From b0e9193b0aa2f75eaf9c6697a1e55b2cbd36e198 Mon Sep 17 00:00:00 2001
From: Kwarde <kevin@kwarde.com>
Date: Sun, 20 Jul 2025 12:18:29 +0200
Subject: [PATCH] atoi(): Add support for lowercase hexadecimal letters

---
 src/convert.asm | 23 ++++++++++++++++++++---
 src/tests.asm   |  4 +++-
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/convert.asm b/src/convert.asm
index e606725..5f10c7d 100644
--- a/src/convert.asm
+++ b/src/convert.asm
@@ -71,19 +71,31 @@ atoi:
 		je	.calculate
 		cmp	byte [rdi], '0'
 		jb	.quit
-		; Test if valid
+
 		cmp	rsi, 16
 		je	.getLenLoop_testHex
+		; Check non-hexadecimal number
 		cmp	byte [rdi], dl
 		ja	.quit
 		jmp	.getLenLoop_cnt
+		; Check hexadecimal number
 		.getLenLoop_testHex:
+		cmp	byte [rdi], 'f'
+		ja	.quit
+		cmp	byte [rdi], 'a'
+		jb	.testHex_validUpper
+		; byte[rdi] is in range a-f
+		jmp	.getLenLoop_cnt
+		.testHex_validUpper:
 		cmp	byte [rdi], 'F'
 		ja	.quit
 		cmp	byte [rdi], 'A'
-		jb	.testHex_isNum
+		jb	.testHex_validNum
+		; byte[rdi] is in range A-F
 		jmp	.getLenLoop_cnt
-		.testHex_isNum:
+		.testHex_validNum:
+		cmp	byte [rdi], '0'
+		jb	.quit
 		cmp	byte [rdi], '9'
 		ja	.quit
 		
@@ -125,8 +137,13 @@ atoi:
 		mov	al, byte [rdi]
 		cmp	al, 'A'
 		jb	.calcNum_notHex
+		cmp	al, 'F'
+		ja	.calcNum_lowerHex
 		sub	al, 55 ;'A'-10 (65-10)
 		jmp	.calcNum_cnt
+		.calcNum_lowerHex:
+		sub	al, 87 ;'a'-10 (97-10)
+		jmp	.calcNum_cnt
 		.calcNum_notHex:
 		sub	al, '0'
 
diff --git a/src/tests.asm b/src/tests.asm
index ca5216c..35f508d 100644
--- a/src/tests.asm
+++ b/src/tests.asm
@@ -207,7 +207,7 @@ section .rodata
 
 	; atoi()
 	msgAtoi			db	NL,"TEST atoi()",NL,EOS
-	atoiOutput		db	TAB,"%s = %d",NL,EOS
+	atoiOutput		db	TAB,"atoi(",DQUO,"%s",DQUO,"): %d",NL,EOS
 	atoi1			db	"1234567890",EOS
 	atoi2			db	"0xFFFFFFFF",EOS ;4 294 967 295
 	atoi3			db	"0o776655",EOS ;261 549
@@ -218,6 +218,7 @@ section .rodata
 	atoi8			db	"0x0962GBCDEF",EOS ;0
 	atoi9			db	"0o77865",EOS ;0
 	atoi10			db	"0b102001",EOS;0
+	atoi11			db	"0xffffffff",EOS ;4 294 967 295
 section .data
 
 section .bss
@@ -1105,6 +1106,7 @@ _start:
 	testatoi atoi8
 	testatoi atoi9
 	testatoi atoi10
+	testatoi atoi11
 %endif
 
 ;---