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tcg/i386: Use indexed addressing for softmmu fast path
Since tcg_out_{ld,st}_helper_args, the slow path no longer requires
the address argument to be set up by the tlb load sequence.  Use a
plain load for the addend and indexed addressing with the original
input address register.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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rth7680 committed May 11, 2023
1 parent 530074c commit 1fac464
Showing 1 changed file with 10 additions and 15 deletions.
25 changes: 10 additions & 15 deletions tcg/i386/tcg-target.c.inc
Expand Up @@ -1837,7 +1837,8 @@ static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
tcg_out_sti(s, TCG_TYPE_PTR, (uintptr_t)l->raddr, TCG_REG_ESP, ofs);
} else {
tcg_out_mov(s, TCG_TYPE_PTR, tcg_target_call_iarg_regs[0], TCG_AREG0);
/* The second argument is already loaded with addrlo. */
tcg_out_mov(s, TCG_TYPE_TL, tcg_target_call_iarg_regs[1],
l->addrlo_reg);
tcg_out_movi(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[2], oi);
tcg_out_movi(s, TCG_TYPE_PTR, tcg_target_call_iarg_regs[3],
(uintptr_t)l->raddr);
Expand Down Expand Up @@ -1910,7 +1911,8 @@ static bool tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
tcg_out_st(s, TCG_TYPE_PTR, retaddr, TCG_REG_ESP, ofs);
} else {
tcg_out_mov(s, TCG_TYPE_PTR, tcg_target_call_iarg_regs[0], TCG_AREG0);
/* The second argument is already loaded with addrlo. */
tcg_out_mov(s, TCG_TYPE_TL, tcg_target_call_iarg_regs[1],
l->addrlo_reg);
tcg_out_mov(s, (s_bits == MO_64 ? TCG_TYPE_I64 : TCG_TYPE_I32),
tcg_target_call_iarg_regs[2], l->datalo_reg);
tcg_out_movi(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[3], oi);
Expand Down Expand Up @@ -2085,16 +2087,6 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
tcg_out_modrm_offset(s, OPC_CMP_GvEv + trexw,
TCG_REG_L1, TCG_REG_L0, cmp_ofs);

/*
* Prepare for both the fast path add of the tlb addend, and the slow
* path function argument setup.
*/
*h = (HostAddress) {
.base = TCG_REG_L1,
.index = -1
};
tcg_out_mov(s, ttype, h->base, addrlo);

/* jne slow_path */
tcg_out_opc(s, OPC_JCC_long + JCC_JNE, 0, 0, 0);
ldst->label_ptr[0] = s->code_ptr;
Expand All @@ -2111,10 +2103,13 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
}

/* TLB Hit. */
tcg_out_ld(s, TCG_TYPE_PTR, TCG_REG_L0, TCG_REG_L0,
offsetof(CPUTLBEntry, addend));

/* add addend(TCG_REG_L0), TCG_REG_L1 */
tcg_out_modrm_offset(s, OPC_ADD_GvEv + hrexw, h->base, TCG_REG_L0,
offsetof(CPUTLBEntry, addend));
*h = (HostAddress) {
.base = addrlo,
.index = TCG_REG_L0,
};
#else
if (a_bits) {
ldst = new_ldst_label(s);
Expand Down

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