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84 lines
2.2 KiB
84 lines
2.2 KiB
#include "boot.h"
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "cpu.h"
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#include "insn.h"
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#include "log.h"
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#include "psx.h"
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static const uint8_t MAGIC[0x10] = "PS-X EXE";
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static const uint8_t RESERVED[0x10] = {0};
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psx_header_t parse_psx_header(byte_arr_t *prgm) {
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psx_header_t header;
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// TODO: Convert asserts into recoverable error
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debug("Checking header struct size");
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assert(sizeof header == 0x38 - 0x10);
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debug("Checking program size is greater than header");
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assert(prgm->size >= 0x800);
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debug("Checking magic number in header");
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assert(memcmp(MAGIC, prgm->data, sizeof MAGIC) == 0);
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memcpy(&header, &prgm->data[sizeof MAGIC], sizeof header);
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debug("Checking file size in header matches program size");
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assert(header.size_file == prgm->size - 0x800);
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debug("Checking A34h region is zero");
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assert(memcmp(RESERVED, &prgm->data[0x38], sizeof RESERVED) == 0);
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return header;
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}
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uint32_t translate_addr(uint32_t addr) {
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if (addr >= 0xA0000000) {
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addr = addr - 0xA0000000;
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} else if (addr >= 0x80000000) {
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addr = addr - 0x80000000;
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}
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return addr;
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}
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void boot_psx_prgm(byte_arr_t *prgm) {
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debug("Parsing program header");
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psx_header_t header = parse_psx_header(prgm);
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debug("Program header");
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debug("size=%u bytes", header.size_file);
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debug("pc=%08x, gp=%08x, sp=%08x, fp=%08x", header.pc, header.gp, header.sp,
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header.fp);
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debug("data=%08x (%u bytes)", header.addr_data, header.size_data);
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debug("bss=%08x (%u bytes)", header.addr_bss, header.size_bss);
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debug("dest=%08x", header.addr_dest);
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cpu_t *cpu = malloc(sizeof *cpu);
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uint32_t start = translate_addr(header.addr_dest);
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assert(start + header.size_file < MAIN_RAM_SIZE);
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memcpy(&cpu->main_ram[start], &prgm->data[0x800], header.size_file);
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cpu->pc = header.pc;
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cpu->regs[REG_GP] = header.gp;
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cpu->regs[REG_SP] = header.sp;
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cpu->regs[REG_FP] = header.fp;
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psx_t psx = {header, cpu};
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while (1) {
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debug("Executing instruction at %08x", psx.cpu->pc);
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const uint32_t insn = cpu_read32(cpu, psx.cpu->pc);
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insn_execute(cpu, insn);
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psx.cpu->pc += 4;
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}
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}
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