luxos/stage2/stdio.inc

299 lines
7.2 KiB
PHP

;*************************************************
; stdio.inc
; -Input/Output routines
;
; OS Development Series
;*************************************************
%ifndef __STDIO_INC_67343546FDCC56AAB872_INCLUDED__
%define __STDIO_INC_67343546FDCC56AAB872_INCLUDED__
;==========================================================
;
; 16 Bit Real Mode Routines
;==========================================================
;************************************************;
; Puts16 ()
; -Prints a null terminated string
; DS=>SI: 0 terminated string
;************************************************;
bits 16
Puts16:
pusha ; save registers
.Loop1:
lodsb ; load next byte from string from SI to AL
or al, al ; Does AL=0?
jz Puts16Done ; Yep, null terminator found-bail out
mov ah, 0eh ; Nope-Print the character
int 10h ; invoke BIOS
jmp .Loop1 ; Repeat until null terminator found
Puts16Done:
popa ; restore registers
ret ; we are done, so return
;==========================================================
;
; 32 Bit Protected Mode Routines
;==========================================================
bits 32
%define VIDMEM 0xB8000 ; video memory
%define COLS 80 ; width and height of screen
%define LINES 25
%define CHAR_ATTRIB 63 ; character attribute (White text on light blue background)
_CurX db 0 ; current x/y location
_CurY db 0
;**************************************************;
; Putch32 ()
; - Prints a character to screen
; BL => Character to print
;**************************************************;
Putch32:
pusha ; save registers
mov edi, VIDMEM ; get pointer to video memory
;-------------------------------;
; Get current position ;
;-------------------------------;
xor eax, eax ; clear eax
;--------------------------------
; Remember: currentPos = x + y * COLS! x and y are in _CurX and _CurY.
; Because there are two bytes per character, COLS=number of characters in a line.
; We have to multiply this by 2 to get number of bytes per line. This is the screen width,
; so multiply screen with * _CurY to get current line
;--------------------------------
mov ecx, COLS*2 ; Mode 7 has 2 bytes per char, so its COLS*2 bytes per line
mov al, byte [_CurY] ; get y pos
mul ecx ; multiply y*COLS
push eax ; save eax--the multiplication
;--------------------------------
; Now y * screen width is in eax. Now, just add _CurX. But, again remember that _CurX is relative
; to the current character count, not byte count. Because there are two bytes per character, we
; have to multiply _CurX by 2 first, then add it to our screen width * y.
;--------------------------------
mov al, byte [_CurX] ; multiply _CurX by 2 because it is 2 bytes per char
mov cl, 2
mul cl
pop ecx ; pop y*COLS result
add eax, ecx
;-------------------------------
; Now eax contains the offset address to draw the character at, so just add it to the base address
; of video memory (Stored in edi)
;-------------------------------
xor ecx, ecx
add edi, eax ; add it to the base address
;-------------------------------;
; Watch for new line ;
;-------------------------------;
cmp bl, 0x0A ; is it a newline character?
je .Row ; yep--go to next row
;-------------------------------;
; Print a character ;
;-------------------------------;
mov dl, bl ; Get character
mov dh, CHAR_ATTRIB ; the character attribute
mov word [edi], dx ; write to video display
;-------------------------------;
; Update next position ;
;-------------------------------;
inc byte [_CurX] ; go to next character
; cmp byte [_CurX], COLS ; are we at the end of the line?
; je .Row ; yep-go to next row
jmp .done ; nope, bail out
;-------------------------------;
; Go to next row ;
;-------------------------------;
.Row:
mov byte [_CurX], 0 ; go back to col 0
inc byte [_CurY] ; go to next row
;-------------------------------;
; Restore registers & return ;
;-------------------------------;
.done:
popa ; restore registers and return
ret
;**************************************************;
; Puts32 ()
; - Prints a null terminated string
; parm\ EBX = address of string to print
;**************************************************;
Puts32:
;-------------------------------;
; Store registers ;
;-------------------------------;
pusha ; save registers
push ebx ; copy the string address
pop edi
.loop:
;-------------------------------;
; Get character ;
;-------------------------------;
mov bl, byte [edi] ; get next character
cmp bl, 0 ; is it 0 (Null terminator)?
je .done ; yep-bail out
;-------------------------------;
; Print the character ;
;-------------------------------;
call Putch32 ; Nope-print it out
;-------------------------------;
; Go to next character ;
;-------------------------------;
inc edi ; go to next character
jmp .loop
.done:
;-------------------------------;
; Update hardware cursor ;
;-------------------------------;
; Its more efficiant to update the cursor after displaying
; the complete string because direct VGA is slow
mov bh, byte [_CurY] ; get current position
mov bl, byte [_CurX]
call MovCur ; update cursor
popa ; restore registers, and return
ret
;**************************************************;
; MoveCur ()
; - Update hardware cursor
; parm/ bh = Y pos
; parm/ bl = x pos
;**************************************************;
bits 32
MovCur:
pusha ; save registers (aren't you getting tired of this comment?)
;-------------------------------;
; Get current position ;
;-------------------------------;
; Here, _CurX and _CurY are relitave to the current position on screen, not in memory.
; That is, we don't need to worry about the byte alignment we do when displaying characters,
; so just follow the forumla: location = _CurX + _CurY * COLS
xor eax, eax
mov ecx, COLS
mov al, bh ; get y pos
mul ecx ; multiply y*COLS
add al, bl ; Now add x
mov ebx, eax
;--------------------------------------;
; Set low byte index to VGA register ;
;--------------------------------------;
mov al, 0x0f
mov dx, 0x03D4
out dx, al
mov al, bl
mov dx, 0x03D5
out dx, al ; low byte
;---------------------------------------;
; Set high byte index to VGA register ;
;---------------------------------------;
xor eax, eax
mov al, 0x0e
mov dx, 0x03D4
out dx, al
mov al, bh
mov dx, 0x03D5
out dx, al ; high byte
popa
ret
;**************************************************;
; ClrScr32 ()
; - Clears screen
;**************************************************;
bits 32
ClrScr32:
pusha
cld
mov edi, VIDMEM
mov cx, 2000
mov ah, CHAR_ATTRIB
mov al, ' '
rep stosw
mov byte [_CurX], 0
mov byte [_CurY], 0
popa
ret
;**************************************************;
; GotoXY ()
; - Set current X/Y location
; parm\ AL=X position
; parm\ AH=Y position
;**************************************************;
bits 32
GotoXY:
pusha
mov [_CurX], al ; just set the current position
mov [_CurY], ah
popa
ret
%endif ;__STDIO_INC_67343546FDCC56AAB872_INCLUDED__