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[Qemu-devel] [PATCH v3 02/15] target/sh4: get rid of DELAY_SLOT_CLEARME


From: Aurelien Jarno
Subject: [Qemu-devel] [PATCH v3 02/15] target/sh4: get rid of DELAY_SLOT_CLEARME
Date: Wed, 10 May 2017 20:26:23 +0200

Now that ctx->flags has been split, it becomes clear that
DELAY_SLOT_CLEARME has not impact on the code generation: in both case
ctx->envflags is cleared, either by clearing all the flags, or by
setting it to 0. This is left-over from pre-TCG era.

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
Reviewed-by: Richard Henderson <address@hidden>
Signed-off-by: Aurelien Jarno <address@hidden>
---
 target/sh4/cpu.h       |  3 +--
 target/sh4/helper.c    |  2 --
 target/sh4/translate.c | 17 +++++------------
 3 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/target/sh4/cpu.h b/target/sh4/cpu.h
index cad8989f7e..9445cc779f 100644
--- a/target/sh4/cpu.h
+++ b/target/sh4/cpu.h
@@ -93,7 +93,6 @@
 #define DELAY_SLOT             (1 << 0)
 #define DELAY_SLOT_CONDITIONAL (1 << 1)
 #define DELAY_SLOT_TRUE        (1 << 2)
-#define DELAY_SLOT_CLEARME     (1 << 3)
 /* The dynamic value of the DELAY_SLOT_TRUE flag determines whether the jump
  * after the delay slot should be taken or not. It is calculated from SR_T.
  *
@@ -384,7 +383,7 @@ static inline void cpu_get_tb_cpu_state(CPUSH4State *env, 
target_ulong *pc,
     *pc = env->pc;
     *cs_base = 0;
     *flags = (env->flags & (DELAY_SLOT | DELAY_SLOT_CONDITIONAL
-                    | DELAY_SLOT_TRUE | DELAY_SLOT_CLEARME))   /* Bits  0- 3 */
+                    | DELAY_SLOT_TRUE))                        /* Bits  0- 2 */
             | (env->fpscr & (FPSCR_FR | FPSCR_SZ | FPSCR_PR))  /* Bits 19-21 */
             | (env->sr & ((1u << SR_MD) | (1u << SR_RB)))      /* Bits 29-30 */
             | (env->sr & (1u << SR_FD))                        /* Bit 15 */
diff --git a/target/sh4/helper.c b/target/sh4/helper.c
index 036c5ca56c..71bb49a670 100644
--- a/target/sh4/helper.c
+++ b/target/sh4/helper.c
@@ -170,8 +170,6 @@ void superh_cpu_do_interrupt(CPUState *cs)
        /* Clear flags for exception/interrupt routine. */
        env->flags &= ~(DELAY_SLOT | DELAY_SLOT_CONDITIONAL | DELAY_SLOT_TRUE);
     }
-    if (env->flags & DELAY_SLOT_CLEARME)
-        env->flags = 0;
 
     if (do_exp) {
         env->expevt = cs->exception_index;
diff --git a/target/sh4/translate.c b/target/sh4/translate.c
index 6b526a02f2..d84a7a2e6e 100644
--- a/target/sh4/translate.c
+++ b/target/sh4/translate.c
@@ -1804,15 +1804,9 @@ static void decode_opc(DisasContext * ctx)
     _decode_opc(ctx);
 
     if (old_flags & (DELAY_SLOT | DELAY_SLOT_CONDITIONAL)) {
-        if (ctx->envflags & DELAY_SLOT_CLEARME) {
-            gen_store_flags(0);
-        } else {
-           /* go out of the delay slot */
-            uint32_t new_flags = ctx->envflags;
-           new_flags &= ~(DELAY_SLOT | DELAY_SLOT_CONDITIONAL);
-           gen_store_flags(new_flags);
-        }
-        ctx->envflags = 0;
+        /* go out of the delay slot */
+        ctx->envflags &= ~(DELAY_SLOT | DELAY_SLOT_CONDITIONAL);
+        gen_store_flags(ctx->envflags);
         ctx->bstate = BS_BRANCH;
         if (old_flags & DELAY_SLOT_CONDITIONAL) {
            gen_delayed_conditional_jump(ctx);
@@ -1840,8 +1834,7 @@ void gen_intermediate_code(CPUSH4State * env, struct 
TranslationBlock *tb)
     pc_start = tb->pc;
     ctx.pc = pc_start;
     ctx.tbflags = (uint32_t)tb->flags;
-    ctx.envflags = tb->flags & (DELAY_SLOT | DELAY_SLOT_CONDITIONAL |
-                                DELAY_SLOT_CLEARME);
+    ctx.envflags = tb->flags & (DELAY_SLOT | DELAY_SLOT_CONDITIONAL);
     ctx.bstate = BS_NONE;
     ctx.memidx = (ctx.tbflags & (1u << SR_MD)) == 0 ? 1 : 0;
     /* We don't know if the delayed pc came from a dynamic or static branch,
@@ -1908,7 +1901,7 @@ void gen_intermediate_code(CPUSH4State * env, struct 
TranslationBlock *tb)
             /* fall through */
         case BS_NONE:
             if (ctx.envflags) {
-                gen_store_flags(ctx.envflags | DELAY_SLOT_CLEARME);
+                gen_store_flags(ctx.envflags);
            }
             gen_goto_tb(&ctx, 0, ctx.pc);
             break;
-- 
2.11.0




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