implement add to index instruction.rs

src/emulator.rs

@@ -350,6 +350,18 @@ where
                 trace!("SetSoundTimer");
                 self.sound_timer = self.registers[vx as usize]
             }
+            ProcessorInstruction::AddToIndex(vx) => {
+                trace!("AddToIndex");
+                let (result, overflow) = self
+                    .index_register
+                    .overflowing_add(self.registers[vx as usize] as u16);
+                self.index_register = result;
+                if overflow {
+                    self.registers[0xF] = 1
+                } else {
+                    self.registers[0xF] = 0
+                }
+            }
             _ => {
                 warn!("Unknown instruction: {:04x}, skipping.", instruction);
             }

src/instruction.rs

@@ -68,6 +68,7 @@ pub enum ProcessorInstruction {
     SetDelayTimer(u8),
     /// Sets the sound timer to the value in VX.
     SetSoundTimer(u8),
+    AddToIndex(u8),
     /// Unknown instruction
     UnknownInstruction,
 }
@@ -206,6 +207,7 @@ impl Instruction {
             (0xF, _, 0x1, 0x8) => {
                 ProcessorInstruction::SetSoundTimer(Self::grab_first_nibble(data))
             }
+            (0xF, _, 0x1, 0xE) => ProcessorInstruction::AddToIndex(Self::grab_first_nibble(data)),
             // Unknown instruction
             _ => ProcessorInstruction::UnknownInstruction,
         }