On 09/22/2017 10:59 AM, Peter Maydell wrote: > + if ((env->regs[15] & 1) && !arm_feature(env, ARM_FEATURE_V8)) { > qemu_log_mask(LOG_GUEST_ERROR, > "M profile return from interrupt with misaligned " > - "PC is UNPREDICTABLE\n"); > - /* Actual hardware seems to ignore the lsbit, and there are > several > - * RTOSes out there which incorrectly assume the r15 in the stack > - * frame should be a Thumb-style "lsbit indicates ARM/Thumb" > value. > - */ > - env->regs[15] &= ~1U; > + "PC is UNPREDICTABLE on v7M\n"); > } > + env->regs[15] &= ~1U;
If you're going to always test regs[15] & 1, you might as well use that and avoid an unlikely(?) writeback. if (env->regs[15] & 1) { if (!arm_feature(env, ARM_FEATURE_V8)) { qemu_log_mask(...); } env->regs[15] &= ~1U; } Otherwise, Reviewed-by: Richard Henderson <richard.hender...@linaro.org> r~