Search found 160 matches

by thomas3
Mon Oct 05, 2020 10:27 pm
Forum: 680x0
Topic: Fast sequential reading data and writing non sequentially
Replies: 19
Views: 658

Re: Fast sequential reading data and writing non sequentially

You should get some movems into this thing. Load some regs and then use move.l d0,.... Etc. Word aligning your data structure (a0) would save you cycles and allow you to use words in your index table (a2). Using lower memory for your a0 table would be even faster. Or, if the write positions are cons...
by thomas3
Sun Sep 06, 2020 11:40 am
Forum: 680x0
Topic: Printing 6 lines of text in 4-planes font in less than 1 vbl
Replies: 22
Views: 1390

Re: Printing 6 lines of text in 4-planes font in less than 1 vbl

I'm foolishly using 3 timers in the music
Ha, OK, forget my suggestion ;)
by thomas3
Sat Sep 05, 2020 6:56 pm
Forum: 680x0
Topic: Printing 6 lines of text in 4-planes font in less than 1 vbl
Replies: 22
Views: 1390

Re: Printing 6 lines of text in 4-planes font in less than 1 vbl

Hey YQN, Finally checked this out - a nice little dissolve effect! The implementation you are using does feel quite convoluted though. If your music isn't too timer intensive (HA!- I bet it is ;) ) then I would be tempted to do this with palette switching instead of physically "dissolving" the pixel...
by thomas3
Thu Sep 03, 2020 11:36 am
Forum: 680x0
Topic: Printing 6 lines of text in 4-planes font in less than 1 vbl
Replies: 22
Views: 1390

Re: Printing 6 lines of text in 4-planes font in less than 1 vbl

Hey, I'm probably not being clear enough - I was advocating pre-rendering. If he's doing a scrolltext he needs to use a different method entirely but I thought he was just writing chars to screen. Incidentally in the above example you can skip the second movem read and just use or.l (a2)+, d0 ;) Tom...
by thomas3
Thu Sep 03, 2020 7:35 am
Forum: 680x0
Topic: Printing 6 lines of text in 4-planes font in less than 1 vbl
Replies: 22
Views: 1390

Re: Printing 6 lines of text in 4-planes font in less than 1 vbl

If this is for a demo, I think movep is unnecessarily slow... I'd want to be writing to screen with move.l or movem.l. It's the cleanest and most elegant solution code wise, but adds an unnecessary overhead when what is being written to screen is highly predictable...
by thomas3
Wed Sep 02, 2020 6:51 pm
Forum: 680x0
Topic: Allocating a variable to a DS directive allocated memory block?
Replies: 13
Views: 493

Re: Allocating a variable to a DS directive allocated memory block?

Yeah mshrink is gemdos $4a. So you want something like this at the start of your prog... start: move.l 4(sp),a0 ; basepage move.l $18(a0),d0 ; base of bss add.l $1c(a0),d0 ; +size of bss add.l #1000,d0 ; +size of stack (1k in this example) andi.l #-2,d0 ; make it even move.l d0,sp ; set my stack sub...
by thomas3
Wed Sep 02, 2020 6:16 pm
Forum: 680x0
Topic: Allocating a variable to a DS directive allocated memory block?
Replies: 13
Views: 493

Re: Allocating a variable to a DS directive allocated memory block?

Ah, then you indeed want mshrink and then malloc. :)
by thomas3
Wed Sep 02, 2020 5:49 pm
Forum: 680x0
Topic: Allocating a variable to a DS directive allocated memory block?
Replies: 13
Views: 493

Re: Allocating a variable to a DS directive allocated memory block?

Declare a big block of memory in your bss section. Call it "membase" or something. Then have a bunch of pointers to different sections/pages within that. Declaring more than you need is not a problem :)
by thomas3
Wed Sep 02, 2020 4:14 pm
Forum: 680x0
Topic: Printing 6 lines of text in 4-planes font in less than 1 vbl
Replies: 22
Views: 1390

Re: Printing 6 lines of text in 4-planes font in less than 1 vbl

Great. If you're using (3), remember that movem.l is your best friend....
by thomas3
Wed Sep 02, 2020 1:57 pm
Forum: 680x0
Topic: Printing 6 lines of text in 4-planes font in less than 1 vbl
Replies: 22
Views: 1390

Re: Printing 6 lines of text in 4-planes font in less than 1 vbl

Hey, ok, so, this is inefficient as you've realised (obviously!). If you're writing four bitplane data to screen, you need to be using move.l or movem.l for optimal efficiency. So in this case, you need to come up with a way to organise your source data/font more efficiently to allow this. A couple ...
by thomas3
Wed Sep 02, 2020 12:42 pm
Forum: 680x0
Topic: Printing 6 lines of text in 4-planes font in less than 1 vbl
Replies: 22
Views: 1390

Re: Printing 6 lines of text in 4-planes font in less than 1 vbl

Haha edit. Didn't read your code right ;)

Are you using move.b to draw to screen?
by thomas3
Wed Aug 26, 2020 6:10 pm
Forum: 680x0
Topic: 680x0 obscure wrong branching and other coding dangers...
Replies: 19
Views: 1370

Re: 680x0 obscure wrong branching and other coding dangers...

These are different commands for dealing with signed/unsigned numbers. It'll cause a bug if you get it the wrong way around (e.g. branch isn't taken) although you'd know about it pretty fast and then fix it. Like czietz says, it isn't "wrong", just a different command, like mulu vs muls. I'm saying ...
by thomas3
Mon Aug 03, 2020 9:50 pm
Forum: Coding
Topic: Best C2P routine?
Replies: 15
Views: 1013

Re: Best C2P routine?

Couple of things. 1) on ste you can change the video address pointer on interrupt to copy lines at almost no cost 2) for 2x2, some algorithms allow you to hold four copies of your texture (each consisting of masks for chunky pixels 0, 1, 2 and 3 for each 8 real pixel block) which means you can skip ...
by thomas3
Sat Aug 01, 2020 10:59 am
Forum: STOS
Topic: New STOS modules, including syncscroll
Replies: 1
Views: 547

New STOS modules, including syncscroll

Hi all, Been a while since I've done anything with STOS, but I've made a couple of things to share. 1) I've converted the Evl/DHS syncscroll to work in STOS. Joystick input still works, and Missing Link timer B commands such as palsplit and raster SHOULD also work. There are still some relatively sm...
by thomas3
Fri Jul 31, 2020 7:30 pm
Forum: Coding
Topic: How to perform vertical scrolling of the screen?
Replies: 9
Views: 953

Re: How to perform vertical scrolling of the screen?

On ST, you cannot do a vertical scroll as simply as you can do on STe by changing the screen address. You have to use the syncscroll technique that is not so obvious. If I remember well there should be several posts in the forum that describe how it works. I haven't found any useful info on syncscr...
by thomas3
Wed Jul 29, 2020 7:57 pm
Forum: Coding
Topic: How to perform vertical scrolling of the screen?
Replies: 9
Views: 953

Re: How to perform vertical scrolling of the screen?

Depending on how much memory you're willing to burn and the size of playfield you are working with, you can also hold several preshifted copies of your screen (e.g. 4, each shifted by 2 lines) and then add multiples of 1280 to your screen addresses to shift in 8 line units. Zero processor time!
by thomas3
Tue Jul 07, 2020 10:14 am
Forum: Demos - General
Topic: SOMMARHACK 2020 - just started!
Replies: 8
Views: 1316

Re: SOMMARHACK 2020 - just started!

The chat was lolz, but probably for the best that it wasn't recorded ;)
by thomas3
Mon Apr 13, 2020 6:38 pm
Forum: Ym rockin'
Topic: Looking for tune in SNDH archive
Replies: 2
Views: 499

Re: Looking for tune in SNDH archive

mOdmate wrote:David Whittaker - Weird Dreams #1: https://demozoo.org/music/116144/

Demozoo lists 12 productions using this tune.
Ah I suspected it was Whittaker! Credits on the demo are wrong. Thanks!
by thomas3
Mon Apr 13, 2020 3:03 pm
Forum: Ym rockin'
Topic: Looking for tune in SNDH archive
Replies: 2
Views: 499

Looking for tune in SNDH archive

Hello. I'm looking for an SNDH rip of the Mad Max tune from the second Vector screen (Vector the crew) in the European Demos. (its at the four hour mark on this video - https://m.youtube.com/watch?v=6Z8F5WL7VWg) Does anyone know its title in the SNDH archive? Also, a question for archivists - anyone...
by thomas3
Sun Apr 05, 2020 9:05 am
Forum: 680x0
Topic: synclock twice in a vbl
Replies: 8
Views: 1555

Re: synclock twice in a vbl

Hi Michael,

Glad it helped. Although I've never looked into it, I'm sure that gvodan would use syncscroll. The question is, how, in relation to the overall effect... ;)

Tom
by thomas3
Thu Apr 02, 2020 6:49 am
Forum: 680x0
Topic: synclock twice in a vbl
Replies: 8
Views: 1555

Re: synclock twice in a vbl

Hi Michael, So, all timers all have various ways that they can be configured, and also run at different priority levels. You can absolutely have multiple timers set at the same time. Timer B ticks once per scan line, but only in the visible area of screen. Timer A, conversely, can be configured more...
by thomas3
Wed Apr 01, 2020 6:13 am
Forum: 680x0
Topic: synclock twice in a vbl
Replies: 8
Views: 1555

Re: synclock twice in a vbl

Thanks both!

That solution is beautifully elegant and exactly the kind of thing I was looking for. Thank you so much!
by thomas3
Tue Mar 31, 2020 12:50 am
Forum: 680x0
Topic: synclock twice in a vbl
Replies: 8
Views: 1555

Re: synclock twice in a vbl

UPDATE: well i fixed it, but lost some cycles in the process. depending on whether the syncscroll offset was a multiple of 320, the timer B hardsync was delayed by exactly 16 nops. i hacked out a solution but if anyone knows something neater, that would be great. (also need to test it on different T...
by thomas3
Mon Mar 30, 2020 9:55 pm
Forum: 680x0
Topic: synclock twice in a vbl
Replies: 8
Views: 1555

synclock twice in a vbl

here's one for you clever guys out there. so i'm using a standard syncscroll sitting in a timer A. i then want to have a second synclocked effect in a timer B... let's say half-way down the screen. for the sake of argument, let's say this is a rasterspam plasma or something. i don't need or want the...
by thomas3
Sat Feb 29, 2020 5:03 pm
Forum: CosmosEx
Topic: CosmosEX 3.0
Replies: 217
Views: 98375

Re: CosmosEX 3.0

When/if these things hit the street...
If anyone who is receiving one has an older version of CosmosEX that they wanna sell...
Message me :)

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