From 48032d65b9b9a1df312d632c12909813f04fa135 Mon Sep 17 00:00:00 2001
From: Samuel Perrouault <samuel.perrouault@gmail.com>
Date: Wed, 26 Mar 2025 15:27:51 +0100
Subject: implement SUBN Vx, Vy

---
 src/chip8.rs | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'src/chip8.rs')

diff --git a/src/chip8.rs b/src/chip8.rs
index eae4a4f..ea3790b 100644
--- a/src/chip8.rs
+++ b/src/chip8.rs
@@ -140,6 +140,11 @@ impl Chip8 {
                     self.v[0xF] = if self.v[x] & 1 == 1 { 1 } else { 0 };
                     self.v[x] /= 2;
                 }
+                0x0007 => {
+                    eprintln!("SUBN V{}, V{}", x, y);
+                    self.v[0xF] = if self.v[y] > self.v[x] { 1 } else { 0 };
+                    self.v[x] = self.v[y].wrapping_sub(self.v[x]);
+                }
                 0x000E => {
                     eprintln!("SHL V{}", x);
                     self.v[0xF] = if (self.v[x] >> 7) & 1 == 1 { 1 } else { 0 };
-- 
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