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target/i386: pull computation of string update value out of loop

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This is a common operation that is executed many times in rep
movs or rep stos loops.  It can improve performance by several
percentage points.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20241215090613.89588-13-pbonzini@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2024-12-15 10:06:11 +01:00
parent 456709db50
commit 4f094e27f3
1 changed files with 26 additions and 28 deletions
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54
target/i386/tcg/translate.c
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@ -832,16 +832,13 @@ static bool gen_check_io(DisasContext *s, MemOp ot, TCGv_i32 port,
#endif
}
static void gen_movs(DisasContext *s, MemOp ot)
static void gen_movs(DisasContext *s, MemOp ot, TCGv dshift)
{
TCGv dshift;
gen_string_movl_A0_ESI(s);
gen_op_ld_v(s, ot, s->T0, s->A0);
gen_string_movl_A0_EDI(s);
gen_op_st_v(s, ot, s->T0, s->A0);
dshift = gen_compute_Dshift(s, ot);
gen_op_add_reg(s, s->aflag, R_ESI, dshift);
gen_op_add_reg(s, s->aflag, R_EDI, dshift);
}
@ -1246,22 +1243,22 @@ static inline void gen_jcc(DisasContext *s, int b, TCGLabel *l1)
}
}
static void gen_stos(DisasContext *s, MemOp ot)
static void gen_stos(DisasContext *s, MemOp ot, TCGv dshift)
{
gen_string_movl_A0_EDI(s);
gen_op_st_v(s, ot, s->T0, s->A0);
gen_op_add_reg(s, s->aflag, R_EDI, gen_compute_Dshift(s, ot));
gen_op_add_reg(s, s->aflag, R_EDI, dshift);
}
static void gen_lods(DisasContext *s, MemOp ot)
static void gen_lods(DisasContext *s, MemOp ot, TCGv dshift)
{
gen_string_movl_A0_ESI(s);
gen_op_ld_v(s, ot, s->T0, s->A0);
gen_op_mov_reg_v(s, ot, R_EAX, s->T0);
gen_op_add_reg(s, s->aflag, R_ESI, gen_compute_Dshift(s, ot));
gen_op_add_reg(s, s->aflag, R_ESI, dshift);
}
static void gen_scas(DisasContext *s, MemOp ot)
static void gen_scas(DisasContext *s, MemOp ot, TCGv dshift)
{
gen_string_movl_A0_EDI(s);
gen_op_ld_v(s, ot, s->T1, s->A0);
@ -1270,13 +1267,11 @@ static void gen_scas(DisasContext *s, MemOp ot)
tcg_gen_sub_tl(cpu_cc_dst, s->T0, s->T1);
set_cc_op(s, CC_OP_SUBB + ot);
gen_op_add_reg(s, s->aflag, R_EDI, gen_compute_Dshift(s, ot));
gen_op_add_reg(s, s->aflag, R_EDI, dshift);
}
static void gen_cmps(DisasContext *s, MemOp ot)
static void gen_cmps(DisasContext *s, MemOp ot, TCGv dshift)
{
TCGv dshift;
gen_string_movl_A0_EDI(s);
gen_op_ld_v(s, ot, s->T1, s->A0);
gen_string_movl_A0_ESI(s);
@ -1286,7 +1281,6 @@ static void gen_cmps(DisasContext *s, MemOp ot)
tcg_gen_sub_tl(cpu_cc_dst, s->T0, s->T1);
set_cc_op(s, CC_OP_SUBB + ot);
dshift = gen_compute_Dshift(s, ot);
gen_op_add_reg(s, s->aflag, R_ESI, dshift);
gen_op_add_reg(s, s->aflag, R_EDI, dshift);
}
@ -1305,7 +1299,7 @@ static void gen_bpt_io(DisasContext *s, TCGv_i32 t_port, int ot)
}
}
static void gen_ins(DisasContext *s, MemOp ot)
static void gen_ins(DisasContext *s, MemOp ot, TCGv dshift)
{
gen_string_movl_A0_EDI(s);
/* Note: we must do this dummy write first to be restartable in
@ -1316,11 +1310,11 @@ static void gen_ins(DisasContext *s, MemOp ot)
tcg_gen_andi_i32(s->tmp2_i32, s->tmp2_i32, 0xffff);
gen_helper_in_func(ot, s->T0, s->tmp2_i32);
gen_op_st_v(s, ot, s->T0, s->A0);
gen_op_add_reg(s, s->aflag, R_EDI, gen_compute_Dshift(s, ot));
gen_op_add_reg(s, s->aflag, R_EDI, dshift);
gen_bpt_io(s, s->tmp2_i32, ot);
}
static void gen_outs(DisasContext *s, MemOp ot)
static void gen_outs(DisasContext *s, MemOp ot, TCGv dshift)
{
gen_string_movl_A0_ESI(s);
gen_op_ld_v(s, ot, s->T0, s->A0);
@ -1329,14 +1323,14 @@ static void gen_outs(DisasContext *s, MemOp ot)
tcg_gen_andi_i32(s->tmp2_i32, s->tmp2_i32, 0xffff);
tcg_gen_trunc_tl_i32(s->tmp3_i32, s->T0);
gen_helper_out_func(ot, s->tmp2_i32, s->tmp3_i32);
gen_op_add_reg(s, s->aflag, R_ESI, gen_compute_Dshift(s, ot));
gen_op_add_reg(s, s->aflag, R_ESI, dshift);
gen_bpt_io(s, s->tmp2_i32, ot);
}
#define REP_MAX 65535
static void do_gen_rep(DisasContext *s, MemOp ot,
void (*fn)(DisasContext *s, MemOp ot),
static void do_gen_rep(DisasContext *s, MemOp ot, TCGv dshift,
void (*fn)(DisasContext *s, MemOp ot, TCGv dshift),
bool is_repz_nz)
{
TCGLabel *last = gen_new_label();
@ -1401,7 +1395,7 @@ static void do_gen_rep(DisasContext *s, MemOp ot,
}
gen_set_label(loop);
fn(s, ot);
fn(s, ot, dshift);
tcg_gen_mov_tl(cpu_regs[R_ECX], cx_next);
gen_update_cc_op(s);
@ -1438,7 +1432,7 @@ static void do_gen_rep(DisasContext *s, MemOp ot,
*/
gen_set_label(last);
set_cc_op(s, CC_OP_DYNAMIC);
fn(s, ot);
fn(s, ot, dshift);
tcg_gen_mov_tl(cpu_regs[R_ECX], cx_next);
gen_update_cc_op(s);
}
@ -1453,23 +1447,27 @@ static void do_gen_rep(DisasContext *s, MemOp ot,
}
static void gen_repz(DisasContext *s, MemOp ot,
void (*fn)(DisasContext *s, MemOp ot))
void (*fn)(DisasContext *s, MemOp ot, TCGv dshift))
{
TCGv dshift = gen_compute_Dshift(s, ot);
if (s->prefix & (PREFIX_REPZ | PREFIX_REPNZ)) {
do_gen_rep(s, ot, fn, false);
do_gen_rep(s, ot, dshift, fn, false);
} else {
fn(s, ot);
fn(s, ot, dshift);
}
}
static void gen_repz_nz(DisasContext *s, MemOp ot,
void (*fn)(DisasContext *s, MemOp ot))
void (*fn)(DisasContext *s, MemOp ot, TCGv dshift))
{
TCGv dshift = gen_compute_Dshift(s, ot);
if (s->prefix & (PREFIX_REPZ | PREFIX_REPNZ)) {
do_gen_rep(s, ot, fn, true);
do_gen_rep(s, ot, dshift, fn, true);
} else {
fn(s, ot);
fn(s, ot, dshift);
}
}