Hi,
I have my exam on Tuesday and there is one question in the exam that I am really unsure about. The trouble is I cant learn the model way to answer the question, because im not even really able to answer it yet. Attached is the exact question.
![q7.png q7.png](https://www.electro-tech-online.com/data/attachments/45/45044-e9ebc34f413d0f1fd833e412e927243e.jpg)
So, im guessing the way to answer the first question is to do something like this:
================================
check_value equ 0x20
movlw .43
movwf check_value
<how do I get portb value into working?>
subwf check_value,w
btfsc STATUS, C ; If c bit is set, then there is a carry, then it wont be skipped
goto grtr_than
================================
Can someone please help me finished this question off. I dont know how to check a binary value on portB.
================================
================================
b) I literally have no idea about this question but here is my stab at it.
1) I's nibbles are swapped, and the result is stored in F. Therefore f is the file which is changed as the result. Its original value was A (.10) which is 0000 1010, and its binary value will now be 1010 0000.
2) The working register is affected. i is still 10, so it is 3+10, and the result 13 is stored in w (0000 1101).
3) 13 is still in the working register, so k is given the value (0000 1101)
Is this the kind of thing I should be doing?
================================
================================
Im stressing out about these, especially part one, any any help or advice would be much appreciated.
James
I have my exam on Tuesday and there is one question in the exam that I am really unsure about. The trouble is I cant learn the model way to answer the question, because im not even really able to answer it yet. Attached is the exact question.
![q7.png q7.png](https://www.electro-tech-online.com/data/attachments/45/45044-e9ebc34f413d0f1fd833e412e927243e.jpg)
So, im guessing the way to answer the first question is to do something like this:
================================
check_value equ 0x20
movlw .43
movwf check_value
<how do I get portb value into working?>
subwf check_value,w
btfsc STATUS, C ; If c bit is set, then there is a carry, then it wont be skipped
goto grtr_than
================================
Can someone please help me finished this question off. I dont know how to check a binary value on portB.
================================
================================
b) I literally have no idea about this question but here is my stab at it.
1) I's nibbles are swapped, and the result is stored in F. Therefore f is the file which is changed as the result. Its original value was A (.10) which is 0000 1010, and its binary value will now be 1010 0000.
2) The working register is affected. i is still 10, so it is 3+10, and the result 13 is stored in w (0000 1101).
3) 13 is still in the working register, so k is given the value (0000 1101)
Is this the kind of thing I should be doing?
================================
================================
Im stressing out about these, especially part one, any any help or advice would be much appreciated.
James
Last edited: