diff options
| author | Paul Davis <paul@linuxaudiosystems.com> | 2009-12-31 18:20:13 +0000 |
|---|---|---|
| committer | Paul Davis <paul@linuxaudiosystems.com> | 2009-12-31 18:20:13 +0000 |
| commit | 87127bae2d1a1066a5b9650890babbbb62ab397b (patch) | |
| tree | 49b3452048c9392680a11ffdba4bbd6b855baf85 | |
| parent | 05f68565cc5513223937eae620d9c7d676eff854 (diff) | |
un-fix register clobber for gcc on x86 and update comments on register clobbering
git-svn-id: svn://localhost/ardour2/branches/2.0-ongoing@6424 d708f5d6-7413-0410-9779-e7cbd77b26cf
| -rw-r--r-- | libs/pbd/fpu.cc | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/libs/pbd/fpu.cc b/libs/pbd/fpu.cc index a55166b139..954f9b39e0 100644 --- a/libs/pbd/fpu.cc +++ b/libs/pbd/fpu.cc @@ -21,12 +21,6 @@ FPU::FPU () #else - /* asm notes: although we explicitly save&restore ebx/rbx (stack pointer), we must tell - gcc that ebx,rbx is clobbered so that it doesn't try to use it as an intermediate - register when storing edx/rdx. gcc 4.3 didn't make this "mistake", but gcc 4.4 - does, at least on x86_64. - */ - #ifndef USE_X86_64_ASM asm volatile ( "mov $1, %%eax\n" @@ -36,11 +30,17 @@ FPU::FPU () "popl %%ebx\n" : "=r" (cpuflags) : - : "%eax", "%ebx", "%ecx", "%edx" + : "%eax", "%ecx", "%edx" ); #else + /* asm notes: although we explicitly save&restore rbx, we must tell + gcc that ebx,rbx is clobbered so that it doesn't try to use it as an intermediate + register when storing rbx. gcc 4.3 didn't make this "mistake", but gcc 4.4 + does, at least on x86_64. + */ + asm volatile ( "pushq %%rbx\n" "movq $1, %%rax\n" |