printf(): Allow padding (spaces or zeroes) for %b

src/convert.asm

@@ -1,5 +1,7 @@
 %include "src/constants.asm"
 
+extern	clamp
+
 section .bss
 	cnvtBuff	resb	67
 	cnvtBuffRev	resb	67
@@ -178,24 +180,30 @@ hex2str:
 	lea	rax, [rel cnvtBuff]
 	ret
 
-;----- bin2str(uint) -----;
+;----- bin2str(uint, padLen, bool padZeroes) -----;
 ; Converts an unsigned integer to a string (binary 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) If padLen>0, use Zeroes (rdx!=0) or spaces (rdx=0) >> modulo as calculated by div >> character storage for cnvtBuff
 ;	rdi*	(arg) integer to convert to string
-;	rsi*	Points to cnvtBuff for writing characters
+;	rsi*	(arg) Padding length
 ;	r8*	Dividor for div
+;	r9*	Points to cnvtBuff for writing characters
+;	r10*	padZeroes arg (since rdx used by DIV)
 bin2str:
-	lea	rsi, [rel cnvtBuffRev]
+	mov	r10, ' '
+	mov	r9, '0'
+	test	rdx, rdx
+	cmovnz	r10, r9
+	lea	r9, [rel cnvtBuffRev]
 	test	rdi, rdi
 	jnz	.notZero
-	lea	rsi, [rel cnvtBuff]
-	mov	word [rsi], '0b'
-	mov	byte [rsi + 2], '0'
-	mov	byte [rsi + 3], EOS
+	lea	r9, [rel cnvtBuff]
+	mov	word [r9], '0b'
+	mov	byte [r9 + 2], '0'
+	mov	byte [r9 + 3], EOS
 	jmp	.quit
 
 	.notZero:
@@ -206,20 +214,38 @@ bin2str:
 		mov	r8, 2
 		div	r8
 		add	rdx, '0'
-		mov	[rsi], dl
-		inc	rsi
+		mov	[r9], dl
+		inc	r9
 		inc	rcx
 		test	rax, rax
 		jnz	.convert
-	mov	word [rsi], 'b0'
-	add	rcx, 2
-	inc	rsi
+	sub	rsi, rcx
+	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
+		inc	r9
+		inc	r8
+		loop	.paddingLoop
+	mov	rcx, r8
+	.noPadding:
+	dec	r9
 	lea	rdi, [rel cnvtBuff]
 	.makeStringLoop:
-		mov	al, [rsi]
+		mov	al, [r9]
 		mov	[rdi], al
 		inc	rdi
-		dec	rsi
+		dec	r9
 		loop	.makeStringLoop
 	mov	byte [rdi], EOS