target-i386: Split up gen_lea_modrm

This is immediately usable by lea and multi-byte nop,
and will be required to implement parts of the mpx spec.

Backports commit a074ce42a3186bd9f96ef541bb2e01419181dae3 from qemu
This commit is contained in:
Richard Henderson 2018-02-20 13:46:21 -05:00 committed by Lioncash
parent 159e837a6c
commit e11a7bcede
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GPG key ID: 4E3C3CC1031BA9C7

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@ -2065,40 +2065,54 @@ static void gen_shifti(DisasContext *s, int op, TCGMemOp ot, int d, int c)
}
}
static void gen_lea_modrm(CPUX86State *env, DisasContext *s, int modrm)
{
/* Decompose an address. */
typedef struct AddressParts {
int def_seg;
int base;
int index;
int scale;
target_long disp;
int havesib, base, index, scale;
int mod, rm, code, def_seg, ovr_seg;
TCGv sum;
TCGContext *tcg_ctx = s->uc->tcg_ctx;
TCGv cpu_A0 = *(TCGv *)tcg_ctx->cpu_A0;
TCGv **cpu_regs = (TCGv **)tcg_ctx->cpu_regs;
} AddressParts;
static AddressParts gen_lea_modrm_0(CPUX86State *env, DisasContext *s,
int modrm)
{
int def_seg, base, index, scale, mod, rm;
target_long disp;
bool havesib;
AddressParts result;
def_seg = R_DS;
ovr_seg = s->override;
index = -1;
scale = 0;
disp = 0;
mod = (modrm >> 6) & 3;
rm = modrm & 7;
base = rm | REX_B(s);
if (mod == 3) {
/* Normally filtered out earlier, but including this path
simplifies multi-byte nop, as well as bndcl, bndcu, bndcn. */
goto done;
}
switch (s->aflag) {
case MO_64:
case MO_32:
havesib = 0;
base = rm;
index = -1;
scale = 0;
if (base == 4) {
havesib = 1;
code = cpu_ldub_code(env, s->pc++);
if (rm == 4) {
int code = cpu_ldub_code(env, s->pc++);
scale = (code >> 6) & 3;
index = ((code >> 3) & 7) | REX_X(s);
if (index == 4) {
index = -1; /* no index */
}
base = (code & 7);
base = (code & 7) | REX_B(s);
havesib = 1;
}
base |= REX_B(s);
switch (mod) {
case 0:
@ -2107,10 +2121,9 @@ static void gen_lea_modrm(CPUX86State *env, DisasContext *s, int modrm)
disp = (int32_t)cpu_ldl_code(env, s->pc);
s->pc += 4;
if (CODE64(s) && !havesib) {
base = -2;
disp += s->pc + s->rip_offset;
}
} else {
disp = 0;
}
break;
case 1:
@ -2128,45 +2141,19 @@ static void gen_lea_modrm(CPUX86State *env, DisasContext *s, int modrm)
disp += s->popl_esp_hack;
}
/* Compute the address, with a minimum number of TCG ops. */
TCGV_UNUSED(sum);
if (index >= 0) {
if (scale == 0) {
sum = *cpu_regs[index];
} else {
tcg_gen_shli_tl(tcg_ctx, cpu_A0, *cpu_regs[index], scale);
sum = cpu_A0;
}
if (base >= 0) {
tcg_gen_add_tl(tcg_ctx, cpu_A0, sum, *cpu_regs[base]);
sum = cpu_A0;
}
} else if (base >= 0) {
sum = *cpu_regs[base];
}
if (TCGV_IS_UNUSED(sum)) {
tcg_gen_movi_tl(tcg_ctx, cpu_A0, disp);
sum = cpu_A0;
} else if (disp != 0) {
tcg_gen_addi_tl(tcg_ctx, cpu_A0, sum, disp);
sum = cpu_A0;
}
if (base == R_EBP || base == R_ESP) {
def_seg = R_SS;
}
break;
case MO_16:
sum = cpu_A0;
if (mod == 0) {
if (rm == 6) {
base = -1;
disp = cpu_lduw_code(env, s->pc);
s->pc += 2;
tcg_gen_movi_tl(tcg_ctx, cpu_A0, disp);
break;
}
disp = 0;
} else if (mod == 1) {
disp = (int8_t)cpu_ldub_code(env, s->pc++);
} else {
@ -2176,104 +2163,97 @@ static void gen_lea_modrm(CPUX86State *env, DisasContext *s, int modrm)
switch (rm) {
case 0:
tcg_gen_add_tl(tcg_ctx, cpu_A0, *cpu_regs[R_EBX], *cpu_regs[R_ESI]);
base = R_EBX;
index = R_ESI;
break;
case 1:
tcg_gen_add_tl(tcg_ctx, cpu_A0, *cpu_regs[R_EBX], *cpu_regs[R_EDI]);
base = R_EBX;
index = R_EDI;
break;
case 2:
tcg_gen_add_tl(tcg_ctx, cpu_A0, *cpu_regs[R_EBP], *cpu_regs[R_ESI]);
base = R_EBP;
index = R_ESI;
def_seg = R_SS;
break;
case 3:
tcg_gen_add_tl(tcg_ctx, cpu_A0, *cpu_regs[R_EBP], *cpu_regs[R_EDI]);
base = R_EBP;
index = R_EDI;
def_seg = R_SS;
break;
case 4:
sum = *cpu_regs[R_ESI];
base = R_ESI;
break;
case 5:
sum = *cpu_regs[R_EDI];
base = R_EDI;
break;
case 6:
sum = *cpu_regs[R_EBP];
base = R_EBP;
def_seg = R_SS;
break;
default:
case 7:
sum = *cpu_regs[R_EBX];
base = R_EBX;
break;
}
tcg_gen_addi_tl(tcg_ctx, cpu_A0, sum, disp);
tcg_gen_ext16u_tl(tcg_ctx, cpu_A0, cpu_A0);
if (disp != 0) {
tcg_gen_addi_tl(tcg_ctx, cpu_A0, sum, disp);
sum = cpu_A0;
}
break;
default:
tcg_abort();
}
gen_lea_v_seg(s, s->aflag, sum, def_seg, ovr_seg);
done:
result.def_seg = def_seg;
result.base = base;
result.index = index;
result.scale = scale;
result.disp = disp;
return result;
}
/* Compute the address, with a minimum number of TCG ops. */
static TCGv gen_lea_modrm_1(DisasContext *s, AddressParts a)
{
TCGContext *tcg_ctx = s->uc->tcg_ctx;
TCGv cpu_A0 = *(TCGv *)tcg_ctx->cpu_A0;
TCGv **cpu_regs = (TCGv **)tcg_ctx->cpu_regs;
TCGv ea;
TCGV_UNUSED(ea);
if (a.index >= 0) {
if (a.scale == 0) {
ea = *cpu_regs[a.index];
} else {
tcg_gen_shli_tl(tcg_ctx, cpu_A0, *cpu_regs[a.index], a.scale);
ea = cpu_A0;
}
if (a.base >= 0) {
tcg_gen_add_tl(tcg_ctx, cpu_A0, ea, *cpu_regs[a.base]);
ea = cpu_A0;
}
} else if (a.base >= 0) {
ea = *cpu_regs[a.base];
}
if (TCGV_IS_UNUSED(ea)) {
tcg_gen_movi_tl(tcg_ctx, cpu_A0, a.disp);
ea = cpu_A0;
} else if (a.disp != 0) {
tcg_gen_addi_tl(tcg_ctx, cpu_A0, ea, a.disp);
ea = cpu_A0;
}
return ea;
}
static void gen_lea_modrm(CPUX86State *env, DisasContext *s, int modrm)
{
AddressParts a = gen_lea_modrm_0(env, s, modrm);
TCGv ea = gen_lea_modrm_1(s, a);
gen_lea_v_seg(s, s->aflag, ea, a.def_seg, s->override);
}
static void gen_nop_modrm(CPUX86State *env, DisasContext *s, int modrm)
{
int mod, rm, base, code;
mod = (modrm >> 6) & 3;
if (mod == 3)
return;
rm = modrm & 7;
switch (s->aflag) {
case MO_64:
case MO_32:
base = rm;
if (base == 4) {
code = cpu_ldub_code(env, s->pc++);
base = (code & 7);
}
switch (mod) {
case 0:
if (base == 5) {
s->pc += 4;
}
break;
case 1:
s->pc++;
break;
default:
case 2:
s->pc += 4;
break;
}
break;
case MO_16:
switch (mod) {
case 0:
if (rm == 6) {
s->pc += 2;
}
break;
case 1:
s->pc++;
break;
default:
case 2:
s->pc += 2;
break;
}
break;
default:
tcg_abort();
}
(void)gen_lea_modrm_0(env, s, modrm);
}
/* used for LEA and MOV AX, mem */
@ -5951,19 +5931,16 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s,
break;
case 0x8d: /* lea */
ot = dflag;
modrm = cpu_ldub_code(env, s->pc++);
mod = (modrm >> 6) & 3;
if (mod == 3)
goto illegal_op;
reg = ((modrm >> 3) & 7) | rex_r;
/* we must ensure that no segment is added */
s->override = -1;
val = s->addseg;
s->addseg = 0;
gen_lea_modrm(env, s, modrm);
s->addseg = val;
gen_op_mov_reg_v(tcg_ctx, ot, reg, cpu_A0);
{
AddressParts a = gen_lea_modrm_0(env, s, modrm);
TCGv ea = gen_lea_modrm_1(s, a);
gen_op_mov_reg_v(tcg_ctx, dflag, reg, ea);
}
break;
case 0xa0: /* mov EAX, Ov */