From 3619a20703bc599f3f63ff797d6a570137092386 Mon Sep 17 00:00:00 2001
From: Ain <41307858+nero@users.noreply.github.com>
Date: Thu, 23 Apr 2020 21:35:28 +0200
Subject: [PATCH] Implement some console i/o

---
 boot/kernel.asm | 54 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 46 insertions(+), 8 deletions(-)

diff --git a/boot/kernel.asm b/boot/kernel.asm
index f971134..4f5fd03 100644
--- a/boot/kernel.asm
+++ b/boot/kernel.asm
@@ -41,8 +41,8 @@ iret:	iret
 sfptr:	dw 0
 
 	; Subfunction table
-sftab:	dw sferr, sferr, putc, sferr
-	dw sferr, sferr, sferr, sferr
+sftab:	dw sferr, getc, putc, sferr
+	dw sferr, sferr, conout, conin
 	dw sferr, puts, sferr, sferr
 	dw sferr, sferr, sferr, sferr
 	; 10
@@ -61,18 +61,56 @@ sftab:	dw sferr, sferr, putc, sferr
 	dw sferr, sferr, sferr, sferr
 	dw sferr, sferr, sferr, sferr
 
-	; DOS 1+ 2h - WRITE CHARACTER TO STANDARD OUTPUT
+	; OUT	al	character read
+getc:	xor ax, ax
+	int 0x16
+	push ax
+	jmp putc.2
+
 	; IN	dl	character to write
 putc:	push ax
-	push bx
-	mov ah, 0x0E
 	mov al, dl
-	xor bx, bx
-	int 0x10
-	pop bx
+.2:	int 0x29
 	pop ax
 	ret
 
+	; console output
+	; IN	dl	character
+conout:	cmp dl, 0xFF
+	je conine
+	push ax
+	mov al, dl
+	int 0x29
+	pop ax
+	ret
+
+	; console input with echo
+	; OUT	al	character
+	;	zf	clear when character available
+conine:	mov ah, 1
+	int 0x16
+	jnz .has
+	xor al, al
+	ret
+.has:	xor ax, ax
+	int 0x16
+	int 0x29
+	test ax, ax
+	ret
+
+	; console input without echo
+	; OUT	al	character
+	;	zf	clear when character available
+conin:	mov ah, 1
+	int 0x16
+	jnz .has
+	xor al, al
+	ret
+.has:	xor ax, ax
+	int 0x16
+	test ax, ax
+	ret
+
 	; DOS 1+ 9h - WRITE STRING TO STANDARD OUTPUT
 	; IN	ds:dx	'$'-terminated string
 puts:	push si