diff options
Diffstat (limited to 'target/arm/translate-vfp.c')
| -rw-r--r-- | target/arm/translate-vfp.c | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/target/arm/translate-vfp.c b/target/arm/translate-vfp.c index e2eb797c82..59bcaec5be 100644 --- a/target/arm/translate-vfp.c +++ b/target/arm/translate-vfp.c @@ -109,7 +109,7 @@ static inline long vfp_f16_offset(unsigned reg, bool top) * Generate code for M-profile lazy FP state preservation if needed; * this corresponds to the pseudocode PreserveFPState() function. */ -static void gen_preserve_fp_state(DisasContext *s) +static void gen_preserve_fp_state(DisasContext *s, bool skip_context_update) { if (s->v7m_lspact) { /* @@ -128,6 +128,20 @@ static void gen_preserve_fp_state(DisasContext *s) * any further FP insns in this TB. */ s->v7m_lspact = false; + /* + * The helper might have zeroed VPR, so we do not know the + * correct value for the MVE_NO_PRED TB flag any more. + * If we're about to create a new fp context then that + * will precisely determine the MVE_NO_PRED value (see + * gen_update_fp_context()). Otherwise, we must: + * - set s->mve_no_pred to false, so this instruction + * is generated to use helper functions + * - end the TB now, without chaining to the next TB + */ + if (skip_context_update || !s->v7m_new_fp_ctxt_needed) { + s->mve_no_pred = false; + s->base.is_jmp = DISAS_UPDATE_NOCHAIN; + } } } @@ -169,12 +183,19 @@ static void gen_update_fp_context(DisasContext *s) TCGv_i32 z32 = tcg_const_i32(0); store_cpu_field(z32, v7m.vpr); } - /* - * We don't need to arrange to end the TB, because the only - * parts of FPSCR which we cache in the TB flags are the VECLEN - * and VECSTRIDE, and those don't exist for M-profile. + * We just updated the FPSCR and VPR. Some of this state is cached + * in the MVE_NO_PRED TB flag. We want to avoid having to end the + * TB here, which means we need the new value of the MVE_NO_PRED + * flag to be exactly known here and the same for all executions. + * Luckily FPDSCR.LTPSIZE is always constant 4 and the VPR is + * always set to 0, so the new MVE_NO_PRED flag is always 1 + * if and only if we have MVE. + * + * (The other FPSCR state cached in TB flags is VECLEN and VECSTRIDE, + * but those do not exist for M-profile, so are not relevant here.) */ + s->mve_no_pred = dc_isar_feature(aa32_mve, s); if (s->v8m_secure) { bits |= R_V7M_CONTROL_SFPA_MASK; @@ -238,7 +259,7 @@ bool vfp_access_check_m(DisasContext *s, bool skip_context_update) /* Handle M-profile lazy FP state mechanics */ /* Trigger lazy-state preservation if necessary */ - gen_preserve_fp_state(s); + gen_preserve_fp_state(s, skip_context_update); if (!skip_context_update) { /* Update ownership of FP context and create new FP context if needed */ |