[Coco] OSK, 68K question

[Gene Heskett]

On Monday 24 May 2010, Willard Goosey wrote:
>So, I was reading http://www.folklore.org/ about the creation of the
>Macintosh, and came across the comment that the 68000's relative jump
>only has a range of 32K.
>
Wow!  That sounds as bad for what was supposedly a 24 bit cpu, as the 8 bit 
2's complement the z80 had.  What a pima that was.  You had to pick a spot 
somewhere in every 'page' of memory, which was 256 bytes, for a set of 
absolute jump addresses because a conditional with a builtin jump had the 
+126, -129 range limit, so a long conditional jump was actually 2 jumps.

For obvious reasons that was my first and last pass at writing Z80 code for a 
transmitter ATS system.  I could have done it faster with an RCA 1802, 
although the code would probably have been slower.  The 6809 hadn't arrived 
on my horizon then.

>I only ever did 68K assembly on UN*X, where absolute memory references
>are normal (and handled by the MMU).
>
>And I started wondering, what effects this had on OSK?
>
>Willard
>


-- 
Cheers, Gene
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