Re: LZ: Advanced CP instructions


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Re: LZ: Advanced CP instructions



KEITH T BURZINSKI wrote:
> 
> Hey, does anyone know about CPD, CPDR, CPI, and CPIR?
> 
> How do they work?
> 
> I tried using CPIR, but i can't seem 2 get it 2 work correctly...
> 
> ____
> ~Keith
> FFNP69C@PRODIGY.COM


They work like scansb in 8086 asm


CPI:    CP (DE),(HL) / INC DE / INC HL
CPD:    CP (DE),(HL) / INC DE / DEC HL   (or DEC DE / INC HL - don't remember)


CPIR (CPDR) does CPI (CPD) and decs B until the zero flag is set or B equals 0.


Useful when you want to search after a byte in a string. For example if you enter a sentence and 
you want to know if there is a space somewhere.


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