I am starting to write a assembly program for a mc68hc12. I will be reading a 8
bit signed number into PortA and outputting the results to 7 segment LED's,
common anode. I will be using Port P to output the segments and PortCan to
control the LED's displayed. I assume I need 4 LED's, 1 for the sign and 3 LEDs
for the max number of 128. How would I go about pulling the data in from a port and then displaying the number on a set of LED's?

Is there a straight forward way to do the signed number conversion using a lookup table or do I need to go through a more in depth conversion algorithm?

I'm not sure how to handle the input number once I read it from PORTA, should I
store it in memory or work with it directly. I am new to assembly programming so
pardon the simple questions, how would I pull off the digits of the inputed number to convert?