;---------------------------------------------------;
;	App: MASM printf usage							;
;	Version: 1.0									;
;---------------------------------------------------;
;	Date: 04 June 2017								;
;	Author: Jose Madureira							;
;	License: copy at will, just give credit			;
;---------------------------------------------------;

; ## Global Constants ##
NL EQU 0Dh,0Ah		;new line
TAB EQU 09h			;tab character
STRMAX	EQU 21		;max string size
T64 EQU TYPE RAX	;64 bit size (8 BYTES)

; ## External Prototypes ## 
includelib msvcrt.lib	;necessary for printf
EXTRN printf:PROC	;display formatted string with args

ExitProcess PROTO	;terminate program


.data
	msgNl byte NL,0		;simply a new line

	;simple formats
	msgInt byte "%d",0
	msgFlt byte "%f",0
	msgStr byte "%s",0

	;test data
	valInt qword 666
	valFlt real8 6.54321
	valStr byte "This is not a test",0
	valStrNlTab byte NL,TAB,"new lined and tabbed",0

.code
PUBLIC Main

Main PROC
	;display an integer
	mov rax,1
	mov rcx,offset msgInt	;"%d"
	mov rdx,valInt			;some integer value
	call PrintfMe64

	;display new line using PrintfMe64
	mov rax,1
	mov rcx,offset msgStr	;"%s"
	mov rdx,offset msgNl	;crlf
	call PrintfMe64
	
	;display a float
	mov rax,1
	mov rcx,offset msgFlt	;"%f"
	mov rdx,valFlt			;some float value
	call PrintfMe64

	;display new line using PNL -> PrintfMe64
	call PNL

	;display a string
	mov rax,1
	mov rcx,offset msgStr	;"%s"
	mov rdx,offset valStr	;some string
	call PrintfMe64

	;display a string with new line and tab before it
	mov rax,1
	mov rcx,offset msgStr	;"%s"
	mov rdx,offset valStrNlTab ;new line -> tab -> string
	call PrintfMe64

	

finish:
	call PNL
	call PNL
	call ExitProcess

Main ENDP


; *******************************************************************
PrintfMe64 PROC uses RAX
; * Purpose: display a 'c' style formated message and arguments		*
; *-----------------------------------------------------------------*
; * IN : RAX, number of arguments									*
; *		 RCX, message with format flags								*
; *		 RDX...R15, arguments for formatted message					*
; * OUT: none														*
; *+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*
; * implementation idea:											*
; *		http://cx20.main.jp/blog/hello/2012/01/04/hello-masm-world	*
; *******************************************************************
	;prevent disaster
	push RBP
	mov RBP, RSP

	imul RAX, 8			;allocate additional 8 bytes per argument 
	add RAX, 64			;(8*args) + 64 bytes
	mov [RBP], RAX		;save total allocated local space 	
	sub RSP, RAX		;allocate local stack space

	call printf			;display formated message

    add RSP, [RBP]		;clean the stack
	pop RBP

	ret
PrintfMe64 ENDP

; *******************************************************************
PNL PROC uses RAX RCX RDX
; * Purpose: displays a new line									*
; *-----------------------------------------------------------------*
; * IN : none														*
; * OUT: none														*
; *******************************************************************
	mov rax,1
	mov rcx,offset msgStr		;"%s"
	mov rdx,offset msgNl		; cr lf
	call PrintfMe64

ret
PNL ENDP

END