Hello Martin, Very intriguing, just when I am away from my machine so I can’t test things out!
If I remember correctly, the default Amforth avr build uses (rx,tx) interrupts to handle the serial prompt. If at the serial prompt I type in the word -int and “all” -int did was to issue the assembler cli instruction I should lose my serial prompt. I can’t check now but if the serial prompt does not disappear then there is other machinery at work. Best wishes, Tristan Sent from my iPhone > On 19 Oct 2018, at 10:36, Martin Nicholas via Amforth-devel > <amforth-devel@lists.sourceforge.net> wrote: > > On Wed, 17 Oct 2018 13:27:09 +0100 > Tristan Williams <h...@tjnw.co.uk> wrote: > >>> 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! >>> >>> >> >> 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 >> > > No, thie problem with 1ms is specific to 1ms. I suspect the tight inner > loop is uninterruptable. It is: >> sbiw Z, 1 >> brne pc-1 > > Interrupts are enabled at all times (by APPLTURNKEY) unless you > specifically disable them. > > Looking at the vanilla build at: > amforth-6.7/appl/template/template.lst > These words enable interrupts: +INT APPLTURNKEY. > These disable: -INT. > These temporarily disable interrupts: RP! !E @E (!I-NRWW). They are > re-enabled before exit. > That's it. Search for "cli" and "sei". > > When I have time I'll test my theory about 1ms. Atmel documentation is > no help on this, although there are dark hints in the documentation > for BRNE. > > Confirm interrupt status with: > "hex 5f c@ ." > > Cheers! > > -- > Regards, > > Martin Nicholas. > > E-mail: m...@mgn.org.uk. > > > _______________________________________________ > Amforth-devel mailing list for http://amforth.sf.net/ > Amforth-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/amforth-devel > _______________________________________________ Amforth-devel mailing list for http://amforth.sf.net/ Amforth-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/amforth-devel
