More real ELF loading and brk handling; more tests pass.
This commit is contained in:
David Given
parent
396795105f
commit
2682c125e0
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@ -1,6 +1,8 @@
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include <stdint.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <errno.h>
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@ -13,12 +15,11 @@ void disassemble_program();
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#define RAM_BASE 0x08000000
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#define RAM_TOP 0x08100000
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#define BRK_TOP (RAM_TOP - 0x1000)
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#define INIT_SP RAM_TOP
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#define INIT_PC 0x08000054
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#define BRK_BOTTOM (RAM_BASE + 0x20000)
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#define BRK_TOP (RAM_TOP - 0x1000)
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/* Read/write macros */
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#define READ_BYTE(BASE, ADDR) (BASE)[ADDR]
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#define READ_WORD(BASE, ADDR) (((BASE)[ADDR]<<8) | \
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@ -40,23 +41,24 @@ void disassemble_program();
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static void exit_error(char* fmt, ...);
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static void emulated_syscall(void);
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unsigned int cpu_read_byte(unsigned int address);
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unsigned int cpu_read_word(unsigned int address);
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unsigned int cpu_read_long(unsigned int address);
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void cpu_write_byte(unsigned int address, unsigned int value);
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void cpu_write_word(unsigned int address, unsigned int value);
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void cpu_write_long(unsigned int address, unsigned int value);
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uint32_t cpu_read_byte(uint32_t address);
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uint32_t cpu_read_word(uint32_t address);
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uint32_t cpu_read_long(uint32_t address);
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void cpu_write_byte(uint32_t address, uint32_t value);
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void cpu_write_word(uint32_t address, uint32_t value);
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void cpu_write_long(uint32_t address, uint32_t value);
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unsigned char g_ram[RAM_TOP - RAM_BASE];
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unsigned int brkpos = BRK_BOTTOM;
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uint32_t brkbase = RAM_BASE;
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uint32_t brkpos = RAM_BASE;
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uint32_t entrypoint = RAM_BASE;
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/* Exit with an error message. Use printf syntax. */
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void exit_error(char* fmt, ...)
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{
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static int guard_val = 0;
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char buff[100];
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unsigned int pc;
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uint32_t pc;
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va_list args;
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if(guard_val)
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@ -75,71 +77,78 @@ void exit_error(char* fmt, ...)
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exit(EXIT_FAILURE);
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}
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static inline unsigned int transform_address(unsigned int address)
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static inline uint32_t transform_address(uint32_t address)
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{
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unsigned int i = (address & ADDRESS_MASK) - RAM_BASE;
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if (i >= (unsigned int)(RAM_TOP - RAM_BASE))
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uint32_t i = (address & ADDRESS_MASK) - RAM_BASE;
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if (i >= (uint32_t)(RAM_TOP - RAM_BASE))
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exit_error("Attempted to read from RAM address %08x", address);
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return i;
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}
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unsigned int cpu_read_long(unsigned int address)
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uint32_t cpu_read_long(uint32_t address)
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{
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switch (address)
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{
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case 0x00: return INIT_SP;
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case 0x04: return INIT_PC;
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case 0x04: return entrypoint;
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case 0x80: emulated_syscall(); return 0x10000;
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case 0x10000: return 0x4e734e73; /* rte; rte */
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case 0x10004: return 0;
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default: return READ_LONG(g_ram, transform_address(address));
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default:
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{
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uint32_t value = READ_LONG(g_ram, transform_address(address));
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#if 0
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printf("read %08x from %08x\n", value, address);
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#endif
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return value;
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}
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}
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}
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unsigned int cpu_read_word(unsigned int address)
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uint32_t cpu_read_word(uint32_t address)
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{
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unsigned int l = cpu_read_long(address & ~3);
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uint32_t l = cpu_read_long(address & ~3);
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l >>= 16 - (address & 2)*8;
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return l & 0xffff;
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}
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unsigned int cpu_read_byte(unsigned int address)
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uint32_t cpu_read_byte(uint32_t address)
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{
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unsigned int l = cpu_read_long(address & ~3);
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uint32_t l = cpu_read_long(address & ~3);
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l >>= 24 - (address & 3)*8;
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return l & 0xff;
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}
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unsigned int cpu_read_word_dasm(unsigned int address)
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uint32_t cpu_read_word_dasm(uint32_t address)
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{
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return cpu_read_word(address);
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}
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unsigned int cpu_read_long_dasm(unsigned int address)
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uint32_t cpu_read_long_dasm(uint32_t address)
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{
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return cpu_read_long(address);
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}
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/* Write data to RAM or a device */
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void cpu_write_byte(unsigned int address, unsigned int value)
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void cpu_write_byte(uint32_t address, uint32_t value)
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{
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WRITE_BYTE(g_ram, transform_address(address), value);
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}
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void cpu_write_word(unsigned int address, unsigned int value)
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void cpu_write_word(uint32_t address, uint32_t value)
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{
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WRITE_WORD(g_ram, transform_address(address), value);
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}
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void cpu_write_long(unsigned int address, unsigned int value)
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void cpu_write_long(uint32_t address, uint32_t value)
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{
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WRITE_LONG(g_ram, transform_address(address), value);
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}
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/* Disassembler */
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void make_hex(char* buff, unsigned int pc, unsigned int length)
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void make_hex(char* buff, uint32_t pc, uint32_t length)
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{
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char* ptr = buff;
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@ -155,8 +164,8 @@ void make_hex(char* buff, unsigned int pc, unsigned int length)
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void disassemble_program()
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{
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unsigned int pc;
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unsigned int instr_size;
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uint32_t pc;
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uint32_t instr_size;
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char buff[100];
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char buff2[100];
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@ -174,7 +183,7 @@ void disassemble_program()
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void cpu_instr_callback()
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{
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unsigned int pc = m68k_get_reg(NULL, M68K_REG_PC);
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uint32_t pc = m68k_get_reg(NULL, M68K_REG_PC);
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if (pc == 0xc)
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exit_error("address exception");
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@ -183,7 +192,7 @@ void cpu_instr_callback()
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#if 0
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static char buff[100];
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static char buff2[100];
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static unsigned int instr_size;
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static uint32_t instr_size;
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instr_size = m68k_disassemble(buff, pc, M68K_CPU_TYPE_68020);
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make_hex(buff2, pc, instr_size);
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@ -220,19 +229,19 @@ static void emulated_syscall(void)
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case 4: /* write */
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{
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unsigned int fd = m68k_get_reg(NULL, M68K_REG_D1);
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unsigned int ptr = m68k_get_reg(NULL, M68K_REG_D2);
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unsigned int len = m68k_get_reg(NULL, M68K_REG_D3);
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uint32_t fd = m68k_get_reg(NULL, M68K_REG_D1);
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uint32_t ptr = m68k_get_reg(NULL, M68K_REG_D2);
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uint32_t len = m68k_get_reg(NULL, M68K_REG_D3);
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m68k_set_reg(M68K_REG_D0, write(fd, g_ram + transform_address(ptr), len));
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break;
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}
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case 45: /* brk */
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{
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unsigned int newpos = m68k_get_reg(NULL, M68K_REG_D1);
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uint32_t newpos = m68k_get_reg(NULL, M68K_REG_D1);
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if (newpos == 0)
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m68k_set_reg(M68K_REG_D0, brkpos);
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else if ((newpos < BRK_BOTTOM) || (newpos >= BRK_TOP))
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else if ((newpos < brkbase) || (newpos >= BRK_TOP))
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m68k_set_reg(M68K_REG_D0, -ENOMEM);
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else
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{
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@ -251,6 +260,37 @@ static void emulated_syscall(void)
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}
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}
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static void load_program(FILE* fd)
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{
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fseek(fd, 0, SEEK_SET);
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if (fread(g_ram, 1, 0x34, fd) != 0x34)
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exit_error("couldn't read ELF header");
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uint32_t phoff = READ_LONG(g_ram, 0x1c);
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uint16_t phentsize = READ_WORD(g_ram, 0x2a);
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uint16_t phnum = READ_WORD(g_ram, 0x2c);
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entrypoint = READ_LONG(g_ram, 0x18);
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if ((phentsize != 0x20) || (phnum != 1))
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exit_error("unsupported ELF file");
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fseek(fd, phoff, SEEK_SET);
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if (fread(g_ram, 1, phentsize, fd) != phentsize)
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exit_error("couldn't read program header");
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uint32_t offset = READ_LONG(g_ram, 0x04);
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uint32_t vaddr = READ_LONG(g_ram, 0x08);
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uint32_t filesz = READ_LONG(g_ram, 0x10);
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uint32_t memsz = READ_LONG(g_ram, 0x14);
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brkbase = brkpos = vaddr + memsz;
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uint32_t vaddroffset = transform_address(vaddr);
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transform_address(vaddr + memsz); /* bounds check */
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memset(g_ram+vaddroffset, 0, memsz);
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fseek(fd, offset, SEEK_SET);
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if (fread(g_ram+vaddroffset, 1, filesz, fd) != filesz)
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exit_error("couldn't read program data");
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}
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/* The main loop */
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int main(int argc, char* argv[])
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{
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@ -265,8 +305,7 @@ int main(int argc, char* argv[])
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if((fhandle = fopen(argv[1], "rb")) == NULL)
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exit_error("Unable to open %s", argv[1]);
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if(fread(g_ram, 1, RAM_TOP - RAM_BASE, fhandle) <= 0)
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exit_error("Error reading %s", argv[1]);
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load_program(fhandle);
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// disassemble_program();
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@ -287,9 +326,9 @@ int main(int argc, char* argv[])
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*/
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{
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unsigned int sp = INIT_SP;
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uint32_t sp = INIT_SP;
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cpu_write_long(sp -= 4, 0);
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unsigned int envp = sp;
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uint32_t envp = sp;
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cpu_write_long(sp -= 4, envp);
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cpu_write_long(sp -= 4, 0);
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unsigned long argv = sp;
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