From 1c5ba65f49cb786d38b0ed919bbc485487535f6b Mon Sep 17 00:00:00 2001
From: Kwarde <kevin@kwarde.com>
Date: Thu, 17 Jul 2025 14:56:35 +0200
Subject: [PATCH] Correctly set padding length when using prefix (fixes #1)

---
 src/convert.asm |  8 +++++++-
 src/tests.asm   | 16 ++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/convert.asm b/src/convert.asm
index b182b72..3045b04 100644
--- a/src/convert.asm
+++ b/src/convert.asm
@@ -256,7 +256,6 @@ utoa:
 	test	r15, r15 ;prefix now? (padding with spaces; r15 is zero)
 	jnz	.checkPadding
 		insert_prefix
-	add	r14, 2
 	
 	.checkPadding:
 	; Substract length of converted number from padLen
@@ -264,6 +263,13 @@ utoa:
 	cmp	r14, 0
 	jle	.checkPrefix
 	mov	rcx, r14
+	test	r13, r13
+	jns	.addPadding
+	test	r15, r15
+	jz	.addPadding
+	sub	rcx, 2
+	cmp	rcx, 2
+	jl	.checkPrefix
 	.addPadding:
 		mov	byte [r10], r11b
 		inc	r10
diff --git a/src/tests.asm b/src/tests.asm
index d07f20a..09c04a6 100644
--- a/src/tests.asm
+++ b/src/tests.asm
@@ -103,6 +103,8 @@ section .rodata
 	printf14Str		db	"%#b | %#08b | %#x | %#8X | %#o\n",EOS
 	printf15		db	TAB,"printf(",DQUO,"%p | %#p | %8p | %#8p | %08p | %#08p\n",DQUO,", str5, str5, str5, str5, strBuff1, strBuff1): ",NL,TAB,TAB,EOS
 	printf15Str		db	"%p | %#p | %8p | %#8p | %08p | %#08p\n",EOS
+	printf16		db	TAB,"printf(",DQUO,"%x | %#10x | %10x | %#10x | %010x | %#010x\n",DQUO,", str5, str5, str5, str5, strBuff1, strBuff1): ",NL,TAB,TAB,EOS
+	printf16Str		db	"%x | %#10x | %10x | %#10x | %010x | %#010x\n",EOS
 	; strlen()
 	msgStrlen		db	NL,"TEST strlen()",NL,EOS
 	strlen1			db	TAB,"strlen(str1): %d",NL,EOS
@@ -411,6 +413,20 @@ _start:
 	push	strBuff1
 	call	printf
 	add	rsp, SIZE_QWORD * 2
+
+	; TEST 16
+	lea	rdi, [rel printf16]
+	call	print
+	lea	rdi, [rel printf16Str]
+	lea	rsi, [rel str5]
+	lea	rdx, [rel str5]
+	lea	rcx, [rel str5]
+	lea	r8, [rel str5]
+	lea	r9, [rel strBuff1]
+	sub	rsp, SIZE_QWORD
+	push	strBuff1
+	call	printf
+	add	rsp, SIZE_QWORD * 2
 %endif
 
 ;---