From e11a7bcede8fe1de3764c668f807f290ba812190 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 20 Feb 2018 13:46:21 -0500 Subject: [PATCH] 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 --- qemu/target-i386/translate.c | 223 ++++++++++++++++------------------- 1 file changed, 100 insertions(+), 123 deletions(-) diff --git a/qemu/target-i386/translate.c b/qemu/target-i386/translate.c index 10de07dc..467b05a2 100644 --- a/qemu/target-i386/translate.c +++ b/qemu/target-i386/translate.c @@ -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 */