DOSGame/trunk/BIOSFUNC.ASM

; AL = Character
BIOS_WriteTTYChar:
    ;MOV AL, [0]
    MOV AH, 0Eh
    INT 10h
    RET

BIOS_SetVideoMode13H:
    CMP BYTE [CurrentVideoMode], 0x13 ; Prevent a switch if we're already mode 13.
    ; This prevents clearing the framebuffer if clearing wasn't intended
    JE .already
    MOV AX, 0x0013
    INT 10h
    MOV BYTE [CurrentVideoMode], 0x13
    .already:
    RET

BIOS_SetVideoMode03H:
    CMP BYTE [CurrentVideoMode], 0x03 ; Prevent a switch if we're already mode 03.
    ; This prevents clearing the framebuffer if clearing wasn't intended, and also whenever
    ; we show an error in fallback mode, and then call an error handler, the latter will not
    ; clear the screen by switching from 03 to 03.
    JE .already
    MOV AX, 0x0003
    INT 10h
    MOV BYTE [CurrentVideoMode], 0x03
    .already:
    RET
Revision:	4
Committed:	Wed Feb 11 15:26:06 2026 UTC (8 weeks, 3 days ago) by figdor32
File size:	852 byte(s)
Log Message:	Initial check-in
#	Content
1	; AL = Character
2	BIOS_WriteTTYChar:
3	;MOV AL, [0]
4	MOV AH, 0Eh
5	INT 10h
6	RET
7
8	BIOS_SetVideoMode13H:
9	CMP BYTE [CurrentVideoMode], 0x13 ; Prevent a switch if we're already mode 13.
10	; This prevents clearing the framebuffer if clearing wasn't intended
11	JE .already
12	MOV AX, 0x0013
13	INT 10h
14	MOV BYTE [CurrentVideoMode], 0x13
15	.already:
16	RET
17
18	BIOS_SetVideoMode03H:
19	CMP BYTE [CurrentVideoMode], 0x03 ; Prevent a switch if we're already mode 03.
20	; This prevents clearing the framebuffer if clearing wasn't intended, and also whenever
21	; we show an error in fallback mode, and then call an error handler, the latter will not
22	; clear the screen by switching from 03 to 03.
23	JE .already
24	MOV AX, 0x0003
25	INT 10h
26	MOV BYTE [CurrentVideoMode], 0x03
27	.already:
28	RET