Commit 2529ab43 authored Oct 25, 2019 by Christophe Lyon Committed by Peter Maydell Nov 01, 2019

target/arm: Allow reading flags from FPSCR for M-profile



rt==15 is a special case when reading the flags: it means the
destination is APSR. This patch avoids rejecting
vmrs apsr_nzcv, fpscr
as illegal instruction.

Cc: qemu-stable@nongnu.org
Signed-off-by: Christophe Lyon <christophe.lyon@linaro.org>
Message-id: 20191025095711.10853-1-christophe.lyon@linaro.org
[PMM: updated the comment]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

parent 98be6b7d

target/arm/translate-vfp.inc.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -703,9 +703,10 @@ static bool trans_VMSR_VMRS(DisasContext s, arg_VMSR_VMRS a)
		if (arm_dc_feature(s, ARM_FEATURE_M)) {
		/*
		* The only M-profile VFP vmrs/vmsr sysreg is FPSCR.
		* Writes to R15 are UNPREDICTABLE; we choose to undef.
		* Accesses to R15 are UNPREDICTABLE; we choose to undef.
		* (FPSCR -> r15 is a special case which writes to the PSR flags.)
		*/
		if (a->rt == 15 \|\| a->reg != ARM_VFP_FPSCR) {
		if (a->rt == 15 && (!a->l \|\| a->reg != ARM_VFP_FPSCR)) {
		return false;
		}
		}