|Program Counter with Displacement/Relative
|Page 1 of 1|
|Author:||unnamed [ Sun Oct 01, 2017 2:12 pm ]|
|Post subject:||Program Counter with Displacement/Relative|
MOVE.B DATA(PC), D4
How to insert values into the DATA and PC registers?
Thanks to anyone that would help me.
|Author:||profkelly [ Sun Oct 01, 2017 5:02 pm ]|
|Post subject:||Re: Program Counter with Displacement/Relative|
The Program Counter (PC) register always contains the address of the currently executing instruction.
PC relative addressing uses the relative offset from the current PC to the desired destination. The machine code will contain the offset address instead of the absolute address of the destination.
000020A0 183A 000C 52 move.b LABEL(PC),D4
000020A4 1839 000020AE 53 move.b LABEL,D4
000020AA 6000 FF54 56 BRA start
In the above code the move.b on line 52 contains the relative offset 000C in the machine code, whereas the
code from line 53 contains the absolute address of LABEL which is $000020AE.
|Page 1 of 1||All times are UTC|
|Powered by phpBB® Forum Software © phpBB Group