From af34e3208c45e3a83de63a7d871edeee3268e601 Mon Sep 17 00:00:00 2001
From: Kwarde <kevin@kwarde.com>
Date: Wed, 9 Jul 2025 11:16:04 +0200
Subject: [PATCH] Adds hex2str

---
 src/convert.asm | 77 ++++++++++++++++++++++++++++++++++++++++++++-----
 src/tests.asm   | 36 +++++++++++++++++++++++
 2 files changed, 105 insertions(+), 8 deletions(-)

diff --git a/src/convert.asm b/src/convert.asm
index 6591b24..b945631 100644
--- a/src/convert.asm
+++ b/src/convert.asm
@@ -5,15 +5,16 @@ section .bss
 section .text
 	global	dec2str
 	global	udec2str
+	global	hex2str
 
-;----- dec2str(num) -----;
+;----- dec2str(int) -----;
 ; Converts a signed integer to a string (decimal output)
-; Return value: Pointer to string containing the converted number
+; Return value: Pointer to string containing the converted integer
 ; Used registers:
-;	rax*	num stored for div >> (ret) pointer to cnvtBuff[]
+;	rax*	int stored for div >> (ret) pointer to cnvtBuff[]
 ;	rcx*	Counts length of created string
 ;	rdx*	modulo as calculated by div >> character storage for cnvtBuff
-;	rdi*	(arg) number to convert to string >> Remembers if num is negative
+;	rdi*	(arg) integer to convert to string >> Remembers if num is negative
 ;	rsi*	Points to cnvtBuff for writing characters
 ;	r8*	Dividor for div
 dec2str:
@@ -56,14 +57,14 @@ dec2str:
 	mov	rax, cnvtBuff
 	ret
 
-;----- udec2str(num) -----;
+;----- udec2str(uint) -----;
 ; Converts an unsigned integer to a string (decimal output)
-; Return value: Pointer to string containing the converted number
+; Return value: Pointer to string containing the converted integer
 ; Used registers:
-;	rax*	num stored for div >> (ret) pointer to cnvtBuff[]
+;	rax*	uint stored for div >> (ret) pointer to cnvtBuff[]
 ;	rcx*	Counts length of created string
 ;	rdx*	modulo as calculated by div >> character storage for cnvtBuff
-;	rdi*	(arg) number to convert to string
+;	rdi*	(arg) integer to convert to string
 ;	rsi*	Points to cnvtBuff for writing characters
 ;	r8*	Dividor for div
 udec2str:
@@ -97,3 +98,63 @@ udec2str:
 	.quit:
 	mov	rax, cnvtBuff
 	ret
+
+;----- hex2str(uint, bool uppercase) -----;
+; Converts an unsigned integer to a string (hexadecimal output)
+; Return value: Pointer to string containing the converted integer
+; Used registers:
+;	rax*	uint stored for div >> (ret) Pointer to cnvtBuff[]
+;	rdi	(arg) Integer to convert
+;	rsi*	(arg) 0=convert lowercase, (any other value)=convert uppercase >> Points to cnvtBuff for writing characters
+;	rdx*	module as calculated by div
+;	rcx*	Counts length of created string
+;	r8*	Dividor for div
+;	r9*	Store arg rsi (uppercase)
+hex2str:
+	mov	r9, rsi
+	mov	rsi, cnvtBuff
+	test	rdi, rdi
+	jnz	.notZero
+	mov	word [rsi], '0x'
+	mov	byte [rsi + 2], '0'
+	mov	byte [rsi + 3], EOS
+	jmp	.quit
+
+	.notZero:
+	mov	rax, rdi
+	xor	dil, dil
+	xor	rcx, rcx
+	.convert:
+		xor	rdx, rdx
+		mov	r8, 16
+		div	r8
+		cmp	rdx, 10
+		jb	.num
+		cmp	r9, 1
+		jne	.lower
+		;.upper:
+		add	rdx, 55
+		jmp	.push
+		.lower:
+		add	rdx, 87
+		jmp	.push
+		.num:
+		add	rdx, '0'
+		.push:
+		push	rdx
+		inc	rcx
+		test	rax, rax
+		jnz	.convert
+
+	mov	word [rsi], '0x'
+	add	rsi, 2
+	.makeString:
+		pop	rdx
+		mov	byte [rsi], dl
+		inc	rsi
+		loop	.makeString
+	mov	byte [rsi], EOS
+
+	.quit:
+	mov	rax, cnvtBuff
+	ret
diff --git a/src/tests.asm b/src/tests.asm
index d386af6..fb51025 100644
--- a/src/tests.asm
+++ b/src/tests.asm
@@ -14,11 +14,13 @@ extern	strclr
 ; convert.asm
 extern	dec2str
 extern	udec2str
+extern	hex2str
 
 section .rodata
 	TEST_print		equ	1
 	TEST_puts		equ	1
 	TEST_dec2str		equ	1 ;includes udec2str
+	TEST_hex2str		equ	1
 	TEST_printf		equ	1
 	TEST_strlen		equ	1
 	TEST_strcpy		equ	1
@@ -125,6 +127,40 @@ _start:
 	call	udec2str
 %endif
 
+;---
+;--- hex2str()
+;---
+%if TEST_hex2str
+	; TEST 1
+	xor	rdi, rdi
+	mov	rsi, 0
+	call	hex2str
+	mov	rdi, -1
+	mov	rsi, 0
+	call	hex2str
+
+	; TEST 2
+	xor	rdi, rdi
+	mov	rsi, 1
+	call	hex2str
+	mov	rdi, -1
+	mov	rsi, 1
+	call	hex2str
+
+	; TEST 3
+	mov	rdi, 0x123456789ABCDEF
+	mov	rsi, 0
+	call	hex2str
+	mov	rdi, 0x123456789ABCDEF
+	mov	rsi, 1
+	call	hex2str
+
+	; TEST 4
+	mov	rdi, 128
+	mov	rsi, 0
+	call	hex2str
+%endif
+
 ;---
 ;--- printf()
 ;---