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Loïc Guégan 2023-12-25 11:00:27 +01:00
parent 8d56e4a953
commit 5a6aecc0f5
1 changed files with 119 additions and 1 deletions
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120
src/vcpu.c
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@ -2,6 +2,8 @@
#include "mem.h"
#include "screen.h"
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
// Current VCPU state
VCPU_State State;
@ -9,6 +11,7 @@ VCPU_State State;
void VCPUInit(){
State.PC=ADDR_ROM;
State.S=0;
srand(time(NULL));
}
void VCPUFetch(){
@ -65,7 +68,7 @@ void VCPUExecute(){
State.PC+=2;
break;
;;
case 0x5: // SNE: VX, VY
case 0x5: // SE: VX, VY
if(State.V[State.X]==State.V[State.Y])
State.PC+=2;
break;
@ -78,10 +81,81 @@ void VCPUExecute(){
State.V[State.X]+=State.NN;
break
;;
case 0x8: // Register operations
switch(State.N){
case 0x1: // VX = VX OR VY
State.V[State.X]=State.V[State.X] | State.V[State.Y];
break;
;;
case 0x2: // VX = VX AND VY
State.V[State.X]=State.V[State.X] & State.V[State.Y];
break;
;;
case 0x3: // VX = VX XOR VY
State.V[State.X]=State.V[State.X] ^ State.V[State.Y];
break;
;;
case 0x4: // VX = VX + VY
if(State.V[State.X] + State.V[State.Y] > 255)
State.V[REG_FLAG]=1;
else
State.V[REG_FLAG]=0;
State.V[State.X]=(State.V[State.X] + State.V[State.Y]) & 0xFF;
break;
;;
case 0x5: // VX = VX - VY
if(State.V[State.X] > State.V[State.Y])
State.V[REG_FLAG]=1;
else
State.V[REG_FLAG]=0;
State.V[State.X]=State.V[State.X] - State.V[State.Y];
break;
;;
case 0x6: // VX = VX SHR 1
if(State.V[State.X] & 0x1 == 1)
State.V[REG_FLAG]=1;
else
State.V[REG_FLAG]=0;
State.V[State.X]=State.V[State.X] >> 1;
break;
;;
case 0x7: // VX = VY - VX
if(State.V[State.X] < State.V[State.Y])
State.V[REG_FLAG]=1;
else
State.V[REG_FLAG]=0;
State.V[State.X]=State.V[State.Y] - State.V[State.X];
break;
;;
case 0xE: // VX = VX SHL 1
if(State.V[State.X] >> 15 == 1)
State.V[REG_FLAG]=1;
else
State.V[REG_FLAG]=0;
State.V[State.X]=State.V[State.X] << 1;
break;
;;
}
break
;;
case 0x9: // SNE: VX, VY
if(State.V[State.X]!=State.V[State.Y])
State.PC+=2;
break;
;;
case 0xA:
State.I=State.NNN;
break
;;
case 0xB:
State.PC=State.V[0]+State.NNN;
break
;;
case 0xC:
unsigned short n = rand() % 255 + 1;
State.V[State.X]=n & State.NN;
break
;;
case 0xD: // Draw a sprite
int X=State.V[State.X]%63;
int Y=State.V[State.Y]%31;
@ -105,6 +179,50 @@ void VCPUExecute(){
}
break;
;;
case 0xE:
// TODO
break;;
case 0xF:
switch(State.NN){
case 0x07: // Get timer
State.V[State.X]=State.DT;
break;
;;
case 0x0A:
// TODO
break;
;;
case 0x15: // Set timer
State.DT=State.V[State.X];
break;
;;
case 0x18: // Set sound timer
State.ST=State.V[State.X];
break;
;;
case 0x1E: // I = I + VX
State.I=State.I+State.V[State.X];
break;
;;
case 0x29:
// TODO
break;
;;
case 0x33:
// TODO
break;
;;
case 0x55:
MemCopy(State.V,0xF,State.I);
break;
;;
case 0x65:
MemRead(State.V,0xF,State.I);
break;
;;
}
break;
;;
}
}