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author | Rich Felker <dalias@aerifal.cx> | 2019-05-11 19:44:21 -0400 |
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committer | Rich Felker <dalias@aerifal.cx> | 2019-05-11 19:44:21 -0400 |
commit | bdb0817599325e6ca6838717dfe18290695a59a2 (patch) | |
tree | 9ec908dfc35ac48bef7bf19126147289a3561eb2 /src/unistd/mipsn32 | |
parent | c8798ef974d21c338a7d8d874a402978ffc6168e (diff) | |
download | musl-bdb0817599325e6ca6838717dfe18290695a59a2.tar.gz musl-bdb0817599325e6ca6838717dfe18290695a59a2.tar.xz musl-bdb0817599325e6ca6838717dfe18290695a59a2.zip |
improve i386 inline syscall asm on non-broken compilers
we have to avoid using ebx unconditionally in asm constraints for i386, because gcc 3 and 4 and possibly other simplistic compilers (pcc?) implement PIC via making ebx a fixed-use register, and disallow its use for anything else. rather than hard-coding knowledge of which compilers work (at least gcc 5+ and clang), perform a configure test; this should give us the good codegen on any new compilers we don't yet know about. swapping ebx and edx is kept for 1- and 2-arg syscalls because it avoids having any spills/stack-frame at all in small functions. for 6-arg, if ebx is directly usable, the complex shuffling introduced in commit c8798ef974d21c338a7d8d874a402978ffc6168e can be avoided, and ebp can be loaded the same way ebx is in 5-arg syscalls for compilers that don't support direct use of ebx.
Diffstat (limited to 'src/unistd/mipsn32')
0 files changed, 0 insertions, 0 deletions