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target/sh4: move DELAY_SLOT_TRUE flag into a separate global 

Instead of using one bit of the env flags to store the condition of the
next delay slot, use a separate global. It simplifies reading and
writing the flags variable and also removes some confusion between
ctx->envflags and env->flags.

Note that the global is first transfered to a temp in order to be
able to discard the global before the brcond.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Aurelien Jarno 2017-05-01 23:20:43 +02:00
parent 24b09d9d8b
commit 47b9f4d5a4
3 changed files with 16 additions and 18 deletions
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10
target/sh4/cpu.h
View File

@ -92,13 +92,6 @@
#define DELAY_SLOT (1 << 0)
#define DELAY_SLOT_CONDITIONAL (1 << 1)
#define DELAY_SLOT_TRUE (1 << 2)
/* 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.
*
* It is unclear if it is permitted to modify the SR_T flag in a delay slot.
* The use of DELAY_SLOT_TRUE flag makes us accept such SR_T modification.
*/
typedef struct tlb_t {
uint32_t vpn; /* virtual page number */
@ -148,7 +141,8 @@ typedef struct CPUSH4State {
uint32_t sgr; /* saved global register 15 */
uint32_t dbr; /* debug base register */
uint32_t pc; /* program counter */
uint32_t delayed_pc; /* target of delayed jump */
uint32_t delayed_pc; /* target of delayed branch */
uint32_t delayed_cond; /* condition of delayed branch */
uint32_t mach; /* multiply and accumulate high */
uint32_t macl; /* multiply and accumulate low */
uint32_t pr; /* procedure register */

2
target/sh4/helper.c
View File

@ -168,7 +168,7 @@ void superh_cpu_do_interrupt(CPUState *cs)
/* Branch instruction should be executed again before delay slot. */
env->spc -= 2;
/* Clear flags for exception/interrupt routine. */
env->flags &= ~(DELAY_SLOT | DELAY_SLOT_CONDITIONAL | DELAY_SLOT_TRUE);
env->flags &= ~(DELAY_SLOT | DELAY_SLOT_CONDITIONAL);
}
if (do_exp) {

22
target/sh4/translate.c
View File

@ -72,7 +72,7 @@ static TCGv cpu_pr, cpu_fpscr, cpu_fpul, cpu_ldst;
static TCGv cpu_fregs[32];
/* internal register indexes */
static TCGv cpu_flags, cpu_delayed_pc;
static TCGv cpu_flags, cpu_delayed_pc, cpu_delayed_cond;
#include "exec/gen-icount.h"
@ -147,6 +147,10 @@ void sh4_translate_init(void)
cpu_delayed_pc = tcg_global_mem_new_i32(cpu_env,
offsetof(CPUSH4State, delayed_pc),
"_delayed_pc_");
cpu_delayed_cond = tcg_global_mem_new_i32(cpu_env,
offsetof(CPUSH4State,
delayed_cond),
"_delayed_cond_");
cpu_ldst = tcg_global_mem_new_i32(cpu_env,
offsetof(CPUSH4State, ldst), "_ldst_");
@ -252,11 +256,12 @@ static void gen_jump(DisasContext * ctx)
static inline void gen_branch_slot(uint32_t delayed_pc, int t)
{
TCGLabel *label = gen_new_label();
tcg_gen_movi_i32(cpu_delayed_pc, delayed_pc);
tcg_gen_brcondi_i32(t ? TCG_COND_EQ : TCG_COND_NE, cpu_sr_t, 0, label);
tcg_gen_ori_i32(cpu_flags, cpu_flags, DELAY_SLOT_TRUE);
gen_set_label(label);
if (t) {
tcg_gen_mov_i32(cpu_delayed_cond, cpu_sr_t);
} else {
tcg_gen_xori_i32(cpu_delayed_cond, cpu_sr_t, 1);
}
}
/* Immediate conditional jump (bt or bf) */
@ -278,18 +283,17 @@ static void gen_delayed_conditional_jump(DisasContext * ctx)
l1 = gen_new_label();
ds = tcg_temp_new();
tcg_gen_andi_i32(ds, cpu_flags, DELAY_SLOT_TRUE);
tcg_gen_mov_i32(ds, cpu_delayed_cond);
tcg_gen_discard_i32(cpu_delayed_cond);
tcg_gen_brcondi_i32(TCG_COND_NE, ds, 0, l1);
gen_goto_tb(ctx, 1, ctx->pc + 2);
gen_set_label(l1);
tcg_gen_andi_i32(cpu_flags, cpu_flags, ~DELAY_SLOT_TRUE);
gen_jump(ctx);
}
static inline void gen_store_flags(uint32_t flags)
{
tcg_gen_andi_i32(cpu_flags, cpu_flags, DELAY_SLOT_TRUE);
tcg_gen_ori_i32(cpu_flags, cpu_flags, flags);
tcg_gen_movi_i32(cpu_flags, flags);
}
static inline void gen_load_fpr64(TCGv_i64 t, int reg)