365 lines
11 KiB
C
365 lines
11 KiB
C
#include <merror.h>
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#include <mips.h>
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#include <mips32.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <elf.h>
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#include <string.h>
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#include <stddef.h>
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#include "asm.h"
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#include "mlimits.h"
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#include "parse.h"
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#include "parse_mips32.h"
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extern char *current_file;
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#define SHDR_SYMTBL 0
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#define SHDR_STRTBL 1
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#define SHDR_SECTIONS 2
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static int parse_file(struct parser *parser)
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{
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while (1) {
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struct expr expr;
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if (parser_next(parser, &expr)) {
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break;
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}
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if (expr.type == EXPR_INS)
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if (sectbl_push(&parser->sec_tbl,
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parser->sec_tbl.current, expr.ins))
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return M_ERROR;
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}
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for (uint32_t i = 0; i < parser->ref_tbl.count; i++) {
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struct reference *ref = &parser->ref_tbl.references[i];
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struct symbol *sym;
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struct mips32_instruction *ins;
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if (symtbl_find(&parser->sym_tbl, &sym, ref->name)) {
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ERROR("undefined symbol '%s'", ref->name);
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return M_ERROR;
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}
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ins = &ref->section->ins[ref->index].mips32;
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switch (ref->type) {
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case REF_OFFESET:
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ins->B_data.offset += sym->position -
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(ref->section->start + ref->index);
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break;
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case REF_TARGET:
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ins->J_data.target += sym->position;
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break;
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}
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};
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return M_SUCCESS;
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}
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static int assemble_phdr(struct assembler *asm, Elf32_Phdr **res,
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uint32_t *res2)
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{
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struct parser *parser = asm->parser;
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Elf32_Phdr *phdr = malloc(sizeof(Elf32_Phdr) *
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parser->sec_tbl.count);
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size_t ins_sz = sizeof(struct mips32_instruction);
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if (phdr == NULL) {
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ERROR("cannot alloc");
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return M_ERROR;;
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}
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for (uint32_t i = 0; i < parser->sec_tbl.count; i++) {
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Elf32_Phdr *hdr = &phdr[i];
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struct section *sec = &parser->sec_tbl.sections[i];
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hdr->p_type = PT_LOAD;
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hdr->p_flags = PF_X | PF_W | PF_R; // FIXME: this is bad
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hdr->p_offset = sec->start * ins_sz;
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hdr->p_vaddr = sec->start * ins_sz;
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hdr->p_paddr = 0x00;
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hdr->p_filesz = sec->count * ins_sz;
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hdr->p_memsz = sec->count * ins_sz;
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hdr->p_align = sec->alignment;
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}
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*res = phdr;
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*res2 = parser->sec_tbl.count;
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return M_SUCCESS;
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}
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static int assemble_symtbl(struct assembler *asm, Elf32_Sym **res,
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uint32_t *res2)
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{
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Elf32_Sym *stbl = malloc(sizeof(Elf32_Sym) * asm->parser->sym_tbl
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.count);
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if (stbl == NULL)
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return M_ERROR;
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for (uint32_t i = 0; i < asm->parser->sym_tbl.count; i++) {
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struct symbol *sym = &asm->parser->sym_tbl.symbols[i];
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size_t str_off;
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if (strtbl_write_str(&asm->str_tbl, sym->name, &str_off)) {
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free(stbl);
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return M_ERROR;
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}
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int viz = STB_LOCAL;
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switch (sym->flag) {
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case SYM_LOCAL:
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viz = STB_LOCAL;
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break;
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case SYM_GLOBAL:
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case SYM_EXTERNAL:
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viz = STB_GLOBAL;
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break;
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}
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stbl[i] = (Elf32_Sym) {
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.st_name = str_off,
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.st_value = sym->position,
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.st_size = 0,
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.st_info = (unsigned char)
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ELF32_ST_INFO(SYMINFO_BT_SELF,
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SYMINFO_FLG_DIRECT),
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.st_other = (unsigned char)
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ELF32_ST_VISIBILITY(viz),
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.st_shndx = 0, // FIXME: specify section
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};
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};
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*res = stbl;
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*res2 = asm->parser->sym_tbl.count;
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return M_SUCCESS;
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}
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static int assemble_shdr(struct assembler *asm, Elf32_Shdr **res,
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uint32_t *res2)
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{
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uint32_t entries = 2; // str table and sym tabel
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entries += asm->parser->sec_tbl.count; // sections
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Elf32_Shdr *shdr = malloc(sizeof(Elf32_Shdr) * entries);
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size_t str_off;
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if (strtbl_write_str(&asm->str_tbl, ".shsymtab", &str_off)) {
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free(shdr);
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return M_ERROR;
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}
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// symbol table
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shdr[SHDR_SYMTBL] = (Elf32_Shdr) {
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.sh_name = str_off,
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.sh_type = SHT_SYMTAB,
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.sh_flags = 0,
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.sh_addr = 0,
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.sh_offset = 0,
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.sh_size = 0,
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.sh_link = 1,
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.sh_info = 0,
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.sh_addralign = 1,
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.sh_entsize = sizeof(Elf32_Sym),
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};
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if (strtbl_write_str(&asm->str_tbl, ".shstrtab", &str_off)) {
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free(shdr);
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return M_ERROR;
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}
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// string table
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shdr[SHDR_STRTBL] = (Elf32_Shdr) {
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.sh_name = str_off,
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.sh_type = SHT_STRTAB,
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.sh_flags = SHF_STRINGS,
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.sh_addr = 0,
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.sh_offset = 0,
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.sh_size = 0,
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.sh_link = 0,
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.sh_info = 0,
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.sh_addralign = 1,
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.sh_entsize = 0,
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};
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// for each section
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for (uint32_t i = 0; i < asm->parser->sec_tbl.count; i++) {
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struct section *sec = &asm->parser->sec_tbl.sections[i];
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char name[MAX_LEX_LENGTH+1] = ".";
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strcat(name, sec->name);
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if (strtbl_write_str(&asm->str_tbl, name, &str_off)) {
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free(shdr);
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return M_ERROR;
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}
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shdr[i+SHDR_SECTIONS] = (Elf32_Shdr) {
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.sh_name = str_off,
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.sh_type = SHT_PROGBITS,
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.sh_flags = SHF_WRITE | SHF_ALLOC | SHF_EXECINSTR,
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.sh_addr = 0,
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.sh_offset = 0,
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.sh_size = 0,
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.sh_link = 0,
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.sh_info = 0,
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.sh_addralign = sec->alignment,
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.sh_entsize = sizeof(struct mips32_instruction),
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};
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}
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*res = shdr;
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*res2 = entries;
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return M_SUCCESS;
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}
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static int assemble_file(struct assembler *asm)
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{
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Elf32_Phdr *phdr;
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Elf32_Shdr *shdr;
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Elf32_Sym *symtbl;
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uint32_t phdr_len;
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uint32_t shdr_len;
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uint32_t symtbl_len;
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if (assemble_symtbl(asm, &symtbl, &symtbl_len))
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return M_ERROR;
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if (assemble_phdr(asm, &phdr, &phdr_len)) {
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free(symtbl);
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return M_ERROR;
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}
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if (assemble_shdr(asm, &shdr, &shdr_len)) {
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free(symtbl);
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free(phdr);
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return M_ERROR;
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};
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Elf32_Ehdr ehdr = {
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.e_ident = {
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[EI_MAG0] = ELFMAG0,
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[EI_MAG1] = ELFMAG1,
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[EI_MAG2] = ELFMAG2,
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[EI_MAG3] = ELFMAG3,
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[EI_CLASS] = ELFCLASS32,
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[EI_DATA] = ELFDATA2LSB,
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[EI_VERSION] = EV_CURRENT,
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[EI_OSABI] = ELFOSABI_NONE,
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[EI_ABIVERSION] = 0x00,
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[EI_PAD] = 0x00,
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},
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.e_type = ET_REL,
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.e_machine = EM_MIPS,
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.e_version = EV_CURRENT,
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.e_entry = 0x00,
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.e_phoff = 0x00,
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.e_shoff = 0x00,
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.e_flags = EF_MIPS_ARCH_32R6,
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.e_ehsize = sizeof(Elf32_Ehdr),
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.e_phentsize = sizeof(Elf32_Phdr),
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.e_phnum = phdr_len,
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.e_shentsize = sizeof(Elf32_Shdr),
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.e_shnum = shdr_len,
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.e_shstrndx = SHDR_STRTBL,
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};
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uint32_t ptr = 0;
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// we must now correct offets and sizes inside the ehdr, phdr,
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// and shdr
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ptr += sizeof(Elf32_Ehdr);
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// phdr
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ehdr.e_phoff = ptr;
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ptr += phdr_len * sizeof(Elf32_Phdr);
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// sections
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for (uint32_t i = 0; i < asm->parser->sec_tbl.count; i++) {
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phdr[i].p_offset = ptr;
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phdr[i].p_vaddr = ptr;
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shdr[i+SHDR_SECTIONS].sh_offset = ptr;
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shdr[i+SHDR_SECTIONS].sh_size = phdr[i].p_filesz;
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ptr += phdr[i].p_filesz;
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}
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// symtbl
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shdr[SHDR_SYMTBL].sh_offset = ptr;
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shdr[SHDR_SYMTBL].sh_size = symtbl_len * sizeof(Elf32_Sym);
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ptr += symtbl_len * sizeof(Elf32_Sym);
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// strtbl
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shdr[SHDR_STRTBL].sh_offset = ptr;
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shdr[SHDR_STRTBL].sh_size = asm->str_tbl.size;
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ptr += asm->str_tbl.size;
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// shdr
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ehdr.e_shoff = ptr;
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FILE *out = fopen("out.o", "w");
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// ehdr
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fwrite(&ehdr, sizeof(Elf32_Ehdr), 1, out);
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// phdr
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fwrite(phdr, sizeof(Elf32_Phdr), phdr_len, out);
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// sections
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for (uint32_t i = 0; i < asm->parser->sec_tbl.count; i++) {
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struct section *sec = &asm->parser->sec_tbl.sections[i];
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for (uint32_t j = 0; j < sec->count; j++) {
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struct mips32_instruction *ins = &sec->ins[j].mips32;
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fwrite(ins, sizeof(struct mips32_instruction),
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1, out);
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}
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}
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// sym tbl
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fwrite(symtbl, sizeof(Elf32_Sym), symtbl_len, out);
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// str tbl
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fwrite(asm->str_tbl.ptr, asm->str_tbl.size, 1, out);
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// shdr
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fwrite(shdr, sizeof(Elf32_Shdr), shdr_len, out);
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fclose(out);
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free(shdr);
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free(phdr);
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free(symtbl);
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return M_SUCCESS;
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}
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int assemble_file_mips32(char *path)
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{
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struct lexer lexer;
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struct parser parser;
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current_file = path;
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int res = M_SUCCESS;
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if (lexer_init(current_file, &lexer))
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return M_ERROR;
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if (mips32_parser_init(&lexer, &parser))
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return M_ERROR;
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if (res == M_SUCCESS)
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res = parse_file(&parser);
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struct assembler assembler;
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assembler.parser = &parser;
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strtbl_init(&assembler.str_tbl);
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if (res == M_SUCCESS)
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res = assemble_file(&assembler);
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strtbl_free(&assembler.str_tbl);
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lexer_free(&lexer);
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parser_free(&parser);
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return res;
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}
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