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author | Sverker Eriksson <[email protected]> | 2016-02-24 17:55:04 +0100 |
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committer | Sverker Eriksson <[email protected]> | 2016-02-24 17:55:04 +0100 |
commit | 03743cd4193a2ca97f9b9a52a25e63f616e8fc07 (patch) | |
tree | 9c1f4094a2105ec4bf19dd0d16e76b598d0e608d /erts/include/internal/i386 | |
parent | 1b094d72ffc56069c72f17c7edd673dbbfe47e39 (diff) | |
parent | 35739bd06776f90526006486b3f4ab7e54f7f951 (diff) | |
download | otp-03743cd4193a2ca97f9b9a52a25e63f616e8fc07.tar.gz otp-03743cd4193a2ca97f9b9a52a25e63f616e8fc07.tar.bz2 otp-03743cd4193a2ca97f9b9a52a25e63f616e8fc07.zip |
Merge branch 'master' into sverk/master/halt-INT_MIN
Diffstat (limited to 'erts/include/internal/i386')
-rw-r--r-- | erts/include/internal/i386/ethr_dw_atomic.h | 73 |
1 files changed, 48 insertions, 25 deletions
diff --git a/erts/include/internal/i386/ethr_dw_atomic.h b/erts/include/internal/i386/ethr_dw_atomic.h index e8c4119ef0..5444a6345c 100644 --- a/erts/include/internal/i386/ethr_dw_atomic.h +++ b/erts/include/internal/i386/ethr_dw_atomic.h @@ -115,13 +115,19 @@ ethr_native_dw_atomic_addr(ethr_native_dw_atomic_t *var) return (ethr_sint_t *) ETHR_DW_NATMC_MEM__(var); } -#if ETHR_SIZEOF_PTR == 4 && defined(__PIC__) && __PIC__ +#if defined(ETHR_CMPXCHG8B_PIC_NO_CLOBBER_EBX) && defined(__PIC__) && __PIC__ +#if ETHR_SIZEOF_PTR != 4 +# error unexpected pic issue +#endif /* * When position independent code is used in 32-bit mode, the EBX register - * is used for storage of global offset table address, and we may not - * use it as input or output in an asm. We need to save and restore the - * EBX register explicitly (for some reason gcc doesn't provide this - * service to us). + * is used for storage of global offset table address. When compiling with + * an old gcc (< vsn 5) we may not use it as input or output in an inline + * asm. We then need to save and restore the EBX register explicitly (for + * some reason old gcc compilers didn't provide this service to us). + * ETHR_CMPXCHG8B_PIC_NO_CLOBBER_EBX will be defined if we need to + * explicitly manage EBX ourselves. + * */ # define ETHR_NO_CLOBBER_EBX__ 1 #else @@ -151,36 +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; } |