This one needs the same fix for x86_64 and i386 as the fsetenv() function.
2023-10-30 Bruno Haible <br...@clisp.org>
fenv-exceptions-state-c99: Fix the x86_64 and i386 case.
* lib/fenv-except-state-set.c (fesetexceptflag): Make sure to restore
the exception trap bits in all cases.
From 9c82dee623c1dca092d050d6e2289e9e7e07a687 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Mon, 30 Oct 2023 16:26:46 +0100
Subject: [PATCH 1/8] fenv-exceptions-state-c99: Fix the x86_64 and i386 case.
* lib/fenv-except-state-set.c (fesetexceptflag): Make sure to restore
the exception trap bits in all cases.
---
ChangeLog | 6 ++++++
lib/fenv-except-state-set.c | 27 ++++++++++++---------------
2 files changed, 18 insertions(+), 15 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index e0bf89a9e2..0476828c50 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2023-10-30 Bruno Haible <br...@clisp.org>
+
+ fenv-exceptions-state-c99: Fix the x86_64 and i386 case.
+ * lib/fenv-except-state-set.c (fesetexceptflag): Make sure to restore
+ the exception trap bits in all cases.
+
2023-10-30 Bruno Haible <br...@clisp.org>
fenv-exceptions-state-c23: Add tests.
diff --git a/lib/fenv-except-state-set.c b/lib/fenv-except-state-set.c
index 6ba4d63a7d..2035f61e27 100644
--- a/lib/fenv-except-state-set.c
+++ b/lib/fenv-except-state-set.c
@@ -72,33 +72,30 @@ fesetexceptflag (fexcept_t const *saved_flags, int exceptions)
/* Modify the flags in the 387 unit, but only by clearing bits, not by
setting bits. */
x86_387_fenv_t env;
- unsigned short orig_status_word;
__asm__ __volatile__ ("fnstenv %0" : "=m" (*&env));
- orig_status_word = env.__status_word;
+ /* Note: fnstenv masks all floating-point exceptions until the fldenv
+ below. */
env.__status_word &= ~ (exceptions & ~desired_flags);
- if (env.__status_word != orig_status_word)
- __asm__ __volatile__ ("fldenv %0" : : "m" (*&env));
+ __asm__ __volatile__ ("fldenv %0" : : "m" (*&env));
}
# if !(defined __x86_64__ || defined _M_X64)
else
{
/* Modify the flags in the 387 unit. */
x86_387_fenv_t env;
- unsigned short orig_status_word;
__asm__ __volatile__ ("fnstenv %0" : "=m" (*&env));
- orig_status_word = env.__status_word;
+ /* Note: fnstenv masks all floating-point exceptions until the fldenv
+ or fldcw below. */
env.__status_word ^= ((env.__status_word ^ desired_flags) & exceptions);
- if (env.__status_word != orig_status_word)
+ if ((~env.__control_word) & env.__status_word & exceptions)
{
- if ((~env.__control_word) & env.__status_word & exceptions)
- {
- /* Setting the exception flags may trigger a trap (at the next
- floating-point instruction, but that does not matter).
- ISO C 23 § 7.6.4.5 does not allow it. */
- return -1;
- }
- __asm__ __volatile__ ("fldenv %0" : : "m" (*&env));
+ /* Setting the exception flags may trigger a trap (at the next
+ floating-point instruction, but that does not matter).
+ ISO C 23 § 7.6.4.5 does not allow it. */
+ __asm__ __volatile__ ("fldcw %0" : : "m" (*&env.__control_word));
+ return -1;
}
+ __asm__ __volatile__ ("fldenv %0" : : "m" (*&env));
}
# endif
# endif
--
2.34.1
