Adding cassette support and improving timing
This commit is contained in:
parent
1fc1395805
commit
9e036f143d
1
cpu.h
1
cpu.h
|
@ -32,6 +32,7 @@ struct CPU_6502{
|
|||
uint16_t PC_reg;
|
||||
//The bits status register are all of the processor flags, but it is its own register whose value can be pushed to the stack
|
||||
uint8_t P_reg;
|
||||
unsigned long long int cycles;
|
||||
};
|
||||
|
||||
|
||||
|
|
173
emulate.c
173
emulate.c
|
@ -1,18 +1,61 @@
|
|||
#include <stdlib.h>
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
#include <conio.h>
|
||||
#include <sys/time.h>
|
||||
#include "cpu.h"
|
||||
|
||||
unsigned DEBUG_STEP = 0;
|
||||
unsigned char DEBUG_STEP = 0;
|
||||
|
||||
uint8_t memory[0x10000];
|
||||
|
||||
uint32_t tape[0x100000];
|
||||
|
||||
uint32_t tape_index;
|
||||
|
||||
char str_buffer[256];
|
||||
|
||||
unsigned char next_tape_index;
|
||||
|
||||
unsigned char tape_active;
|
||||
|
||||
unsigned char tape_writing;
|
||||
|
||||
unsigned char tape_reading;
|
||||
|
||||
unsigned char current_tape_value;
|
||||
|
||||
void print_state(CPU_6502 cpu){
|
||||
printf("A: %02x X:%02x Y:%02x SP:%02x P:%02x PC:%02x\n", (int) cpu.A_reg, (int) cpu.X_reg, (int) cpu.Y_reg, (int) cpu.SP_reg, (int) cpu.P_reg, (int) cpu.PC_reg);
|
||||
printf("\nNext: %02x %02x %02x\n", (int) memory[cpu.PC_reg], (int) memory[cpu.PC_reg + 1], (int) memory[cpu.PC_reg + 2]);
|
||||
}
|
||||
|
||||
void load_tape(char *file_name){
|
||||
FILE *fp;
|
||||
fp = fopen(file_name, "rb");
|
||||
printf("Reading from tape file named \"%s\"\n", file_name);
|
||||
if(fp){
|
||||
fread(tape, 4, 0x100000, fp);
|
||||
fclose(fp);
|
||||
} else {
|
||||
printf("file error\n");
|
||||
}
|
||||
|
||||
return;
|
||||
}
|
||||
|
||||
void store_tape(char *file_name){
|
||||
FILE *fp;
|
||||
printf("Storing tape to file named \"%s\"\n", file_name);
|
||||
fp = fopen(file_name, "wb");
|
||||
if(fp){
|
||||
fwrite(tape, 4, 0x100000, fp);
|
||||
fclose(fp);
|
||||
} else {
|
||||
printf("file error\n");
|
||||
}
|
||||
}
|
||||
|
||||
//Special read memory routine for memory-mapped I/O
|
||||
uint8_t read_mem(uint16_t index){
|
||||
uint8_t output;
|
||||
|
@ -20,7 +63,19 @@ uint8_t read_mem(uint16_t index){
|
|||
if(DEBUG_STEP){
|
||||
printf("READ: %04x ", index);
|
||||
}
|
||||
|
||||
if(tape_writing && index >= 0xC000 && index <= 0xC0FF){
|
||||
next_tape_index = 1;
|
||||
} else if(index >= 0xC081 && index <= 0xC0FF){
|
||||
if(current_tape_value){
|
||||
output = memory[index];
|
||||
} else {
|
||||
output = memory[index&0xFFFE];
|
||||
}
|
||||
} else {
|
||||
output = memory[index];
|
||||
}
|
||||
|
||||
if(index == 0xD010){
|
||||
memory[0xD011] &= 0x7F;
|
||||
} else if((index&0xFF0F) == 0xD002){
|
||||
|
@ -59,6 +114,10 @@ int main(){
|
|||
unsigned long int last_time;
|
||||
unsigned long int next_time;
|
||||
struct timeval current_time;
|
||||
char temp_char;
|
||||
unsigned char str_index;
|
||||
unsigned long long int last_cycles;
|
||||
unsigned char last_cycle_diff;
|
||||
|
||||
cpu.A_reg = 0;
|
||||
cpu.X_reg = 0;
|
||||
|
@ -66,45 +125,62 @@ int main(){
|
|||
cpu.SP_reg = 0;
|
||||
cpu.P_reg = 0;
|
||||
cpu.PC_reg = 0xE000;
|
||||
tape_writing = 0;
|
||||
tape_reading = 0;
|
||||
|
||||
//Load Integer Basic
|
||||
fp = fopen("BASIC", "rb");
|
||||
if(fp){
|
||||
fread(memory + 0xE000, 1, 0x2000, fp);
|
||||
fread(memory + 0xE000, 1, 0x1000, fp);
|
||||
} else {
|
||||
printf("Warning: could not load file named \"BASIC\".\nStarting without apple 1 BASIC loaded.\nApple 1 basic can still be loaded from a cassette file into address 0xE000.\n---\n");
|
||||
}
|
||||
fclose(fp);
|
||||
|
||||
//Load Woz's ACI
|
||||
fp = fopen("WOZACI", "rb");
|
||||
if(fp){
|
||||
fread(memory + 0xC000, 1, 0x100, fp);
|
||||
} else {
|
||||
printf("file error\n");
|
||||
exit(1);
|
||||
}
|
||||
fclose(fp);
|
||||
|
||||
//The emulator does not support ACI at the moment
|
||||
memcpy(memory + 0xC100, memory + 0xC000, 0x100);
|
||||
|
||||
//Load Woz's monitor
|
||||
fp = fopen("WOZMON", "rb");
|
||||
if(fp){
|
||||
fread(memory + 0xFF00, 1, 0x100, fp);
|
||||
} else {
|
||||
printf("file error 3\n");
|
||||
printf("file error\n");
|
||||
exit(1);
|
||||
}
|
||||
fclose(fp);
|
||||
reset_6502(&cpu, read_mem);//Reset the cpu
|
||||
cpu.cycles = 0;
|
||||
last_cycles = 0;
|
||||
|
||||
//Initialize the timing
|
||||
gettimeofday(¤t_time, NULL);
|
||||
last_time = current_time.tv_usec + current_time.tv_sec*1000000;
|
||||
last_cycle_diff = 0;
|
||||
next_tape_index = 0;
|
||||
while(1){
|
||||
/* Limit the speed of the processor to
|
||||
* a realistic 4usec per instruction
|
||||
* a realistic 4nsec per instruction
|
||||
*
|
||||
* Will count cpu cycles soon to make
|
||||
* better timing.
|
||||
*/
|
||||
if(!DEBUG_STEP){
|
||||
do{
|
||||
gettimeofday(¤t_time, NULL);
|
||||
next_time = current_time.tv_usec + current_time.tv_sec*1000000;
|
||||
} while(next_time - last_time < 4);
|
||||
last_time = last_time + 4;
|
||||
} while(next_time - last_time < last_cycle_diff);
|
||||
last_time = last_time + last_cycle_diff;
|
||||
}
|
||||
|
||||
//Execute the instruction
|
||||
execute_6502(&cpu, read_mem, write_mem);
|
||||
|
@ -112,13 +188,60 @@ int main(){
|
|||
|
||||
//Debugging I/O
|
||||
if(DEBUG_STEP){
|
||||
print_state(cpu);
|
||||
key_hit = getchar();
|
||||
if(key_hit == '|'){
|
||||
memset(str_buffer, 256, 0);
|
||||
fgets(str_buffer, 256, stdin);
|
||||
temp_char = str_buffer[6];
|
||||
str_buffer[6] = (char) 0;
|
||||
|
||||
if(!strcmp(str_buffer, "resume")){
|
||||
DEBUG_STEP = 0;
|
||||
} else if(key_hit != ' '){
|
||||
memory[0xD010] = key_hit|0x80;
|
||||
memory[0xD011] = 0xFF;
|
||||
gettimeofday(¤t_time, NULL);
|
||||
last_time = current_time.tv_usec + current_time.tv_sec*1000000;
|
||||
} else if(temp_char == ' ' && !strcmp(str_buffer, "tstart")){
|
||||
tape_active = 1;
|
||||
str_buffer[12] = (char) 0;
|
||||
if(temp_char == ' ' && !strcmp(str_buffer + 7, "write")){
|
||||
tape_writing = 1;
|
||||
printf("WRITING TO TAPE\n");
|
||||
}
|
||||
str_buffer[11] = (char) 0;
|
||||
if(temp_char == ' ' && !strcmp(str_buffer + 7, "read")){
|
||||
tape_reading = 1;
|
||||
current_tape_value = 0;
|
||||
printf("READING FROM TAPE\n");
|
||||
}
|
||||
tape_index = 0;
|
||||
} else if(temp_char == ' ' && !strcmp(str_buffer, "tstore")){
|
||||
str_index = 0;
|
||||
while(str_buffer[str_index] != '\n' && str_index < 255){
|
||||
str_index++;
|
||||
}
|
||||
str_buffer[str_index] = (char) 0;
|
||||
store_tape(str_buffer + 7);
|
||||
}
|
||||
|
||||
str_buffer[6] = temp_char;
|
||||
temp_char = str_buffer[5];
|
||||
str_buffer[5] = (char) 0;
|
||||
|
||||
if(!strcmp(str_buffer, "tstop")){
|
||||
tape_active = 0;
|
||||
tape_writing = 0;
|
||||
tape_reading = 0;
|
||||
}
|
||||
|
||||
if(temp_char == ' ' && !strcmp(str_buffer, "tload")){
|
||||
str_index = 0;
|
||||
while(str_buffer[str_index] != '\n' && str_index < 255){
|
||||
str_index++;
|
||||
}
|
||||
str_buffer[str_index] = (char) 0;
|
||||
load_tape(str_buffer + 6);
|
||||
}
|
||||
|
||||
if(str_buffer[0] != (char) 0 && str_buffer[1] == (char) 0){
|
||||
memory[0xD010] = str_buffer[0]|0x80;
|
||||
memory[0xD011] |= 0x80;
|
||||
}
|
||||
}
|
||||
|
||||
|
@ -128,10 +251,34 @@ int main(){
|
|||
|
||||
if(key_hit == '|'){
|
||||
DEBUG_STEP = 1;
|
||||
printf("\n");
|
||||
} else {
|
||||
memory[0xD010] = key_hit|0x80;
|
||||
memory[0xD011] |= 0x80;
|
||||
}
|
||||
}
|
||||
|
||||
last_cycle_diff = cpu.cycles - last_cycles;
|
||||
|
||||
//Handle tape
|
||||
if(tape_active && tape_reading){
|
||||
while(last_cycles < cpu.cycles){
|
||||
if(!tape[tape_index]){
|
||||
tape_index++;
|
||||
current_tape_value = !current_tape_value;
|
||||
}
|
||||
tape[tape_index] -= 1;
|
||||
last_cycles++;
|
||||
}
|
||||
} else if(tape_active && tape_writing){
|
||||
tape[tape_index] += cpu.cycles - last_cycles;
|
||||
if(next_tape_index){
|
||||
tape_index++;
|
||||
next_tape_index = 0;
|
||||
}
|
||||
last_cycles = cpu.cycles;
|
||||
} else {
|
||||
last_cycles = cpu.cycles;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
Loading…
Reference in New Issue