From c485ce2c491a6e5d66da1d1555ecd474b450db98 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 14 Jun 2021 16:09:12 +0100 Subject: [PATCH] target/arm: Enable FPSCR.QC bit for MVE MVE has an FPSCR.QC bit similar to the A-profile Neon one; when MVE is implemented make the bit writeable, both in the generic "load and store FPSCR" helper functions and in the code for handling the NZCVQC sysreg which we had previously left as "TODO when we implement MVE". Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 20210614151007.4545-3-peter.maydell@linaro.org --- target/arm/translate-vfp.c | 30 +++++++++++++++++++++--------- target/arm/vfp_helper.c | 3 ++- 2 files changed, 23 insertions(+), 10 deletions(-) diff --git a/target/arm/translate-vfp.c b/target/arm/translate-vfp.c index d01e465821..728856dfd4 100644 --- a/target/arm/translate-vfp.c +++ b/target/arm/translate-vfp.c @@ -784,10 +784,17 @@ static bool gen_M_fp_sysreg_write(DisasContext *s, int regno, { TCGv_i32 fpscr; tmp = loadfn(s, opaque); - /* - * TODO: when we implement MVE, write the QC bit. - * For non-MVE, QC is RES0. - */ + if (dc_isar_feature(aa32_mve, s)) { + /* QC is only present for MVE; otherwise RES0 */ + TCGv_i32 qc = tcg_temp_new_i32(); + tcg_gen_andi_i32(qc, tmp, FPCR_QC); + /* + * The 4 vfp.qc[] fields need only be "zero" vs "non-zero"; + * here writing the same value into all elements is simplest. + */ + tcg_gen_gvec_dup_i32(MO_32, offsetof(CPUARMState, vfp.qc), + 16, 16, qc); + } tcg_gen_andi_i32(tmp, tmp, FPCR_NZCV_MASK); fpscr = load_cpu_field(vfp.xregs[ARM_VFP_FPSCR]); tcg_gen_andi_i32(fpscr, fpscr, ~FPCR_NZCV_MASK); @@ -869,6 +876,11 @@ static bool gen_M_fp_sysreg_read(DisasContext *s, int regno, break; } + if (regno == ARM_VFP_FPSCR_NZCVQC && !dc_isar_feature(aa32_mve, s)) { + /* QC is RES0 without MVE, so NZCVQC simplifies to NZCV */ + regno = QEMU_VFP_FPSCR_NZCV; + } + switch (regno) { case ARM_VFP_FPSCR: tmp = tcg_temp_new_i32(); @@ -876,11 +888,11 @@ static bool gen_M_fp_sysreg_read(DisasContext *s, int regno, storefn(s, opaque, tmp); break; case ARM_VFP_FPSCR_NZCVQC: - /* - * TODO: MVE has a QC bit, which we probably won't store - * in the xregs[] field. For non-MVE, where QC is RES0, - * we can just fall through to the FPSCR_NZCV case. - */ + tmp = tcg_temp_new_i32(); + gen_helper_vfp_get_fpscr(tmp, cpu_env); + tcg_gen_andi_i32(tmp, tmp, FPCR_NZCVQC_MASK); + storefn(s, opaque, tmp); + break; case QEMU_VFP_FPSCR_NZCV: /* * Read just NZCV; this is a special case to avoid the diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c index 496f003477..8a71660059 100644 --- a/target/arm/vfp_helper.c +++ b/target/arm/vfp_helper.c @@ -220,7 +220,8 @@ void HELPER(vfp_set_fpscr)(CPUARMState *env, uint32_t val) FPCR_LTPSIZE_LENGTH); } - if (arm_feature(env, ARM_FEATURE_NEON)) { + if (arm_feature(env, ARM_FEATURE_NEON) || + cpu_isar_feature(aa32_mve, cpu)) { /* * The bit we set within fpscr_q is arbitrary; the register as a * whole being zero/non-zero is what counts. -- 2.11.4.GIT