[PULL 21/41] target/arm: Hoist computation of TBFLAG_A32.VFPEN

[Peter Maydell <peter.maydell@linaro.org>]

From: Richard Henderson <richard.henderson@linaro.org>

There are 3 conditions that each enable this flag.  M-profile always
enables; A-profile with EL1 as AA64 always enables.  Both of these
conditions can easily be cached.  The final condition relies on the
FPEXC register which we are not prepared to cache.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20191018174431.1784-12-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/cpu.h    |  2 +-
 target/arm/helper.c | 14 ++++++++++----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 4d961474ce7..9909ff89d4f 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -3192,7 +3192,7 @@ FIELD(TBFLAG_A32, XSCALE_CPAR, 4, 2)
  * the same thing as the current security state of the processor!
  */
 FIELD(TBFLAG_A32, NS, 6, 1)
-FIELD(TBFLAG_A32, VFPEN, 7, 1)          /* Not cached. */
+FIELD(TBFLAG_A32, VFPEN, 7, 1)          /* Partially cached, minus FPEXC. */
 FIELD(TBFLAG_A32, CONDEXEC, 8, 8)       /* Not cached. */
 FIELD(TBFLAG_A32, SCTLR_B, 16, 1)
 /* For M profile only, set if FPCCR.LSPACT is set */
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 398e5f5d6df..89aa6fd9339 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -11088,6 +11088,9 @@ static uint32_t rebuild_hflags_m32(CPUARMState *env, int fp_el,
 {
     uint32_t flags = 0;
 
+    /* v8M always enables the fpu.  */
+    flags = FIELD_DP32(flags, TBFLAG_A32, VFPEN, 1);
+
     if (arm_v7m_is_handler_mode(env)) {
         flags = FIELD_DP32(flags, TBFLAG_A32, HANDLER, 1);
     }
@@ -11119,6 +11122,10 @@ static uint32_t rebuild_hflags_a32(CPUARMState *env, int fp_el,
                                    ARMMMUIdx mmu_idx)
 {
     uint32_t flags = rebuild_hflags_aprofile(env);
+
+    if (arm_el_is_aa64(env, 1)) {
+        flags = FIELD_DP32(flags, TBFLAG_A32, VFPEN, 1);
+    }
     return rebuild_hflags_common_32(env, fp_el, mmu_idx, flags);
 }
 
@@ -11250,14 +11257,13 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
                 flags = FIELD_DP32(flags, TBFLAG_A32, VECSTRIDE,
                                    env->vfp.vec_stride);
             }
+            if (env->vfp.xregs[ARM_VFP_FPEXC] & (1 << 30)) {
+                flags = FIELD_DP32(flags, TBFLAG_A32, VFPEN, 1);
+            }
         }
 
         flags = FIELD_DP32(flags, TBFLAG_A32, THUMB, env->thumb);
         flags = FIELD_DP32(flags, TBFLAG_A32, CONDEXEC, env->condexec_bits);
-        if (env->vfp.xregs[ARM_VFP_FPEXC] & (1 << 30)
-            || arm_el_is_aa64(env, 1) || arm_feature(env, ARM_FEATURE_M)) {
-            flags = FIELD_DP32(flags, TBFLAG_A32, VFPEN, 1);
-        }
         pstate_for_ss = env->uncached_cpsr;
     }
 
-- 
2.20.1