diff options
author | Rich Felker <dalias@aerifal.cx> | 2012-12-05 12:52:40 -0500 |
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committer | Rich Felker <dalias@aerifal.cx> | 2012-12-05 12:52:40 -0500 |
commit | b088f85582d8787911ef48449574bed4131b44a2 (patch) | |
tree | 24ff727622ed97f3467e4384a4fdba670745e6ba /src | |
parent | 91b05889098c65425920b4c3bcd0712b73ea97eb (diff) | |
download | musl-b088f85582d8787911ef48449574bed4131b44a2.tar.gz |
remove mips setjmp/longjmp code to save/restore fenv
nothing in the standard requires or even allows the fenv state to be
restored by longjmp. restoring the exception flags is not such a big
deal since it's probably valid to clobber them completely, but
restoring the rounding mode yields an observable side effect not
sanctioned by ISO C. saving/restoring it also wastes a few cycles and
16 bytes of code.
as for historical behavior, reportedly SGI IRIX did save/restore fenv,
and this is where glibc and uClibc got the behavior from. a few other
systems save/restore it too (on archs other than mips), even though
this is apparently wrong. further details are documented here:
http://www-personal.umich.edu/~williams/archive/computation/setjmp-fpmode.html
as musl aims for standards conformance rather than coddling historical
programs expecting non-conforming behavior, and as it's unlikely that
any historical programs actually depend on the incorrect behavior
(such programs would break on other archs, anyway), I'm making the
change not to save/restore fenv on mips.
Diffstat (limited to 'src')
-rw-r--r-- | src/setjmp/mips/longjmp.s | 4 | ||||
-rw-r--r-- | src/setjmp/mips/setjmp.s | 2 |
2 files changed, 1 insertions, 5 deletions
diff --git a/src/setjmp/mips/longjmp.s b/src/setjmp/mips/longjmp.s index fc8e7260..a972d677 100644 --- a/src/setjmp/mips/longjmp.s +++ b/src/setjmp/mips/longjmp.s @@ -10,9 +10,7 @@ longjmp: bne $2, $0, 1f nop addu $2, $2, 1 -1: lw $8, 48($4) - ctc1 $8, $31 - lwc1 $20, 56($4) +1: lwc1 $20, 56($4) lwc1 $21, 60($4) lwc1 $22, 64($4) lwc1 $23, 68($4) diff --git a/src/setjmp/mips/setjmp.s b/src/setjmp/mips/setjmp.s index 1b79525f..53d702a9 100644 --- a/src/setjmp/mips/setjmp.s +++ b/src/setjmp/mips/setjmp.s @@ -21,8 +21,6 @@ setjmp: sw $23, 36($4) sw $30, 40($4) sw $28, 44($4) - cfc1 $8, $31 - sw $8, 48($4) swc1 $20, 56($4) swc1 $21, 60($4) swc1 $22, 64($4) |