| Message ID | 20170706002401.10507-3-rth@twiddle.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 2017-07-05 14:23, Richard Henderson wrote: > 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 <rth@twiddle.net> > --- > 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 6b247fa..e1661e9 100644 > --- a/target/sh4/translate.c > +++ b/target/sh4/translate.c > @@ -1856,7 +1856,6 @@ 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; > @@ -1864,9 +1863,23 @@ 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; This could be written as num_insn = -(ctx.pc | TARGET_PAGE_SIZE) / 2; > + if (max_insns > num_insns) { > + max_insns = num_insns; > + } You are following the existing pattern, so I can really blame you, but maybe it's the moment to change the existing code into something like: max_insns = MIN(max_insn, ...) > + /* 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++; > > @@ -1890,18 +1903,10 @@ 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); Besides the minor nitpicks above: Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/target/sh4/translate.c b/target/sh4/translate.c index 6b247fa..e1661e9 100644 --- a/target/sh4/translate.c +++ b/target/sh4/translate.c @@ -1856,7 +1856,6 @@ 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; @@ -1864,9 +1863,23 @@ 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++; @@ -1890,18 +1903,10 @@ 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);
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 <rth@twiddle.net> --- target/sh4/translate.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-)