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fpe: prevent spurious floating point exceptions in WITH_LISP_FPE

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feenableexcept may generate a SIGFPE signal if exception status flags
are not cleared beforehand. Happens for example on powerpc platforms.

Fixes #612.
This commit is contained in:
Marius Gerbershagen 2020-10-31 11:34:28 +01:00
parent 7f1813cd93
commit cdb602e40d
2 changed files with 3 additions and 4 deletions
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3
src/doc/manual/user-guide/embedding.txi
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@ -258,8 +258,7 @@ booting. This macro allows for execution of Lisp code while saving and
later restoring the floating point environment of surrounding C code later restoring the floating point environment of surrounding C code
so that changes in the floating point environment don't leak outside. so that changes in the floating point environment don't leak outside.
@coderef{ECL_WITH_LISP_FPE} can be also used before ECL has booted or @coderef{ECL_WITH_LISP_FPE} can be also used before ECL has booted.
before an external thread has been imported.
@exindex Safely executing Lisp code with floating point exceptions in embedding program @exindex Safely executing Lisp code with floating point exceptions in embedding program
@paragraph Example @paragraph Example

4
src/h/impl/math_fenv.h
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@ -75,12 +75,12 @@
# define ECL_WITH_LISP_FPE_BEGIN do { \ # define ECL_WITH_LISP_FPE_BEGIN do { \
fenv_t __fenv; \ fenv_t __fenv; \
fegetenv(&__fenv); \ fegetenv(&__fenv); \
feclearexcept(FE_ALL_EXCEPT); \
if (ecl_get_option(ECL_OPT_BOOTED) > 0) { \ if (ecl_get_option(ECL_OPT_BOOTED) > 0) { \
int bits = ecl_process_env()->trap_fpe_bits; \ int bits = ecl_process_env()->trap_fpe_bits; \
fedisableexcept(FE_ALL_EXCEPT & ~bits); \ fedisableexcept(FE_ALL_EXCEPT & ~bits); \
feenableexcept(FE_ALL_EXCEPT & bits); \ feenableexcept(FE_ALL_EXCEPT & bits); \
} \ }
feclearexcept(FE_ALL_EXCEPT);
# else # else
# define ECL_WITH_LISP_FPE_BEGIN do { \ # define ECL_WITH_LISP_FPE_BEGIN do { \
fenv_t __fenv; \ fenv_t __fenv; \