From e9ec67945034935931c975ddb9522a5dbb69e6a9 Mon Sep 17 00:00:00 2001
From: Loic Guegan <loic.guegan@mailbox.org>
Date: Tue, 26 Dec 2023 13:17:52 +0100
Subject: Minor changes

---
 src/vcpu.c | 65 +++++++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 39 insertions(+), 26 deletions(-)

(limited to 'src/vcpu.c')

diff --git a/src/vcpu.c b/src/vcpu.c
index 11181f0..4682f0b 100644
--- a/src/vcpu.c
+++ b/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(){
-- 
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