Low memory Bios detec

[IAO]

Hi to all:
My English is poor. But I try.

How can I detect the number of ltp port and what is the address of each port detected in Assembler ?
One example or tutorial. Something.

All December, January and don´t work. No ethernet document, no englihs, no espanish, please help me.

-EYE--. Don't work.   Test only.

Seg_LPT   EQU  0400H
;Ofs_LPT   EQU  08H
True      EQU  1H
False     EQU  -1H
;Len_Str   EQU  $-LPT_Is 

LPT_Addr EQU 0400H
Ofs_LPT1 EQU 08h  ; \
Ofs_LPT2 EQU 0Ah  ;  >Offset de los puertos
Ofs_LPT3 EQU 0Ch  ; /
Byte_R_W EQU 44H

jmp start

There_is  DB   False
;LPT_Is    LABEL BYTE
;          DB  'First',  '$'
;          DB  'Second', '$'
;          DB  'Third',  '$'
Lpt_Found DB   13,10,'   LPT port found !',13,10,'$'
No_LPT    DB   'There is: no LPT adapter installed !',13,10,'$'


;There_is DB  ?
port1   dw   ?
port2   dw   ?
port3   dw   ?
pru   dw   ?

p_dec1   db   'Puerto 1 es: Hex: 378h, Dec: 888 $'
p_dec2   db   'Puerto 2 es: Hex: 278h, Dec: 632 $'
p_dec3   db   'Puerto 3 es: Hex: 3BCh, Dec: 956 $'


Start:

Check_LPT PROC NEAR
          MOV  CX,3      ;Carga el contador con 3
          MOV  AX,Seg_LPT       ;Carga AX con 0040:0000
          ADD  AX,Ofs_LPT3   
          MOV  ES,AX      ;carga ES con 0040:0000
          MOV  DI,ES
         
          ;MOV  ES,Ofs_LPT3 ;Ofs_LPT
     MOV  BX,DI
     XOR   BH,BH
    ;lea  ax,[bx]


Lop_LPT:  MOV  AX,WORD PTR ES:[BX]     
    
     MOV   DX,ES:[0408H]
     ;LES   DX,[SP]
     ;POP   DI
    
     MOV    DX,ES:[DI] ;-
     ;mov   dx,SP ;-bl
     ;pop   DX ;-
     mov   pru,dx  ;-
    
          CMP  AL,0       ;This statement checking LPT Port

         
          JZ   Next_LPT
          MOV  There_Is,True
          MOV  AX,Ofs_LPT3 ;Len_Str
          MUL  CL
          MOV  DX,AX
          ADD  DX,OFFSET Lpt_Found ;Lpt_Is

          ;LEA  DX,LPT_Found
;Interrup para mostrar en Pantalla.         
          MOV  AH,09H
          INT  21H
     LEA  DX,LPT_Found
;Interrup para mostrar en Pantalla.         
          MOV  AH,09H
          INT  21H
              
Next_LPT: DEC  BL
          DEC  BL
          MOV  AX,ES
          XOR  AL,AL
          ADD  AL,BL
          MOV  ES,AX
           
          LOOP Lop_LPT
          CMP  There_Is,False
          JNE  End_Check_LPT
          LEA  DX,No_LPT

;Interrup para mostrar en Pantalla.
          MOV  AH,09H
          INT  21H


End_Check_LPT:

          ;RET
Check_LPT ENDP


INT  20h
end start


Thank.  By(t)e ('-')

[MichaelW]

You cannot assume that the port I/O addresses will be in the order 378h, 278h, 3BCh, and even though these addresses are normal other addresses are possible. I used my support file just to make it easier to display hex values and pause the program waiting for the user to press a key.

Code Select Expand


.model small,c
    .386
    .stack
    .NOLIST
    include support.asm
    .LIST
.data
.code
.startup

    push  40h
    pop   es
    mov   bx, 8
  runloop:
    mov   ax, es:[bx]
    cmp   ax, 0
    je    @F
    print hexword$(ax),"h",NL
  @@:
    add   bx, 2
    cmp   bx, 0eh
    jb    runloop

    print NL,"Press any normal key to exit...",NL
    call waitkey
.exit
end





[attachment deleted by admin]

[farrier]

IAO,

As you didn't say what was working, I will add something that confused me the first time I worked with more than one LPT port.  The BIOS POST code looks at the standard addresses: 03bch, 0378h, & 0278h   The one found with the highest address is assigned to LPT1, the next highest address--if found--is assigned to LPT2, and the next highest address--if found--is assigned LPT3

Therefore is 0278h would be LPT1 if it is the only port found on the machine!

hth,

farrier

[IAO]

Hi to all:
My English is poor. But I try.

Mr. MichaelW:
Thank you. I  goto my home to  probe your example-- tomorrow write.

Mr.Farrier:
I have a single C program.
It scan and show all address in hex.
If no port device, show cero (00).
Is difficult for me in english.
I like that program, but in assembler.


Thank.
By(t)e ('-').

[IAO]

Hi to all:
My English is poor. But I try.

Mr. MichaelW:
I modified his code for the EMU8086 emulator. It worked perfect.
Sometimes, a small example, is more valuable that four books.

#make_COM#
ORG 100h

start:
  push  40h
    pop   SS
    mov   bx, 0ch
    mov   bp,bx   
  runloop:
    mov   bx, ss:[bp] 
    mov   dx,bx
    cmp   dx,0
    je    aqui

  aqui:
    dec    bp
    dec    bp
    cmp    bp,06h 
    ja     runloop
.exit
end

You are a brain. You are lamp on my feet.
Two months tried, without profits. It was so easy.

I do not know like expressing thanks. But:
THANKS = (THANKS)^1'000'000 <=> THANKS == (THANKS + THANKS + THANKS....bis.... bis...)

God blesses to you.

By(t)e ('-').

[MichaelW]

You're welcome.

You should avoid using BP as a general-purpose base or index register because BP is a special register that is normally used to access procedure parameters. If you changed the value of BP within a procedure that had parameters the program could crash. Even outside of a procedure there is a potential problem in programs where DS != SS, because for instructions that reference BP the default segment register is SS instead of DS.

[IAO]

Hi to all:
My English is poor. But I try.

Mr. MichaelW:
I understand.
But, in the emulator (EMU8086) it worked perfect, with BP.
It did not work with ES.


The EMU8086, it is very good to beginner.
It does not require data or code segment.
You see the register, stack, stepper motor and more.
EMU8086 is very nice.


THANKS = (THANKS)^1'000'000 <=> THANKS == (THANKS + THANKS + THANKS....bis.... bis...)
God blesses to you.

by(t)e ('-').

[sinsi]

start:
  push  40h
    pop   SS

I think you are asking for problems if your SS points to 0040.
DOS lives from 0070, so your SP could be killing DOS...