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Add needed volatile qualifications.

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Add volatile qualifications to two blocks of inline asm to stop GCC from
eliminating them as dead code.
This commit is contained in:
Adam Langley 2014-06-20 12:00:00 -07:00
parent 4d4bff89bb
commit ebebf87d6d
1 changed files with 6 additions and 4 deletions
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10
crypto/bn/asm/x86_64-gcc.c
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@ -191,7 +191,8 @@ BN_ULONG bn_add_words(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
if (n <= 0)
return 0;
asm(" subq %0,%0 \n" /* clear carry */
asm volatile (
" subq %0,%0 \n" /* clear carry */
" jmp 1f \n"
".p2align 4 \n"
"1: movq (%4,%2,8),%0 \n"
@ -202,7 +203,7 @@ BN_ULONG bn_add_words(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
" sbbq %0,%0 \n"
: "=&r"(ret), "+c"(n), "+r"(i)
: "r"(rp), "r"(ap), "r"(bp)
: "cc");
: "cc", "memory");
return ret & 1;
}
@ -216,7 +217,8 @@ BN_ULONG bn_sub_words(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
if (n <= 0)
return 0;
asm(" subq %0,%0 \n" /* clear borrow */
asm volatile (
" subq %0,%0 \n" /* clear borrow */
" jmp 1f \n"
".p2align 4 \n"
"1: movq (%4,%2,8),%0 \n"
@ -227,7 +229,7 @@ BN_ULONG bn_sub_words(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
" sbbq %0,%0 \n"
: "=&r"(ret), "+c"(n), "+r"(i)
: "r"(rp), "r"(ap), "r"(bp)
: "cc");
: "cc", "memory");
return ret & 1;
}