Added simple keypad and interrupt handling

Author: dbuchwald

samples/int_test/int_test.asm

@@ -0,0 +1,40 @@
+ROM_START     .equ $8000
+
+RESET_VECTOR  .equ $fffc
+
+  .org ROM_START
+
+data_display:
+  ldx #$00                 ; Initialize counter
+loop_data:
+  lda data,x               ; Load data bytes from address data + x
+  beq end_prog             ; On end of stream move to end of program
+  jsr write_data
+  inx                      ; Increase counter
+  jmp loop_data
+end_prog:
+  cli
+loop:
+  jmp loop
+
+write_data:
+  jsr pulse                ; Pulse 6522
+  rts                      ; Return
+
+pulse:
+  sta $ff00
+  rts                      ; Return from subroutine
+
+data:
+  string "Merry Christmas!"
+
+interrupt:
+  pha
+  lda #$42
+  pla
+  rti
+
+  .org RESET_VECTOR
+  word data_display
+  word interrupt
+

samples/int_test/make.sh

@@ -0,0 +1,2 @@
+vasm6502_oldstyle -dotdir -wdc02 -Fbin int_test.asm -L int_test.lst -o int_test.bin
+hexdump -C int_test.bin

samples/int_test/test.sh

@@ -0,0 +1,2 @@
+#!/bin/bash
+x6502 int_test.bin

src/cpu.c

@@ -16,11 +16,13 @@ cpu * new_cpu() {
     memset(m->mem, 0xFF, MEMORY_SIZE);
     m->v1 = new_via();
     m->l = new_lcd();
+    m->k = new_keys();
     return m;
 }
 
 void destroy_cpu(cpu* m) {
   destroy_via(m->v1);
   destroy_lcd(m->l);
+  destroy_keys(m->k);
   free(m);
 }

src/cpu.h

@@ -5,6 +5,7 @@
 #include <stdbool.h>
 #include "via.h"
 #include "lcd.h"
+#include "keys.h"
 
 #define MEMORY_SIZE 65536
 #define STACK_START 0x0100
@@ -58,8 +59,8 @@ typedef struct {
     via* v1;
     // LCD
     lcd* l;
-    // noninteractive mode
-    bool noninteractive;
+    // keys
+    keys* k;
 } cpu;
 
 cpu * new_cpu();

src/gui.c

@@ -215,6 +215,12 @@ void update_gui(cpu *m) {
     } else {      
       input_cycle_skip=0;
 
+      m->k->key_up=false;
+      m->k->key_down=false;
+      m->k->key_left=false;
+      m->k->key_right=false;
+      m->k->key_enter=false;
+
       switch (m->clock_mode) {
         case CLOCK_SPRINT:
         case CLOCK_FAST:
@@ -253,6 +259,26 @@ void update_gui(cpu *m) {
             m->clock_mode = CLOCK_FAST;
           }
           break;
+        case 10:
+          m->k->key_enter = true;
+          keep_going = true;
+          break;
+        case KEY_UP:
+          m->k->key_up = true;
+          keep_going = true;
+          break;
+        case KEY_DOWN:
+          m->k->key_down = true;
+          keep_going = true;
+          break;
+        case KEY_LEFT:
+          m->k->key_left = true;
+          keep_going = true;
+          break;
+        case KEY_RIGHT:
+          m->k->key_right = true;
+          keep_going = true;
+          break;
         case '[':
           if (memory_start > 0x00) {
             memory_start--;
@@ -277,10 +303,6 @@ void update_gui(cpu *m) {
             memory_start = 0xfe;
           }
           break;
-        default:
-          m->interrupt_waiting = 0x01;
-          m->mem[IO_GETCHAR] = read;
-          keep_going = true;
       } 
     }
   } while (!keep_going && m->clock_mode != CLOCK_SPRINT);

src/io.c

@@ -45,9 +45,21 @@ void handle_io(cpu *m, bool rwb) {
       }
     }
   } else {
+    uint8_t old_porta_input = m->v1->porta & ~m->v1->ddra;
+
     m->v1->portb &= m->v1->ddrb;
     m->v1->portb |= (m->l->data & ~m->v1->ddrb);
     m->v1->porta &= m->v1->ddra;
+    m->v1->porta |= m->k->key_enter ? 0x01 : 0;
+    m->v1->porta |= m->k->key_up ? 0x02 : 0;
+    m->v1->porta |= m->k->key_down ? 0x04 : 0;
+    m->v1->porta |= m->k->key_left ? 0x08 : 0;
+    m->v1->porta |= m->k->key_right ? 0x10 : 0;
+
+    if (old_porta_input != (m->v1->porta & ~m->v1->ddra)) {
+      m->interrupt_waiting = 0x01;
+    }
+
     // read operation
     m->mem[0x6000] = m->v1->portb;
     m->mem[0x6001] = m->v1->porta;

src/keys.c

@@ -0,0 +1,20 @@
+#include "keys.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+keys * new_keys() {
+  keys *k = malloc(sizeof(keys));
+
+  k->key_up = false;
+  k->key_down = false;
+  k->key_left = false;
+  k->key_right = false;
+  k->key_enter = false;
+
+  return k;
+}
+
+void destroy_keys(keys* k) {
+  free(k);
+}
+

src/keys.h

@@ -0,0 +1,20 @@
+#ifndef __6502_KEYS__
+#define __6502_KEYS__
+
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef struct {
+  // key states
+  bool key_up;
+  bool key_down;
+  bool key_left;
+  bool key_right;
+  bool key_enter;
+} keys;
+
+keys* new_keys();
+
+void destroy_keys(keys* l);
+
+#endif