#start=robot.exe#

name "robot"

#make_bin#
#cs = 500#
#ds = 500#
#ss = 500#    ; stack 
#sp = ffff#
#ip = 0#

; this is an example of contoling the robot. 

; this code randomly moves the robot, 
; and makes it to switch the lamps on and off. 

; robot is a mechanical creature and it takes  
; some time for it to complete a task. 
; status register is used to see if robot is busy or not. 

; c:\emu8086\devices\robot.exe uses ports 9, 10 and 11 
; source code of the robot and other devices is in: 
; c:\emu8086\devices\developer\sources\ 
; robot is programmed in visual basic 6.0 


; robot base i/o port: 
r_port equ 9

;=================================== 

eternal_loop:
; wait until robot 
; is ready: 
call wait_robot

; examine the area 
; in front of the robot: 
mov al, 4
out r_port, al

call wait_exam

; get result from 
; data register: 
in al, r_port + 1

; nothing found? 
cmp al, 0
je cont  ; - yes, so continue. 

; wall? 
cmp al, 255
je cont  ; - yes, so continue. 

; switched-on lamp? 
cmp al, 7
jne lamp_off  ; - no, so skip. 
; - yes, so switch it off, 
;   and turn: 
call switch_off_lamp
jmp  cont  ; continue 

lamp_off: nop

; if gets here, then we have 
; switched-off lamp, because 
; all other situations checked 
; already: 
call switch_on_lamp

cont:
call random_turn

call wait_robot

; try to step forward: 
mov al, 1
out r_port, al

call wait_robot

; try to step forward again: 
mov al, 1
out r_port, al

jmp eternal_loop ; go again! 

;=================================== 

; this procedure does not 
; return until robot is ready 
; to receive next command: 
wait_robot proc
; check if robot busy: 
busy: in al, r_port+2
      test al, 00000010b
      jnz busy ; busy, so wait. 
ret
wait_robot endp

;=================================== 

; this procedure does not 
; return until robot completes 
; the examination: 
wait_exam proc
; check if has new data: 
busy2: in al, r_port+2
       test al, 00000001b
       jz busy2 ; no new data, so wait. 
ret
wait_exam endp

;=================================== 

; switch off the lamp: 
switch_off_lamp proc
mov al, 6
out r_port, al
ret
switch_off_lamp endp

;=================================== 

; switch on the lamp: 
switch_on_lamp proc
mov al, 5
out r_port, al
ret
switch_on_lamp endp

;=================================== 

; generates a random turn using 
; system timer: 
random_turn proc

; get number of clock 
; ticks since midnight 
; in cx:dx 
mov ah, 0
int 1ah

; randomize using xor: 
xor dh, dl
xor ch, cl
xor ch, dh

test ch, 2
jz no_turn

test ch, 1
jnz turn_right

; turn left: 
mov al, 2
out r_port, al
; exit from procedure: 
ret

turn_right:
mov al, 3
out r_port, al

no_turn:
ret
random_turn endp

;===================================