From 4c4110d6529a502efba928ffb03af64816053eb9 Mon Sep 17 00:00:00 2001
From: Andrew Opalach <andrew@akon.city>
Date: Mon, 23 Sep 2019 22:39:37 -0400
Subject: improve ui and implement 2 more instructions

---
 Makefile |  2 +-
 chip8.c  | 16 +++++++++++++---
 chip8.h  |  2 ++
 ui.c     | 40 ++++++++++++++++++++++++++++++++++------
 4 files changed, 50 insertions(+), 10 deletions(-)

diff --git a/Makefile b/Makefile
index b504d98..a7976fe 100755
--- a/Makefile
+++ b/Makefile
@@ -9,7 +9,7 @@ win: BIN = chip8.exe
 all: executable
 win: executable
 
-all: LDFLAGS  = -lncursesw -ltinfow -lpthread
+all: LDFLAGS  = -lncursesw -lpthread
 win: LDFLAGS  = ./win/pdcurses.a
 
 executable: chip8.c ui.c util.c
diff --git a/chip8.c b/chip8.c
index c48f543..ad1b6bf 100644
--- a/chip8.c
+++ b/chip8.c
@@ -55,9 +55,6 @@ void push_top_of_stack(u16 val) {
 }
 
 void vm_thread(void* v) {
-  if (vm.PC > vm.rom_size) {
-    return;
-  }
 
   // read 2 bytes and convert to big-endian
   u16 instr = htons(vm.rom[(vm.PC) - 0x1FF]<<8 | vm.rom[(vm.PC) - 0x200]);
@@ -113,6 +110,19 @@ void vm_thread(void* v) {
         case '2':
           vm.Vx[hex_char(str[1])] &= vm.Vx[hex_char(str[2])];
           break;
+        case '3':
+          vm.Vx[hex_char(str[1])] ^= vm.Vx[hex_char(str[2])];
+          break;
+        case '4':
+          vm.Vx[hex_char(str[1])] += vm.Vx[hex_char(str[2])]
+          if (vm.Vx[hex_char(str[1])] + vm.Vx[hex_char(str[2])] > 255) {
+            vm.Vx[15] = 1;
+            vm.Vx[hex_char(str[1])] &= 0x255;
+          } else {
+            vm.Vx[15] = 0;
+          }
+          break;
+
       }
   }
 
diff --git a/chip8.h b/chip8.h
index 4ea248f..ce47d75 100644
--- a/chip8.h
+++ b/chip8.h
@@ -19,6 +19,8 @@ typedef struct {
   u16 I;
 
   u8 Vx[16];
+
+  u8 screen[64][32];
 } chip8_vm;
 
 extern chip8_vm vm;
diff --git a/ui.c b/ui.c
index d48f3e1..2691674 100644
--- a/ui.c
+++ b/ui.c
@@ -5,6 +5,7 @@
 #include <stdlib.h>
 
 #include "chip8.h"
+#include "util.h"
 
 void init_curses() {
   initscr();
@@ -14,6 +15,38 @@ void init_curses() {
   clear();
 }
 
+void draw() {
+  for (int x = 0; x < 64; x++) {
+    for (int y = 0; y < 32; y++) {
+      if (vm.screen[x][y]) {
+        mvaddstr(x * 2, y, "[]");
+      }
+    }
+  }
+
+  char buf[25];
+  for (int i = 0; i < 7; i++) {
+    sprintf(buf, "V%x: 0x%x", i, vm.Vx[i]);
+    mvaddstr(34, 9 * i, buf);
+  }
+  for (int i = 7; i < 15; i++) {
+    sprintf(buf, "V%x: 0x%x", i, vm.Vx[i]);
+    mvaddstr(35, 9 * (i - 8), buf);
+  }
+  sprintf(buf, "Vf: 0x%x", vm.Vx[15]);
+  mvaddstr(36, 0, buf);
+  sprintf(buf, "SP: 0x%x", vm.SP);
+  mvaddstr(36, 9, buf);
+  sprintf(buf, "DT: 0x%x", vm.DT);
+  mvaddstr(36, 18, buf);
+  sprintf(buf, "ST: 0x%x", vm.ST);
+  mvaddstr(36, 27, buf);
+  sprintf(buf, "PC: 0x%x", vm.PC);
+  mvaddstr(36, 36, buf);
+  sprintf(buf, "I: 0x%x", vm.I);
+  mvaddstr(36, 46, buf);
+}
+
 void curses_thread(void* v) {
   char c;
   while(1) {
@@ -22,12 +55,7 @@ void curses_thread(void* v) {
       endwin();
       exit(1);
     }
-    mvaddstr(0, 0, "V0  V1  V2  V3  V4  V5  V6  V7  V8  V9  VA  VB  VC  VD  VE  VF");
-    char buf[5];
-    for (int i = 0; i < 16; i++) {
-      sprintf(buf, "%i", vm.Vx[i]);
-      mvaddstr(1, i * 4, buf);
-    }
+    draw();
     usleep(100);
   }
 }
-- 
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