From dc6b746faa656729de3ffc5b3ec5b087328dbd27 Mon Sep 17 00:00:00 2001
From: Benji Dial <Benji3.141@gmail.com>
Date: Thu, 26 Dec 2019 16:24:32 -0500
Subject: just learned you can index with ecx, updated assembly accordingly

---
 src/kernel/serial.asm | 29 +++++++++++------------------
 1 file changed, 11 insertions(+), 18 deletions(-)

(limited to 'src/kernel')

diff --git a/src/kernel/serial.asm b/src/kernel/serial.asm
index 9077d99..6318bc5 100644
--- a/src/kernel/serial.asm
+++ b/src/kernel/serial.asm
@@ -22,18 +22,14 @@ send_byte:;void send_byte(uint8_t value, uint8_t port)
   push ebp
   mov ebp, esp
 
-  mov cl, byte [ebp + 8] ;value
-  xor edx, edx
-  mov dl, byte [ebp + 12];port
+  xor ecx, ecx
+  mov cl, byte [ebp + 12];port
 
-  test dl, 0xfc
+  test cl, 0xfc
   jnz .leave
 
-  xchg ebx, edx
-  shl bl, 1
-  mov ax, word [ebx + com_ports]
-  mov ebx, edx
-  mov dx, ax
+  shl cl, 1
+  mov dx, word [ecx + com_ports]
 
   or dx, 5
 
@@ -44,7 +40,7 @@ send_byte:;void send_byte(uint8_t value, uint8_t port)
 
   and dx, 0xfff8
 
-  mov al, cl
+  mov al, byte [ebp + 8];value
   out dx, al
 
 .leave:
@@ -57,17 +53,14 @@ read_byte:;uint8_t read_byte(uint8_t port)
 
   xor eax, eax
 
-  xor edx, edx
-  mov dl, byte [ebp + 8];port
+  xor ecx, ecx
+  mov cl, byte [ebp + 8];port
 
-  test dl, 0xfc
+  test cl, 0xfc
   jnz .leave
 
-  xchg ebx, edx
-  shl bl, 1
-  mov cx, word [ebx + com_ports]
-  mov ebx, edx
-  mov dx, cx
+  shl cl, 1
+  mov dx, word [ecx + com_ports]
 
   or dx, 5
 
-- 
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