If Then statements in Assembly

[SamanthaL]

Hello all!

Below is a subroutine that is supposed to call different things based on the value of Test_Count. What the code below should be doing is taking Test_Count (which is initialized to 3) and seeing what its value is by subtracting values from it and seeing if the output is zero. It calls Test# which does other stuff then returns. After this, it goes to Continue, where the Test_Count variable is decremented and the subroutine is called again.

The output is only calling Test4. It keeps repeating this without going through the other test cases. Am I doing something wrong with the status register?

Generate_Test_Cases_2
movf Test_Count,W
sublw b'00000011'
btfsc STATUS,Z ; if W = 3,
call Test4
movf Test_Count,W
sublw b'00000010'
btfsc STATUS,Z ; if W = 2,
call Test3
movf Test_Count,W ; W = Test_Count
sublw b'00000001' ; if W = 1;
btfsc STATUS,Z
call Test2
movf Test_Count,W ; W = Test_count
sublw b'00000000'
btfsc STATUS,Z ; if W = 0,
call Test1
bsf PORTC,7 ; MC code is 01
bcf PORTC,6 ; MC now ready to send data
call Wait
goto Continue

Continue
decfsz Test_Count ; Move on to next test case
goto Start ; Reinitialize Test_Count to 3
call Wait
goto Generate_Test_Cases_2

 

[jankop]

Continue 
    decfsz Test_Count ; Move on to next test case 
    goto Start ; Reinitialize Test_Count to 3 
    call Wait 
    goto Generate_Test_Cases_2

Your condition "decfsz Test_Count" is wrong.
It can be:

Continue 
    decf Test_Count,F
    btfsc STATUS,Z
    goto Start ; Reinitialize Test_Count to 3 
    call Wait
    goto Generate_Test_Cases_2

But your loop is 1,2,3 only, not 0,1,2,3. Test1 is not realized never. Modify it.
It can be:

Continue 
    decf Test_Count,F
    movlw b'00000011'
    andwf Test_Count,F
    call Wait
    goto Generate_Test_Cases_2

 

[Rafael]

try this software from microchip.... there are some ready usefull assembly functions...

**broken link removed**

 

[btbass]

Some time ago I uploaded in the software uploads/downloads forum a program PicHelp. A utility to generate pic assembler code for common constructs in programming. Using this tool will help you write pic code. Give it a try.

www.elektroda.pl/eboard/viewtopic.php?p=205856