commit 1f507d0a4020fb4e7670371d6f047ca0ee5d09cd
from: Witcher01 <witcher01+github@posteo.net>
date: Sun Aug  1 17:28:31 2021 UTC

added instruction SNE + fixed SE bug

commit - 830b524dd8e1b18caf0e5e3237a6b04e8a5be715
commit + 1f507d0a4020fb4e7670371d6f047ca0ee5d09cd
blob - 229bc8bfa94c4c29a2ab62e2404f861703ad7a4b
blob + 317d1913eea524c00014a76d9ebf55b6546cbd7d
--- src/chip8.rs
+++ src/chip8.rs
@@ -83,9 +83,23 @@ impl Chip8 {
 
                 // skip next instruction if Vx == byte
                 if self.regs[reg as usize] == byte {
-                    self.pc = self.pc + 4;
+                    self.pc += 4;
+                } else {
+                    self.pc += 2;
                 }
             },
+            // SNE
+            0x4 {
+                let reg = instruction & 0x0F00;
+                let byte = (instruction & 0x00FF) as u8;
+
+                // skip next instruction if Vk != byte
+                if self.regs[reg as usize] != byte {
+                    self.pc += 4;
+                } else {
+                    self.pc += 2;
+                }
+            }
             _ => {
                 return Err(format!("{:#06x}: not an instruction", instruction));
             }