print.nasm

;; Copyright (c) 2020, Florian Büstgens
;; All rights reserved.
;;
;; Redistribution and use in source and binary forms, with or without
;; modification, are permitted provided that the following conditions are met:
;;     1. Redistributions of source code must retain the above copyright
;;        notice, this list of conditions and the following disclaimer.
;;
;;     2. Redistributions in binary form must reproduce the above copyright notice,
;;        this list of conditions and the following disclaimer in the
;;        documentation and/or other materials provided with the distribution.
;;
;; THIS SOFTWARE IS PROVIDED BY <copyright holder> ''AS IS'' AND ANY
;; EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
;; DISCLAIMED. IN NO EVENT SHALL <copyright holder> BE LIABLE FOR ANY
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;; (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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;; print.nasm
;; Routines to output strings to TTY

;; How to use:
;;
;; mov si, MSG
;; call printer
;;
[BITS 16]
	
printer:
	push bx

	mov ah, 0x0E 		; BIOS Printing Mode
	mov bx, 0x00

.loop:
	lodsb			; For reference see https://www.i8086.de/asm/8086-88-asm-lodsb.html
	cmp al, 0		; If the null terminator is reached, we're finished.
	je .end

	call _print_char
	jmp .loop
	
.end:
	pop bx
	ret

_print_char:
	mov ah, 0x0E
	int 0x10
	ret