From 8e3363b1e8dd0e925fd99b1ed06b6fb11464ea47 Mon Sep 17 00:00:00 2001
From: Preston Skupinski <skupinsk@cse.msu.edu>
Date: Sun, 8 May 2011 00:58:50 -0400
Subject: [PATCH] added ORA and many addressing modes for it

---
 cpu.js | 116 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 115 insertions(+), 1 deletion(-)

diff --git a/cpu.js b/cpu.js
index 7193699..0912ccb 100644
--- a/cpu.js
+++ b/cpu.js
@@ -99,7 +99,12 @@ function CPU_65816() {
                       0x32 : AND_direct_page_indirect,
                       0x3d : AND_absolute_indexed_x,
                       0x39 : AND_absolute_indexed_y,
-                      0x35 : AND_direct_page_indexed_x };
+                      0x35 : AND_direct_page_indexed_x, 0x09 : ORA_const,
+                      0x0d : ORA_absolute, 0x05 : ORA_direct_page,
+                      0x12 : ORA_direct_page_indirect, 
+                      0x1d : ORA_absolute_indexed_x, 
+                      0x1f : ORA_absolute_indexed_y,
+                      0x15 : ORA_direct_page_indexed_x };
 
   /**
    * Take a raw hex string representing the program and execute it.
@@ -178,6 +183,115 @@ var MMU = {
   }
 };
 
+var ORA_const = {
+  bytes_required:function(cpu) {
+    if(cpu.p.m) {
+      return 2;
+    } else {
+      return 3; 
+    }
+  },
+  execute:function(cpu, bytes) {
+    if(cpu.p.m) {
+      cpu.r.a |= bytes[0];
+      cpu.p.n = cpu.r.a >> 7;
+    } else {
+      cpu.r.a |= (bytes[1]<<8)|bytes[0];
+      cpu.p.n = cpu.r.a >> 15;
+    }
+
+    if(cpu.r.a===0) {
+      cpu.p.z = 1;
+    } else {
+      cpu.p.z = 0;
+    }  
+  }
+};
+
+var ORA_absolute = {
+  bytes_required:function() {
+    return 3;
+  },
+  execute:function(cpu, bytes) {
+    var location = (bytes[1]<<8)|bytes[0];
+    if(cpu.p.m) {
+      ORA_const.execute(cpu, [cpu.mmu.read_byte(location)]);
+    } else {
+      var low_byte = cpu.mmu.read_byte(location);
+      var high_byte = cpu.mmu.read_byte(location+1);
+      ORA_const.execute(cpu, [low_byte, high_byte]);
+    }
+  }
+};
+
+var ORA_direct_page = {
+  bytes_required:function() {
+    return 2;
+  },
+  execute:function(cpu, bytes) {
+    var location = bytes[0] + cpu.r.d;
+    if(cpu.p.m) {
+      ORA_const.execute(cpu, cpu.mmu.read_byte(location));
+    } else {
+      var low_byte = cpu.mmu.read_byte(location);
+      var high_byte = cpu.mmu.read_byte(location+1);
+      ORA_const.execute(cpu, [low_byte, high_byte]);
+    } 
+  }
+};
+
+var ORA_direct_page_indirect = {
+   bytes_required:function() {
+    return 2;
+  },
+  execute:function(cpu, bytes) {
+    var location = bytes[0] + cpu.r.d;
+    var low_byte_loc = cpu.mmu.read_byte(location);
+    var high_byte_loc = cpu.mmu.read_byte(location+1);
+    var absolute_location = (high_byte_loc<<8) | low_byte_loc;
+    if(cpu.p.m) {
+      ORA_const.execute(cpu, [cpu.mmu.read_byte(absolute_location)]);
+    } else {
+      var low_byte = cpu.mmu.read_byte(absolute_location);
+      var high_byte = cpu.mmu.read_byte(absolute_location+1);
+      ORA_const.execute(cpu, [low_byte, high_byte]);
+    }
+  } 
+};
+
+var ORA_absolute_indexed_x = {
+  bytes_required:function() {
+    return 3;
+  },
+  execute:function(cpu, bytes) {
+    var location = ((bytes[1]<<8)|bytes[0])+cpu.r.x;
+    var location_high_byte = (location & 0xff00)>>8;
+    var location_low_byte = location & 0x00ff;
+    ORA_absolute.execute(cpu, [location_low_byte, location_high_byte]);  
+  }
+};
+
+var ORA_absolute_indexed_y = {
+  bytes_required:function() {
+    return 3;
+  },
+  execute:function(cpu, bytes) {
+    var location = ((bytes[1]<<8)|bytes[0])+cpu.r.y;
+    var location_high_byte = (location & 0xff00)>>8;
+    var location_low_byte = location & 0x00ff;
+    ORA_absolute.execute(cpu, [location_low_byte, location_high_byte]);  
+  }
+};
+
+var ORA_direct_page_indexed_x = {
+  bytes_required:function() {
+    return 2;
+  },
+  execute:function(cpu, bytes) {
+    ORA_direct_page.execute(cpu, [bytes[0]+cpu.r.x]);  
+  }
+};
+
 var AND_const = {
   bytes_required:function(cpu) {
     if(cpu.p.m) {