Re: A86: FindPixel
[Prev][Next][Index][Thread]
Re: A86: FindPixel
>> It moves the bits 0, 1, 2 and 3 of (hl) to bits 4, 5, 6, and 7 of (hl).
>> It also moves the high bits to where the low one used to be.
>>
>
>Not exactly. The A register is involved, too. Here's my cheesy ASCII
>version of the picture in the Z80 databook:
Yeah RLD plays a very major part in Findpixel. If you think it as A(HL) is
acted as one big 16-bit register, then (HL) is shifted left 4-bits (leaving
a 4-bit gap), and the previous value of the low order nibble of A is shifted
into (HL) to fill that low order nibble "gap"
Tutorial #4 on my web page explains Findpixel line by line
-Matt