[Qemu-devel] [PATCH v2 07/26] armv7m: simpler/faster exception start

[Michael Davidsaver <mdavidsaver@gmail.com>]

No need to bounce through EXCP_IRQ handling
for non-IRQ exceptions.  just update CPU
state directly.
---
 target-arm/helper.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/target-arm/helper.c b/target-arm/helper.c
index 7b76f32..4490b74 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -5451,23 +5451,21 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs)
 
     /* For exceptions we just mark as pending on the NVIC, and let that
        handle it.  */
-    /* TODO: Need to escalate if the current priority is higher than the
-       one we're raising.  */
     switch (cs->exception_index) {
     case EXCP_UDEF:
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE);
-        return;
+        break;
     case EXCP_SWI:
         /* The PC already points to the next instruction.  */
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SVC);
-        return;
+        break;
     case EXCP_PREFETCH_ABORT:
     case EXCP_DATA_ABORT:
         /* TODO: if we implemented the MPU registers, this is where we
          * should set the MMFAR, etc from exception.fsr and exception.vaddress.
          */
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_MEM);
-        return;
+        break;
     case EXCP_BKPT:
         if (semihosting_enabled()) {
             int nr;
@@ -5484,7 +5482,6 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs)
         armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_DEBUG);
         return;
     case EXCP_IRQ:
-        env->v7m.exception = armv7m_nvic_acknowledge_irq(env->nvic);
         break;
     case EXCP_EXCEPTION_EXIT:
         do_v7m_exception_exit(env);
@@ -5494,6 +5491,10 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs)
         return; /* Never happens.  Keep compiler happy.  */
     }
 
+    armv7m_nvic_acknowledge_irq(env->nvic);
+
+    qemu_log_mask(CPU_LOG_INT, "... as %d\n", env->v7m.exception);
+
     /* Align stack pointer.  */
     /* ??? Should only do this if Configuration Control Register
        STACKALIGN bit is set.  */
-- 
2.1.4