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Kevin Edwards assembler series in Micro User

Posted: Wed Jan 11, 2017 6:53 pm
by sydney
I've been scouring the Retrosoftware forums today and came across a few references to the Kevin Edwards series in The Micro User but no actual links to it. I've gone through most of the covers hosted on 8bs and found it! It starts in issue 24, which is Feb 85. Here is a link to the Micro user section on 8bs,click on the PDF not the image.
http://8bs.com/tmucovers.htm

Re: Kevin Edwards assembler series in Micro User

Posted: Thu Jan 12, 2017 11:18 am
by jbnbeeb
Thanks for the link ! I actually had most of these issues as a kid. I remember the covers! At the time, the articles would have gone over my head as assembler looked scary. Reading now, I think the articles are very thorough and explain things well. And I'm reminded of why I"ll still be sticking with 256x256 screen resolution :)

Re: Kevin Edwards assembler series in Micro User

Posted: Tue Jan 17, 2017 12:47 am
by simonm
Wow, seriously warm feels from those MU covers. Thanks for the link!

Re: Kevin Edwards assembler series in Micro User

Posted: Sat Feb 03, 2018 3:35 pm
by thearttrooper
I extracted each episode of the series and stuck them in a single PDF. If someone knows of a good place to make the PDF available, I'll upload it.

For reference: I found episodes from Feb 85 (pointed out by OP) through Sep 85.

Re: Kevin Edwards assembler series in Micro User

Posted: Sat Feb 03, 2018 3:52 pm
by hoglet
thearttrooper wrote:I extracted each episode of the series and stuck them in a single PDF. If someone knows of a good place to make the PDF available, I'll upload it.
What about http://archive.org

Re: Kevin Edwards assembler series in Micro User

Posted: Sun Feb 04, 2018 7:53 am
by thearttrooper

Re: Kevin Edwards assembler series in Micro User

Posted: Mon Feb 05, 2018 8:57 pm
by mlouka
Nice -- thanks for taking the time to do that!

Re: Kevin Edwards assembler series in Micro User

Posted: Sun Feb 18, 2018 4:56 pm
by markdryan
Thanks so much for posting this. I've been having fun reading through the articles and trying some of the examples on my model B.

I have a question about the example on page 18, "Program V Screen locator calculator". The program uses a multiplcation table in the OS 1.20 ROM to work out the starting screen memory location of a sprite based on X and Y coordinates. The table begins at memory address &C375 and is 64 bytes in length. My understanding is that this code won't work on a master ( although I haven't actually tried it ) as the table has moved. Does anyone know where it went or whether there's an OS call to retrieve its location in a portable way? I've read some threads that describe how to get older games working on the master by re-creating the table in RAM where the game expects it to be, but I couldn't actually figure out what its new location in the master is.

[ edited to remove some misplaced apostrophes ]

Re: Kevin Edwards assembler series in Micro User

Posted: Sun Feb 18, 2018 6:19 pm
by jbnbeeb
I don't know where it is in Master MOS. Before now as a quick and dirty workaround to find where a routine is in Master OS, I've found the sequence of bytes I'm interested in in OS 1.2 and then opened up B-em in Master 128 mode. If you call up debug option from the menu, you can then use m <addr in hex> to view a 256 byte page in memory. I've cut and paste a few pages of memory >=&8000 in to Excel and then searched for the sequence of bytes. The memory dump displays the address on each row of 16 bytes.

But I suspect you can save yourself some hassle as there's a good article on screen addressing for Beeb here, including 64 byte table:
http://www.retrosoftware.co.uk/wiki/ind ... en_Address

Re: Kevin Edwards assembler series in Micro User

Posted: Sun Feb 18, 2018 6:36 pm
by kieranhj
TBH I just include my own look up tables because let’s face it, unless you’re actually Kevin Edwards, most of us aren’t going to be that strapped for RAM. We’re talking 32*2=64 bytes for the row lookup (y DIV 8 * 320 or 640) and another 40 or 80*2 bytes for the column lookup (x * 8 ). Total is less than 1 page either way and usually somewhere to stash it lower down in memory.

Re: Kevin Edwards assembler series in Micro User

Posted: Sun Feb 18, 2018 6:50 pm
by Kecske Bak
There was a follow-up series on writing 6502 games in The Micro User much later, written by Roland Waddilove. One of the things he tackled was making a multiplication table to use that would work on a Master.

Re: Kevin Edwards assembler series in Micro User

Posted: Tue Feb 20, 2018 10:34 pm
by markdryan
Thanks for the advice, links and references. I managed to track down the follow up series by Roland Waddilove, well the first article at least. For reference, it appeared in the Jan 87 edition of the Micro User, available via the link provided in the original post.