我一直在尝试将 CHIP-8 仿真器作为个人项目编写，但我一直坚持实现它的图形。
到目前为止，我正在尝试将帧缓冲区实现为 8 位元素的数组，其中每个元素的值应该是 1 或 0，并通过将所述元素的前一个值与新元素进行异或来设置。
我还尝试编写一个 SDL2 例程来将其呈现到屏幕上。我显然在某个地方失败了，因为它显示的只是屏幕的一半白色和另一个黑色，此时程序停止响应。
这是我实现时的 DXYN 指令：
case 0xd:
{
gfxflag=1;
V[0xf]=0;
cny=(RAM[PC+1]>>4);
cnx=(((RAM[PC]>>4)<<4)^RAM[PC]);
//n=((RAM[pc+1] ^ (RAM[pc+1]>>4)))
//THIS WILL XOR N BYETS OF RAM (N elements of char) INTO 8*N CONSECUTIVE ELEMENTS OF FB LEFT TO RIGHT
for(gfxcn=0; gfxcn < (((RAM[PC+1]>>4)<<4)^RAM[PC+1]); gfxcn++)
{
FRAMEBUFFER[((cnx*cny)+(8*gfxcn))] = FRAMEBUFFER[((cnx*cny)+(8*gfxcn))] ^ (RAM[I]>>7);
FRAMEBUFFER[(((cnx*cny)+1)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+1)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>6 ^ ((RAM[I+gfxcn]>>7)<<1));
FRAMEBUFFER[(((cnx*cny)+2)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+2)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>5 ^ ((RAM[I+gfxcn]>>6)<<1));
FRAMEBUFFER[(((cnx*cny)+3)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+3)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>4 ^ ((RAM[I+gfxcn]>>5)<<1));
FRAMEBUFFER[(((cnx*cny)+4)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+4)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>3 ^ ((RAM[I+gfxcn]>>4)<<1));
FRAMEBUFFER[(((cnx*cny)+5)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+5)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>2 ^ ((RAM[I+gfxcn]>>3)<<1));
FRAMEBUFFER[(((cnx*cny)+6)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+6)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>1 ^ ((RAM[I+gfxcn]>>2)<<1));
FRAMEBUFFER[(((cnx*cny)+7)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+7)+(8*gfxcn))] ^ (RAM[I+gfxcn] ^ ((RAM[I+gfxcn]>>1)<<1));
if (((FRAMEBUFFER[(((cnx*cny)+7)+(8*gfxcn))]) != ((FRAMEBUFFER[(((cnx*cny)+7)+(8*gfxcn))])) ^ ((RAM[I+gfxcn] ^ ((RAM[I+gfxcn]>>1)<<1)))))
{
V[0xf]=1;
}
}
PC+=2;
break;
}
这里也是 SDL2 代码
gfxflag=0;
for(cnx=0; cnx<64; cnx++)
{
for(cny=0; cny<32; cny++)
{
switch(FRAMEBUFFER[cnx*cny])
{
case 0:
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
SDL_RenderDrawPoint(renderer, cnx, cny);
case 1:
SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
SDL_RenderDrawPoint(renderer, cnx, cny);
}
SDL_RenderPresent(renderer);
}
}
它可能相关也可能不相关，但我也在附加整个程序：
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <conio.h>
#include <SDL2/SDL.h>
unsigned short PC=0x200, I=0, STACK[16]={0};
unsigned char V[16], SP=0, DT=0, ST=0, FRAMEBUFFER[64*32]={0};
unsigned char RAM[4096]=
{0xf0, 0x90, 0x90, 0x90, 0xf0, /* 0 */// 0-4 key 0|map each font sprite is 8x5 column x row
0x20, 0x60, 0x20, 0x20, 0x70, /* 1 */// 5-9 key 1|map each number is a row, 8 columns wide
0xf0, 0x10, 0xf0, 0x80, 0xf0, /* 2 */// 10-14 key 2|map in ram each array element is a row, 8 col/one byte
0xf0, 0x10, 0xf0, 0x10, 0xf0, /* 3 */// 15-19 key 3|map total memory occupied by font: 80/0x50 bytes
0x90, 0x90, 0xf0, 0x10, 0x10, /* 4 */// 20-24 key 4|map
0xf0, 0x80, 0xf0, 0x10, 0xf0, /* 5 */// 25-29 key 5|map
0xf0, 0x80, 0xf0, 0x90, 0xf0, /* 6 */// 30-34 key 6|map
0xf0, 0x10, 0x20, 0x40, 0x40, /* 7 */// 35-39 key 7|map
0xf0, 0x90, 0xf0, 0x90, 0xf0, /* 8 */// 40-44 key 8|map
0xf0, 0x90, 0xf0, 0x10, 0xf0, /* 9 */// 45-49 key 9|map
0xf0, 0x90, 0xf0, 0x90, 0x90, /* A */// 50-54 key 10|map
0xe0, 0x90, 0xe0, 0x90, 0xe0, /* B */// 55-59 key 11|map
0xf0, 0x80, 0x80, 0x80, 0xf0, /* C */// 60-64 key 12|map
0xe0, 0x90, 0x90, 0x90, 0xe0, /* D */// 65-69 key 13|map
0xf0, 0x80, 0xf0, 0x80, 0xf0, /* E */// 70-74 key 14|map
0xf0, 0x80, 0xf0, 0x80, 0x80, /* F */// 75-79 key 15|map
0};
unsigned char ponggame[246]=
{0x6A, 0x02 ,0x6B ,0x0C ,0x6C,
0x3F ,0x6D ,0x0C ,0xA2 ,0xEA,
0xDA ,0xB6 ,0xDC ,0xD6 ,0x6E,
0x00 ,0x22 ,0xD4 ,0x66 ,0x03,
0x68 ,0x02 ,0x60 ,0x60 ,0xF0,
0x15 ,0xF0 ,0x07 ,0x30 ,0x00,
0x12 ,0x1A ,0xC7 ,0x17 ,0x77,
0x08 ,0x69 ,0xFF ,0xA2 ,0xF0,
0xD6 ,0x71 ,0xA2 ,0xEA ,0xDA,
0xB6 ,0xDC ,0xD6 ,0x60 ,0x01,
0xE0 ,0xA1 ,0x7B ,0xFE ,0x60,
0x04 ,0xE0 ,0xA1 ,0x7B ,0x02,
0x60 ,0x1F ,0x8B ,0x02 ,0xDA,
0xB6 ,0x60 ,0x0C ,0xE0 ,0xA1,
0x7D ,0xFE ,0x60 ,0x0D ,0xE0,
0xA1 ,0x7D ,0x02 ,0x60 ,0x1F,
0x8D ,0x02 ,0xDC ,0xD6 ,0xA2,
0xF0 ,0xD6 ,0x71 ,0x86 ,0x84,
0x87 ,0x94 ,0x60 ,0x3F ,0x86,
0x02 ,0x61 ,0x1F ,0x87 ,0x12,
0x46 ,0x02 ,0x12 ,0x78 ,0x46,
0x3F ,0x12 ,0x82 ,0x47 ,0x1F,
0x69 ,0xFF ,0x47 ,0x00 ,0x69,
0x01 ,0xD6 ,0x71 ,0x12 ,0x2A,
0x68 ,0x02 ,0x63 ,0x01 ,0x80,
0x70 ,0x80 ,0xB5 ,0x12 ,0x8A,
0x68 ,0xFE ,0x63 ,0x0A ,0x80,
0x70 ,0x80 ,0xD5 ,0x3F ,0x01,
0x12 ,0xA2 ,0x61 ,0x02 ,0x80,
0x15 ,0x3F ,0x01 ,0x12 ,0xBA,
0x80 ,0x15 ,0x3F ,0x01 ,0x12,
0xC8 ,0x80 ,0x15 ,0x3F ,0x01,
0x12 ,0xC2 ,0x60 ,0x20 ,0xF0,
0x18 ,0x22 ,0xD4 ,0x8E ,0x34,
0x22 ,0xD4 ,0x66 ,0x3E ,0x33,
0x01 ,0x66 ,0x03 ,0x68 ,0xFE,
0x33 ,0x01 ,0x68 ,0x02 ,0x12,
0x16 ,0x79 ,0xFF ,0x49 ,0xFE,
0x69 ,0xFF ,0x12 ,0xC8 ,0x79,
0x01 ,0x49 ,0x02 ,0x69 ,0x01,
0x60 ,0x04 ,0xF0 ,0x18 ,0x76,
0x01 ,0x46 ,0x40 ,0x76 ,0xFE,
0x12 ,0x6C ,0xA2 ,0xF2 ,0xFE,
0x33 ,0xF2 ,0x65 ,0xF1 ,0x29,
0x64 ,0x14 ,0x65 ,0x00 ,0xD4,
0x55 ,0x74 ,0x15 ,0xF2 ,0x29,
0xD4 ,0x55 ,0x00 ,0xEE ,0x80,
0x80 ,0x80 ,0x80 ,0x80 ,0x80,
0x80 ,0x00 ,0x00 ,0x00 ,0x00,
0x00};
char genflag=0, debugflag=0, imemcounter=0, keybuf, gfxflag;//used to determine 0nnn//used to toggle debug mode// inst 'f5' and 'f6' gfxcn// used in E insts, retains key//tels interpreter to update screen
short gfxcn, ldcn, debugcn; //used in d instruction to aid graphing to framebuffer//used for debug console
short clearcn=0, res8=0, cny=0, cnx=0, cn=0, cn2=0;//used to clear display//used to calculate 8xy5-6 carry according to higher 8 bits//used in d inst x4
short spriteloc[16]={ //stores locations of sprite
00, 05, 10, 15,
20, 25, 30, 35,
40, 45, 50, 55,
60, 65, 70, 75};
int main(int argc, char **argv)
{
init:
for(ldcn=0; ldcn<246; ldcn++)//ROMLOAD
{
//printf("%x ", RAM[0x200 + ldcn]);
RAM[0x200+ldcn]=ponggame[ldcn];
//printf("%x %x ", ldcn, RAM[0x200 + ldcn]);
}
srand(time(NULL));
SDL_Init(SDL_INIT_EVERYTHING);
SDL_Window *window=NULL;
SDL_Renderer *renderer=NULL;
SDL_CreateWindowAndRenderer(64, 32, 0, &window, &renderer); // surface -> texture -> window
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
SDL_RenderClear(renderer);
SDL_RenderPresent(renderer);
//SDL_RenderClear(renderer); WHY IS THIS EVEN HERE
emuthread:
returnfromgfx:
while(1)
{
if(debugflag==1)
{
//if(debugcn>=5)
//{
// return 0;
//}
//debugcn++;
printf("%x ", PC);
printf("%x %x ", RAM[PC], RAM[PC+1]); //print next instruction to be executed
}
if(gfxflag==1)
{
goto gfx;
}
switch((RAM[PC]>>4)) // CONDITIONAL BASED ON HIGHER 4 BITS OF INSTRUCTION
{
case 0x0:
{
if(RAM[PC+1]==0xEE) //CONDITIONAL BASED ON SECOND BYTE OF INSTRUCTION
{
PC=STACK[SP];
SP--;
genflag++;
}
if(RAM[PC+1]==0xE0)
{
for(clearcn=0; clearcn<2048; clearcn++)
{
FRAMEBUFFER[clearcn]=0;
}
genflag++;
PC+=2;
}
if(genflag==0)
{
PC = ((((RAM[PC]>>4)<<4) ^ RAM[PC])<<8) ^ RAM[PC+1];
}
if(genflag>0)
{
genflag=0;
}
break;
}
case 0x1:
{
PC = ((((RAM[PC]>>4)<<4) ^ RAM[PC])<<8) ^ RAM[PC+1];
break;
}
case 0x2:
{
SP++;
STACK[SP]=PC;
PC = ((((RAM[PC]>>4)<<4) ^ RAM[PC])<<8) ^ RAM[PC+1];
break;
}
case 0x3:
{
if(V[(((RAM[PC]>>4)<<4)^RAM[PC])]==RAM[PC+1])
{
PC+=2;
}
PC+=2;
break;
}
case 0x4:
{
if(V[(((RAM[PC]>>4)<<4)^RAM[PC])]!=RAM[PC+1])
{
PC+=2;
}
PC+=2;
break;
}
case 0x5:
{
if(V[(((RAM[PC]>>4)<<4)^RAM[PC])]==(RAM[PC+1]>>4))
{
PC+=2;
}
PC+=2;
break;
}
case 0x6:
{
V[(((RAM[PC]>>4)<<4)^RAM[PC])]=RAM[PC+1];
PC+=2;
break;
}
case 0x7:
{
V[(((RAM[PC]>>4)<<4)^RAM[PC])] = (RAM[PC+1] + V[(((RAM[PC]>>4)<<4)^RAM[PC])]);
PC+=2;
break;
}
case 0x8:
{
switch((((RAM[PC+1]>>4)<<4)^RAM[PC+1])) //conditional based on lower 4 bits of lower byte
{
case 0x0:
{
V[(((RAM[PC]>>4)<<4)^RAM[PC])] = (RAM[PC+1]>>4);
PC+=2;
break;
}
case 0x1:
{
V[(((RAM[PC]>>4)<<4)^RAM[PC])] = V[(((RAM[PC]>>4)<<4)^RAM[PC])] | (RAM[PC+1]>>4);
PC+=2;
break;
}
case 0x2:
{
V[(((RAM[PC]>>4)<<4)^RAM[PC])] = V[(((RAM[PC]>>4)<<4)^RAM[PC])] & (RAM[PC+1]>>4);
PC+=2;
break;
}
case 0x3:
{
V[(((RAM[PC]>>4)<<4)^RAM[PC])] = V[(((RAM[PC]>>4)<<4)^RAM[PC])] ^ (RAM[PC+1]>>4);
PC+=2;
break;
}
case 0x4:
{
V[0xf]=0;
res8= V[(((RAM[PC]>>4)<<4)^RAM[PC])] + (RAM[PC+1]>>4);
if((res8>>8)>0)
{
V[0xf]=1;
}
V[(((RAM[PC]>>4)<<4)^RAM[PC])] = (((res8>>8)<<8)^res8);
PC+=2;
break;
}
case 0x5:
{
V[0xf]=0;
if(V[(((RAM[PC]>>4)<<4)^RAM[PC])] > (RAM[PC+1]>>4))
{
V[0xf]=0;
}
PC+=2;
break;
}
case 0x6:
{
V[0xf]=0;
if((((V[(((RAM[PC]>>4)<<4)^RAM[PC])]>>1)<<1)^V[(((RAM[PC]>>4)<<4)^RAM[PC])])==1)
{
V[0XF]=1;
}
PC+=2;
break;
}
case 0x7:
{
V[0xf]=0;
if((RAM[PC+1]>>4) > V[(((RAM[PC]>>4)<<4)^RAM[PC])])
{
V[0xf]=1;
}
V[(((RAM[PC]>>4)<<4)^RAM[PC])] = (RAM[PC+1]>>4) - V[(((RAM[PC]>>4)<<4)^RAM[PC])];
PC+=2;
break;
}
case 0xe:
{
V[0xf]=0;
if((V[(((RAM[PC]>>4)<<4)^RAM[PC])]>>7)==1)
{
V[0xf]=1;
}
PC+=2;
break;
}
break;
}
}
case 0x9:
{
if(V[(((RAM[PC]>>4)<<4)^RAM[PC])]!=(RAM[PC+1]>>4))
{
PC+=2;
}
PC+=2;
break;
}
case 0xa:
{
I = ((((RAM[PC]>>4)<<4) ^ RAM[PC])<<8) ^ RAM[PC+1];
PC+=2;
break;
}
case 0xb:
{
PC = (((((RAM[PC]>>4)<<4) ^ RAM[PC])<<8) ^ RAM[PC+1]) + V[0x0];
PC+=2;
break;
}
case 0xc:
{
V[(((RAM[PC]>>4)<<4)^RAM[PC])] = (RAM[PC+1] & (rand() % 256));
PC+=2;
break;
}
case 0xd:
{
gfxflag=1;
V[0xf]=0;
cny=(RAM[PC+1]>>4);
cnx=(((RAM[PC]>>4)<<4)^RAM[PC]);
//n=((RAM[pc+1] ^ (RAM[pc+1]>>4)))
//THIS WILL XOR N BYETS OF RAM (N elements of char) INTO 8*N CONSECUTIVE ELEMENTS OF FB LEFT TO RIGHT
for(gfxcn=0; gfxcn < (((RAM[PC+1]>>4)<<4)^RAM[PC+1]); gfxcn++)
{
FRAMEBUFFER[((cnx*cny)+(8*gfxcn))] = FRAMEBUFFER[((cnx*cny)+(8*gfxcn))] ^ (RAM[I]>>7);
FRAMEBUFFER[(((cnx*cny)+1)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+1)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>6 ^ ((RAM[I+gfxcn]>>7)<<1));
FRAMEBUFFER[(((cnx*cny)+2)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+2)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>5 ^ ((RAM[I+gfxcn]>>6)<<1));
FRAMEBUFFER[(((cnx*cny)+3)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+3)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>4 ^ ((RAM[I+gfxcn]>>5)<<1));
FRAMEBUFFER[(((cnx*cny)+4)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+4)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>3 ^ ((RAM[I+gfxcn]>>4)<<1));
FRAMEBUFFER[(((cnx*cny)+5)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+5)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>2 ^ ((RAM[I+gfxcn]>>3)<<1));
FRAMEBUFFER[(((cnx*cny)+6)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+6)+(8*gfxcn))] ^ (RAM[I+gfxcn]>>1 ^ ((RAM[I+gfxcn]>>2)<<1));
FRAMEBUFFER[(((cnx*cny)+7)+(8*gfxcn))] = FRAMEBUFFER[(((cnx*cny)+7)+(8*gfxcn))] ^ (RAM[I+gfxcn] ^ ((RAM[I+gfxcn]>>1)<<1));
if (((FRAMEBUFFER[(((cnx*cny)+7)+(8*gfxcn))]) != ((FRAMEBUFFER[(((cnx*cny)+7)+(8*gfxcn))])) ^ ((RAM[I+gfxcn] ^ ((RAM[I+gfxcn]>>1)<<1)))))
{
V[0xf]=1;
}
}
PC+=2;
break;
}
case 0xe:
{
if(keybuf==V[(((RAM[PC]>>4)<<4)^RAM[PC])])
{
PC+=2;
}
if(keybuf!=V[(((RAM[PC]>>4)<<4)^RAM[PC])])
{
PC+=2;
}
PC+=2;
break;
}
case 0xf:
{
switch(RAM[PC+1]>>4)
{
case 0x0:
{
if((((RAM[PC+1]>>4)<<4)^RAM[PC+1]>>4)==7)
{
V[(((RAM[PC]>>4)<<4)^RAM[PC])] = DT;
}
if((((RAM[PC+1]>>4)<<4)^RAM[PC+1]>>4)==0xa)
{
goto input;
returnfrominput:
V[(((RAM[PC]>>4)<<4)^RAM[PC])] = keybuf;
}
PC+=2;
break;
}
case 0x1:
{
if((((RAM[PC+1]>>4)<<4)^RAM[PC+1]>>4)==5)
{
DT = V[(((RAM[PC]>>4)<<4)^RAM[PC])];
}
if((((RAM[PC+1]>>4)<<4)^RAM[PC+1]>>4)==8)
{
ST = V[(((RAM[PC]>>4)<<4)^RAM[PC])];
}
if((((RAM[PC+1]>>4)<<4)^RAM[PC+1]>>4)==0xe)
{
I = I + V[(((RAM[PC]>>4)<<4)^RAM[PC])];
}
PC+=2;
break;
}
case 0x2:
{
I = spriteloc[V[(((RAM[PC]>>4)<<4)^RAM[PC])]];
PC+=2;
break;
}
case 0x3:
{
//mod 100 -> 0xx
//then mod 10 -> 00x
RAM[I]= ((V[(((RAM[PC]>>4)<<4)^RAM[PC])] ^ ((V[(((RAM[PC]>>4)<<4)^RAM[PC])] % 100) % 10)) - ((V[(((RAM[PC]>>4)<<4)^RAM[PC])] ^ ((V[(((RAM[PC]>>4)<<4)^RAM[PC])] % 100) % 10)) % 100)); //100
RAM[I+1]= (((V[(((RAM[PC]>>4)<<4)^RAM[PC])] ^ ((V[(((RAM[PC]>>4)<<4)^RAM[PC])] % 100) % 10)) % 100) / 10); //10
RAM[I+2]= ((V[(((RAM[PC]>>4)<<4)^RAM[PC])] % 100) % 10); //1
PC+=2;
break;
}
case 0x5:
{
for(imemcounter=0; imemcounter<16; imemcounter++)
{
RAM[I+imemcounter]=V[imemcounter];
}
PC+=2;
break;
}
case 0x6:
{
for(imemcounter=0; imemcounter<16; imemcounter++)
{
V[imemcounter]=RAM[I+imemcounter];
}
PC+=2;
break;
}
break;
}
break;
}
}
if(DT>0)
{
DT--;
}
if(ST<0)
{
ST--;
}
}
input:
switch(getch())
{
case '1':
keybuf= 1;
case '2':
keybuf= 2;
case '3':
keybuf= 3;
case '4':
keybuf= 12;
case 'q':
keybuf= 4;
case 'w':
keybuf= 5;
case 'e':
keybuf= 6;
case 'r':
keybuf= 13;
case 'a':
keybuf= 7;
case 's':
keybuf= 8;
case 'd':
keybuf= 9;
case 'f':
keybuf= 14;
case 'z':
keybuf= 10;
case 'x':
keybuf= 0;
case 'c':
keybuf= 11;
case 'v':
keybuf= 15;
default:
goto input;
}
goto returnfrominput;
gfx:
gfxflag=0;
for(cnx=0; cnx<64; cnx++)
{
for(cny=0; cny<32; cny++)
{
switch(FRAMEBUFFER[cnx*cny])
{
case 0:
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
SDL_RenderDrawPoint(renderer, cnx, cny);
case 1:
SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
SDL_RenderDrawPoint(renderer, cnx, cny);
}
SDL_RenderPresent(renderer);
}
}
goto returnfromgfx;
return 0;
}
在进行了 ctx 建议的更正后，颜色问题似乎已基本修复。但是，该程序将 hogwash 渲染到屏幕上，或者看起来如此。此外，我通过使其显示随机像素来测试 SDL2 代码，它似乎可以工作，除了下半部分，它仍然是黑色的，但我想它毕竟与问题无关。
如果例程能够自行渲染，则错误一定是在仿真块的某个地方，但我已经看了好几天了，但我仍然没有找到它。