Simple Library for Bare Metal

4bm.asm

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;-------------------------------------------------------------------;
; Why a library for bare metal? Its just for study purposes
; References:
; http://stanislavs.org/helppc/idx_interrupt.html
;-------------------------------------------------------------------;

; TODO LIST
; [ ] - dinamic memory alocation (malloc like)
; [X] - clear the screen
; [X] - print char on terminal
; [X] - print cstring on terminal
; [ ] - print 8 bits integer on terminal
; [ ] - print 16 bits integer on terminal
; [ ] - print 32 bits integer on terminal
; [ ] - print 64 bits integer on terminal
; [ ] - print 8 bits float on terminal
; [ ] - print 16 bits float on terminal
; [ ] - print 32 bits float on terminal
; [ ] - print 64 bits float on terminal
; [ ] - convert integer to cstring
; [ ] - convert float to cstring
; [ ] - reverse cstring
; [ ] - resize cstring
; [ ] - concat cstring
; [ ] - replace cstring
; [X] - read keyboard input chr
; [ ] - read keyboard input until specified limit
; [ ] - read keyboard input until new line
; ------------------------------------------------------------------;

; ------------------------------------------------------------------;
; Name: clear
; Description: clear the screen using int 10h/0eh bios function
; Complexity: O(1)
; Arguments: null
; Return: null
; ------------------------------------------------------------------;
pchr:
  mov ah, 0x00
  mov al, 0x03
  int 10h
  ret


; ------------------------------------------------------------------;
; Name: pchr
; Description: print char on tty using int 10h/0eh bios function
; Arguments:
; - al: ascii char to be printed
; Return: null
; ------------------------------------------------------------------;
pchr:
  mov ah, 0eh
  int 10h
  ret

; ------------------------------------------------------------------;
; Name: pcstr
; Description: print cstring on tty using int 10h/0eh bios function
; Arguments:
; - si: cstring pointer
; Return: null
; alert: if string does not have a 0 at end, this will run until find it
; ------------------------------------------------------------------;
pcstr:
  mov ah, 0eh
  pcstr_j1:
    lodsb
    or al, 0
    jnz j2
    ret
  pcstr_j2:
    int 10h
    jmp pcstr_j1
    
; ------------------------------------------------------------------;
; Name: rchr
; Description: read char from keyboard input using 16h bios function
; Arguments: null
; Return:
; - al: ascii char read from keyboard
; alert: if string does not have a 0 at end, this will run until find it
; ------------------------------------------------------------------;
rchr:
  mov ah, 0
  int 16h
  ret