Re: [Amforth] 16/32 Bit Fetch & Store.

[Tristan W. <ho...@tj...>]

On 17Oct18 10:25, Martin Nicholas via Amforth-devel wrote:
> Hi,
> 
> I think that @ ! +! 2@ 2! d+! should disable interrupts on the AVR.
> Although it's possible to code around a variable being changed by an
> interrupt (using C@ C! for example), the 16-bit counter registers can't
> be dealt with in a similar way. Section 17.3 of the datasheet
> "Accessing 16-bit Registers" deals with all this. @ and ! do do the byte
> accesses in the right order, but an interrupt using the 16-bit
> registers associated with a particular counter will overwrite the "TEMP
> (8-bit)" register (see Figure 17-4).
> 
> Cheers!
> 
> -- 
> Regards,
> 
> Martin Nicholas.
> 
> E-mail: rep...@mg...
> 
> 
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Hello Martin,

This page http://amforth.sourceforge.net/TG/AVR8.html sets out how
AmForth handles interrupts and I think it is relevant to your post. 

Earlier this year I wrote some forth[1] that used the word 1ms and it
was not running as I expected. I had not realised that the execution
of AmForth words written in assembler would not be interrupted. @ ! +!
are assembler words and so will not be interrupted.

Tristan

[1] https://sourceforge.net/p/amforth/mailman/amforth-devel/?viewmonth=201806