Author Topic: 8 Bit machines?  (Read 19347 times)

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Offline sigh

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Re: 8 Bit machines?
« Reply #25 on: 16:02, 26 December 10 »
That's true of the colours! That's one of the things that the PLUS had revised very well. Reading more, I'm putting these 2 machines at pretty much the same level.

Offline MacDeath

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Re: 8 Bit machines?
« Reply #26 on: 16:10, 26 December 10 »
To be fair, a C64 with +64k RAM, this could only be awesome... but also with a 4096 palette... this would have been the ultimate 8bit.

It wasn't really.


That's what was good with all those old machines : none were perfect (perhaps the Amiga ? well...)


Offline sigh

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Re: 8 Bit machines?
« Reply #27 on: 20:19, 26 December 10 »
Hmmm. Well the C128 still only had room for 8 hardwars sprites compared to the PLUS 16 hardware sprites. However, the dimensions were larger on the C128. The ultimate 8bit is looking like the MSX Turbo R at the moment.....

Offline mahlemiut

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Re: 8 Bit machines?
« Reply #28 on: 22:51, 26 December 10 »
What about the PC Engine / TG-16?  I'm pretty sure the Hu6280 CPU it uses is only 8-bit...
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Offline ivarf

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Re: 8 Bit machines?
« Reply #29 on: 01:42, 27 December 10 »
Hmmm. Well the C128 still only had room for 8 hardwars sprites compared to the PLUS 16 hardware sprites. However, the dimensions were larger on the C128. The ultimate 8bit is looking like the MSX Turbo R at the moment.....


True, it must be hard for the CPC+ to compete with a machine with processor equal to a 28MHz Z80, 512 kB RAM. From its spec, it seems to have hardwaresprites and registers for scrolling, so I assume it can animate the screen at a rapid pace.

Offline sigh

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Re: 8 Bit machines?
« Reply #30 on: 04:06, 27 December 10 »

http://www.youtube.com/watch?v=tcZBtk7JkSc

Here's a shmup on the MSX called Space Manbow. Very nice graphics and the sound is excellent.
The PC engine indeed had an 8bit CPU but a 16 bit GPU. More like a hybrid machine. I never really felt that the PC engine was an 8 bit machine...

Offline steve

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Re: 8 Bit machines?
« Reply #31 on: 05:24, 27 December 10 »

http://www.youtube.com/watch?v=tcZBtk7JkSc

Here's a shmup on the MSX called Space Manbow. Very nice graphics and the sound is excellent.
The PC engine indeed had an 8bit CPU but a 16 bit GPU. More like a hybrid machine. I never really felt that the PC engine was an 8 bit machine...

The turbo R must surely qualify as a 16bit computer, as the R800 processor had a 16bit ALU which makes it a 16 bit processor and the 9958 graphics controller probably also uses 16bit processing to speed up screen drawing.

The modern successor to the z80 is the eZ80 which can execute up to one instruction per clock cycle by using a 16 bit ALU and a pipelined architecture with a top speed of 50mhz, but I will not argue if anyone produces an accelerator for the cpc/+ using it, I would jump at the chance of a compatible machine running at a speed equivalent to a 200mhz z80, add a blitter and 16 bit DAC with DMA for sound and we may have a machine that is faster than an accelerated Amiga.
And for 100% compatibility it should load software from cassette tapes. :laugh:

Offline sigh

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Re: 8 Bit machines?
« Reply #32 on: 05:41, 27 December 10 »
The turbo R must surely qualify as a 16bit computer, as the R800 processor had a 16bit ALU which makes it a 16 bit processor and the 9958 graphics controller probably also uses 16bit processing to speed up screen drawing.

The modern successor to the z80 is the eZ80 which can execute up to one instruction per clock cycle by using a 16 bit ALU and a pipelined architecture with a top speed of 50mhz, but I will not argue if anyone produces an accelerator for the cpc/+ using it, I would jump at the chance of a compatible machine running at a speed equivalent to a 200mhz z80, add a blitter and 16 bit DAC with DMA for sound and we may have a machine that is faster than an accelerated Amiga.
And for 100% compatibility it should load software from cassette tapes. :laugh:

Yup, your right! It is 16 bit!
Okay - I vote Amstrad Plus as being the most poweful 8 bit machine :laugh:

Offline steve

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Re: 8 Bit machines?
« Reply #33 on: 06:51, 27 December 10 »
Yup, your right! It is 16 bit!
Okay - I vote Amstrad Plus as being the most poweful 8 bit machine :laugh:

Not so fast, the sam coupe is probably the most powerful, if you don't count hobbyist projects like the v680p+ @ 16mhz with blitter, there are even people building new S100 systems using a 10 mhz z80, not the fastest, but an interesting project if you want that type of system.

There is no reason, other than commercial failure, why a multiprocessor system could not be built with 17 eZ80's based on the S100/IEEE 696 standard and it could run the first microcomputer operating system CP/M (or MP/M), which microsoft copied and called MS-DOS.
« Last Edit: 15:12, 27 December 10 by steve »

Offline andycadley

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Re: 8 Bit machines?
« Reply #34 on: 10:59, 27 December 10 »
Not so fast, the sam coupe is probably the most powerful, if you don't count hobbyist projects like the v680p+ @ 16mhz with blitter, there are even people building new S100 systems using a 10 mhz z80, not the fastest, but an interesting project if you want that type of system.
Not a chance. The SAM may be clocked marginally faster but it's video ram is significantly larger and without hardware assistance for things like sprites and scrolling it is massively underpowered for the kind of data it needs to push around. It's even worse than the original CPC in that respect. To make matters worse you can't even get away with choosing a lower res video mode, since that increases memory contention deliberately to slow the machine down for Spectrum compatibility. Rumour had it that, at the time, it would have cost just £2 more per machine to add hardware scrolling. Had MGT done that rather than excessive cost cutting, it might even have been a contender. I'd still quite like to get one though.  ;)

The only real competition for the 6128+ in the 8-bit home computer market would have been the C65. However I don't think that can really count as only a handful of prototypes ever saw the light of day and they aren't even entirely compatible with each other.

Offline PhilZeVibe

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Re: 8 Bit machines?
« Reply #35 on: 13:20, 27 December 10 »
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« Last Edit: 17:49, 30 June 21 by PhilZeVibe »

Offline robcfg

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Re: 8 Bit machines?
« Reply #36 on: 13:33, 27 December 10 »
Try "The Swiss Demo" ina TurboR or in BlueMSX in TurboR emulation mode.


Sweeeeeeeeeet!  8)

Offline MacDeath

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Re: 8 Bit machines?
« Reply #37 on: 14:18, 27 December 10 »
Were 8 bit "duocore" ever crafted ?


Many of those actually had many CPUs...

exemple : TurboR is like a 16bit with a Z80 for retro-compatibility...
Even the SEGA Megadrive has a Z80 (as a sound card... coupled with an AY psg) that could be used for retrocompatibility (SMS...)

Thre C128 had 2 kind of CPU, yet couldn't properly get them working together...


But a machine based on a set of two Z80...
this would be a 2x8bit = 16bit... sort of.
This could have worked well.

Alway wondering what if the Amstrad Plus had actually 2xZ80 and 2 Asics (one for video, the other for the rest)...
One of those Z80 would have been handicaped by the display (wait states and -16K...) as in a proper CPC but the other would not.

Of course designing softwares could get triky... but. ::)

such a machine with 256K RAM and an upgraded set of video modes (32K based ones, 160x200x256, 320x200x16, 640x200x4... and overscan trick still availlable... 8) )...could certainly rape an Atari ST IMO.

Offline steve

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Re: 8 Bit machines?
« Reply #38 on: 14:23, 27 December 10 »
R800 is Z80 compatible, uses the same 8-bit registers, and has an 8-bit data bus.
It's true that it has an internal 16-bit ALU but that doesn't make it a 16-bit processor.
It's even better than that. According to Wikipedia, eZ80 has a 24-bit ALU.

Processor definitions are something people have argued over for decades, I think the size of the ALU is the important factor, the 68008 and 8088 both have 8 bit databusses yet are classified as 16 bit processors, the 8-bit databus only affects the speed of the chip, not it's 16-bit status.

The eZ80 has a 24-bit address bus but for data it only uses a 16 bit ALU since it can only handle 8 or 16-bit data, it (and the z80) has 16bit instructions and a few 16-bit registers, so the 16-bit ALU makes the eZ80 a 16-bit processor, but you can think otherwise if you choose.
« Last Edit: 15:15, 27 December 10 by steve »

Offline steve

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Re: 8 Bit machines?
« Reply #39 on: 14:36, 27 December 10 »
Were 8 bit "duocore" ever crafted ?


Many of those actually had many CPUs...

exemple : TurboR is like a 16bit with a Z80 for retro-compatibility...
Even the SEGA Megadrive has a Z80 (as a sound card... coupled with an AY psg) that could be used for retrocompatibility (SMS...)

Thre C128 had 2 kind of CPU, yet couldn't properly get them working together...


But a machine based on a set of two Z80...
this would be a 2x8bit = 16bit... sort of.
This could have worked well.

Alway wondering what if the Amstrad Plus had actually 2xZ80 and 2 Asics (one for video, the other for the rest)...
One of those Z80 would have been handicaped by the display (wait states and -16K...) as in a proper CPC but the other would not.

Of course designing softwares could get triky... but. ::)

such a machine with 256K RAM and an upgraded set of video modes (32K based ones, 160x200x256, 320x200x16, 640x200x4... and overscan trick still availlable... 8) )...could certainly rape an Atari ST IMO.

The Fairlight CMI used two 6800 processors, it's successor used "multiple" 6800's, the fourth machine used 16-bit 68000 and 8-bit 6809 processors, it sold for about £18,000 to £50,000.

In the late 70's businesses used iee696 systems which could have up to 17 processors which could be a mix of processors 8080, z80, 8085, 8088/8086  and 68000 these were multi-user systems used in offices.
« Last Edit: 14:40, 27 December 10 by steve »

Offline steve

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Re: 8 Bit machines?
« Reply #40 on: 14:46, 27 December 10 »
The c64 had a disk drive that had it's own 6502 as a disk controller.

The BBC microcomputer could be extended with a second processor which used a z80 to run CP/M software.

Offline andycadley

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Re: 8 Bit machines?
« Reply #41 on: 14:57, 27 December 10 »
But a machine based on a set of two Z80...
this would be a 2x8bit = 16bit... sort of.
This could have worked well.
I'm not sure Z80s were ever made with suitable bus arbitration logic to make them effectively work in parallel. You could probably use them in a NUMA style architecture, so they aren't accessing the same memory for the most part, but I'm not sure you'd really get much advantage and certainly not enough to make it worthwhile over just sticking a 16-bit processor in instead.

Offline PhilZeVibe

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Re: 8 Bit machines?
« Reply #42 on: 15:22, 27 December 10 »
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« Last Edit: 17:50, 30 June 21 by PhilZeVibe »

Offline steve

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Re: 8 Bit machines?
« Reply #43 on: 16:07, 27 December 10 »
True. It depens whether you look at the processor with a programmer's point of view (ie: the instruction set and the registers), an Electrical Engineer POV (ie: databus), or from a microprocessor designer's view (ie: the internal ALU).


Motorola 68008 is a really puzzling thing. It has a 32-bit ALU, with a 32-bit instruction set, but has an 8-bit databus, and 24-bit adressing. So good luck classifying that beast :D
From what I understand, eZ80 really handles 24-bit datas. Wikipedia says that most registers (HL, BC, DE, IX, IY, SP, and PC) are extended from 16 to 24 bits.

The 68008, 68000, 68010 and 68012 all have three 16-bit ALU's, 2 work on address calculations and the third is for data processing, 68020 is the first in the family to get 32 bit ALU's, and the ability to use register pairs to process 64-bit data.

So, the programmer could think of the 68008 as a 32-bit processor and the 68020 as a 64-bit processor as it has 64 bit instructions and pairs of registers to hold 64-bit data.

The only use of 24-bit registers on the eZ80 is for addressing, the instruction set is still limited to 1/8 or 16 bit data.
« Last Edit: 16:53, 27 December 10 by steve »

Offline PhilZeVibe

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Re: 8 Bit machines?
« Reply #44 on: 16:22, 27 December 10 »
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« Last Edit: 17:50, 30 June 21 by PhilZeVibe »

Offline robcfg

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Re: 8 Bit machines?
« Reply #45 on: 22:43, 27 December 10 »
Quote
Were 8 bit "duocore" ever crafted ?


I think the Dragon Data Beta prototypes had twin 68E09 processors.

Offline mahlemiut

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Re: 8 Bit machines?
« Reply #46 on: 23:27, 27 December 10 »
The Fujitsu FM-7 has dual 6809 CPUs.  And that was in 1982.
The FM-77AV (released in 1985) added an MMU that allowed you to access the second CPU's address space, including the video hardware.  The FM-7 was limited to only communicating between CPUs via shared RAM.
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Offline sigh

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Re: 8 Bit machines?
« Reply #47 on: 20:58, 31 December 10 »
http://en.wikipedia.org/wiki/Commodore_65

Commodore 65 specs!!! Also a few prototypes out in the wild. Surely the most powerful 8 bit machine?

Offline robcfg

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Re: 8 Bit machines?
« Reply #48 on: 21:08, 31 December 10 »
I think the MSX Turbo R still remains the most powerful 8-bit machine.


If you think the Turbo R should be cataloged as a 16-bit machine, then the C65 would fall in that category  :D


Anyway, the C65 does look suspiciosly like the CPC6128, isn't it?

Offline sigh

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Re: 8 Bit machines?
« Reply #49 on: 21:19, 31 December 10 »
Yeah, it does have a slightly 6128 feel with the disk drive.

Looking at the C65 specs, aren't both the cpu and vic III operating only as a 8 bits with nothing relating to 16bit processing?