Merge remote-tracking branch 'origin/master'

build.sh

@@ -17,4 +17,4 @@ mkdir -p $OBJ_FOLDER
 mv *.o $OBJ_FOLDER
 
 # create executable out of the objects
-cc -g -o $EXEC_NAME $OBJ_FOLDER/*.o
+cc -g -o $EXEC_NAME $OBJ_FOLDER/*.o -lcurses

src/6502.c

@@ -1,14 +1,15 @@
-#include <stdio.h>
-
 #include "inc/types.h"
 #include "inc/memory.h"
 #include "inc/opcodes.h"
+#include "inc/interface.h"
 
 ocl opcode_in_list;
 oct opcode_in_table;
 
 void init()
 {
+    io_init();
+    
     // pc is set using 0xFFFC
     pc = read_word(0xFFFC);
     sp = 0xFF;
@@ -81,7 +82,7 @@ void execute()
         case BMI: return bmi();
         case BNE: return bne();
         case BPL: return bpl();
-        case BRK: return bkk();
+        case BRK: return brk();
         case BVC: return bvc();
         case BVS: return bvs();
         case CLC: return clc();
@@ -139,25 +140,6 @@ void execute()
     }
 }
 
-void display()
-{
-    //if (display_control == 0xA7)
-    {
-        // display is ready to ouptup
-        if (display_buffer & 0x80)
-        {
-            // outputs the buffer character
-            display_buffer = display_buffer & 0x7F;
-            printf("%c", display_buffer);
-        }
-    }
-}
-
-void read_input()
-{
-    // verifies if the keyboard is being pressed...
-}
-
 void run()
 {
     while (1)
@@ -166,8 +148,8 @@ void run()
         decode();
         execute();
         
-        display();
-        read_input();
+        input();
+        output();
     }
     
 }

src/inc/interface.h

@@ -0,0 +1,8 @@
+#ifndef _APPLE_I_INTERFACE_H_
+#define _APPLE_I_INTERFACE_H_
+
+void io_init(void);
+void input(void);
+void output(void);
+
+#endif

src/inc/opcodes.h

@@ -64,7 +64,7 @@ void bit(void); // test bits in memory with accumulator
 void bmi(void); // branch on result minus
 void bne(void); // branch on result not zero
 void bpl(void); // branch on result plus
-void bkk(void); // force break
+void brk(void); // force break
 void bvc(void); // branch on overflow clear
 void bvs(void); // branch on overflow set
 void clc(void); // clear carry flag

src/interface.c

@@ -0,0 +1,41 @@
+#include <curses.h>
+#include "inc/interface.h"
+#include "inc/memory.h"
+
+void io_init()
+{
+    initscr();
+    noecho();
+    cbreak();
+    nodelay(stdscr, TRUE);
+    
+    keyboard_control = 0x00;
+}
+
+void input()
+{
+    int ch = getch();
+    if (ch == '\n') { ch = '\r'; }
+    if (ch == '\r' || ch == '.' || ch == ':' ||
+       (ch >= '0' && ch <= '9') ||
+       (ch >= 'A' && ch <= 'Z'))
+    {
+        keyboard_buffer  = ch | 0x80;
+        keyboard_control = 0xFF;
+    }
+}
+
+void output()
+{
+    // display is ready to ouptup
+    if (display_buffer & 0x80)
+    {
+        // outputs the buffer character
+        display_buffer = display_buffer & 0x7F;
+        if (display_buffer == '\r')
+        {
+            display_buffer = '\n';
+        }
+        addch(display_buffer);
+    }
+}

src/main.c

@@ -1,11 +1,7 @@
-#include <stdio.h>
 #include "inc/6502.h"
 
 int main(int argc, char **argv)
 {
-    setbuf(stdout, NULL);
-    printf("Apple-I Computer\n");
-    
     init(); // start the processor
     run();  // and runs it
     

src/memory.c

@@ -48,6 +48,7 @@ db read_byte(dw address)
     }
     else if (address == 0xD010)
     {
+        keyboard_control = 0x00;
         return keyboard_buffer;
     }
     else if (address == 0xD011)
@@ -58,10 +59,10 @@ db read_byte(dw address)
     {
         return display_buffer;
     }
-    /*else if (address == 0xD013)
+    else if (address == 0xD013)
     {
         return display_control;
-    }*/
+    }
     else if (address >= 0xFF00 && address <= 0xFFFF)
     {
         // wozmon ROM
@@ -98,22 +99,22 @@ void write_mem(dw address, db data)
         // 4KB memory RAM
         ram_memory[address] = data;
     }
-    /*else if (address == 0xD010)
+    else if (address == 0xD010)
     {
         keyboard_buffer = data;
-    }*/
-    /*else if (address == 0xD011)
+    }
+    else if (address == 0xD011)
     {
         keyboard_control = data;
-    }*/
+    }
     else if (address == 0xD012)
     {
         display_buffer = data;
     }
-    /*else if (address == 0xD013)
+    else if (address == 0xD013)
     {
         display_control = data;
-    }*/
+    }
     
     // any other addressed memory will be ignored on write
 }

src/opcodes.c

@@ -95,22 +95,22 @@ void fetch_operand()
 
 void adjustNZ(db r)
 {
-    if (r == 0) { Z_SET; } else { Z_UNSET;}
+    if (r == 0) { Z_SET; } else { Z_UNSET; }
     r = r >> 7;
     if (r == 1) { N_SET; } else { N_UNSET; } 
 }
 
 db adder(db a, db b)
 {
-    db r =  a + b;
-    db c = (a + b) >> 8;
+    db r =  a + b + C_IS_SET;
+    db c = (a + b + C_IS_SET) >> 8;
     
-    a = a & 0b01111111;
-    b = b & 0b01111111;
-    db cc = (a + b) >> 7;
-    db v  =  c ^ cc;
+    a = a & 0x7F;
+    b = b & 0x7F;
+    db z = (a + b + C_IS_SET) >> 7;
+    db v =  c ^ z;
     
-    if (c == 1) { C_SET; } else { C_UNSET;}
+    if (c == 1) { C_SET; } else { C_UNSET; }
     if (v == 1) { V_SET; } else { V_UNSET; } 
         
     adjustNZ(r);
@@ -118,15 +118,6 @@ db adder(db a, db b)
     return r;
 }
 
-db subtractor(db a, db b)
-{
-    // negate b operand using 2's complement
-    b = b ^ 0xFF;
-    b = b + 1;
-    
-    return adder(a, b);
-}
-
 void push_byte(db data)
 {
     write_mem(sp, data);
@@ -161,7 +152,7 @@ void adc()
 {
     // add memory to accumulator with carry
     fetch_operand();
-    ac = adder(ac, operand + C_IS_SET);
+    ac = adder(ac, operand);
 }
 
 void and()
@@ -261,7 +252,7 @@ void bpl()
     }
 }
 
-void bkk()
+void brk()
 {
     // force break
     I_SET;
@@ -316,22 +307,28 @@ void clv()
 void cmp()
 {
     // compare memory with accumulator
+    C_SET;
     fetch_operand();
-    subtractor(ac, operand);
+    operand = operand ^ 0xFF;
+    adder(ac, operand);
 }
 
 void cpx()
 {
     // compare memory and index x
+    C_SET;
     fetch_operand();
-    subtractor(x, operand);
+    operand = operand ^ 0xFF;
+    adder(x, operand);
 }
 
 void cpy()
 {
     // compare memory and index y
+    C_SET;
     fetch_operand();
-    subtractor(y, operand);
+    operand = operand ^ 0xFF;
+    adder(y, operand);
 }
 
 void dec()
@@ -557,7 +554,8 @@ void sbc()
 {
     // subtract memory from accumulator with borrow
     fetch_operand();
-    ac = subtractor(ac, operand - C_IS_SET);
+    operand = operand ^ 0xFF;
+    ac = adder(ac, operand);
 }
 
 void sec()