From 55fb99f0e12ec0b4bcf11b66bb2849e48aaf7d90 Mon Sep 17 00:00:00 2001
From: Jarkko Toivanen <jt@jakest.us>
Date: Wed, 6 Sep 2023 20:28:25 +0300
Subject: [PATCH] Not the whole screenbuffer width was accessible

---
 src/framebuffer.asm | 3 ++-
 src/start32.asm     | 9 +++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/framebuffer.asm b/src/framebuffer.asm
index 7d14615..d831dec 100644
--- a/src/framebuffer.asm
+++ b/src/framebuffer.asm
@@ -17,7 +17,8 @@ putpixel:
 	add edi, eax
 
 	mov eax, [ebp+8]   ;x
-	mul byte [mbootinfo.fb_bytespp]
+	movzx ebx, byte [mbootinfo.fb_bytespp]
+	mul ebx
 	add edi, eax
 
 
diff --git a/src/start32.asm b/src/start32.asm
index 8577d67..fc3ae85 100644
--- a/src/start32.asm
+++ b/src/start32.asm
@@ -98,6 +98,15 @@ start:
 
 	add esp, 36	;Clean reserved uitoa return string from stack
 
+	; Draw a test pixel to bottom right corner
+	mov eax, 0xff
+	mov ebx, 767
+	mov ecx, 1023
+	push 0xff
+	push 767
+	push 1023
+	call putpixel
+	add esp, 3*4
 
 rOSkalogodraw:
 	mov esi, roskalogo