void emu_run(uint32_t usec)
{
uint32_t tickCount = (EMU_TICKS_PER_SEC*1e-6) * usec;
if(gEmu.irqPending)
{
irq6502();
gEmu.irqPending = 0;
}
exec6502(tickCount);
}
//NES 帧周期循环
void NesFrameCycle(GContext *ctx)
{
int clocks; //CPU执行时间
//启动模拟器循环，检查VROM设置，若卡带为0，初始化VROM
//if ( NesHeader.byVRomSize == 0)
//设置VROM存储区位置。
//frame_cnt=0;
nesruning=1;
//while(nesruning)
{
//scanline: 0~19 VBANK 段，若PPU使能NMI，将产生NMI 中断
frame_cnt++;//帧计数器
SpriteHitFlag=FALSE;
for(PPU_scanline=0; PPU_scanline<20; PPU_scanline++)
{
exec6502(CLOCKS_PER_SCANLINE);
}
//scanline: 20, PPU加载设置，执行一次空的扫描时间
exec6502(CLOCKS_PER_SCANLINE);
//NesHBCycle(); //水平周期
PPU_scanline++; //20++
PPU_Reg.NES_R2 &= ~R2_SPR0_HIT;
//scanline: 21~261
for(; PPU_scanline < SCAN_LINE_DISPALY_END_NUM; PPU_scanline++)
{
if((SpriteHitFlag == TRUE) && ((PPU_Reg.NES_R2 & R2_SPR0_HIT) == 0))
{
clocks = sprite[0].x * CLOCKS_PER_SCANLINE / NES_DISP_WIDTH;
exec6502(clocks);
PPU_Reg.NES_R2 |= R2_SPR0_HIT;
exec6502(CLOCKS_PER_SCANLINE - clocks);
}else exec6502(CLOCKS_PER_SCANLINE);
if(PPU_Reg.NES_R1 & (R1_BG_VISIBLE | R1_SPR_VISIBLE))//若为假，关闭显示
{
if(SpriteHitFlag == FALSE)
NES_GetSpr0HitFlag(PPU_scanline - SCAN_LINE_DISPALY_START_NUM);//查找Sprite #0 碰撞标志
}
//if((frame_cnt%3)==0)//每2帧显示一次
{
NES_RenderLine(PPU_scanline - SCAN_LINE_DISPALY_START_NUM, ctx);//水平同步与显示一行
}
}
//layer_mark_dirty(s_canvas_layer);
//scanline: 262 完成一帧
exec6502(CLOCKS_PER_SCANLINE);
PPU_Reg.NES_R2 |= R2_VBlank_Flag;//设置VBANK 标志
//若使能PPU VBANK中断，则设置VBANK
if(PPU_Reg.NES_R0 & R0_VB_NMI_EN)
{
NMI_Flag = SET1;//完成一帧扫描，产生NMI中断
}
//设置帧IRQ标志，同步计数器，APU等
//A mapper function in V-Sync 存储器切换垂直VBANK同步
//MapperVSync();
//读取控制器JoyPad状态,更新JoyPad控制器值
//NES_JoyPadUpdateValue(); //systick 中断读取按键值
}
}
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]));
}
}
