From data memory to registers

Question

Is there a way to increment the memory in the 8051 architecture?

for example:

Memory Slot:

mov 0x71, #0x01 mov 0x72, #0x02 mov 0x73, #0x03

is there a way to in a for loop say

mov 0x71, A do something; mov 0x72, A do something;

in a for loop?

in java you just do the simple for(int i = 0; i < variable; i++) but I dont know how to do that in 8051 architecture.

Answer 1

Sure, there are a number of ways you can do this. I would probably use DJNZ or CJNE instruction depending on the surrounding code.

    ;Load your control variable into B. From a table, GPIO, etc.
    MOV  B,#3H

    ;Build your loop. This is basically a Do While loop.

    ;int i=0, (really a byte since 8 is 8-bit)
    CLR A

    ;Start of the loop, notice this is AFTER the CLR op
FN_LOOP:

    ;Do something...

    ;i++
    INC A

    ;i < variable. Stops when A == B
    CJNE A,B,FN_LOOP

    ;Rest of your code

I would recommend reading up on addressing modes in assembly as well. That knowledge is essential to reading assembly instruction set documentation.