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target/i386: Use gen_jmp_rel for loop, repz, jecxz insns 

With gen_jmp_rel, we may chain to the next tb instead of merely
writing to eip and exiting.  For repz, subtract cur_insn_len to
restart the current insn.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221001140935.465607-19-richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Richard Henderson 2022-10-01 07:09:27 -07:00 committed by Paolo Bonzini
parent 8760ded661
commit 2255da493a
1 changed files with 15 additions and 21 deletions
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36
target/i386/tcg/translate.c
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@ -224,9 +224,9 @@ STUB_HELPER(wrmsr, TCGv_env env)
static void gen_eob(DisasContext *s);
static void gen_jr(DisasContext *s);
static void gen_jmp(DisasContext *s, target_ulong eip);
static void gen_jmp_tb(DisasContext *s, target_ulong eip, int tb_num);
static void gen_jmp_rel(DisasContext *s, MemOp ot, int diff, int tb_num);
static void gen_jmp_rel_csize(DisasContext *s, int diff, int tb_num);
static void gen_op(DisasContext *s1, int op, MemOp ot, int d);
static void gen_exception_gpf(DisasContext *s);
@ -1185,7 +1185,7 @@ static TCGLabel *gen_jz_ecx_string(DisasContext *s)
TCGLabel *l2 = gen_new_label();
gen_op_jnz_ecx(s, s->aflag, l1);
gen_set_label(l2);
gen_jmp_tb(s, s->pc - s->cs_base, 1);
gen_jmp_rel_csize(s, 0, 1);
gen_set_label(l1);
return l2;
}
@ -1288,7 +1288,7 @@ static void gen_repz(DisasContext *s, MemOp ot,
if (s->repz_opt) {
gen_op_jz_ecx(s, s->aflag, l2);
}
gen_jmp(s, s->base.pc_next - s->cs_base);
gen_jmp_rel_csize(s, -cur_insn_len(s), 0);
}
#define GEN_REPZ(op) \
@ -1308,7 +1308,7 @@ static void gen_repz2(DisasContext *s, MemOp ot, int nz,
if (s->repz_opt) {
gen_op_jz_ecx(s, s->aflag, l2);
}
gen_jmp(s, s->base.pc_next - s->cs_base);
gen_jmp_rel_csize(s, -cur_insn_len(s), 0);
}
#define GEN_REPZ2(op) \
@ -2793,6 +2793,7 @@ static void gen_jmp_tb(DisasContext *s, target_ulong eip, int tb_num)
}
}
/* Jump to eip+diff, truncating the result to OT. */
static void gen_jmp_rel(DisasContext *s, MemOp ot, int diff, int tb_num)
{
target_ulong dest = s->pc - s->cs_base + diff;
@ -2808,9 +2809,11 @@ static void gen_jmp_rel(DisasContext *s, MemOp ot, int diff, int tb_num)
gen_jmp_tb(s, dest, tb_num);
}
static void gen_jmp(DisasContext *s, target_ulong eip)
/* Jump to eip+diff, truncating to the current code size. */
static void gen_jmp_rel_csize(DisasContext *s, int diff, int tb_num)
{
gen_jmp_tb(s, eip, 0);
/* CODE64 ignores the OT argument, so we need not consider it. */
gen_jmp_rel(s, CODE32(s) ? MO_32 : MO_16, diff, tb_num);
}
static inline void gen_ldq_env_A0(DisasContext *s, int offset)
@ -7404,24 +7407,18 @@ static bool disas_insn(DisasContext *s, CPUState *cpu)
case 0xe2: /* loop */
case 0xe3: /* jecxz */
{
TCGLabel *l1, *l2, *l3;
tval = (int8_t)insn_get(env, s, MO_8);
tval += s->pc - s->cs_base;
if (dflag == MO_16) {
tval &= 0xffff;
}
TCGLabel *l1, *l2;
int diff = (int8_t)insn_get(env, s, MO_8);
l1 = gen_new_label();
l2 = gen_new_label();
l3 = gen_new_label();
gen_update_cc_op(s);
b &= 3;
switch(b) {
case 0: /* loopnz */
case 1: /* loopz */
gen_op_add_reg_im(s, s->aflag, R_ECX, -1);
gen_op_jz_ecx(s, s->aflag, l3);
gen_op_jz_ecx(s, s->aflag, l2);
gen_jcc1(s, (JCC_Z << 1) | (b ^ 1), l1);
break;
case 2: /* loop */
@ -7434,14 +7431,11 @@ static bool disas_insn(DisasContext *s, CPUState *cpu)
break;
}
gen_set_label(l3);
gen_update_eip_next(s);
tcg_gen_br(l2);
gen_set_label(l2);
gen_jmp_rel_csize(s, 0, 1);
gen_set_label(l1);
gen_jmp_im(s, tval);
gen_set_label(l2);
s->base.is_jmp = DISAS_EOB_ONLY;
gen_jmp_rel(s, dflag, diff, 0);
}
break;
case 0x130: /* wrmsr */