//返回值:0,执行OK;
// 其他,错误代码
u8 nes_main(GContext *ctx)
{
u16 offset=0;
u8 res;
NesHeader *neshreader = (NesHeader *) rom_file;
//由于NES文件头类型以0x1A结束，（0x1a是Ctrl+Z,这是模拟文件结束的符号）
//所以使用strcncmp比较前3个字节。
if(strncmp(neshreader->filetype, "NES", 3) != 0)
{
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n文件未加载或文件类型错误, NES模拟器退出。");
return 1;
}else
{
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n文件加载完成。");
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n 16kB ROM 的数目: %d", neshreader->romnum);
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n 8kB VROM 的数目: %d", neshreader->vromnum);
if((neshreader->romfeature & 0x01) == 0){
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n 水平镜像");
}else{
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n 垂直镜像");
}
if((neshreader->romfeature & 0x02) == 0){
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n 无记忆SRAM");
}else{
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n 有记忆SRAM");
}
if((neshreader->romfeature & 0x04) == 0)
{
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n 无512字节的trainer($7000-$71FF)");
}else
{
offset=512;
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n 有512字节的trainer(ROM格式暂不支持)");
}
if((neshreader->romfeature & 0x08) == 0){
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n 2屏幕VRAM布局");
}else{
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n 4屏幕VRAM布局(暂不支持)");
}
APP_LOG(APP_LOG_LEVEL_INFO, "\r\n iNES Mapper Numbers: %d", (neshreader->rommappernum & 0xF0)|( neshreader->romfeature >> 4));
}
res=nes_mem_creat();//申请内存
if(res==0)//申请成功了.则运行游戏
{
//初始化nes 模拟器
init6502mem(0, //exp_rom
0, //sram 由卡类型决定, 暂不支持
((u8*)&rom_file[offset+0x10]), //prg_rombank, 存储器大小 由卡类型决定
neshreader->romnum
);//初始化6502存储器镜像
reset6502();//复位
PPU_Init(((u8*)&rom_file[offset+0x10] + (neshreader->romnum * 0x4000)), (neshreader->romfeature & 0x01));//PPU_初始化
NES_JoyPadInit();
NesFrameCycle(ctx);//模拟器循环执行
}
nes_mem_delete();//释放内存
return res;
}
int main(int argc, char **argv)
{
int cycles_to_run;
char *machine_code; // This will hold our "ASCII Object File"
char debug_command[180]="init";
char *cmdptr;
unsigned int dbg_addr;
printf("6502 simulator front end for CS 2208a.\n\n");
// Did the user specify an object file on the command line?
// If not... help them.
if(argc < 3) {
printf("Usage: %s [ASCII Object File name] [# cycles to simulate] {-d}\n",argv[0]);
printf(" e.g.: %s test.obj 3000 -d\n\n",argv[0]);
exit(-1);
}
// Read the object file into a string.
machine_code = read_obj_file(argv[1]);
// Fire up the system RAM
initMem();
// Load the object file from the string into our simulated RAM,
// starting at memory location 'code_location'.
loadMem(machine_code,code_location);
// We did something horribly underhanded in read_obj_file()...
// we allocated memory with 'malloc' and then passed back a pointer.
// But note that the onus is on us, the C programmer, to _remember_
// that we did that and free up the memory when it's no longer needed.
// Not a big deal here, but imagine a bigger program where you're keeping
// track of hundreds of mallocs and frees. Now you know why C programs
// leak memory like the titanic.
free(machine_code);
// Initialize the 6502
init6502();
reset6502();
PC = code_location; // Make sure the program counter points to our code!
// All set to run the simulator now!
// Everything below is just fanciness to give you a rudimentry 6502 debugger
// to help with your assignment. Without the fancyness, all we're really doing
// is one call:
//
// exec6502(num_cycles);
// Run in debug mode, if requested
if( (argc > 3) && (!strcmp(argv[3],"-d"))) {
printf("Running in DEBUG MODE.\n\nType '?' for help.\n");
// Debug loop
while(strcmp(debug_command,"quit")) {
//dumpMem(0x0021); // Check the value we stored to the zero page
//dumpMem(0x01FF); // Peek at the top of the stack. Remember, the stack
// is hard-coded to addresses $0100–$01FF.
//dump6502reg(); // print registers to the screen
printf("debug> ");
if( (gets(debug_command))[0] != '\0'){
cmdptr = strtok(debug_command," ");
switch(cmdptr[0]) {
case 'p':
if(cmdptr = strtok(NULL," ")) {
sscanf(cmdptr, "%x", &dbg_addr);
dumpMem((WORD)dbg_addr);
}
break;
case 'r':
dump6502reg();
break;
case 's':
exec6502(1); // Execute 1 command
break;
case '?':
printf("\n\np [0xAddress] - print value at memory location\n");
printf("r - print register values\n");
printf("s - step through program\n");
printf("quit - exit\n\n");
break;
default:
(cmdptr[0] % 2) ? printf("Herp.\n") : printf("Derp.\n");
}
}
}
} else {
// Otherwise, run in regular mode.
exec6502(atoi(argv[2]));
}
}
