Casading of 2 general purpose register

[scdoro]

Hi,
I am new to PIC assembly .
would like to know for PIC16F872, can i casade two general purpose register together ( 8 bit + 8 bit = 16 bit ) and increment the two register from 0 - 65535 , as if it is a 16 bit counter ?
is that possible ?
if so, may i know how can the source code be written in assembly?
thanks

 

[glenjoy]

I cannot give you the code in assembly because it will be a no challenge for you to do.

To do it is to monitor the most significant bit of your first byte, if it becomes 1 and returned to zero, it means the next increment stage will be the least significant bit of your 2nd byte.

 

[IanP]

The way you can do it is to clear the C flag, then add 01h to lower register using standard ADD instruction. Next put C into a byte in such a way that it will look like this: 0000 000C and clear C flag and the last thing to do is to ADD this byte to the upper register and check C flag if you have overflow ie FFFFh - to - 0000h ..