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Groups > comp.sys.apple2.programmer > #1615
| From | David Schmidt <schmidtd@my-deja.com> |
|---|---|
| Newsgroups | comp.sys.apple2.programmer |
| Subject | Re: test for presence of BASIC.SYSTEM |
| Date | 2015-04-20 07:34 -0400 |
| Organization | A noiseless patient Spider |
| Message-ID | <mh2o79$or0$1@dont-email.me> (permalink) |
| References | <10257333-0545-4358-9e51-770ba945208b@googlegroups.com> <mh1bnu$odh$1@dont-email.me> <0913dae4-d9eb-4663-b6eb-f4f72b1f6118@googlegroups.com> |
On 4/19/2015 11:00 PM, ivanx%ivanx.com@gtempaccount.com wrote: > On Sunday, April 19, 2015 at 6:55:53 PM UTC-4, schmidtd wrote: >> On 4/19/2015 1:18 PM, Ivan X wrote: >>> Assuming ProDOS 8 itself is booted, Is there a canonical way of determining from machine language whether BASIC.SYSTEM is running or not? I figured one way would be by looking at $0036/37, but I was wondering if there's something less ad-hoc. >> >> When I asked the same question not so long ago, this is the solution I >> ended up with: >> >> lda $3f2 ; Where does our reset vector point? >> bne @Quit ; Not BASIC >> lda $3f3 >> cmp #$be >> bne @Quit ; Not BASIC >> rts ; Yay - BASIC! >> @Quit: ; Run the (in my case) ProDOS Quit MLI > > Gee, Dave, why did you expend your effort on such a thing? This is from my virtual drive device driver installer code. In my case, I needed to be able to return "from whence I came..." meaning if I was invoked as a SYS program from BASIC, I needed to return there (RTS). If I was invoked from, say, a program launcher, I needed to call the Quit MLI.
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test for presence of BASIC.SYSTEM ivanx%ivanx.com@gtempaccount.com - 2015-04-19 10:18 -0700
Re: test for presence of BASIC.SYSTEM gids.rs@sasktel.net - 2015-04-19 11:53 -0700
Re: test for presence of BASIC.SYSTEM gids.rs@sasktel.net - 2015-04-19 12:10 -0700
Re: test for presence of BASIC.SYSTEM ivanx%ivanx.com@gtempaccount.com - 2015-04-19 15:12 -0700
Re: test for presence of BASIC.SYSTEM gids.rs@sasktel.net - 2015-04-19 21:46 -0700
Re: test for presence of BASIC.SYSTEM David Schmidt <schmidtd@my-deja.com> - 2015-04-19 18:55 -0400
Re: test for presence of BASIC.SYSTEM ivanx%ivanx.com@gtempaccount.com - 2015-04-19 20:00 -0700
Re: test for presence of BASIC.SYSTEM David Schmidt <schmidtd@my-deja.com> - 2015-04-20 07:34 -0400
Re: test for presence of BASIC.SYSTEM ol.sc@web.de (Oliver Schmidt) - 2015-04-24 15:41 +0000
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