| Message ID | 1507556919-24992-6-git-send-email-peter.maydell@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | v8M: BLXNS, SG, secure function return | expand |
On 10/09/2017 06:48 AM, Peter Maydell wrote: > 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.) > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > target/arm/translate.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
diff --git a/target/arm/translate.c b/target/arm/translate.c index 58d706c..f5ca87f 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -9722,8 +9722,7 @@ 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;
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.) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- target/arm/translate.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) -- 2.7.4