printf: Add padding support for %d, %i, %u, %x, %X

2025-07-12 16:33:07 +02:00
parent b327248e0c
commit efeded5547
3 changed files with 176 additions and 58 deletions
--- a/src/convert.asm
+++ b/src/convert.asm
@@ -11,26 +11,27 @@ section .text
 	global	hex2str
 	global	bin2str

-;----- dec2str(int) -----;
+;----- dec2str(int, padLen, bool padZeroes) -----;
 ; Converts a signed integer to a string (decimal output)
 ; Return value: Pointer to string containing the converted integer
 ; Used registers:
 ;	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
+;	rdx*	(arg) padZeroes >> modulo as calculated by div >> character storage for cnvtBuff
 ;	rdi*	(arg) integer to convert to string >> Remembers if num is negative
-;	rsi*	Points to cnvtBuff for writing characters
+;	rsi*	(arg) Padding length
 ;	r8*	Dividor for div
+;	r9*	Points to cnvtBuff[]
+;	r10*	padZeroes arg (since rdx used by DIV)
+;	r12	Remembers if number is negative
 dec2str:
-	lea	rsi, [rel cnvtBuffRev]
-	test	rdi, rdi
-	jnz	.notZero
-	lea	rsi, [rel cnvtBuff]
-	mov	byte [rsi], '0'
-	mov	byte [rsi+1], EOS
-	jmp	.quit
-
-	.notZero:
+	push	r12
+	xor	r12, r12
+	mov	r10, ' '
+	mov	r9, '0'
+	test	rdx, rdx
+	cmovnz	r10, r9
+	lea	r9, [rel cnvtBuffRev]
 	mov	rax, rdi
 	xor	dil, dil
 	xor	rcx, rcx
@@ -43,51 +44,78 @@ dec2str:
 		mov	r8, 10
 		div	r8
 		add	rdx, '0'
-		mov	[rsi], dl
-		inc	rsi
+		mov	[r9], dl
+		inc	r9
 		inc	rcx
 		test	rax, rax
 		jnz	.convert
 		test	dil, dil
 		jz	.makeString
-	mov	[rsi], byte '-'
-	inc	rcx
-	inc	rsi
+	mov	r12, 1
 	.makeString:
+	sub	rsi, rcx
+	cmp	rsi, rcx
+	jl	.noPadding
+	mov	r8, rcx
+	mov	rdi, rsi
+	xor	rsi, rsi
+	mov	rdx, 64
+	call	clamp
+	mov	rcx, rax
+	test	r12, r12
+	jz	.paddingLoop
+	cmp	r10, '0'
+	je	.paddingLoop
+	mov	byte [r9], '-'
+	inc	r9
+	inc	r8
+	xor	r12, r12
+	.paddingLoop:
+		mov	byte [r9], r10b
+		inc	r9
+		inc	r8
+		loop	.paddingLoop
+	mov	rcx, r8
+	.noPadding:
+	test	r12, r12
+	jz	.positive
+	mov	[r9], byte '-'
+	inc	r9
+	inc	rcx
+	.positive:
 	lea	rdi, [rel cnvtBuff]
-	dec	rsi
+	dec	r9
 	.makeStringLoop:
-		mov	al, [rsi]
+		mov	al, [r9]
 		mov	[rdi], al
 		inc	rdi
-		dec	rsi
+		dec	r9
 		loop	.makeStringLoop
 	mov	byte [rdi], EOS

 	.quit:
 	lea	rax, [rel cnvtBuff]
+	pop	r12
 	ret

-;----- udec2str(uint) -----;
+;----- udec2str(uint, padLen, bool padZeroes) -----;
 ; Converts an unsigned integer to a string (decimal output)
 ; Return value: Pointer to string containing the converted integer
 ; Used registers:
 ;	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
+;	rdx*	(arg) padZeroes >> modulo as calculated by div
 ;	rdi*	(arg) integer to convert to string
-;	rsi*	Points to cnvtBuff for writing characters
+;	rsi*	(arg) padLen
 ;	r8*	Dividor for div
+;	r9*	Points to cnvtBuff for writing characters
+;	r10*	padZeroes arg (since rdx used by DIV)
 udec2str:
-	lea	rsi, [rel cnvtBuffRev]
-	test	rdi, rdi
-	jnz	.notZero
-	lea	rsi, [rel cnvtBuff]
-	mov	byte [rsi], '0'
-	mov	byte [rsi+1], EOS
-	jmp	.quit
-
-	.notZero:
+	mov	r10, ' '
+	mov	r9, '0'
+	test	rdx, rdx
+	cmovnz	r10, r9
+	lea	r9, [rel cnvtBuffRev]
 	mov	rax, rdi
 	xor	rcx, rcx
 	.convert:
@@ -95,18 +123,34 @@ udec2str:
 		mov	r8, 10
 		div	r8
 		add	rdx, '0'
-		mov	[rsi], dl
-		inc	rsi
+		mov	[r9], dl
+		inc	r9
 		inc	rcx
 		test	rax, rax
 		jnz	.convert
+	sub	rsi, rcx
+	cmp	rsi, rcx
+	jl	.noPadding
+	mov	r8, rcx
+	mov	rdi, rsi
+	xor	rsi, rsi
+	mov	rdx, 64
+	call	clamp
+	mov	rcx, rax
+	.paddingLoop:
+		mov	byte [r9], r10b
+		inc	r9
+		inc	r8
+		loop	.paddingLoop
+	mov	rcx, r8	
+	.noPadding:
 	lea	rdi, [rel cnvtBuff]
-	dec	rsi
+	dec	r9
 	.makeStringLoop:
-		mov	al, [rsi]
+		mov	al, [r9]
 		mov	[rdi], al
 		inc	rdi
-		dec	rsi
+		dec	r9
 		loop	.makeStringLoop
 	mov	byte [rdi], EOS

@@ -114,33 +158,31 @@ udec2str:
 	lea	rax, [rel cnvtBuff]
 	ret

-;----- hex2str(uint, bool uppercase) -----;
+;----- hex2str(uint, bool uppercase, padLen, bool padZeroes) -----;
 ; 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
+;	rdx*	(arg) Padding length >> module as calculated by div
+;	rcx*	(arg) padZeroes >> Counts length of created string
 ;	r8*	Dividor for div
 ;	r9*	Store arg rsi (uppercase)
+;	r10*	Store arg rdx
 ;	r11*	Amount to add to number (for ASCII conversion, lowercase or uppercase)
+;	r12	Store arg padZeroes
 hex2str:
+	push	r12
 	mov	r9, rsi
+	mov	r10, rdx
+	mov	r12, ' '
+	mov	rsi, '0'
+	test	rcx, rcx
+	cmovnz	r12, rsi
 	lea	rsi, [rel cnvtBuffRev]
-	test	rdi, rdi
-	jnz	.notZero
-	lea	rsi, [rel cnvtBuff]
-	mov	word [rsi], '0x'
-	mov	byte [rsi + 2], '0'
-	mov	byte [rsi + 3], EOS
-	jmp	.quit
-
-	.notZero:
 	mov	rax, rdi
 	xor	rcx, rcx
-
 	mov	r8, 87
 	test	r9, r9
 	cmovz	r11, r8
@@ -163,10 +205,25 @@ hex2str:
 		inc	rcx
 		test	rax, rax
 		jnz	.convert
-
-	mov	word [rsi], 'x0'
-	inc	rsi
-	add	rcx, 2
+	sub	r10, rcx
+	cmp	r10, rcx
+	jl	.noPadding
+	mov	r8, rcx
+	push	rsi
+	mov	rdi, r10
+	xor	rsi, rsi
+	mov	rdx, 64
+	call	clamp
+	pop	rsi
+	mov	rcx, rax
+	.paddingLoop:
+		mov	byte[rsi], r12b
+		inc	rsi
+		inc	r8
+		loop	.paddingLoop
+	mov	rcx, r8
+	.noPadding:
+	dec	rsi
 	lea	rdi, [rel cnvtBuff]
 	.makeString:
 		mov	al, [rsi]
@@ -178,6 +235,7 @@ hex2str:

 	.quit:
 	lea	rax, [rel cnvtBuff]
+	pop	r12
 	ret

 ;----- bin2str(uint, padLen, bool padZeroes) -----;
@@ -223,14 +281,10 @@ bin2str:
 	cmp	rsi, rcx
 	jl	.noPadding
 	mov	r8, rcx
-	push	rsi
-	push	rdx
 	mov	rdi, rsi
 	xor	rsi, rsi
 	mov	rdx, 64
 	call	clamp
-	pop	rdx
-	pop	rsi
 	mov	rcx, rax
 	.paddingLoop:
 		mov	byte [r9], r10b