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Diffstat (limited to 'tinyc/i386-asm.c')
| -rw-r--r-- | tinyc/i386-asm.c | 1211 |
1 files changed, 1211 insertions, 0 deletions
diff --git a/tinyc/i386-asm.c b/tinyc/i386-asm.c new file mode 100644 index 000000000..12ff8f2ba --- /dev/null +++ b/tinyc/i386-asm.c @@ -0,0 +1,1211 @@ +/* + * i386 specific functions for TCC assembler + * + * Copyright (c) 2001, 2002 Fabrice Bellard + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#define MAX_OPERANDS 3 + +typedef struct ASMInstr { + uint16_t sym; + uint16_t opcode; + uint16_t instr_type; +#define OPC_JMP 0x01 /* jmp operand */ +#define OPC_B 0x02 /* only used zith OPC_WL */ +#define OPC_WL 0x04 /* accepts w, l or no suffix */ +#define OPC_BWL (OPC_B | OPC_WL) /* accepts b, w, l or no suffix */ +#define OPC_REG 0x08 /* register is added to opcode */ +#define OPC_MODRM 0x10 /* modrm encoding */ +#define OPC_FWAIT 0x20 /* add fwait opcode */ +#define OPC_TEST 0x40 /* test opcodes */ +#define OPC_SHIFT 0x80 /* shift opcodes */ +#define OPC_D16 0x0100 /* generate data16 prefix */ +#define OPC_ARITH 0x0200 /* arithmetic opcodes */ +#define OPC_SHORTJMP 0x0400 /* short jmp operand */ +#define OPC_FARITH 0x0800 /* FPU arithmetic opcodes */ +#define OPC_GROUP_SHIFT 13 + +/* in order to compress the operand type, we use specific operands and + we or only with EA */ +#define OPT_REG8 0 /* warning: value is hardcoded from TOK_ASM_xxx */ +#define OPT_REG16 1 /* warning: value is hardcoded from TOK_ASM_xxx */ +#define OPT_REG32 2 /* warning: value is hardcoded from TOK_ASM_xxx */ +#define OPT_MMX 3 /* warning: value is hardcoded from TOK_ASM_xxx */ +#define OPT_SSE 4 /* warning: value is hardcoded from TOK_ASM_xxx */ +#define OPT_CR 5 /* warning: value is hardcoded from TOK_ASM_xxx */ +#define OPT_TR 6 /* warning: value is hardcoded from TOK_ASM_xxx */ +#define OPT_DB 7 /* warning: value is hardcoded from TOK_ASM_xxx */ +#define OPT_SEG 8 +#define OPT_ST 9 +#define OPT_IM8 10 +#define OPT_IM8S 11 +#define OPT_IM16 12 +#define OPT_IM32 13 +#define OPT_EAX 14 /* %al, %ax or %eax register */ +#define OPT_ST0 15 /* %st(0) register */ +#define OPT_CL 16 /* %cl register */ +#define OPT_DX 17 /* %dx register */ +#define OPT_ADDR 18 /* OP_EA with only offset */ +#define OPT_INDIR 19 /* *(expr) */ + +/* composite types */ +#define OPT_COMPOSITE_FIRST 20 +#define OPT_IM 20 /* IM8 | IM16 | IM32 */ +#define OPT_REG 21 /* REG8 | REG16 | REG32 */ +#define OPT_REGW 22 /* REG16 | REG32 */ +#define OPT_IMW 23 /* IM16 | IM32 */ + +/* can be ored with any OPT_xxx */ +#define OPT_EA 0x80 + + uint8_t nb_ops; + uint8_t op_type[MAX_OPERANDS]; /* see OP_xxx */ +} ASMInstr; + +typedef struct Operand { + uint32_t type; +#define OP_REG8 (1 << OPT_REG8) +#define OP_REG16 (1 << OPT_REG16) +#define OP_REG32 (1 << OPT_REG32) +#define OP_MMX (1 << OPT_MMX) +#define OP_SSE (1 << OPT_SSE) +#define OP_CR (1 << OPT_CR) +#define OP_TR (1 << OPT_TR) +#define OP_DB (1 << OPT_DB) +#define OP_SEG (1 << OPT_SEG) +#define OP_ST (1 << OPT_ST) +#define OP_IM8 (1 << OPT_IM8) +#define OP_IM8S (1 << OPT_IM8S) +#define OP_IM16 (1 << OPT_IM16) +#define OP_IM32 (1 << OPT_IM32) +#define OP_EAX (1 << OPT_EAX) +#define OP_ST0 (1 << OPT_ST0) +#define OP_CL (1 << OPT_CL) +#define OP_DX (1 << OPT_DX) +#define OP_ADDR (1 << OPT_ADDR) +#define OP_INDIR (1 << OPT_INDIR) + +#define OP_EA 0x40000000 +#define OP_REG (OP_REG8 | OP_REG16 | OP_REG32) +#define OP_IM OP_IM32 + int8_t reg; /* register, -1 if none */ + int8_t reg2; /* second register, -1 if none */ + uint8_t shift; + ExprValue e; +} Operand; + +static const uint8_t reg_to_size[5] = { +/* + [OP_REG8] = 0, + [OP_REG16] = 1, + [OP_REG32] = 2, +*/ + 0, 0, 1, 0, 2 +}; + +#define WORD_PREFIX_OPCODE 0x66 + +#define NB_TEST_OPCODES 30 + +static const uint8_t test_bits[NB_TEST_OPCODES] = { + 0x00, /* o */ + 0x01, /* no */ + 0x02, /* b */ + 0x02, /* c */ + 0x02, /* nae */ + 0x03, /* nb */ + 0x03, /* nc */ + 0x03, /* ae */ + 0x04, /* e */ + 0x04, /* z */ + 0x05, /* ne */ + 0x05, /* nz */ + 0x06, /* be */ + 0x06, /* na */ + 0x07, /* nbe */ + 0x07, /* a */ + 0x08, /* s */ + 0x09, /* ns */ + 0x0a, /* p */ + 0x0a, /* pe */ + 0x0b, /* np */ + 0x0b, /* po */ + 0x0c, /* l */ + 0x0c, /* nge */ + 0x0d, /* nl */ + 0x0d, /* ge */ + 0x0e, /* le */ + 0x0e, /* ng */ + 0x0f, /* nle */ + 0x0f, /* g */ +}; + +static const uint8_t segment_prefixes[] = { + 0x26, /* es */ + 0x2e, /* cs */ + 0x36, /* ss */ + 0x3e, /* ds */ + 0x64, /* fs */ + 0x65 /* gs */ +}; + +static const ASMInstr asm_instrs[] = { +#define ALT(x) x +#define DEF_ASM_OP0(name, opcode) +#define DEF_ASM_OP0L(name, opcode, group, instr_type) { TOK_ASM_ ## name, opcode, (instr_type | group << OPC_GROUP_SHIFT), 0 }, +#define DEF_ASM_OP1(name, opcode, group, instr_type, op0) { TOK_ASM_ ## name, opcode, (instr_type | group << OPC_GROUP_SHIFT), 1, { op0 }}, +#define DEF_ASM_OP2(name, opcode, group, instr_type, op0, op1) { TOK_ASM_ ## name, opcode, (instr_type | group << OPC_GROUP_SHIFT), 2, { op0, op1 }}, +#define DEF_ASM_OP3(name, opcode, group, instr_type, op0, op1, op2) { TOK_ASM_ ## name, opcode, (instr_type | group << OPC_GROUP_SHIFT), 3, { op0, op1, op2 }}, +#include "i386-asm.h" + + /* last operation */ + { 0, }, +}; + +static const uint16_t op0_codes[] = { +#define ALT(x) +#define DEF_ASM_OP0(x, opcode) opcode, +#define DEF_ASM_OP0L(name, opcode, group, instr_type) +#define DEF_ASM_OP1(name, opcode, group, instr_type, op0) +#define DEF_ASM_OP2(name, opcode, group, instr_type, op0, op1) +#define DEF_ASM_OP3(name, opcode, group, instr_type, op0, op1, op2) +#include "i386-asm.h" +}; + +static inline int get_reg_shift(TCCState *s1) +{ + int shift, v; + + v = asm_int_expr(s1); + switch(v) { + case 1: + shift = 0; + break; + case 2: + shift = 1; + break; + case 4: + shift = 2; + break; + case 8: + shift = 3; + break; + default: + expect("1, 2, 4 or 8 constant"); + shift = 0; + break; + } + return shift; +} + +static int asm_parse_reg(void) +{ + int reg; + if (tok != '%') + goto error_32; + next(); + if (tok >= TOK_ASM_eax && tok <= TOK_ASM_edi) { + reg = tok - TOK_ASM_eax; + next(); + return reg; + } else { + error_32: + expect("32 bit register"); + return 0; + } +} + +static void parse_operand(TCCState *s1, Operand *op) +{ + ExprValue e; + int reg, indir; + const char *p; + + indir = 0; + if (tok == '*') { + next(); + indir = OP_INDIR; + } + + if (tok == '%') { + next(); + if (tok >= TOK_ASM_al && tok <= TOK_ASM_db7) { + reg = tok - TOK_ASM_al; + op->type = 1 << (reg >> 3); /* WARNING: do not change constant order */ + op->reg = reg & 7; + if ((op->type & OP_REG) && op->reg == TREG_EAX) + op->type |= OP_EAX; + else if (op->type == OP_REG8 && op->reg == TREG_ECX) + op->type |= OP_CL; + else if (op->type == OP_REG16 && op->reg == TREG_EDX) + op->type |= OP_DX; + } else if (tok >= TOK_ASM_dr0 && tok <= TOK_ASM_dr7) { + op->type = OP_DB; + op->reg = tok - TOK_ASM_dr0; + } else if (tok >= TOK_ASM_es && tok <= TOK_ASM_gs) { + op->type = OP_SEG; + op->reg = tok - TOK_ASM_es; + } else if (tok == TOK_ASM_st) { + op->type = OP_ST; + op->reg = 0; + next(); + if (tok == '(') { + next(); + if (tok != TOK_PPNUM) + goto reg_error; + p = tokc.cstr->data; + reg = p[0] - '0'; + if ((unsigned)reg >= 8 || p[1] != '\0') + goto reg_error; + op->reg = reg; + next(); + skip(')'); + } + if (op->reg == 0) + op->type |= OP_ST0; + goto no_skip; + } else { + reg_error: + error("unknown register"); + } + next(); + no_skip: ; + } else if (tok == '$') { + /* constant value */ + next(); + asm_expr(s1, &e); + op->type = OP_IM32; + op->e.v = e.v; + op->e.sym = e.sym; + if (!op->e.sym) { + if (op->e.v == (uint8_t)op->e.v) + op->type |= OP_IM8; + if (op->e.v == (int8_t)op->e.v) + op->type |= OP_IM8S; + if (op->e.v == (uint16_t)op->e.v) + op->type |= OP_IM16; + } + } else { + /* address(reg,reg2,shift) with all variants */ + op->type = OP_EA; + op->reg = -1; + op->reg2 = -1; + op->shift = 0; + if (tok != '(') { + asm_expr(s1, &e); + op->e.v = e.v; + op->e.sym = e.sym; + } else { + op->e.v = 0; + op->e.sym = NULL; + } + if (tok == '(') { + next(); + if (tok != ',') { + op->reg = asm_parse_reg(); + } + if (tok == ',') { + next(); + if (tok != ',') { + op->reg2 = asm_parse_reg(); + } + if (tok == ',') { + next(); + op->shift = get_reg_shift(s1); + } + } + skip(')'); + } + if (op->reg == -1 && op->reg2 == -1) + op->type |= OP_ADDR; + } + op->type |= indir; +} + +/* XXX: unify with C code output ? */ +static void gen_expr32(ExprValue *pe) +{ + if (pe->sym) + greloc(cur_text_section, pe->sym, ind, R_386_32); + gen_le32(pe->v); +} + +/* XXX: unify with C code output ? */ +static void gen_disp32(ExprValue *pe) +{ + Sym *sym; + sym = pe->sym; + if (sym) { + if (sym->r == cur_text_section->sh_num) { + /* same section: we can output an absolute value. Note + that the TCC compiler behaves differently here because + it always outputs a relocation to ease (future) code + elimination in the linker */ + gen_le32(pe->v + (long)sym->next - ind - 4); + } else { + greloc(cur_text_section, sym, ind, R_386_PC32); + gen_le32(pe->v - 4); + } + } else { + /* put an empty PC32 relocation */ + put_elf_reloc(symtab_section, cur_text_section, + ind, R_386_PC32, 0); + gen_le32(pe->v - 4); + } +} + + +static void gen_le16(int v) +{ + g(v); + g(v >> 8); +} + +/* generate the modrm operand */ +static inline void asm_modrm(int reg, Operand *op) +{ + int mod, reg1, reg2, sib_reg1; + + if (op->type & (OP_REG | OP_MMX | OP_SSE)) { + g(0xc0 + (reg << 3) + op->reg); + } else if (op->reg == -1 && op->reg2 == -1) { + /* displacement only */ + g(0x05 + (reg << 3)); + gen_expr32(&op->e); + } else { + sib_reg1 = op->reg; + /* fist compute displacement encoding */ + if (sib_reg1 == -1) { + sib_reg1 = 5; + mod = 0x00; + } else if (op->e.v == 0 && !op->e.sym && op->reg != 5) { + mod = 0x00; + } else if (op->e.v == (int8_t)op->e.v && !op->e.sym) { + mod = 0x40; + } else { + mod = 0x80; + } + /* compute if sib byte needed */ + reg1 = op->reg; + if (op->reg2 != -1) + reg1 = 4; + g(mod + (reg << 3) + reg1); + if (reg1 == 4) { + /* add sib byte */ + reg2 = op->reg2; + if (reg2 == -1) + reg2 = 4; /* indicate no index */ + g((op->shift << 6) + (reg2 << 3) + sib_reg1); + } + + /* add offset */ + if (mod == 0x40) { + g(op->e.v); + } else if (mod == 0x80 || op->reg == -1) { + gen_expr32(&op->e); + } + } +} + +static void asm_opcode(TCCState *s1, int opcode) +{ + const ASMInstr *pa; + int i, modrm_index, reg, v, op1, is_short_jmp, seg_prefix; + int nb_ops, s, ss; + Operand ops[MAX_OPERANDS], *pop; + int op_type[3]; /* decoded op type */ + + /* get operands */ + pop = ops; + nb_ops = 0; + seg_prefix = 0; + for(;;) { + if (tok == ';' || tok == TOK_LINEFEED) + break; + if (nb_ops >= MAX_OPERANDS) { + error("incorrect number of operands"); + } + parse_operand(s1, pop); + if (tok == ':') { + if (pop->type != OP_SEG || seg_prefix) { + error("incorrect prefix"); + } + seg_prefix = segment_prefixes[pop->reg]; + next(); + parse_operand(s1, pop); + if (!(pop->type & OP_EA)) { + error("segment prefix must be followed by memory reference"); + } + } + pop++; + nb_ops++; + if (tok != ',') + break; + next(); + } + + is_short_jmp = 0; + s = 0; /* avoid warning */ + + /* optimize matching by using a lookup table (no hashing is needed + !) */ + for(pa = asm_instrs; pa->sym != 0; pa++) { + s = 0; + if (pa->instr_type & OPC_FARITH) { + v = opcode - pa->sym; + if (!((unsigned)v < 8 * 6 && (v % 6) == 0)) + continue; + } else if (pa->instr_type & OPC_ARITH) { + if (!(opcode >= pa->sym && opcode < pa->sym + 8 * 4)) + continue; + goto compute_size; + } else if (pa->instr_type & OPC_SHIFT) { + if (!(opcode >= pa->sym && opcode < pa->sym + 7 * 4)) + continue; + goto compute_size; + } else if (pa->instr_type & OPC_TEST) { + if (!(opcode >= pa->sym && opcode < pa->sym + NB_TEST_OPCODES)) + continue; + } else if (pa->instr_type & OPC_B) { + if (!(opcode >= pa->sym && opcode <= pa->sym + 3)) + continue; + compute_size: + s = (opcode - pa->sym) & 3; + } else if (pa->instr_type & OPC_WL) { + if (!(opcode >= pa->sym && opcode <= pa->sym + 2)) + continue; + s = opcode - pa->sym + 1; + } else { + if (pa->sym != opcode) + continue; + } + if (pa->nb_ops != nb_ops) + continue; + /* now decode and check each operand */ + for(i = 0; i < nb_ops; i++) { + int op1, op2; + op1 = pa->op_type[i]; + op2 = op1 & 0x1f; + switch(op2) { + case OPT_IM: + v = OP_IM8 | OP_IM16 | OP_IM32; + break; + case OPT_REG: + v = OP_REG8 | OP_REG16 | OP_REG32; + break; + case OPT_REGW: + v = OP_REG16 | OP_REG32; + break; + case OPT_IMW: + v = OP_IM16 | OP_IM32; + break; + default: + v = 1 << op2; + break; + } + if (op1 & OPT_EA) + v |= OP_EA; + op_type[i] = v; + if ((ops[i].type & v) == 0) + goto next; + } + /* all is matching ! */ + break; + next: ; + } + if (pa->sym == 0) { + if (opcode >= TOK_ASM_pusha && opcode <= TOK_ASM_emms) { + int b; + b = op0_codes[opcode - TOK_ASM_pusha]; + if (b & 0xff00) + g(b >> 8); + g(b); + return; + } else { + error("unknown opcode '%s'", + get_tok_str(opcode, NULL)); + } + } + /* if the size is unknown, then evaluate it (OPC_B or OPC_WL case) */ + if (s == 3) { + for(i = 0; s == 3 && i < nb_ops; i++) { + if ((ops[i].type & OP_REG) && !(op_type[i] & (OP_CL | OP_DX))) + s = reg_to_size[ops[i].type & OP_REG]; + } + if (s == 3) { + if ((opcode == TOK_ASM_push || opcode == TOK_ASM_pop) && + (ops[0].type & (OP_SEG | OP_IM8S | OP_IM32))) + s = 2; + else + error("cannot infer opcode suffix"); + } + } + + /* generate data16 prefix if needed */ + ss = s; + if (s == 1 || (pa->instr_type & OPC_D16)) + g(WORD_PREFIX_OPCODE); + else if (s == 2) + s = 1; + /* now generates the operation */ + if (pa->instr_type & OPC_FWAIT) + g(0x9b); + if (seg_prefix) + g(seg_prefix); + + v = pa->opcode; + if (v == 0x69 || v == 0x69) { + /* kludge for imul $im, %reg */ + nb_ops = 3; + ops[2] = ops[1]; + } else if (v == 0xcd && ops[0].e.v == 3 && !ops[0].e.sym) { + v--; /* int $3 case */ + nb_ops = 0; + } else if ((v == 0x06 || v == 0x07)) { + if (ops[0].reg >= 4) { + /* push/pop %fs or %gs */ + v = 0x0fa0 + (v - 0x06) + ((ops[0].reg - 4) << 3); + } else { + v += ops[0].reg << 3; + } + nb_ops = 0; + } else if (v <= 0x05) { + /* arith case */ + v += ((opcode - TOK_ASM_addb) >> 2) << 3; + } else if ((pa->instr_type & (OPC_FARITH | OPC_MODRM)) == OPC_FARITH) { + /* fpu arith case */ + v += ((opcode - pa->sym) / 6) << 3; + } + if (pa->instr_type & OPC_REG) { + for(i = 0; i < nb_ops; i++) { + if (op_type[i] & (OP_REG | OP_ST)) { + v += ops[i].reg; + break; + } + } + /* mov $im, %reg case */ + if (pa->opcode == 0xb0 && s >= 1) + v += 7; + } + if (pa->instr_type & OPC_B) + v += s; + if (pa->instr_type & OPC_TEST) + v += test_bits[opcode - pa->sym]; + if (pa->instr_type & OPC_SHORTJMP) { + Sym *sym; + int jmp_disp; + + /* see if we can really generate the jump with a byte offset */ + sym = ops[0].e.sym; + if (!sym) + goto no_short_jump; + if (sym->r != cur_text_section->sh_num) + goto no_short_jump; + jmp_disp = ops[0].e.v + (long)sym->next - ind - 2; + if (jmp_disp == (int8_t)jmp_disp) { + /* OK to generate jump */ + is_short_jmp = 1; + ops[0].e.v = jmp_disp; + } else { + no_short_jump: + if (pa->instr_type & OPC_JMP) { + /* long jump will be allowed. need to modify the + opcode slightly */ + if (v == 0xeb) + v = 0xe9; + else + v += 0x0f10; + } else { + error("invalid displacement"); + } + } + } + op1 = v >> 8; + if (op1) + g(op1); + g(v); + + /* search which operand will used for modrm */ + modrm_index = 0; + if (pa->instr_type & OPC_SHIFT) { + reg = (opcode - pa->sym) >> 2; + if (reg == 6) + reg = 7; + } else if (pa->instr_type & OPC_ARITH) { + reg = (opcode - pa->sym) >> 2; + } else if (pa->instr_type & OPC_FARITH) { + reg = (opcode - pa->sym) / 6; + } else { + reg = (pa->instr_type >> OPC_GROUP_SHIFT) & 7; + } + if (pa->instr_type & OPC_MODRM) { + /* first look for an ea operand */ + for(i = 0;i < nb_ops; i++) { + if (op_type[i] & OP_EA) + goto modrm_found; + } + /* then if not found, a register or indirection (shift instructions) */ + for(i = 0;i < nb_ops; i++) { + if (op_type[i] & (OP_REG | OP_MMX | OP_SSE | OP_INDIR)) + goto modrm_found; + } +#ifdef ASM_DEBUG + error("bad op table"); +#endif + modrm_found: + modrm_index = i; + /* if a register is used in another operand then it is + used instead of group */ + for(i = 0;i < nb_ops; i++) { + v = op_type[i]; + if (i != modrm_index && + (v & (OP_REG | OP_MMX | OP_SSE | OP_CR | OP_TR | OP_DB | OP_SEG))) { + reg = ops[i].reg; + break; + } + } + + asm_modrm(reg, &ops[modrm_index]); + } + + /* emit constants */ + if (pa->opcode == 0x9a || pa->opcode == 0xea) { + /* ljmp or lcall kludge */ + gen_expr32(&ops[1].e); + if (ops[0].e.sym) + error("cannot relocate"); + gen_le16(ops[0].e.v); + } else { + for(i = 0;i < nb_ops; i++) { + v = op_type[i]; + if (v & (OP_IM8 | OP_IM16 | OP_IM32 | OP_IM8S | OP_ADDR)) { + /* if multiple sizes are given it means we must look + at the op size */ + if (v == (OP_IM8 | OP_IM16 | OP_IM32) || + v == (OP_IM16 | OP_IM32)) { + if (ss == 0) + v = OP_IM8; + else if (ss == 1) + v = OP_IM16; + else + v = OP_IM32; + } + if (v & (OP_IM8 | OP_IM8S)) { + if (ops[i].e.sym) + goto error_relocate; + g(ops[i].e.v); + } else if (v & OP_IM16) { + if (ops[i].e.sym) { + error_relocate: + error("cannot relocate"); + } + gen_le16(ops[i].e.v); + } else { + if (pa->instr_type & (OPC_JMP | OPC_SHORTJMP)) { + if (is_short_jmp) + g(ops[i].e.v); + else + gen_disp32(&ops[i].e); + } else { + gen_expr32(&ops[i].e); + } + } + } + } + } +} + +#define NB_SAVED_REGS 3 +#define NB_ASM_REGS 8 + +/* return the constraint priority (we allocate first the lowest + numbered constraints) */ +static inline int constraint_priority(const char *str) +{ + int priority, c, pr; + + /* we take the lowest priority */ + priority = 0; + for(;;) { + c = *str; + if (c == '\0') + break; + str++; + switch(c) { + case 'A': + pr = 0; + break; + case 'a': + case 'b': + case 'c': + case 'd': + case 'S': + case 'D': + pr = 1; + break; + case 'q': + pr = 2; + break; + case 'r': + pr = 3; + break; + case 'N': + case 'M': + case 'I': + case 'i': + case 'm': + case 'g': + pr = 4; + break; + default: + error("unknown constraint '%c'", c); + pr = 0; + } + if (pr > priority) + priority = pr; + } + return priority; +} + +static const char *skip_constraint_modifiers(const char *p) +{ + while (*p == '=' || *p == '&' || *p == '+' || *p == '%') + p++; + return p; +} + +#define REG_OUT_MASK 0x01 +#define REG_IN_MASK 0x02 + +#define is_reg_allocated(reg) (regs_allocated[reg] & reg_mask) + +static void asm_compute_constraints(ASMOperand *operands, + int nb_operands, int nb_outputs, + const uint8_t *clobber_regs, + int *pout_reg) +{ + ASMOperand *op; + int sorted_op[MAX_ASM_OPERANDS]; + int i, j, k, p1, p2, tmp, reg, c, reg_mask; + const char *str; + uint8_t regs_allocated[NB_ASM_REGS]; + + /* init fields */ + for(i=0;i<nb_operands;i++) { + op = &operands[i]; + op->input_index = -1; + op->ref_index = -1; + op->reg = -1; + op->is_memory = 0; + op->is_rw = 0; + } + /* compute constraint priority and evaluate references to output + constraints if input constraints */ + for(i=0;i<nb_operands;i++) { + op = &operands[i]; + str = op->constraint; + str = skip_constraint_modifiers(str); + if (isnum(*str) || *str == '[') { + /* this is a reference to another constraint */ + k = find_constraint(operands, nb_operands, str, NULL); + if ((unsigned)k >= i || i < nb_outputs) + error("invalid reference in constraint %d ('%s')", + i, str); + op->ref_index = k; + if (operands[k].input_index >= 0) + error("cannot reference twice the same operand"); + operands[k].input_index = i; + op->priority = 5; + } else { + op->priority = constraint_priority(str); + } + } + + /* sort operands according to their priority */ + for(i=0;i<nb_operands;i++) + sorted_op[i] = i; + for(i=0;i<nb_operands - 1;i++) { + for(j=i+1;j<nb_operands;j++) { + p1 = operands[sorted_op[i]].priority; + p2 = operands[sorted_op[j]].priority; + if (p2 < p1) { + tmp = sorted_op[i]; + sorted_op[i] = sorted_op[j]; + sorted_op[j] = tmp; + } + } + } + + for(i = 0;i < NB_ASM_REGS; i++) { + if (clobber_regs[i]) + regs_allocated[i] = REG_IN_MASK | REG_OUT_MASK; + else + regs_allocated[i] = 0; + } + /* esp cannot be used */ + regs_allocated[4] = REG_IN_MASK | REG_OUT_MASK; + /* ebp cannot be used yet */ + regs_allocated[5] = REG_IN_MASK | REG_OUT_MASK; + + /* allocate registers and generate corresponding asm moves */ + for(i=0;i<nb_operands;i++) { + j = sorted_op[i]; + op = &operands[j]; + str = op->constraint; + /* no need to allocate references */ + if (op->ref_index >= 0) + continue; + /* select if register is used for output, input or both */ + if (op->input_index >= 0) { + reg_mask = REG_IN_MASK | REG_OUT_MASK; + } else if (j < nb_outputs) { + reg_mask = REG_OUT_MASK; + } else { + reg_mask = REG_IN_MASK; + } + try_next: + c = *str++; + switch(c) { + case '=': + goto try_next; + case '+': + op->is_rw = 1; + /* FALL THRU */ + case '&': + if (j >= nb_outputs) + error("'%c' modifier can only be applied to outputs", c); + reg_mask = REG_IN_MASK | REG_OUT_MASK; + goto try_next; + case 'A': + /* allocate both eax and edx */ + if (is_reg_allocated(TREG_EAX) || + is_reg_allocated(TREG_EDX)) + goto try_next; + op->is_llong = 1; + op->reg = TREG_EAX; + regs_allocated[TREG_EAX] |= reg_mask; + regs_allocated[TREG_EDX] |= reg_mask; + break; + case 'a': + reg = TREG_EAX; + goto alloc_reg; + case 'b': + reg = 3; + goto alloc_reg; + case 'c': + reg = TREG_ECX; + goto alloc_reg; + case 'd': + reg = TREG_EDX; + goto alloc_reg; + case 'S': + reg = 6; + goto alloc_reg; + case 'D': + reg = 7; + alloc_reg: + if (is_reg_allocated(reg)) + goto try_next; + goto reg_found; + case 'q': + /* eax, ebx, ecx or edx */ + for(reg = 0; reg < 4; reg++) { + if (!is_reg_allocated(reg)) + goto reg_found; + } + goto try_next; + case 'r': + /* any general register */ + for(reg = 0; reg < 8; reg++) { + if (!is_reg_allocated(reg)) + goto reg_found; + } + goto try_next; + reg_found: + /* now we can reload in the register */ + op->is_llong = 0; + op->reg = reg; + regs_allocated[reg] |= reg_mask; + break; + case 'i': + if (!((op->vt->r & (VT_VALMASK | VT_LVAL)) == VT_CONST)) + goto try_next; + break; + case 'I': + case 'N': + case 'M': + if (!((op->vt->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST)) + goto try_next; + break; + case 'm': + case 'g': + /* nothing special to do because the operand is already in + memory, except if the pointer itself is stored in a + memory variable (VT_LLOCAL case) */ + /* XXX: fix constant case */ + /* if it is a reference to a memory zone, it must lie + in a register, so we reserve the register in the + input registers and a load will be generated + later */ + if (j < nb_outputs || c == 'm') { + if ((op->vt->r & VT_VALMASK) == VT_LLOCAL) { + /* any general register */ + for(reg = 0; reg < 8; reg++) { + if (!(regs_allocated[reg] & REG_IN_MASK)) + goto reg_found1; + } + goto try_next; + reg_found1: + /* now we can reload in the register */ + regs_allocated[reg] |= REG_IN_MASK; + op->reg = reg; + op->is_memory = 1; + } + } + break; + default: + error("asm constraint %d ('%s') could not be satisfied", + j, op->constraint); + break; + } + /* if a reference is present for that operand, we assign it too */ + if (op->input_index >= 0) { + operands[op->input_index].reg = op->reg; + operands[op->input_index].is_llong = op->is_llong; + } + } + + /* compute out_reg. It is used to store outputs registers to memory + locations references by pointers (VT_LLOCAL case) */ + *pout_reg = -1; + for(i=0;i<nb_operands;i++) { + op = &operands[i]; + if (op->reg >= 0 && + (op->vt->r & VT_VALMASK) == VT_LLOCAL && + !op->is_memory) { + for(reg = 0; reg < 8; reg++) { + if (!(regs_allocated[reg] & REG_OUT_MASK)) + goto reg_found2; + } + error("could not find free output register for reloading"); + reg_found2: + *pout_reg = reg; + break; + } + } + + /* print sorted constraints */ +#ifdef ASM_DEBUG + for(i=0;i<nb_operands;i++) { + j = sorted_op[i]; + op = &operands[j]; + printf("%%%d [%s]: \"%s\" r=0x%04x reg=%d\n", + j, + op->id ? get_tok_str(op->id, NULL) : "", + op->constraint, + op->vt->r, + op->reg); + } + if (*pout_reg >= 0) + printf("out_reg=%d\n", *pout_reg); +#endif +} + +static void subst_asm_operand(CString *add_str, + SValue *sv, int modifier) +{ + int r, reg, size, val; + char buf[64]; + + r = sv->r; + if ((r & VT_VALMASK) == VT_CONST) { + if (!(r & VT_LVAL) && modifier != 'c' && modifier != 'n') + cstr_ccat(add_str, '$'); + if (r & VT_SYM) { + cstr_cat(add_str, get_tok_str(sv->sym->v, NULL)); + if (sv->c.i != 0) { + cstr_ccat(add_str, '+'); + } else { + return; + } + } + val = sv->c.i; + if (modifier == 'n') + val = -val; + snprintf(buf, sizeof(buf), "%d", sv->c.i); + cstr_cat(add_str, buf); + } else if ((r & VT_VALMASK) == VT_LOCAL) { + snprintf(buf, sizeof(buf), "%d(%%ebp)", sv->c.i); + cstr_cat(add_str, buf); + } else if (r & VT_LVAL) { + reg = r & VT_VALMASK; + if (reg >= VT_CONST) + error("internal compiler error"); + snprintf(buf, sizeof(buf), "(%%%s)", + get_tok_str(TOK_ASM_eax + reg, NULL)); + cstr_cat(add_str, buf); + } else { + /* register case */ + reg = r & VT_VALMASK; + if (reg >= VT_CONST) + error("internal compiler error"); + + /* choose register operand size */ + if ((sv->type.t & VT_BTYPE) == VT_BYTE) + size = 1; + else if ((sv->type.t & VT_BTYPE) == VT_SHORT) + size = 2; + else + size = 4; + if (size == 1 && reg >= 4) + size = 4; + + if (modifier == 'b') { + if (reg >= 4) + error("cannot use byte register"); + size = 1; + } else if (modifier == 'h') { + if (reg >= 4) + error("cannot use byte register"); + size = -1; + } else if (modifier == 'w') { + size = 2; + } + + switch(size) { + case -1: + reg = TOK_ASM_ah + reg; + break; + case 1: + reg = TOK_ASM_al + reg; + break; + case 2: + reg = TOK_ASM_ax + reg; + break; + default: + reg = TOK_ASM_eax + reg; + break; + } + snprintf(buf, sizeof(buf), "%%%s", get_tok_str(reg, NULL)); + cstr_cat(add_str, buf); + } +} + +/* generate prolog and epilog code for asm statement */ +static void asm_gen_code(ASMOperand *operands, int nb_operands, + int nb_outputs, int is_output, + uint8_t *clobber_regs, + int out_reg) +{ + uint8_t regs_allocated[NB_ASM_REGS]; + ASMOperand *op; + int i, reg; + static uint8_t reg_saved[NB_SAVED_REGS] = { 3, 6, 7 }; + + /* mark all used registers */ + memcpy(regs_allocated, clobber_regs, sizeof(regs_allocated)); + for(i = 0; i < nb_operands;i++) { + op = &operands[i]; + if (op->reg >= 0) + regs_allocated[op->reg] = 1; + } + if (!is_output) { + /* generate reg save code */ + for(i = 0; i < NB_SAVED_REGS; i++) { + reg = reg_saved[i]; + if (regs_allocated[reg]) + g(0x50 + reg); + } + + /* generate load code */ + for(i = 0; i < nb_operands; i++) { + op = &operands[i]; + if (op->reg >= 0) { + if ((op->vt->r & VT_VALMASK) == VT_LLOCAL && + op->is_memory) { + /* memory reference case (for both input and + output cases) */ + SValue sv; + sv = *op->vt; + sv.r = (sv.r & ~VT_VALMASK) | VT_LOCAL; + load(op->reg, &sv); + } else if (i >= nb_outputs || op->is_rw) { + /* load value in register */ + load(op->reg, op->vt); + if (op->is_llong) { + SValue sv; + sv = *op->vt; + sv.c.ul += 4; + load(TREG_EDX, &sv); + } + } + } + } + } else { + /* generate save code */ + for(i = 0 ; i < nb_outputs; i++) { + op = &operands[i]; + if (op->reg >= 0) { + if ((op->vt->r & VT_VALMASK) == VT_LLOCAL) { + if (!op->is_memory) { + SValue sv; + sv = *op->vt; + sv.r = (sv.r & ~VT_VALMASK) | VT_LOCAL; + load(out_reg, &sv); + + sv.r = (sv.r & ~VT_VALMASK) | out_reg; + store(op->reg, &sv); + } + } else { + store(op->reg, op->vt); + if (op->is_llong) { + SValue sv; + sv = *op->vt; + sv.c.ul += 4; + store(TREG_EDX, &sv); + } + } + } + } + /* generate reg restore code */ + for(i = NB_SAVED_REGS - 1; i >= 0; i--) { + reg = reg_saved[i]; + if (regs_allocated[reg]) + g(0x58 + reg); + } + } +} + +static void asm_clobber(uint8_t *clobber_regs, const char *str) +{ + int reg; + TokenSym *ts; + + if (!strcmp(str, "memory") || + !strcmp(str, "cc")) + return; + ts = tok_alloc(str, strlen(str)); + reg = ts->tok; + if (reg >= TOK_ASM_eax && reg <= TOK_ASM_edi) { + reg -= TOK_ASM_eax; + } else if (reg >= TOK_ASM_ax && reg <= TOK_ASM_di) { + reg -= TOK_ASM_ax; + } else { + error("invalid clobber register '%s'", str); + } + clobber_regs[reg] = 1; +} |