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[Qemu-devel] [PATCH 3/4] target-arm: A64: Avoid left shifting negative i
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH 3/4] target-arm: A64: Avoid left shifting negative integers in disas_pc_rel_addr |
Date: |
Fri, 6 Feb 2015 14:34:09 +0000 |
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 <address@hidden>
---
target-arm/translate-a64.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
index 94b3bf4..68c5b23 100644
--- a/target-arm/translate-a64.c
+++ b/target-arm/translate-a64.c
@@ -2662,11 +2662,12 @@ static void disas_pc_rel_adr(DisasContext *s, uint32_t
insn)
{
unsigned int page, rd;
uint64_t base;
- int64_t offset;
+ uint64_t offset;
page = extract32(insn, 31, 1);
/* 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);
base = s->pc - 4;
--
1.9.1
- [Qemu-devel] [PATCH 0/4] target-arm: fix various clang UB sanitizer warnings, Peter Maydell, 2015/02/06
- [Qemu-devel] [PATCH 4/4] target-arm: A64: Avoid signed shifts in disas_ldst_pair(), Peter Maydell, 2015/02/06
- [Qemu-devel] [PATCH 2/4] target-arm: A64: Fix handling of rotate in logic_imm_decode_wmask, Peter Maydell, 2015/02/06
- [Qemu-devel] [PATCH 1/4] target-arm: A64: Fix shifts into sign bit, Peter Maydell, 2015/02/06
- [Qemu-devel] [PATCH 3/4] target-arm: A64: Avoid left shifting negative integers in disas_pc_rel_addr,
Peter Maydell <=
- Re: [Qemu-devel] [PATCH 0/4] target-arm: fix various clang UB sanitizer warnings, Greg Bellows, 2015/02/06
- Re: [Qemu-devel] [PATCH 0/4] target-arm: fix various clang UB sanitizer warnings, Richard Henderson, 2015/02/06
- Re: [Qemu-devel] [PATCH 0/4] target-arm: fix various clang UB sanitizer warnings, Eric Blake, 2015/02/06