Search found 334 matches

by at67
23 Jul 2021, 09:33
Forum: Hardware and software hacking
Topic: LCC for the Gigatron. Take two.
Replies: 6
Views: 90

Re: LCC for the Gigatron. Take two.

I decided to give it another try a few months ago. I studied the old compiler and stole the good ideas, such as having a combined assembler-linker written in python. I rewrote a very different code generator (with some novel ideas in fact) and I solved the register spilling problems. Then I started...
by at67
19 Jul 2021, 09:51
Forum: Hardware and software hacking
Topic: New vCPU instructions 2.0
Replies: 91
Views: 8448

Re: New vCPU instructions 2.0

I just ran some experimented with a batch of indirect-indexed instructions. The encoding is as follows: PREFIX VAR OPCODE OFFSET I'm going to use this format, (as you suggested), for PREFX3 to save a few cycles. Overall I believe this is a good idea. The implementation might have to be refined. In ...
by at67
19 Jul 2021, 09:41
Forum: Hardware and software hacking
Topic: Additional facilities for native code programming / a new SYS function calling convention
Replies: 3
Views: 221

Re: Additional facilities for native code programming / a new SYS function calling convention

Variable space. Is there a backwards compatible place that we could put this information? I kinda wish Marcel had allocated some of page 0 as "for future use". I guess this is with future ROM's in mind, if so then you could just use the 0x3X space; Marcel reserved 0x30 to 0x33 for VBlank interrupts...
by at67
04 Jul 2021, 01:16
Forum: Hardware and software hacking
Topic: Additional facilities for native code programming / a new SYS function calling convention
Replies: 3
Views: 221

Re: Additional facilities for native code programming / a new SYS function calling convention

It can't be shared between virtual machines - code that is part of a vCPU or v6502 instruction is destined always to return to its dispatch loop, and SYS functions are all linked to vCPU for the same reason. I'd like to be able to expose SYS functions in my Forth, and it's possible, but it always i...
by at67
04 Jul 2021, 00:11
Forum: Hardware and software hacking
Topic: New vCPU instructions 2.0
Replies: 91
Views: 8448

Re: New vCPU instructions 2.0

Yes, I think to do both bytes and the transfer in 30 is not possible. If you could do it in two-phases it should work (but how would you dispatch to different code the on the second and subsequent calls?). My implementation of Arithmetic shift-right is 45 excluding the cost of dispatch and I though...
by at67
21 Jun 2021, 18:28
Forum: Hardware and software hacking
Topic: New vCPU instructions 2.0
Replies: 91
Views: 8448

Re: New vCPU instructions 2.0

I've implemented a LSRB, (non PREFX instruction), in ROMvX0, so applying this technique, (as a PREFX restart-able instruction), to allow right byte shifts from 1 to 7 should be doable. But I was never able to get a LSRW implemented in under 30 cycles. In fact I wasn't even close, I think my best was...
by at67
20 Jun 2021, 04:52
Forum: Hardware and software hacking
Topic: New vCPU instructions 2.0
Replies: 91
Views: 8448

Re: New vCPU instructions 2.0

Ideas for prefix2. So, before even thinking of supporting long and float arithmetic with SYS calls, it would be desirable to have MOVL v1,v2 (moving 4 bytes) and MOVF v1,v2 (moving 5 bytes), and maybe even LOKEA/LEEKA and fp equivalents (FOKEA might not be a good name.) Doing this might involve wri...
by at67
19 Jun 2021, 01:12
Forum: Hardware and software hacking
Topic: New games for the Gigatron
Replies: 10
Views: 711

Re: New games for the Gigatron

I've added your GT1 files to the GT1 repository at: https://www.dropbox.com/sh/4bbys2afg9y6 ... tlBza?dl=0
by at67
19 Jun 2021, 01:08
Forum: Hardware and software hacking
Topic: Overview of hard/software subprojects
Replies: 5
Views: 2901

Re: Overview of hard/software subprojects

I've updated the GT1 repository with additions from hans61, delpozzo and myself. As always if anyone has GT1 examples/apps/games/etc they would like stored in a central easy to access location, then just send me a PM or reply to this thread; also if anyone wants their GT1 files removed for whatever ...
by at67
17 Jun 2021, 12:31
Forum: Hardware and software hacking
Topic: Sprites
Replies: 7
Views: 1136

Re: Sprites

Sprites with split screen scrolling:

https://www.youtube.com/watch?v=xv5civaoGOM