Dump current state of printf() (adding %d support), adds itoa()

core.asm

@@ -1,3 +1,5 @@
+extern	strclr
+
 section	.text
 	global	min
 	global	minu
@@ -7,6 +9,7 @@ section	.text
 	global	isupper
 	global	tolower
 	global	toupper
+	global	itoa
 
 ;----- min(int a, int b) -----;
 ; return value: lowest value
@@ -120,3 +123,52 @@ toupper:
 	.quit:
 	leave
 	ret
+;----- itoa(int num, char* str) -----;
+; return value: pointer to str
+itoa:
+	push	rbp
+	mov	rbp, rsp
+
+	push	rsi
+	push	rdi
+	mov	rdi, rsi
+	call	strclr
+	pop	rdi
+	mov	rax, rdi
+	mov	r8, rsi
+	xor	rcx, rcx
+
+	test	rax, rax
+	jnz	.checkNeg
+	mov	byte [rsi], '0'
+	mov	byte [rsi+1], 0
+	jmp	.quit
+
+	.checkNeg:
+	xor	rbx, rbx
+	test	rax, rax
+	jns	.convert
+	neg	rax
+	mov	rbx, 1
+
+	.convert:
+	xor	rdx, rdx
+	mov	r10, 10
+	div	r10
+	add	rdx, '0'
+	push	rdx
+	inc	rcx
+	test	rax, rax
+	jnz	.convert
+
+	.toString:
+	pop	rdx
+	mov	byte [rsi], dl
+	inc	rsi
+	loop	.toString
+
+	.quit:
+	pop	rsi
+	mov	rax, rsi
+	leave
+	ret