The Sinclair QL Forum

Hi all. I have a series of questions about the Q68, so I thought it could be a good idea to put them under this thread. Let's go ! 1/ Q68 uses an FPGA. What is necessary to reprogram it ? I am asking that for various reasons, in particular implementing 8 bit per pixel screen modes, like 384 x 288 (o...

What does the Q68 offers to set the address of the video DMA ? How precise in terms of bytes is it ? Also : are the size of the borders programmable ? A list and description of all hardware registers of the video chip, and the memory controller, would be great to know what could be achieved. All thi...

When I read that I can tell you definitively we'll need fast plotting and unplotting routines for the Q68, to get great and fast arcade games. My point is getting an arcade game at all, which has not happened for 20 years. Fast routines, but no game would be of little interest for me. We'll have bo...

CPU access to the normal SDRAM memory is not particularly fast, as it is random access. You can expect about 100 ns per 16-bit word. (No CPU cache, therefore burst access only for video.) When I read that I can tell you definitively we'll need fast plotting and unplotting routines for the Q68, to g...

This is great Peter, in particular if the faster than expected opcodes are the ones accessing memory.
I am really impatient to get the beasties and experiment.
And yes you had already specified only high resolution screen modes slow down the Q68.
Sorry for the waste of time.

My interest would be to see a new arcade game at all. As far I can remember, this has not happened for the QL in about 20 years. The original QL was already fast enough for arcade games. So a machine which is roughly 20 times faster (Q-Top benchmark) does not technically need highly optimized sprit...

It is true generating code at run time makes more sense when your target machine hasn't got much RAM (like 2 Mbytes for an Archie). It also means having the need of a crude memory handler, to kill the generated codes of sprites you do not need to display anymore, move what you must keep to free cont...

No, there is no hardware sprite support in the Q68 (as well as in any QL compatible I know). And yes, there is software support for sprites in the extended environment, "software support", however, is a relative term. Naturally, the EE implements sprites for a WIMP, and not for a game, so...

Hi Xavier, What sort of sprites are you talking about? There are sprite facilities in the extended environment. Sprites : that is, any kind of graphics, whatever heigth or width, whatever the shape, that you intend to plot and possibly move on screen, like, for example in a game like r-type : your ...

Hi all. I start this thread, which in a way is a follow up to this one : http://qlforum.co.uk/viewtopic.php?f=3&t=2190 I propose we think together about what could be the fastest way to fast plot and fast unplot sprites, on the Q68. I have developped some fast routines on the Archie, which in a ...