Re: [Amforth] Assembler listing of some words

[Erich W. <ew....@na...>]

Hello Jan,

Jan Kromhout via Amforth-devel writes:

> Hello,
>
> I was looking into some words (.asm).
> Can someone explain me why the content of the first data word is different.
> PLUSSTORE => .dw $ff02
> RSHIFT => .dw $ff06
> PLUS => .dw $ff01

I'm sure this is explained somewhere, maybe in the technical guide. But
I did not find it in 20 seconds, so here we go:


> $ cat ./avr8/words/plusstore.asm
> VE_PLUSSTORE:
>     .dw $ff02
>     .db "+!"
>     .dw VE_HEAD
> ...

The first .dw entry is "some number", where the low part "02" is the length
of the string to come. That string is "+!", 2 bytes.

The high part "ff" is a flags thing. "immediate" words are different:

> $ cat ./common/words/then.asm
> ...
> VE_THEN:
>     .dw $0004
>     .db "then"
> ...

There might be other values, but I'm not sure.

This stuff is implementation dependant and may be all different in other
Forth implementations.



Cheers,
Erich

--
May the Forth be with you ...