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target-arm: A64: Avoid left shifting negative integers in disas_pc_rel_addr

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Shifting a negative integer left is undefined behaviour in C.
Avoid it by assembling and shifting the offset fields as
unsigned values and then sign extending as the final action.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1423233250-15853-4-git-send-email-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2015-02-13 05:46:09 +00:00
parent e167adc9d9
commit 037e1d009e
1 changed files with 3 additions and 2 deletions
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5
target-arm/translate-a64.c
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@ -2662,11 +2662,12 @@ static void disas_pc_rel_adr(DisasContext *s, uint32_t insn)
{ {
unsigned int page, rd; unsigned int page, rd;
uint64_t base; uint64_t base;
int64_t offset; uint64_t offset;
page = extract32(insn, 31, 1); page = extract32(insn, 31, 1);
/* SignExtend(immhi:immlo) -> offset */ /* SignExtend(immhi:immlo) -> offset */
offset = ((int64_t)sextract32(insn, 5, 19) << 2) | extract32(insn, 29, 2); offset = sextract64(insn, 5, 19);
offset = offset << 2 | extract32(insn, 29, 2);
rd = extract32(insn, 0, 5); rd = extract32(insn, 0, 5);
base = s->pc - 4; base = s->pc - 4;