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Re: P21 quirks


On Tue, 18 Apr 1995 rockwell@nova.umd.edu wrote:

> Consider this instruction sequence:
> a!  @+  a   dup
> dup -or com nop
> +
> 
> This is a distillation of the steps used to increment then decrement
> the stack pointer.  Let's say that TOS is set to pattern 000001, and
> that the corresponding memory is set to the pattern 12345.  Here's an
> image of what I'd expect in the stack for the above instructions:
> 
> 000001
> 	a!
> 	@+
> 012345
> 	a
> 012345
> 000006

I was left with the impression, that the @+ will increment by 1, not by 5.

There is a 20-bit (DRAM) addressing of words, 20 bits wide each, which gives
a total of 1M x 2.5 bytes = 2.5 Mbytes

--
Penio Penev <Penev@venezia.Rockefeller.edu> 1-212-327-7423