Minor changes
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parent
5a6aecc0f5
commit
c6ddcbe2bd
13 changed files with 112 additions and 72 deletions
165
src/vcpu.c
165
src/vcpu.c
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@ -26,83 +26,109 @@ void VCPUFetch(){
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void VCPUDecode(){
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State.X=(State.opcode>>8) & 0xF;
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State.Y=(State.opcode>>4) & 0xF;
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State.N=State.opcode & 0xF;
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State.N=State.opcode & 0x0F;
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State.NN=State.opcode & 0xFF;
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State.NNN=State.opcode & 0x0FFF;
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}
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State.NN=State.Y;
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State.NN=State.NN<<4;
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State.NN=State.NN | State.N;
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State.NNN=State.opcode&0x0FFF;
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void VCPUDoubleDabble(unsigned char x, unsigned char *u, unsigned char *t, unsigned char *h){
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unsigned int bcd=x;
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for(int i=0;i<8;i++){
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bcd=bcd<<1;
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unsigned char byte=bcd & 0xFF;
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unsigned char units=(bcd>>8) & 0xF;
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unsigned char tens=(bcd>>12) & 0xF;
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unsigned char hundreds=(bcd>>16) & 0xF;
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//printf("hundreds:%04b tens:%04b units:%04b byte:%08b\n",hundreds,tens,units,byte);
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if(i<7){
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if(units>4)
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units+=3;
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if(tens>4)
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tens+=3;
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if(hundreds>4)
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hundreds+=3;
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}
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bcd = (hundreds<<16) | (tens << 12) | (units << 8) | byte;
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}
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*u=bcd>>8 & 0xF;
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*t=bcd>>12 & 0xF;
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*h=bcd>>16 & 0xF;
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}
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void VCPUExecute(){
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// VCPUDump();
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VCPUDump();
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switch(State.opcode >> 12){
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case 0x0: // Clear screen or return from subroutine
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if(State.N == 0){ // Clear screen
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if(State.N == 0x0){ // Clear screen
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ScreenClear();
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}
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else { // Return from subroutine
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else if(State.N == 0xE) { // Return from subroutine
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State.PC=State.stack[State.S];
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State.S--;
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}
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break
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;;
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break;
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case 0x1: // Jump
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State.PC=State.NNN;
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break
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;;
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break;
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case 0x2: // Call
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State.S++;
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State.stack[State.S]=State.PC;
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State.PC=State.NNN;
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break
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;;
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break;
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case 0x3: // SE: VX, byte
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if(State.V[State.X]==State.NN)
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State.PC+=2;
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break;
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;;
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case 0x4: // SNE: VX, byte
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if(State.V[State.X]!=State.NN)
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State.PC+=2;
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break;
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;;
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case 0x5: // SE: VX, VY
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if(State.V[State.X]==State.V[State.Y])
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State.PC+=2;
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if(State.N == 0){
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if(State.V[State.X]==State.V[State.Y])
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State.PC+=2;
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}
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break;
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;;
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case 0x6:
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State.V[State.X]=State.NN;
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break
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;;
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break;
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case 0x7:
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State.V[State.X]+=State.NN;
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break
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;;
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State.V[State.X]=State.V[State.X] + State.NN;
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break;
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case 0x8: // Register operations
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switch(State.N){
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case 0x0: // VX = VY
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State.V[State.X]=State.V[State.Y];
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break;
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case 0x1: // VX = VX OR VY
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State.V[State.X]=State.V[State.X] | State.V[State.Y];
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break;
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;;
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case 0x2: // VX = VX AND VY
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State.V[State.X]=State.V[State.X] & State.V[State.Y];
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break;
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;;
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case 0x3: // VX = VX XOR VY
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State.V[State.X]=State.V[State.X] ^ State.V[State.Y];
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break;
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;;
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case 0x4: // VX = VX + VY
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if(State.V[State.X] + State.V[State.Y] > 255)
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if((State.V[State.X] + State.V[State.Y]) > 255)
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State.V[REG_FLAG]=1;
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else
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State.V[REG_FLAG]=0;
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State.V[State.X]=(State.V[State.X] + State.V[State.Y]) & 0xFF;
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State.V[State.X]=State.V[State.X] + State.V[State.Y];
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break;
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;;
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case 0x5: // VX = VX - VY
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if(State.V[State.X] > State.V[State.Y])
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State.V[REG_FLAG]=1;
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@ -110,7 +136,7 @@ void VCPUExecute(){
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State.V[REG_FLAG]=0;
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State.V[State.X]=State.V[State.X] - State.V[State.Y];
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break;
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;;
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case 0x6: // VX = VX SHR 1
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if(State.V[State.X] & 0x1 == 1)
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State.V[REG_FLAG]=1;
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@ -118,55 +144,57 @@ void VCPUExecute(){
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State.V[REG_FLAG]=0;
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State.V[State.X]=State.V[State.X] >> 1;
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break;
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;;
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case 0x7: // VX = VY - VX
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if(State.V[State.X] < State.V[State.Y])
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if(State.V[State.Y] > State.V[State.X])
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State.V[REG_FLAG]=1;
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else
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State.V[REG_FLAG]=0;
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State.V[State.X]=State.V[State.Y] - State.V[State.X];
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break;
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;;
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case 0xE: // VX = VX SHL 1
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if(State.V[State.X] >> 15 == 1)
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if(State.V[State.X] >> 7 == 1)
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State.V[REG_FLAG]=1;
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else
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State.V[REG_FLAG]=0;
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State.V[State.X]=State.V[State.X] << 1;
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break;
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;;
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}
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break
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;;
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case 0x9: // SNE: VX, VY
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if(State.V[State.X]!=State.V[State.Y])
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State.PC+=2;
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break;
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;;
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case 0x9: // SNE: VX, VY
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if(State.N==0){
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if(State.V[State.X]!=State.V[State.Y])
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State.PC+=2;
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}
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break;
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case 0xA:
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State.I=State.NNN;
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break
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;;
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break;
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case 0xB:
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State.PC=State.V[0]+State.NNN;
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break
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;;
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break;
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case 0xC:
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unsigned short n = rand() % 255 + 1;
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State.V[State.X]=n & State.NN;
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break
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;;
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break;
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case 0xD: // Draw a sprite
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int X=State.V[State.X]%63;
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int Y=State.V[State.Y]%31;
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int X=State.V[State.X]&63;
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int Y=State.V[State.Y]&31;
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State.V[REG_FLAG]=0; // Set flag to 0
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int width,height;
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int width, height;
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ScreenWH(&width,&height);
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for(char row=0;row<State.N;row++){
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// Stop if row out of screen
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if(Y+row>=height)
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break;
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char sprite;
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unsigned char sprite;
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MemRead(&sprite,1,State.I+row); // Load sprite
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// Draw sprite
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for(int shift=0;shift<8;shift++){
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@ -178,51 +206,56 @@ void VCPUExecute(){
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}
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}
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break;
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;;
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case 0xE:
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// TODO
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break;;
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break;
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case 0xF:
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switch(State.NN){
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case 0x07: // Get timer
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State.V[State.X]=State.DT;
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break;
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;;
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case 0x0A:
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// TODO
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break;
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;;
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case 0x15: // Set timer
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State.DT=State.V[State.X];
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break;
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;;
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case 0x18: // Set sound timer
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State.ST=State.V[State.X];
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break;
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;;
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case 0x1E: // I = I + VX
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State.I=State.I+State.V[State.X];
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break;
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;;
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case 0x29:
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// TODO
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break;
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;;
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case 0x33:
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// TODO
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unsigned char units, tens, hundreds;
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VCPUDoubleDabble(State.V[State.X],&units,&tens,&hundreds);
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MemCopy(&hundreds,1,State.I);
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MemCopy(&tens,1,State.I+1);
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MemCopy(&units,1,State.I+2);
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// printf("hundreds:%d tens:%d units:%d byte:%d\n",hundreds,tens,units,State.V[State.X]);
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break;
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;;
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case 0x55:
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MemCopy(State.V,0xF,State.I);
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break;
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;;
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case 0x65:
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MemRead(State.V,0xF,State.I);
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break;
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;;
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}
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break;
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;;
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}
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}
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