In sequence:
---
lock negl -0x14(%rbp)
pushf
pop %rax
---
%rax will obtain the wrong value becasue the "lock neg" caculates the
wrong eflags. The "s->T0" is updated by the wrong value.
You can use this to do some test:
---
#include <assert.h>
int main()
{
__volatile__ unsigned test = 0x2363a;
__volatile__ char cond = 0;
asm(
"lock negl %0 \n\t"
"sets %1"
: "=m"(test), "=r"(cond)
:
:);
assert(cond & 1);
return 0;
}
---
Reported-by: Jinyang Shen <shenjinyang@loongson.cn>
Co-Developed-by: Xuehai Chen <chenxuehai@loongson.cn>
Signed-off-by: Xuehai Chen <chenxuehai@loongson.cn>
Signed-off-by: Qi Hu <huqi@loongson.cn>
---
V1 -> V2:
Following Richard's suggestion, just change mov to neg instead of using
local_tmp.
---
target/i386/tcg/translate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)