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[Qemu-devel] [PATCH v2 02/27] target/sh4: Consolidate end-of-TB tests
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH v2 02/27] target/sh4: Consolidate end-of-TB tests |
Date: |
Thu, 6 Jul 2017 16:20:46 -1000 |
We can fold 3 different tests within the decode loop
into a more accurate computation of max_insns to start.
Signed-off-by: Richard Henderson <address@hidden>
---
target/sh4/translate.c | 29 +++++++++++++++++------------
1 file changed, 17 insertions(+), 12 deletions(-)
diff --git a/target/sh4/translate.c b/target/sh4/translate.c
index 82d4d69..663b5c0 100644
--- a/target/sh4/translate.c
+++ b/target/sh4/translate.c
@@ -1848,7 +1848,6 @@ void gen_intermediate_code(CPUSH4State * env, struct
TranslationBlock *tb)
ctx.features = env->features;
ctx.has_movcal = (ctx.tbflags & TB_FLAG_PENDING_MOVCA);
- num_insns = 0;
max_insns = tb->cflags & CF_COUNT_MASK;
if (max_insns == 0) {
max_insns = CF_COUNT_MASK;
@@ -1856,9 +1855,23 @@ void gen_intermediate_code(CPUSH4State * env, struct
TranslationBlock *tb)
if (max_insns > TCG_MAX_INSNS) {
max_insns = TCG_MAX_INSNS;
}
+ /* Since the ISA is fixed-width, we can bound by the number
+ of instructions remaining on the page. */
+ num_insns = (TARGET_PAGE_SIZE - (ctx.pc & (TARGET_PAGE_SIZE - 1))) / 2;
+ if (max_insns > num_insns) {
+ max_insns = num_insns;
+ }
+ /* Single stepping means just that. */
+ if (ctx.singlestep_enabled || singlestep) {
+ max_insns = 1;
+ }
gen_tb_start(tb);
- while (ctx.bstate == BS_NONE && !tcg_op_buf_full()) {
+ num_insns = 0;
+
+ while (ctx.bstate == BS_NONE
+ && num_insns < max_insns
+ && !tcg_op_buf_full()) {
tcg_gen_insn_start(ctx.pc, ctx.envflags);
num_insns++;
@@ -1882,18 +1895,10 @@ void gen_intermediate_code(CPUSH4State * env, struct
TranslationBlock *tb)
ctx.opcode = cpu_lduw_code(env, ctx.pc);
decode_opc(&ctx);
ctx.pc += 2;
- if ((ctx.pc & (TARGET_PAGE_SIZE - 1)) == 0)
- break;
- if (cs->singlestep_enabled) {
- break;
- }
- if (num_insns >= max_insns)
- break;
- if (singlestep)
- break;
}
- if (tb->cflags & CF_LAST_IO)
+ if (tb->cflags & CF_LAST_IO) {
gen_io_end();
+ }
if (cs->singlestep_enabled) {
gen_save_cpu_state(&ctx, true);
gen_helper_debug(cpu_env);
--
2.9.4