef unsigned int fpu_control_t;
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/* Macros for accessing the hardware control word. */
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#define _FPU_GETCW(cw) __asm__ volatile ("efpc %0,0" : "=d" (cw))
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#define _FPU_SETCW(cw) __asm__ volatile ("sfpc %0,0" : : "d" (cw))
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/* Default control word set at startup. */
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extern fpu_control_t __fpu_control;
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#endif /* _FPU_CONTROL_H */
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