Re: A86: loops

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Re: A86: loops

Mark,

The JR instructions are all two bytes long. The displacement is calculated
from the byte FOLLOWING the instruction. It's a 1-byte signed (two's
complement) value. Anyway, a simple loop would look like this:

D748 06 0A	   ld b,10
D74A 3E 00	   ld a,1
D74C 		loop:
D74C 3C		   inc a
D74D 10 FD 	   djnz loop	;offset is (D74F-D74C = -3 or FD)
D74F C9		   ret		;or (offset djnz (or jr) instr+2)-(loop)

This will count a from 1 to 10. Hope this helps...

--Joshua
References: