Recent posts

#11

Applications / Re: HDCPM - boot and run CP/M ...

Last post by GUNHED - Yesterday at 18:37

Sorry, but you can't compare a shell to Z3Plus, which even has a shell stack. 

#12

Games / Re: ZX Spectrum ports

Last post by TotO - Yesterday at 17:31

I think it's one of those thing where, in order to accomplish it from a hardware perspective, you'd have had to completely redesign how the hardware worked. At which point you're basically designing a brand new console from scratch. And that was out of scope for what the GX project was.

Cliff Lawson once said to me that, in essence, if they hadn't broadly used the CPC design, they couldn't afford the R&D costs. It's why it's not a 16-bit machine, why the sprites have to work without impacting on memory bandwidth, why the display modes are still limited to those the original machines had and why things like DMA music is tied to reading data at the same rate the screen display runs etc.

Because the cartridge media and the fact there is an unlock sequence to access the Plus features, in 1990, it would have been possible to run the Z80 at 6MHz or 8MHz for that usage and the CRTC respectively at 1.5MHz or 2MHz to provide the new 256 or 320 screen modes with 16 colours + the sprites over that. No impact for the CPC compatibility while using tape or floppy programs.

#13

Games / Re: ZX Spectrum ports

Last post by Shaun M. Neary - Yesterday at 16:05

Cliff Lawson once said to me that, in essence, if they hadn't broadly used the CPC design, they couldn't afford the R&D costs. It's why it's not a 16-bit machine, why the sprites have to work without impacting on memory bandwidth, why the display modes are still limited to those the original machines had and why things like DMA music is tied to reading data at the same rate the screen display runs etc.

Something else to consider as well back then, but even with the minimal changes that were made, look at all the backward compatibility craziness that happened. Keyboard scanning bugs for games, and then there were the newer port standards which made it a complete nightmare for third party manufacturers.

Had they tried to implement 16bit, Christ only knows what additional backward compatibility issues there would have been, and for six years of software and hardware already available, it would have made horrible business sense to alienate that in itself.

#14

Games / Re: ZX Spectrum ports

Last post by andycadley - Yesterday at 15:49

I think it's one of those thing where, in order to accomplish it from a hardware perspective, you'd have had to completely redesign how the hardware worked. At which point you're basically designing a brand new console from scratch. And that was out of scope for what the GX project was. 

Cliff Lawson once said to me that, in essence, if they hadn't broadly used the CPC design, they couldn't afford the R&D costs. It's why it's not a 16-bit machine, why the sprites have to work without impacting on memory bandwidth, why the display modes are still limited to those the original machines had and why things like DMA music is tied to reading data at the same rate the screen display runs etc.

#15

Games / Re: ZX Spectrum ports

Last post by TotO - Yesterday at 14:35

The CPC video scanning is very linked to the CPU clock and access to the memory bus, it wouldn't be simple to have a different pixel clock like the NES/Spectrum.

I don't said it is simple, but it is missing. I can understand for the CPC but not for the Plus/GX.

#16

Games / Re: ZX Spectrum ports

Last post by Sykobee (Briggsy) - Yesterday at 13:50

The problematic is more to be not able to switch the horizontal clock for the 256x256 display in full screen.
About better Spectrum ports, it will require a 1bit mode with colour attribute and a lineal video memory.

The CPC video scanning is very linked to the CPU clock and access to the memory bus, it wouldn't be simple to have a different pixel clock like the NES/Spectrum.

Very much aside: Now with a more advanced+different scan-out implementation, you could have added a 216-pixel wide mode with 8 colours (i.e., 3-bits per pixel, size would be 3 MODE 2 pixels wide), but I can see how that was not considered originally - never mind the more complex graphics routines required as each pixel is 3 bits, and that doesn't work well with 8-bit bytes (up until 3 bytes worth, but that doesn't fit with the CPC's reading 2 bytes at a time, so you need buffers, etc (these would be needed for smooth horizontal scrolling too, and we're really diverging from the original CPC hardware)). Regardless, 216 pixels is not 256.

I didn't mind the 256-pixel CPC games where the graphics had been adjusted and optimised for the CPC. It was an understandable compromise to support both the CPC and Spectrum, and the limited time CPC ports were allocated. But the number of games that stuck the Spectrum game into the lower 48KB of CPC memory, and added code to copy from the Spectrum screenbuffer memory area to the CPC screen area (i.e., double rendering the game) was shocking.

#17

Programming / Re: create good cpr for gx4000

Last post by siudym - Yesterday at 12:58

I made a simple demo of the game, but still a lot of work because I still don't fully understand some things in CPC+.
I have no idea if it works on real hardware, on WinAPE and Arnold it seems OK..

#18

Games / Re: Converted GX4000 .cpr - Th...

Last post by Shaun M. Neary - Yesterday at 10:19

Got a couple of requests if anyone is interested?

1) Karnov. It doesn't appear to be in my set so not sure if it was ever done. It was 64k so surely this can be done?

A 64K-compatible crack of Karnov is now available from NVG. However I had to perform a lot of compression to get it to fit on one side of a disc. hERMOL at CPCRulez also produced a 64K-compatible crack a couple of months ago, so take your choice.

I can fully understand why there have been so few attempts to crack Karnov. It was a nightmare to get it to work with 64K of RAM - lots of juggling blocks of memory around!

Awesome Nich, be careful advertising your skills around like that. You'll end up with very long lists from the likes of gobshites like me.  

#19

Games / Re: Converted GX4000 .cpr - Th...

Last post by XeNoMoRPH - Yesterday at 08:29

#20

General Discussion - Introductions / Re: Rowan Atkinson Amstrad Ads...

Last post by Anthony Flack - Yesterday at 05:34

Those Rowan Atkinson Amstrad ads definitely played on TV in New Zealand in the 1980s.

As mentioned, he did the hands-as-goggles thing, and as he did so he said "Biggles".

That's all I got.