From f9e2dc33e904fa2cbaac0ab2d08a86335d99b41c Mon Sep 17 00:00:00 2001
From: Jarkko Toivanen <jt@jakest.us>
Date: Sat, 17 Aug 2024 20:21:04 +0300
Subject: [PATCH] Made __uitoa comply with our calling convention

Changed __uitoa order of arguments from
  src,base,target
to
  src,target,base
Also returns target in EAX
---
 src/itoa.asm    | 23 +++++++++++++----------
 src/start32.asm | 43 ++++++++++++++++++++++---------------------
 2 files changed, 35 insertions(+), 31 deletions(-)

diff --git a/src/itoa.asm b/src/itoa.asm
index 429f9cf..3985f9d 100644
--- a/src/itoa.asm
+++ b/src/itoa.asm
@@ -1,8 +1,12 @@
 ;; Modified from: https://gist.github.com/SplittyDev/8e728627012e57ac0deac196660014fb
 
+; __itoa(src int, target addr, base)
+;target address returned in EAX
+;EBX, EBP, ESP preserved as our calling convention,
+;refer to docs or something
+
 ;
 ; Routine to convert a 32-bit integer to a string.
-; Registers are preserved.
 ;
 ; EAX: Source integer
 ; EBX: Target address
@@ -26,9 +30,13 @@
 ; ECX: Target address (active)
 ; EDX: Target address (temporary)
 ;
+; return:
+; put original target at EAX
+; (we trust this blindly)
+
 macro kuitoa src*, dest*, base* {
-	push dest
 	push base
+	push dest
 	push src
 	call __uitoa
 	add esp, 3*4
@@ -39,14 +47,11 @@ __uitoa:
 	push ebp
 	mov ebp, esp
 
-	push eax
 	push ebx
-	push ecx
-	push edx
 
 	mov eax, [ebp+8]
-	mov ecx, [ebp+12]
-	mov ebx, [ebp+16]
+	mov ebx, [ebp+12]
+	mov ecx, [ebp+16]
 
 	mov edx, ecx
 	mov ecx, ebx
@@ -83,11 +88,9 @@ __uitoa:
 	dec ecx
 	jmp .reverse
 .end:
-	pop edx
-	pop ecx
 	pop ebx
-	pop eax
 
+	mov eax, [ebp+12]	; Return target address
 	pop ebp
 	ret
 
diff --git a/src/start32.asm b/src/start32.asm
index b72db5e..a196470 100644
--- a/src/start32.asm
+++ b/src/start32.asm
@@ -52,45 +52,46 @@ start:
 	add esp, 2*4
 
 	sub esp, 36	;Reserve stack for return
-	kuitoa [mbootinfo.fb_addr], esp, 16
-	serw stuff.fbaddrmsgpfx, esp
+	mov ebx, esp	;Store str buff addr
 
-	kuitoa [mbootinfo.fb_width], esp, 10
-	serw stuff.fbdimensionsmsgpfx, esp, stuff.x
+	kuitoa [mbootinfo.fb_addr], ebx, 16
+	serw stuff.fbaddrmsgpfx, ebx
 
-	kuitoa [mbootinfo.fb_height], esp, 10
-	serw esp, stuff.x
+	kuitoa [mbootinfo.fb_width], ebx, 10
+	serw stuff.fbdimensionsmsgpfx, ebx, stuff.x
+
+	kuitoa [mbootinfo.fb_height], ebx, 10
+	serw ebx, stuff.x
 
 	movzx eax, byte [mbootinfo.fb_bpp]
-	kuitoa eax, esp, 10
-	serw esp
+	kuitoa eax, ebx, 10
+	serw ebx
 
 
 	movzx eax, byte [mbootinfo.fb_rpos]
-	kuitoa eax, esp, 10
-	serw stuff.rpostxt, esp
+	kuitoa eax, ebx, 10
+	serw stuff.rpostxt, ebx
 
 	movzx eax, byte [mbootinfo.fb_gpos]
-	kuitoa eax, esp, 10
-	serw stuff.gpostxt, esp
+	kuitoa eax, ebx, 10
+	serw stuff.gpostxt, ebx
 
 	movzx eax, byte [mbootinfo.fb_bpos]
-	kuitoa eax, esp, 10
-	serw stuff.bpostxt, esp
-
+	kuitoa eax, ebx, 10
+	serw stuff.bpostxt, ebx
 
 
 	movzx eax, byte [mbootinfo.fb_rmasksize]
-	kuitoa eax, esp, 10
-	serw stuff.rmasksizetxt, esp
+	kuitoa eax, ebx, 10
+	serw stuff.rmasksizetxt, ebx
 
 	movzx eax, byte [mbootinfo.fb_gmasksize]
-	kuitoa eax, esp, 10
-	serw stuff.gmasksizetxt, esp
+	kuitoa eax, ebx, 10
+	serw stuff.gmasksizetxt, ebx
 
 	movzx eax, byte [mbootinfo.fb_bmasksize]
-	kuitoa eax, esp, 10
-	serw stuff.bmasksizetxt, esp
+	kuitoa eax, ebx, 10
+	serw stuff.bmasksizetxt, ebx
 
 	add esp, 36	;Clean reserved uitoa return string from stack