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target-i386: use inverted setcond when computing NS or NZ
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Make gen_compute_eflags_z and gen_compute_eflags_s able to compute the
inverted condition, and use this in gen_setcc_slow_T0.  We cannot do it
yet in gen_compute_eflags_c, but prepare the code for it anyway.  It is
not worthwhile for PF, as usual.

shr+and+xor could be replaced by and+setcond.  I'm not doing it yet.

Reviewed-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
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@rth7680
rth7680 committed Feb 18, 2013
1 parent 086c407 commit 8115f11
Showing 1 changed file with 31 additions and 18 deletions.
49 changes: 31 additions & 18 deletions target-i386/translate.c
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Expand Up @@ -870,11 +870,14 @@ static void gen_op_update_neg_cc(void)
}

/* compute eflags.C to reg */
static void gen_compute_eflags_c(DisasContext *s, TCGv reg)
static void gen_compute_eflags_c(DisasContext *s, TCGv reg, bool inv)
{
gen_update_cc_op(s);
gen_helper_cc_compute_c(cpu_tmp2_i32, cpu_env, cpu_cc_op);
tcg_gen_extu_i32_tl(reg, cpu_tmp2_i32);
if (inv) {
tcg_gen_xori_tl(reg, reg, 1);
}
}

/* compute all eflags to cc_src */
Expand All @@ -898,7 +901,7 @@ static void gen_compute_eflags_p(DisasContext *s, TCGv reg)
}

/* compute eflags.S to reg */
static void gen_compute_eflags_s(DisasContext *s, TCGv reg)
static void gen_compute_eflags_s(DisasContext *s, TCGv reg, bool inv)
{
switch (s->cc_op) {
case CC_OP_DYNAMIC:
Expand All @@ -907,12 +910,15 @@ static void gen_compute_eflags_s(DisasContext *s, TCGv reg)
case CC_OP_EFLAGS:
tcg_gen_shri_tl(reg, cpu_cc_src, 7);
tcg_gen_andi_tl(reg, reg, 1);
if (inv) {
tcg_gen_xori_tl(reg, reg, 1);
}
break;
default:
{
int size = (s->cc_op - CC_OP_ADDB) & 3;
TCGv t0 = gen_ext_tl(reg, cpu_cc_dst, size, true);
tcg_gen_setcondi_tl(TCG_COND_LT, reg, t0, 0);
tcg_gen_setcondi_tl(inv ? TCG_COND_GE : TCG_COND_LT, reg, t0, 0);
}
break;
}
Expand All @@ -927,7 +933,7 @@ static void gen_compute_eflags_o(DisasContext *s, TCGv reg)
}

/* compute eflags.Z to reg */
static void gen_compute_eflags_z(DisasContext *s, TCGv reg)
static void gen_compute_eflags_z(DisasContext *s, TCGv reg, bool inv)
{
switch (s->cc_op) {
case CC_OP_DYNAMIC:
Expand All @@ -936,27 +942,33 @@ static void gen_compute_eflags_z(DisasContext *s, TCGv reg)
case CC_OP_EFLAGS:
tcg_gen_shri_tl(reg, cpu_cc_src, 6);
tcg_gen_andi_tl(reg, reg, 1);
if (inv) {
tcg_gen_xori_tl(reg, reg, 1);
}
break;
default:
{
int size = (s->cc_op - CC_OP_ADDB) & 3;
TCGv t0 = gen_ext_tl(reg, cpu_cc_dst, size, false);
tcg_gen_setcondi_tl(TCG_COND_EQ, reg, t0, 0);
tcg_gen_setcondi_tl(inv ? TCG_COND_NE : TCG_COND_EQ, reg, t0, 0);
}
break;
}
}

static inline void gen_setcc_slow_T0(DisasContext *s, int jcc_op)
static inline void gen_setcc_slow_T0(DisasContext *s, int jcc_op, bool inv)
{
switch(jcc_op) {
case JCC_O:
gen_compute_eflags_o(s, cpu_T[0]);
break;
case JCC_B:
gen_compute_eflags_c(s, cpu_T[0]);
gen_compute_eflags_c(s, cpu_T[0], inv);
inv = false;
break;
case JCC_Z:
gen_compute_eflags_z(s, cpu_T[0]);
gen_compute_eflags_z(s, cpu_T[0], inv);
inv = false;
break;
case JCC_BE:
gen_compute_eflags(s);
Expand All @@ -965,7 +977,8 @@ static inline void gen_setcc_slow_T0(DisasContext *s, int jcc_op)
tcg_gen_andi_tl(cpu_T[0], cpu_T[0], 1);
break;
case JCC_S:
gen_compute_eflags_s(s, cpu_T[0]);
gen_compute_eflags_s(s, cpu_T[0], inv);
inv = false;
break;
case JCC_P:
gen_compute_eflags_p(s, cpu_T[0]);
Expand All @@ -988,6 +1001,9 @@ static inline void gen_setcc_slow_T0(DisasContext *s, int jcc_op)
tcg_gen_andi_tl(cpu_T[0], cpu_T[0], 1);
break;
}
if (inv) {
tcg_gen_xori_tl(cpu_T[0], cpu_T[0], 1);
}
}

/* return true if setcc_slow is not needed (WARNING: must be kept in
Expand Down Expand Up @@ -1153,7 +1169,7 @@ static inline void gen_jcc1(DisasContext *s, int b, int l1)
break;
default:
slow_jcc:
gen_setcc_slow_T0(s, jcc_op);
gen_setcc_slow_T0(s, jcc_op, false);
tcg_gen_brcondi_tl(inv ? TCG_COND_EQ : TCG_COND_NE,
cpu_T[0], 0, l1);
break;
Expand Down Expand Up @@ -1367,7 +1383,7 @@ static void gen_op(DisasContext *s1, int op, int ot, int d)
}
switch(op) {
case OP_ADCL:
gen_compute_eflags_c(s1, cpu_tmp4);
gen_compute_eflags_c(s1, cpu_tmp4, false);
tcg_gen_add_tl(cpu_T[0], cpu_T[0], cpu_T[1]);
tcg_gen_add_tl(cpu_T[0], cpu_T[0], cpu_tmp4);
if (d != OR_TMP0)
Expand All @@ -1382,7 +1398,7 @@ static void gen_op(DisasContext *s1, int op, int ot, int d)
set_cc_op(s1, CC_OP_DYNAMIC);
break;
case OP_SBBL:
gen_compute_eflags_c(s1, cpu_tmp4);
gen_compute_eflags_c(s1, cpu_tmp4, false);
tcg_gen_sub_tl(cpu_T[0], cpu_T[0], cpu_T[1]);
tcg_gen_sub_tl(cpu_T[0], cpu_T[0], cpu_tmp4);
if (d != OR_TMP0)
Expand Down Expand Up @@ -1456,7 +1472,7 @@ static void gen_inc(DisasContext *s1, int ot, int d, int c)
gen_op_mov_TN_reg(ot, 0, d);
else
gen_op_ld_T0_A0(ot + s1->mem_index);
gen_compute_eflags_c(s1, cpu_cc_src);
gen_compute_eflags_c(s1, cpu_cc_src, false);
if (c > 0) {
tcg_gen_addi_tl(cpu_T[0], cpu_T[0], 1);
set_cc_op(s1, CC_OP_INCB + ot);
Expand Down Expand Up @@ -2407,10 +2423,7 @@ static void gen_setcc(DisasContext *s, int b)
worth to */
inv = b & 1;
jcc_op = (b >> 1) & 7;
gen_setcc_slow_T0(s, jcc_op);
if (inv) {
tcg_gen_xori_tl(cpu_T[0], cpu_T[0], 1);
}
gen_setcc_slow_T0(s, jcc_op, inv);
}
}

Expand Down Expand Up @@ -6881,7 +6894,7 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s,
case 0xd6: /* salc */
if (CODE64(s))
goto illegal_op;
gen_compute_eflags_c(s, cpu_T[0]);
gen_compute_eflags_c(s, cpu_T[0], false);
tcg_gen_neg_tl(cpu_T[0], cpu_T[0]);
gen_op_mov_reg_T0(OT_BYTE, R_EAX);
break;
Expand Down

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