Monday, December 29, 2008


Sinclair C5 coast run

I've not had time to watch all of this video but here it is for your delight and delectation

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Thursday, December 25, 2008


Redefining the ZX Spectrum character set

This was something I always wanted to do as a kid but could never get it to work. Thought I'd have a bash tonight and it was pretty easy after realising two key facts:

(1) The CHARS system variable needs the low byte of the address of the new character stored before the high byte

(2) BUT for some reason, the value of CHARS needs to be 256 less than the start of the new character set.

Here is a screenshot of the BASIC program I knocked up as a simple test of a new 'A' character.

After a break, I remembered a game I really liked in about 1985 called Bored of the Rings which had a good font. I had a think, and came up with this plan:

  1. Load Bored of the Rings into Fuse on my Mac

  2. Open the Memory Browser and look at the contents of 23606 and 23607 which together contained 0xBE68. Adding 256 to this gave a memory location of 49000 for the start of the new character set

  3. I exported using File / Export Binary Data from location 49000 and length 768

  4. I then loaded my test program from earlier, did File / Import to load the binary data back to 49000 and then did POKE 23606,104 and POKE 23607, 190 and lo:

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New Spectrum game: ALBATROSSITY

Knew we could count on him to release something to brighten an otherwise dull day - you can download Albatrossity from Jonathan Cauldwell's web site.

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Wednesday, December 24, 2008


I've single-handedly saved Cronosoft!

Well, maybe not but after ordering SEUD, PGD and splATTR it was nice to hear the following from Simon:

Many thanks for the order of games - I've had so many orders since posting on WOS, it looks like we'll be around for a while yet!

He's sent me the emulator versions of the titles while I wait for the tapes. splATTR looks great under ZXSpin on my PC/Windows but resets as soon as I load it under Fuse/Mac OS x :-(

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Tuesday, December 23, 2008


RST 16 modifies the accumulator...

Aargh - it's taken me a depressing amount of time to realise that the RST16 call to print the contents of the accumulator on the ZX Spectrum has the side effect of modifying the contents of the accumulator. That'll explain why I was getting an "INVALID INK COLOUR" error message in BASIC...

Click on the images for larger versions - they're very exciting...

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Cronosoft order

Now I'm off for a couple of weeks I've had more time to play with my Speccy as you've no doubt noticed from my recent posts!

I've been checking out the Cronosoft forum recently and thinking about how quiet it has been.

Today, I had a look to see if I could find a more active forum, since comp.sys.sinclair seemed a bit dull (!) and saw a thread on the World of Spectrum forum that made me dash off that order for Platform Game Designer (PGD), Shoot 'Em Up Designer (SEUD) and splattr that I've been meaning to place for a while.

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Monday, December 22, 2008


Z80 machine code

It is a bit painful using ZEUS on my real ZX Spectrum, so today I got round to:

I edited the catalog.xml file to ignore the current mapping for Intel x86 assembly files and instead associate with Z80 like this:

<MODE NAME="assembly-x86" FILE="assembly-x86.xml"
FILE_NAME_GLOB="*.asm" />

<MODE NAME="assembly-z80" FILE="assembly-z80.xml"
FILE_NAME_GLOB="*.asm" />

and then created a new XML file for the Z80 instructions by copying the x86 file and modifying it. It's not finished yet as it still contains lots of x86 instructions and not all Z80 ones, but it's a start.

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Sunday, December 21, 2008


Latest order for the C5

I've got some of these on order now.

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Wednesday, December 17, 2008


James McKay's Teenage Programming Atrocities

I came across this link while doing my daily search for ZX Spectrum stuff. Had me laughing out loud at some points - took me back to the days of John Menzies in Stretford Precinct.

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Sunday, December 14, 2008


Lemmings for the DS

I used to play Lemmings on the PC when I was at university (more interesting than Genetic Algorithms and Z!). I was Lemmings playing on my newly-modified composite video ZX Spectrum earlier today when I thought of searching for a version for the DS.

I found this freeware version which seems pretty good so far although I have only played the first level.

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Saturday, December 13, 2008


Composite video for ZX Spectrum

I applied this modification to my ZX Spectrum and while the display is much better, it seems as though the video signal is picking up some noise from the clock as there is a slight shimmering. It is more noticeable when running ZEUS (white text on a blue background) than other combinations of colours such as black ink on white paper.

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Spectrum emulator for DS

This ZXDS emulator is very good - been playing my old games today.

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