diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/atomic/x86-gcc.h | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/include/atomic/x86-gcc.h b/include/atomic/x86-gcc.h index 8baa84e110e..90602ef900c 100644 --- a/include/atomic/x86-gcc.h +++ b/include/atomic/x86-gcc.h @@ -111,9 +111,9 @@ On some platforms (e.g. Mac OS X and Solaris) the ebx register is held as a pointer to the global offset table. Thus we're not allowed to use the b-register on those platforms when compiling - PIC code, to avoid this we push ebx and pop ebx and add a movl - instruction to avoid having ebx in the interface of the assembler - instruction. + PIC code, to avoid this we push ebx and pop ebx. The new value + is copied directly from memory to avoid problems with a implicit + manipulation of the stack pointer by the push. cmpxchg8b works on both 32-bit platforms and 64-bit platforms but the code here is only used on 32-bit platforms, on 64-bit @@ -121,11 +121,13 @@ fine. */ #define make_atomic_cas_body64 \ - int32 ebx=(set & 0xFFFFFFFF), ecx=(set >> 32); \ - asm volatile ("push %%ebx; movl %3, %%ebx;" \ - LOCK_prefix "; cmpxchg8b %0; setz %2; pop %%ebx" \ - : "=m" (*a), "+A" (*cmp), "=c" (ret) \ - : "m" (ebx), "c" (ecx), "m" (*a) \ + asm volatile ("push %%ebx;" \ + "movl (%%ecx), %%ebx;" \ + "movl 4(%%ecx), %%ecx;" \ + LOCK_prefix "; cmpxchg8b %0;" \ + "setz %2; pop %%ebx" \ + : "=m" (*a), "+A" (*cmp), "=c" (ret) \ + : "c" (&set), "m" (*a) \ : "memory", "esp") #endif |