Search found 166 matches

by markdryan
Thu Nov 26, 2020 6:32 pm
Forum: acorn & bbc micro user group (abug) events
Topic: Weeknight 'Virtual' Dev session #7, Thursday 26th November 2020, 7pm - 10pm
Replies: 20
Views: 337

Re: Weeknight 'Virtual' Dev session #7, Thursday 26th November 2020, 7pm - 10pm

I probably won’t be able to join after all. My laptop’s broken. Apologies for the late notice.
by markdryan
Mon Nov 23, 2020 10:24 pm
Forum: 8-bit acorn hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)
Replies: 1272
Views: 171716

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)

dudleysoft71 wrote:
Mon Nov 23, 2020 9:35 am
All of my binaries load at &F000, this seems to work fine, I'm not sure if addresses higher than &10000 will cause issues if you try to use DFS rather than ADFS as your file system, but &F000 is definitely safe to use.
Thanks. I'll give this a go.
by markdryan
Sun Nov 22, 2020 10:18 pm
Forum: 8-bit acorn hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)
Replies: 1272
Views: 171716

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)

I've got a quick question about the Native ARM mode of PiTube direct. What would be the best address to load and execute an absolute binary from? Ideally, I'd like to maximise the available memory but not corrupt anything. If I understand correctly, I should avoid the RiscOS start address of &8000, ...
by markdryan
Sat Nov 21, 2020 10:13 pm
Forum: development tools
Topic: Subtilis: A new BASIC compiler for RiscOS
Replies: 14
Views: 1382

Re: Subtilis: A new BASIC compiler for RiscOS

Subtilis now has an assembler. Currently, it supports all the ARM2 instructions and most of the FPA instructions. WFC, RFC, LFM and SFM aren't implemented yet. The assembler works differently to the BBC BASIC assembler. Assembly takes place at compile time rather than runtime. Inline assembly is not...
by markdryan
Thu Nov 12, 2020 7:26 am
Forum: past weeknight 'developer' sessions
Topic: Weeknight 'Virtual' Dev session #6, Thursday 12th November 2020, 7pm - 10pm
Replies: 26
Views: 760

Re: Weeknight 'Virtual' Dev session #6, Thursday 12th November 2020, 7pm - 10pm

Arcadian wrote:
Wed Nov 11, 2020 11:36 pm
Who'd like to present?
I can give a quick 10 minute demo of Subtilis's Assembler, which is mostly working now. I won't be able to join before 7:45.
by markdryan
Sun Oct 25, 2020 8:24 pm
Forum: 32-bit acorn hardware
Topic: A3000 restoration
Replies: 21
Views: 2617

Re: A3000 restoration

> So stardot, should I just clean the connector, fix the membrane and leave well enough alone, or should I replace the green connector and possibly the green chips? In the end I just replaced the keyboard connector. Soaking the desoldered connector in vinegar for a while did get rid of all the visib...
by markdryan
Fri Oct 23, 2020 4:18 pm
Forum: past weeknight 'developer' sessions
Topic: Weeknight 'Virtual' Dev session #5, Thursday 22nd October 2020, 7pm - 10pm
Replies: 29
Views: 976

Re: Weeknight 'Virtual' Dev session #5, Thursday 22nd October 2020, 7pm - 10pm

Mark asked about the Beeb816 speed up for the Raytrace program running on PiTubeDirect's native Arm copro. https://stardot.org.uk/forums/viewtopic.php?f=2&t=19280&start=30#p272781 On my BBC B with Pi3A+ I got 13.8s Enabling Beeb816 @ 14MHz to accelerate the host, that came down to 2.8s for about a ...
by markdryan
Thu Oct 22, 2020 7:39 pm
Forum: past weeknight 'developer' sessions
Topic: Weeknight 'Virtual' Dev session #5, Thursday 22nd October 2020, 7pm - 10pm
Replies: 29
Views: 976

Re: Weeknight 'Virtual' Dev session #5, Thursday 22nd October 2020, 7pm - 10pm

I don't seem to have an invite to the meeting. Could someone PM me the zoom details?
by markdryan
Wed Oct 21, 2020 9:49 pm
Forum: general
Topic: LET me ask a stupid quieston
Replies: 25
Views: 832

Re: LET me ask a stupid quieston

Memotech perhaps? Just a guess as I've never used or even seen one of these in real life.
by markdryan
Thu Oct 15, 2020 9:25 pm
Forum: 32-bit acorn hardware
Topic: A3000 restoration
Replies: 21
Views: 2617

Re: A3000 restoration

My A3000 has developed an issue with the keyboard. Some keys produce an incorrect character when pressed, for example \ sometimes gives j, return sometimes prints y. Looking at the membrane there does seem to be some damage. IMG_2336.JPG If I decode the keyboard map https://stardot.org.uk/forums/vie...
by markdryan
Tue Oct 13, 2020 9:16 pm
Forum: past weeknight 'developer' sessions
Topic: Weeknight 'Virtual' Dev session #5, Thursday 22nd October 2020, 7pm - 10pm
Replies: 29
Views: 976

Re: Weeknight 'Virtual' Dev session #5, Thursday 22nd October 2020, 7pm - 10pm

Me please. With a bit of luck I'll be able to demo Subtilis' assembler by then.
by markdryan
Tue Oct 13, 2020 9:12 pm
Forum: general
Topic: Today I received.....
Replies: 6056
Views: 640368

Re: Today I received.....

A nice clicky spectrum membrane replacement.

IMG_2328.JPG
by markdryan
Sun Oct 11, 2020 10:44 am
Forum: for sale / freebies
Topic: VideoNuLA boards
Replies: 170
Views: 30692

Re: VideoNuLA boards

Rob, could you add me to the waiting list as well? I'd like to reserve two Video NULAs for my two masters. I'm pretty sure the ULAs are soldered to the motherboard in both machines so I'll be needing the sockets as well.
by markdryan
Sat Oct 03, 2020 2:03 pm
Forum: development tools
Topic: Subtilis: A new BASIC compiler for RiscOS
Replies: 14
Views: 1382

Re: Subtilis: A new BASIC compiler for RiscOS

I've been playing around with the optimisation options in ABC a little and the results are quite interesting. The first thing I tried was to enable the following options: REM {NOESCAPECHECK} REM {NOGOTOSUSED} REM {NOSTACKCHECK} REM {SYSCONSTONLY} REM {SYSKNOWNONLY} Additionally, I placed a REM {ESCA...
by markdryan
Thu Oct 01, 2020 7:47 pm
Forum: development tools
Topic: Subtilis: A new BASIC compiler for RiscOS
Replies: 14
Views: 1382

Re: Subtilis: A new BASIC compiler for RiscOS

Paul, thanks for all the information. This is excellent. Someone to discuss BASIC compilers with :-). The sources for all the benchmarks I used are here https://github.com/markdryan/basic-benchmarks . I built them using the version of ABC that came with my copy of the DDE purchased from ROOL about 3...
by markdryan
Sat Sep 19, 2020 9:33 am
Forum: development tools
Topic: Subtilis: A new BASIC compiler for RiscOS
Replies: 14
Views: 1382

Re: Subtilis: A new BASIC compiler for RiscOS

I've added support for SYS calls. SYS calls mostly work as expected with one big limitation. The id of the SYS call needs to be known at compile time. It can be an integer or a string, but it needs to be constant. So you can do sys &6a or sys "OS_Reset" but not a% := &6a sys a% On the plus side, kno...
by markdryan
Tue Sep 15, 2020 11:33 am
Forum: for sale / freebies
Topic: [SOLD] A3000 Power Supply
Replies: 1
Views: 178

Re: A3000 Power Supply

Hi oide,

I might be interested in this. Does the power supply have a metal case or does it have a cardboard cover?
by markdryan
Fri Sep 11, 2020 10:08 pm
Forum: past weeknight 'developer' sessions
Topic: Weeknight 'Virtual' Dev session #2, Thursday 10th September 2020, 7pm - 10pm
Replies: 55
Views: 2832

Re: Weeknight 'Virtual' Dev session #2, Thursday 10th September 2020, 7pm - 10pm

Another really enoyable and interesting evening. Thanks to Dave for organising and to all the presenters for the great talks and demos. After all this time, I finally understand how interrupts work on the BBC micro and can be put to good use.
by markdryan
Fri Sep 11, 2020 3:26 pm
Forum: 32-bit acorn software: other
Topic: CLOCKSP on a BBC BASIC "emulator" under x64
Replies: 19
Views: 844

Re: CLOCKSP on a BBC BASIC "emulator" under x64

IIRC the string test does a / in several places. If floating point is slow in your VM it might be worth replacing the / with a DIV and re-running to see if it makes any difference.
by markdryan
Tue Sep 08, 2020 9:39 am
Forum: 32-bit acorn software: other
Topic: CLOCKSP on a BBC BASIC "emulator" under x64
Replies: 19
Views: 844

Re: CLOCKSP on a BBC BASIC "emulator" under x64

You might be getting a division by zero error. ClockSp was crashing when I ran it through ABC as ABC actually optimized away some of the for loop tests completly, and as a consequence they took 0 centi seconds, which led to a division by zero error, IIRC.
by markdryan
Fri Sep 04, 2020 9:14 am
Forum: programming
Topic: Plotting desktop sprites in mode 15
Replies: 3
Views: 273

Re: Plotting desktop sprites in mode 15

> Thanks! I didn't realise that some Wimp_ SWI's would work when the desktop was not active.

Neither did I. Thanks for posting the code example. It was good fun playing around with it.
by markdryan
Thu Sep 03, 2020 10:45 pm
Forum: programming
Topic: Plotting desktop sprites in mode 15
Replies: 3
Views: 273

Re: Plotting desktop sprites in mode 15

There's a related question here: https://www.riscosopen.org/forum/forums/11/topics/8980 The issue seems to be with 16 colour mode WIMP sprites without a palette. For these sprites, ColourTrans_SelectTable will return the wrong palette. Apparently, it returns the kernel palette and you want the Wimp ...
by markdryan
Thu Sep 03, 2020 6:46 pm
Forum: past weeknight 'developer' sessions
Topic: Weeknight 'Virtual' Dev session #2, Thursday 10th September 2020, 7pm - 10pm
Replies: 55
Views: 2832

Re: Weeknight 'Virtual' Dev session #2, Thursday 10th September 2020, 7pm - 10pm

I'd like to join as well, from 8pm onwards. I can give a brief update on Subtilis, my perpetually unfinished BASIC compiler.
by markdryan
Thu Sep 03, 2020 6:43 pm
Forum: for sale / freebies
Topic: For sale: RGBtoHDMI boards
Replies: 102
Views: 5104

Re: For sale: RGBtoHDMI boards

Hi Ian,

Could you put me down for 2xRGBtoHDMI kits please?
by markdryan
Sun Aug 30, 2020 5:14 pm
Forum: 32-bit acorn software: other
Topic: Benchmarks
Replies: 20
Views: 1046

Re: Benchmarks

I am aware I'm probably the only person who finds this interesting. I'm interested. Particularly, in the FPA performance. Perhaps you could try something like Mandelbrot in normal BASIC and then again in BASIC64 on the machine with the FPA? I'm guessing, we're not getting a true idea of the floatin...
by markdryan
Sun Aug 30, 2020 1:07 pm
Forum: programming
Topic: A GAME IN BASIC V
Replies: 43
Views: 1693

Re: A GAME IN BASIC V

so not so easy to compile.... It's easy to compile as long as your program uses the subset of BBC BASIC that ABC supports, e.g., doesn't use SWAP or matrix multiplication. If you have a copy of ABC, it's just a matter of launching it and dragging your BASIC program onto the Icon, entering a file na...

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