3b1emu: src/main.c@dbf4ba9563c9 (annotated)

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src/main.c@dbf4ba9563c9 (annotated)

src/main.c

Sun, 28 Nov 2010 22:01:45 +0000

author: Philip Pemberton <philpem@philpem.me.uk>
date: Sun, 28 Nov 2010 22:01:45 +0000
changeset 10: dbf4ba9563c9
parent 9: 3e99497dca33
child 11: 67bf6abb6e79
permissions: -rw-r--r--

rework to use byte arrays to store ROM and RAM

 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <stdbool.h>
 #include <malloc.h>
 #include <string.h>
 #include "musashi/m68k.h"
 #include "version.h"
 void state_done(void);
 void FAIL(char *err)
 {
 	state_done();
 	fprintf(stderr, "ERROR: %s\nExiting...\n", err);
 	exit(EXIT_FAILURE);
 }
 // Maximum size of the Boot PROMs. Must be a binary power of two.
 #define ROM_SIZE 32768
 struct {
 	// Boot PROM can be up to 32Kbytes total size
 	uint8_t		rom[ROM_SIZE];
 	// Main system RAM
 	uint8_t		*ram;
 	size_t		ram_size;			// number of RAM bytes allocated
 	// GENERAL CONTROL REGISTER
 	bool		romlmap;
 } state;
 int state_init()
 {
 	// Free RAM if it's allocated
 	if (state.ram != NULL)
 		free(state.ram);
 	// Initialise hardware registers
 	state.romlmap = false;
 	// Allocate RAM
 	// TODO: make sure ram size selection is valid (512K, 1MB, 1.5MB, 2MB, 2.5MB, 3MB or 4MB)!
 	state.ram = malloc(state.ram_size);
 	if (state.ram == NULL)
 		return -1;
 	// Load ROMs
 	FILE *r14c, *r15c;
 	r14c = fopen("roms/14c.bin", "rb");
 	if (r14c == NULL) FAIL("unable to open roms/14c.bin");
 	r15c = fopen("roms/15c.bin", "rb");
 	if (r15c == NULL) FAIL("unable to open roms/15c.bin");
 	// get ROM file size
 	fseek(r14c, 0, SEEK_END);
 	size_t romlen = ftell(r14c);
 	fseek(r14c, 0, SEEK_SET);
 	fseek(r15c, 0, SEEK_END);
 	size_t romlen2 = ftell(r15c);
 	fseek(r15c, 0, SEEK_SET);
 	if (romlen2 != romlen) FAIL("ROMs are not the same size!");
 	if ((romlen + romlen2) > ROM_SIZE) FAIL("ROMs are too large to fit in memory!");
 	// sanity checks completed; load the ROMs!
 	uint8_t *romdat1, *romdat2;
 	romdat1 = malloc(romlen);
 	romdat2 = malloc(romlen2);
 	fread(romdat1, 1, romlen, r15c);
 	fread(romdat2, 1, romlen2, r14c);
 	// convert the ROM data
 	for (size_t i=0; i<(romlen + romlen2); i+=2) {
 		state.rom[i+0] = romdat1[i/2];
 		state.rom[i+1] = romdat2[i/2];
 	}
 	for (size_t i=0; i<16; i++) printf("%02X ", state.rom[i]);
 	printf("\n");
 	// TODO: if ROM buffer not filled, repeat the ROM data we read until it is.
 	// free the data arrays and close the files
 	free(romdat1);
 	free(romdat2);
 	fclose(r14c);
 	fclose(r15c);
 	return 0;
 }
 void state_done()
 {
 	if (state.ram != NULL)
 		free(state.ram);
 }
 // read m68k memory
 uint32_t m68k_read_memory_32(uint32_t address)
 {
 	uint32_t data = 0xFFFFFFFF;
 	printf("RD32 %08X %d", address, state.romlmap);
 	// If ROMLMAP is set, force system to access ROM
 	if (!state.romlmap)
 		address |= 0x800000;
 	if ((address >= 0x800000) && (address <= 0xBFFFFF)) {
 		// ROM access
 		data = (((uint32_t)state.rom[(address + 0) & (ROM_SIZE - 1)] << 24) |
 				((uint32_t)state.rom[(address + 1) & (ROM_SIZE - 1)] << 16) |
 				((uint32_t)state.rom[(address + 2) & (ROM_SIZE - 1)] << 8)  |
 				((uint32_t)state.rom[(address + 3) & (ROM_SIZE - 1)]));
 	} else if (address < state.ram_size - 1) {
 		// RAM
 		data = (((uint32_t)state.ram[address + 0] << 24) |
 				((uint32_t)state.ram[address + 1] << 16) |
 				((uint32_t)state.ram[address + 2] << 8)  |
 				((uint32_t)state.ram[address + 3]));
 	}
 	printf(" ==> %08X\n", data);
 	return data;
 }
 uint32_t m68k_read_memory_16(uint32_t address)
 {
 	uint16_t data = 0xFFFF;
 	printf("RD16 %08X %d", address, state.romlmap);
 	// If ROMLMAP is set, force system to access ROM
 	if (!state.romlmap)
 		address |= 0x800000;
 	if ((address >= 0x800000) && (address <= 0xBFFFFF)) {
 		// ROM access
 		data = ((state.rom[(address + 0) & (ROM_SIZE - 1)] << 8) |
 				(state.rom[(address + 1) & (ROM_SIZE - 1)]));
 	} else if (address < state.ram_size - 1) {
 		// RAM
 		data = ((state.ram[address + 0] << 8) |
 				(state.ram[address + 1]));
 	}
 	printf(" ==> %04X\n", data);
 	return data;
 }
 uint32_t m68k_read_memory_8(uint32_t address)
 {
 	uint8_t data = 0xFF;
 	printf("RD 8 %08X %d ", address, state.romlmap);
 	// If ROMLMAP is set, force system to access ROM
 	if (!state.romlmap)
 		address |= 0x800000;
 	if ((address >= 0x800000) && (address <= 0xBFFFFF)) {
 		// ROM access
 		data = state.rom[(address + 0) & (ROM_SIZE - 1)];
 	} else if (address < state.ram_size) {
 		// RAM access
 		data = state.ram[address + 0];
 	}
 	printf("==> %02X\n", data);
 	return data;
 }
 // write m68k memory
 void m68k_write_memory_32(uint32_t address, uint32_t value)
 {
 	// If ROMLMAP is set, force system to access ROM
 	if (!state.romlmap)
 		address |= 0x800000;
 	printf("WR32 %08X %d %02X\n", address, state.romlmap, value);
 	if ((address >= 0x800000) && (address <= 0xBFFFFF)) {
 		// ROM access
 		// TODO: bus error here? can't write to rom!
 	} else if (address < state.ram_size) {
 		// RAM access
 		state.ram[address + 0] = (value >> 24) & 0xff;
 		state.ram[address + 1] = (value >> 16) & 0xff;
 		state.ram[address + 2] = (value >> 8)  & 0xff;
 		state.ram[address + 3] =  value        & 0xff;
 	} else {
 		switch (address) {
 			case 0xE43000:	state.romlmap = ((value & 0x8000) == 0x8000);
 		}
 	}
 }
 void m68k_write_memory_16(uint32_t address, uint32_t value)
 {
 	// If ROMLMAP is set, force system to access ROM
 	if (!state.romlmap)
 		address |= 0x800000;
 	printf("WR16 %08X %d %02X\n", address, state.romlmap, value);
 	if ((address >= 0x800000) && (address <= 0xBFFFFF)) {
 		// ROM access
 		// TODO: bus error here? can't write to rom!
 	} else if (address < state.ram_size) {
 		// RAM access
 		state.ram[address + 0] = (value >> 8)  & 0xff;
 		state.ram[address + 1] =  value        & 0xff;
 	} else {
 		switch (address) {
 			case 0xE43000:	state.romlmap = ((value & 0x8000) == 0x8000);
 		}
 	}
 }
 void m68k_write_memory_8(uint32_t address, uint32_t value)
 {
 	// If ROMLMAP is set, force system to access ROM
 	if (!state.romlmap)
 		address |= 0x800000;
 	printf("WR 8 %08X %d %02X\n", address, state.romlmap, value);
 	if ((address >= 0x800000) && (address <= 0xBFFFFF)) {
 		// ROM access
 		// TODO: bus error here? can't write to rom!
 	} else if (address < state.ram_size) {
 		state.ram[address] = value & 0xff;
 	} else {
 		switch (address) {
 			case 0xE43000:	state.romlmap = ((value & 0x80) == 0x80);
 		}
 	}
 }
 // for the disassembler
 uint32_t m68k_read_disassembler_32(uint32_t addr) { return m68k_read_memory_32(addr); }
 uint32_t m68k_read_disassembler_16(uint32_t addr) { return m68k_read_memory_16(addr); }
 uint32_t m68k_read_disassembler_8 (uint32_t addr) { return m68k_read_memory_8 (addr); }
 int main(void)
 {
 	// copyright banner
 	printf("FreeBee: A Quick-and-Dirty AT&T 3B1 Emulator\n");
 	printf("Copyright (C) 2010 P. A. Pemberton.\n");
 	printf("Musashi M680x0 emulator engine developed by Karl Stenerud <kstenerud@gmail.com>\n");
 	// set up system state
 	// 512K of RAM
 	state.ram_size = 512*1024;
 	state_init();
 	// set up musashi
 	m68k_set_cpu_type(M68K_CPU_TYPE_68010);
 	m68k_pulse_reset();
 	char dasm[512];
 	m68k_disassemble(dasm, 0x80001a, M68K_CPU_TYPE_68010);
 	printf("%s\n", dasm);
 	// set up SDL
 	// emulation loop!
 	// repeat:
 	// 		m68k_execute()
 	// 		m68k_set_irq() every 60ms
 	printf("ran for %d cycles\n", m68k_execute(100000));
 	// shut down and exit
 	return 0;
 }

3b1emu / annotate

src/main.c@dbf4ba9563c9 (annotated)

src/main.c