wesmond Posted June 29, 2021 Share Posted June 29, 2021 Hi all, I'm triyng to type up some old listings - this one is some ASM from Monitor issue 2, p27 (http://www.atarimania.com/mags/pdf/UKACOC_Newsletter_No_02.pdf) - a flashing cursor sort of utility by Jon Williams. I think I've transcribed and compiled it correctly, but I'm getting a lock-up hitting an illegal instruction at $FCBD when I call USR(1536). I guess this is after the JSR $FCB3 on line 1210. I'm wondering if the JSRs are specific for a particular version of the OS, and/or BASIC, but that sort of thing is a bit outside of my Atari knowlege. Attached is my listing, the XEX I compiled with MADS (via Eclipse/WUDSN with a couple of edits - *= to ORG, and spaces after .WORD at the end), and a bit of basic to get ready for the USR(1536) call. Any ideas appreciated - it's good to be able to test I've got these type-ins right. Thanks, Wes FCURSOR.LST fcursor.bas FCursor.xex Quote Link to comment Share on other sites More sharing options...
TGB1718 Posted June 29, 2021 Share Posted June 29, 2021 (edited) Those JSR $Fxxx addresses are in ROM and are not guaranteed to work with different versions of the OS. It is a bad practice to use these for the very reason it's not working for you. If you try this in Altirra, you can swap machine types and maybe find out which one it was written for. Have a look at this Edited June 29, 2021 by TGB1718 Quote Link to comment Share on other sites More sharing options...
wesmond Posted June 30, 2021 Author Share Posted June 30, 2021 (edited) Thanks - I thought that might be the case. To be fair, this is 1982 code, pre-XL era, so the landscape of OS versions was different I guess when this was written. My purpose here is to archive what was written, rather than using it or making it compatible code, so it'll be about confirming for myself I've typed it and compiled it correctly, and adding some notes on how it could be used... Edited June 30, 2021 by wesmond clarification Quote Link to comment Share on other sites More sharing options...
wesmond Posted June 30, 2021 Author Share Posted June 30, 2021 I think I might have typed in your 5-liner once upon a time... ? Quote Link to comment Share on other sites More sharing options...
wesmond Posted June 30, 2021 Author Share Posted June 30, 2021 (edited) Yep, that's it. I set Altirra to Hardware type 400/800, PAL, OS-A, and then "insert" the Basic cartridge, and it works. Thanks for the pointer! Edited June 30, 2021 by wesmond Quote Link to comment Share on other sites More sharing options...
TGB1718 Posted June 30, 2021 Share Posted June 30, 2021 1 hour ago, wesmond said: I think I might have typed in your 5-liner once upon a time... ? Nice ?, thank you Quote Link to comment Share on other sites More sharing options...
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