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target-arm: Don't check for "Thumb2 or M profile" for not-Thumb1

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The code which implements the Thumb1 split BL/BLX instructions
is guarded by a check on "not M or THUMB2". All we really need
to check here is "not THUMB2" (and we assume that elsewhere too,
eg in the ARCH(6T2) test that UNDEFs the Thumb2 insns).

This doesn't change behaviour because all M profile cores
have Thumb2 and so ARM_FEATURE_M implies ARM_FEATURE_THUMB2.
(v6M implements a very restricted subset of Thumb2, but we
can cross that bridge when we get to it with appropriate
feature bits.)

Backports commit 6b8acf256df09c8a8dd7dcaa79b06eaff4ad63f7 from qemu
This commit is contained in:
Peter Maydell 2018-03-05 03:34:46 -05:00 committed by Lioncash
parent ee9b8a20c9
commit b85d617bda
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GPG key ID: 4E3C3CC1031BA9C7
1 changed files with 1 additions and 2 deletions
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3
qemu/target/arm/translate.c
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@ -9902,8 +9902,7 @@ static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw
int conds;
int logic_cc;
if (!(arm_dc_feature(s, ARM_FEATURE_THUMB2)
|| arm_dc_feature(s, ARM_FEATURE_M))) {
if (!arm_dc_feature(s, ARM_FEATURE_THUMB2)) {
/* Thumb-1 cores may need to treat bl and blx as a pair of
16-bit instructions to get correct prefetch abort behavior. */
insn = insn_hw1;