printf(): Add %c, add test for %c and args on stack

src/console.asm

@@ -59,6 +59,7 @@ puts:
 ; Return value: Amount of printed characters
 ; Supported specifiers:
 ;	%%	Literal percentage sign
+;	%c	Single character
 ;	%s	String
 ; <!> Unsupported specifiers are printed as-is
 ; <!> For all specifiers (except %%) an argument is expected. Mismatch between arguments given and specifiers provided will lead to issues
@@ -112,6 +113,8 @@ printf:
 		je	.wrapup
 		cmp	byte [rdi + 1], '%'
 		je	.rep_pct
+		cmp	byte [rdi + 1], 'c'
+		je	.rep_c
 		cmp	byte [rdi + 1], 's'
 		je	.rep_s
 
@@ -125,11 +128,19 @@ printf:
 
 		;--- '%%' ---;
 		.rep_pct:
-		mov	[printfBuff+r10], byte '%'
-		add	rdi, 2
-		add	r10, 1
-		add	r11, 1
-		jmp	.process
+		mov	sil, '%'
+		dec	rdx
+		jmp	.insertChar
+
+		;--- '%c' ---;
+		.rep_c:
+		cmp	rdx, 4
+		ja	.c_fromStack
+		mov	rsi, [printfArgs + SIZE_QWORD * rdx]
+		jmp	.insertChar
+		.c_fromStack:
+		mov	rsi, [rbp + RBP_OFFSET_CALLER + ((rdx-5) * SIZE_QWORD)]
+		jmp	.insertChar
 
 		;--- '%s' ---;
 		.rep_s:
@@ -155,9 +166,18 @@ printf:
 			inc	r11
 			jmp	.insertString
 		.endInsertString:
-			inc	rdx
-			add	rdi, 2
-			jmp	.process
+		inc	rdx
+		add	rdi, 2
+		jmp	.process
+
+		;--- Insert char to buffer ---;
+		.insertChar:
+		mov	[printfBuff + r10], sil
+		add	rdi, 2
+		add	r10, 1
+		add	r11, 1
+		inc	rdx
+		jmp	.process
 
 	.flushBuffer:
 	push	rdi