Reserved bits in the Floating-Point Control and Status Register (FCSR)
should not be implicitly cleared by fedisableexcept or feenableexcept,
there is no reason to. Among these are the 8 condition codes and one of
the two bits reserved for architecture implementers (bits #22 & #21).
As to the latter, there is no reason to treat any of them as reserved
either, they should be user controllable and settable via __fpu_control
override as the user sees fit. For example in processors implemented by
MIPS Technologies, such as the 5Kf or the 24Kf, these bits are used to
change the treatment of denormalised operands and tiny results: bit #22
is Flush Override (FO) and bit #21 is Flush to Nearest (FN). They cause
non-IEEE-compliant behaviour, but some programs may have a use for such
modes of operation; the library should not obstruct such use just as it
does not for the architectural Flush to Zero (FS) bit (bit #24).
Therefore the change adjusts the reserved mask accordingly and also
documents the distinction between bits 22:21 and 20:18.
Resolves: #15465
The program name may be unavailable if the user application tampers
with argc and argv[]. Some parts of the dynamic linker caters for
this while others don't, so this patch consolidates the check and
fallback into a single macro and updates all users.
[BZ #15442] This adds support for the inverse interpretation of the
quiet bit of IEEE 754 floating-point NaN data that some processors
use. This includes in particular MIPS architecture processors; the
payload used for the canonical qNaN encoding is updated accordingly
so as not to interfere with the quiet bit.
We've been carrying this in Gentoo for quite a long time to fix some test
failures that people hit.
Original message:
> make[4]: *** [/glibc/glibc-package-2.3/mips-linux/obj/math/test-fpucw.out] Error 1
This test fails since the read back fpu control word is 0x80000 instead
of 0x0. I wonder if this patch is correct:
...
which additionally masks out the condition bit 23 - note that the other
condition bits (25-31) are masked out too?
URL: http://sourceware.org/ml/libc-alpha/2002-10/msg00392.html
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
The original runtime linker auditing interface described
by Solaris allows the 5th argument of la_pltenter() to be
modified. This patch cleans up the ldsodefs.h definitions
such that the 5th argument is not constant.
At one point the 5th argument *was* constant but this was
changed with commit 2413fdba7a.
This patch updates alpha, ia64, mips, sh and sparc with similar
changes.
