From 4e23d9419be08481965782ace58a79928a049a7b Mon Sep 17 00:00:00 2001
From: Marco Thomas <github@marcothms.de>
Date: Wed, 2 Jul 2025 20:58:39 +0900
Subject: [PATCH] fix(interpreter): write to correct 8bit regs

---
 src/interpreter/computer.rs |  1 +
 src/interpreter/register.rs | 13 +++++++------
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/interpreter/computer.rs b/src/interpreter/computer.rs
index eaa6db4..e1d9c6a 100644
--- a/src/interpreter/computer.rs
+++ b/src/interpreter/computer.rs
@@ -402,6 +402,7 @@ impl Computer {
         target: ModRmTarget,
         val: ImmediateOperand,
     ) -> Result<(), InterpreterError> {
+        log::debug!("Writing {val} into {target}");
         match target {
             ModRmTarget::Memory(idx) => self.write(val.into(), idx)?,
             ModRmTarget::Register(reg) => self.regs.write(reg, val),
diff --git a/src/interpreter/register.rs b/src/interpreter/register.rs
index 3307c07..2315dc9 100644
--- a/src/interpreter/register.rs
+++ b/src/interpreter/register.rs
@@ -51,6 +51,7 @@ impl Register {
 
     /// Write an [`ImmediateOperand`] to a [`crate::register::Register`].
     pub fn write(&mut self, reg: crate::register::Register, val: ImmediateOperand) {
+        log::debug!("Writing {val:#04x} into {reg}");
         match val {
             ImmediateOperand::Byte(byte) => match reg {
                 crate::register::Register::AX => self.ax.lower = byte,
@@ -79,12 +80,12 @@ impl Register {
                     crate::register::Register::DX => self.dx.write(word),
                     crate::register::Register::AH => self.ax.upper = high,
                     crate::register::Register::AL => self.ax.lower = low,
-                    crate::register::Register::BH => self.ax.upper = high,
-                    crate::register::Register::BL => self.ax.lower = low,
-                    crate::register::Register::CH => self.ax.upper = high,
-                    crate::register::Register::CL => self.ax.lower = low,
-                    crate::register::Register::DH => self.ax.upper = high,
-                    crate::register::Register::DL => self.ax.lower = low,
+                    crate::register::Register::BH => self.bx.upper = high,
+                    crate::register::Register::BL => self.bx.lower = low,
+                    crate::register::Register::CH => self.cx.upper = high,
+                    crate::register::Register::CL => self.cx.lower = low,
+                    crate::register::Register::DH => self.dx.upper = high,
+                    crate::register::Register::DL => self.dx.lower = low,
                     crate::register::Register::DI => self.di = word,
                     crate::register::Register::SI => self.si = word,
                     crate::register::Register::BP => self.bp = word,