Minor changes

src/Makefile

@@ -1,7 +1,7 @@
 
 EXEC=chip-8
 
-$(EXEC): main.c screen.c mem.c vcpu.c keypad.c
+$(EXEC): main.c screen.c mem.c vcpu.c keypad.c speaker.c
 	gcc -lraylib $^ -o $@
 
 clean:

src/keypad.c

@@ -19,7 +19,7 @@ int map[]={
   KEY_V // F
 };
 
-int KeypadKeycodeValid(int keycode){
+int KeypadGetKey(int keycode){
   for(int i=0;i<16;i++){
     if(map[i]==keycode)
       return i;
@@ -29,9 +29,9 @@ int KeypadKeycodeValid(int keycode){
 
 
 int KeypadGetPressed(){
-  int keycode=GetKeyPressed();
-  if(keycode){
-    return KeypadKeycodeValid(keycode);
+  for(int i=0;i<16;i++){
+    if(IsKeyDown(map[i]))
+      return i;
   }
   return -1;
 }

src/main.c

@@ -1,10 +1,14 @@
 #include "screen.h"
 #include "mem.h"
 #include "vcpu.h"
+#include "speaker.h"
+
 #include <stdio.h>
 
-#define ROM "../roms/chip8-test-suite/5-quirks.ch8"
-//#define ROM "../roms/games/pong_1player.ch8"
+//#define ROM "../roms/chip8-test-suite/5-quirks.ch8"
+//#define ROM "../roms/chip8-test-suite/8-scrolling.ch8"
+#define ROM "../roms/games/pong_1player.ch8"
+//#define ROM "../roms/ibm.ch8"
 
 int main(int argc, char *argv[])
 {
@@ -14,8 +18,9 @@ int main(int argc, char *argv[])
   MemLoadROM(ROM);
   ScreenInit(800,400);
   VCPUInit();
+  SpeakerInit();
 
-  // Set game to run at very high FPS (prevent raylib to interfer with emulator FPS)
+  // Set game to run at very high FPS (prevent raylib to interfer with emulator CPU frequency)
   SetTargetFPS(VCPU_FREQ*100);
 
   // Emulator main loop
@@ -27,8 +32,9 @@ int main(int argc, char *argv[])
     i++;
   }
 
-  // Close screen
+  // Finish
+  SpeakerFinish();
   ScreenClose();
-  
+
   return 0;
 }

src/speaker.c

@@ -0,0 +1,20 @@
+#include "speaker.h"
+
+Sound s;
+
+void SpeakerInit(){
+  InitAudioDevice();              // Initialize audio device
+  s=LoadSound(SPEAKER_AUDIO_FILE);
+}
+
+void SpeakerOn(){
+  PlaySound(s);
+}
+
+void SpeakerOff(){
+  StopSound(s);
+}
+
+void SpeakerFinish(){
+  CloseAudioDevice();
+}

src/speaker.h

@@ -0,0 +1,8 @@
+#include "raylib.h"
+
+#define SPEAKER_AUDIO_FILE "beep.mp3"
+
+void SpeakerInit();
+void SpeakerOn();
+void SpeakerOff();
+void SpeakerFinish();

src/vcpu.c

@@ -2,6 +2,7 @@
 #include "mem.h"
 #include "screen.h"
 #include "keypad.h"
+#include "speaker.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -14,9 +15,10 @@ VCPU_State State;
 void VCPUInit(){
   State.PC=ADDR_ROM;
   State.S=0;
-  State.dtst_ticks=0;
+  State.dt_ticks=0;
+  State.st_ticks=0;
   State.screen_ticks=0;
-  State.keypress=-1;
+  State.keypressed=0;
   srand(time(NULL));
 }
 
@@ -208,19 +210,16 @@ void VCPUExecute(){
     
   case 0xE:
     if(State.NN==0x9E){ // Skip if keypress in VX
-      if(State.keypress >= 0){
-        if(State.V[State.X]&0x0F == State.keypress&0xF){
+      if(State.keypressed){
+        if(State.V[State.X] == State.key)
           State.PC+=2;
-        }
       }
-      State.keypress=-1;
     }else if(State.NN==0xA1){ // Skip if not keypress in VX
-      State.PC+=2; // First skip
-      if(State.keypress >=0){
-        if(State.V[State.X]&0x0F == State.keypress&0x0F)
-          State.PC+=2; // Ignore skip if pressed
+      State.PC+=2;
+      if(State.keypressed){
+        if(State.V[State.X] == State.key)
+          State.PC+=4;
       }
-      State.keypress=-1;
     }
     break;
     
@@ -231,12 +230,8 @@ void VCPUExecute(){
       break;
       
     case 0x0A:
-      if(State.keypress >=0){
-        State.V[State.X]=State.keypress&0xF;
-        if(State.V[State.X]&0x0F != State.keypress&0xF){
-          State.PC+=2;
-        }
-        State.keypress=-1;
+      if(State.keypressed){
+        State.V[State.X]=State.key;
       }
       else
         State.PC-=2; // Go back to last instruction (loop until key is pressed)       
@@ -284,12 +279,23 @@ void VCPUTick(){
   struct timespec start, stop;
   double duration, delay;
 
+  // Update keypressed
+  int key=KeypadGetPressed();
+  if(key>=0){
+    State.keypressed=1;
+    State.key=key&0xF;
+    //printf("Keypressed: %x\n",State.key);
+  }
+  else
+    State.keypressed=0;
+  
   // Run and benchmark CPU pipeline
-  clock_gettime(CLOCK_REALTIME, &start);
+  clock_gettime(CLOCK_REALTIME, &start);  
   VCPUFetch();
   VCPUDecode();
   VCPUExecute();
-  State.dtst_ticks++;
+  State.dt_ticks++;
+  State.st_ticks++;
   State.screen_ticks++;
   clock_gettime(CLOCK_REALTIME, &stop);
 
@@ -300,23 +306,30 @@ void VCPUTick(){
     usleep(delay*1e6);
   }
 
-  // Update Delay Timer and Sound Timer
-  if(State.dtst_ticks>=(1.0*VCPU_FREQ/DTST_FREQ)){
-    State.dtst_ticks=0;
+  // Update Delay Timer
+  if(State.dt_ticks>=(1.0*VCPU_FREQ/DTST_FREQ)){
+    State.dt_ticks=0;
     if(State.DT>0)
       State.DT--;
   }
 
+  // Update Sound Timer
+  if(State.st_ticks>=(1.0*VCPU_FREQ/DTST_FREQ)){
+    State.st_ticks=0;
+    if(State.ST>0)
+      State.ST--;
+  }
+
+  // Play sound
+  if(State.ST>0)
+    SpeakerOn();
+  
   // Refresh screen
   if(State.screen_ticks>=(1.0*VCPU_FREQ/SCREEN_FREQ)){
     State.screen_ticks=0;
     ScreenUpdate();
   }
 
-  // Update keypressed
-  int keypress=KeypadGetPressed();
-  if(keypress>=0)
-    State.keypress=keypress;
 }
 
 void VCPUDump(){

src/vcpu.h

@@ -35,10 +35,12 @@ typedef struct VCPU_State {
   unsigned short NNN;
 
   // Keypressed
-  int keypress;
+  int keypressed; // Not 0 if a key was pressed
+  unsigned char key;
   
   // Count VCPU ticks
-  int dtst_ticks;
+  int dt_ticks;
+  int st_ticks;
   int screen_ticks;
 } VCPU_State;