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"
(
87b9b50f0d4b92248905e95a06a13c513dc45e59) 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.
+2015-08-26 Stefan Liebler <stli@linux.vnet.ibm.com>
+
+ [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.
+
2015-08-25 Roland McGrath <roland@hack.frob.com>
* sysdeps/nacl/start.c (_start): Call __nacl_main instead of main
typedef struct
{
fexcept_t __fpc;
- void *__ieee_instruction_pointer;
- /* failing instruction for ieee exceptions */
+ void *__unused;
+ /* The field __unused (formerly __ieee_instruction_pointer) is a relict from
+ commit "Remove PTRACE_PEEKUSER" (87b9b50f0d4b92248905e95a06a13c513dc45e59)
+ and isn´t used anymore. */
} fenv_t;
/* If the default argument is used we use this value. */
_FPU_GETCW (temp);
/* Clear the relevant bits. */
- temp &= ~((excepts << FPC_DXC_SHIFT)|(excepts << FPC_FLAGS_SHIFT));
+ temp &= ~(excepts << FPC_FLAGS_SHIFT);
+ if ((temp & FPC_NOT_FPU_EXCEPTION) == 0)
+ /* Bits 6, 7 of dxc-byte are zero,
+ thus bits 0-5 of dxc-byte correspond to the flag-bits.
+ Clear the relevant bits in flags and dxc-field. */
+ temp &= ~(excepts << FPC_DXC_SHIFT);
/* Put the new data in effect. */
_FPU_SETCW (temp);
if (envp == FE_DFL_ENV)
{
env.__fpc = _FPU_DEFAULT;
- env.__ieee_instruction_pointer = 0;
}
else if (envp == FE_NOMASK_ENV)
{
env.__fpc = FPC_EXCEPTION_MASK;
- env.__ieee_instruction_pointer = 0;
}
else
env = (*envp);
/* Get the current exceptions. */
_FPU_GETCW (temp);
- newexcepts = (excepts << FPC_DXC_SHIFT) | (excepts << FPC_FLAGS_SHIFT);
+ newexcepts = excepts << FPC_FLAGS_SHIFT;
+ if ((temp & FPC_NOT_FPU_EXCEPTION) == 0)
+ /* Bits 6, 7 of dxc-byte are zero,
+ thus bits 0-5 of dxc-byte correspond to the flag-bits.
+ Evaluate flags and last dxc-exception-code. */
+ newexcepts |= excepts << FPC_DXC_SHIFT;
+
*flagp = temp & newexcepts;
/* Success. */
<http://www.gnu.org/licenses/>. */
#ifndef _FPU_CONTROL_H
-# define _FPU_CONTROL_H
+#define _FPU_CONTROL_H
-# include <features.h>
+#include <features.h>
/* These bits are reserved are not changed. */
-# define _FPU_RESERVED 0x070700FC
+#define _FPU_RESERVED 0x0707FFFC
/* The fdlibm code requires no interrupts for exceptions. Don't
change the rounding mode, it would break long double I/O! */
int
fesetexceptflag (const fexcept_t *flagp, int excepts)
{
- fexcept_t temp,newexcepts;
+ fexcept_t temp, newexcepts;
/* Get the current environment. We have to do this since we cannot
separately set the status word. */
_FPU_GETCW (temp);
/* Install the new exception bits in the Accrued Exception Byte. */
excepts = excepts & FE_ALL_EXCEPT;
- newexcepts = (excepts << FPC_DXC_SHIFT) | (excepts << FPC_FLAGS_SHIFT);
+ newexcepts = excepts << FPC_FLAGS_SHIFT;
temp &= ~newexcepts;
- temp |= *flagp & newexcepts;
+ if ((temp & FPC_NOT_FPU_EXCEPTION) == 0)
+ /* Bits 6, 7 of dxc-byte are zero,
+ thus bits 0-5 of dxc-byte correspond to the flag-bits.
+ Clear given exceptions in dxc-field. */
+ temp &= ~(excepts << FPC_DXC_SHIFT);
+
+ /* Integrate dxc-byte of flagp into flags. The dxc-byte of flagp contains
+ either an ieee-exception or 0 (see fegetexceptflag). */
+ temp |= (*flagp | ((*flagp >> FPC_DXC_SHIFT) << FPC_FLAGS_SHIFT))
+ & newexcepts;
/* Store the new status word (along with the rest of the environment.
Possibly new exceptions are set but they won't get executed unless
int
fetestexcept (int excepts)
{
- fexcept_t temp;
+ fexcept_t temp, res;
/* Get current exceptions. */
_FPU_GETCW (temp);
- temp = (temp >> FPC_DXC_SHIFT) | (temp >> FPC_FLAGS_SHIFT);
- return temp & excepts & FE_ALL_EXCEPT;
+ res = temp >> FPC_FLAGS_SHIFT;
+ if ((temp & FPC_NOT_FPU_EXCEPTION) == 0)
+ /* Bits 6, 7 of dxc-byte are zero,
+ thus bits 0-5 of dxc-byte correspond to the flag-bits.
+ Evaluate flags and last dxc-exception-code. */
+ res |= temp >> FPC_DXC_SHIFT;
+
+ return res & excepts & FE_ALL_EXCEPT;
}
libm_hidden_def (fetestexcept)
git://sourceware.org / glibc.git / commitdiff