From eb59e961ae05048ea30362aafb7f91db26ceb939 Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Wed, 17 Feb 2016 16:56:05 +0100 Subject: Improve cmpxchg8b/cmpxchg16b inline asm Clang didn't like that ecx/rcx was mapped to input and output variables of different types. --- erts/include/internal/i386/ethr_dw_atomic.h | 57 +++++++++++++++++++---------- 1 file changed, 37 insertions(+), 20 deletions(-) (limited to 'erts/include') diff --git a/erts/include/internal/i386/ethr_dw_atomic.h b/erts/include/internal/i386/ethr_dw_atomic.h index 79de5d80da..5444a6345c 100644 --- a/erts/include/internal/i386/ethr_dw_atomic.h +++ b/erts/include/internal/i386/ethr_dw_atomic.h @@ -157,36 +157,53 @@ ethr_native_dw_atomic_cmpxchg_mb(ethr_native_dw_atomic_t *var, ETHR_DW_DBG_ALIGNED__(p); +#if ETHR_NO_CLOBBER_EBX__ && ETHR_CMPXCHG8B_REGISTER_SHORTAGE + /* + * gcc wont let us use ebx as input and we + * get a register shortage + */ + __asm__ __volatile__( -#if ETHR_NO_CLOBBER_EBX__ "pushl %%ebx\n\t" -# if ETHR_CMPXCHG8B_REGISTER_SHORTAGE "movl (%7), %%ebx\n\t" "movl 4(%7), %%ecx\n\t" -# else - "movl %8, %%ebx\n\t" -# endif -#endif - "lock; cmpxchg" ETHR_DW_CMPXCHG_SFX__ " %0\n\t" + "lock; cmpxchg8b %0\n\t" "setz %3\n\t" -#if ETHR_NO_CLOBBER_EBX__ "popl %%ebx\n\t" -#endif : "=m"(*p), "=d"(xchg[1]), "=a"(xchg[0]), "=c"(xchgd) - : "m"(*p), "1"(xchg[1]), "2"(xchg[0]), -#if ETHR_NO_CLOBBER_EBX__ -# if ETHR_CMPXCHG8B_REGISTER_SHORTAGE - "3"(new) -# else - "3"(new[1]), - "r"(new[0]) -# endif + : "m"(*p), "1"(xchg[1]), "2"(xchg[0]), "r"(new) + : "cc", "memory"); + +#elif ETHR_NO_CLOBBER_EBX__ + /* + * gcc wont let us use ebx as input + */ + + __asm__ __volatile__( + "pushl %%ebx\n\t" + "movl %8, %%ebx\n\t" + "lock; cmpxchg8b %0\n\t" + "setz %3\n\t" + "popl %%ebx\n\t" + : "=m"(*p), "=d"(xchg[1]), "=a"(xchg[0]), "=q"(xchgd) + : "m"(*p), "1"(xchg[1]), "2"(xchg[0]), "c"(new[1]), "r"(new[0]) + : "cc", "memory"); + #else - "3"(new[1]), - "b"(new[0]) -#endif + /* + * gcc lets us place values in the registers where + * we want them + */ + + __asm__ __volatile__( + "lock; cmpxchg" ETHR_DW_CMPXCHG_SFX__ " %0\n\t" + "setz %3\n\t" + : "=m"(*p), "=d"(xchg[1]), "=a"(xchg[0]), "=q"(xchgd) + : "m"(*p), "1"(xchg[1]), "2"(xchg[0]), "c"(new[1]), "b"(new[0]) : "cc", "memory"); +#endif + return (int) xchgd; } -- cgit v1.2.3