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<1…16171819202122…34>
  • Which is the most technically accurate Spectrum Emulator?Ok, which is the most technically accurate Spectrum Emulator? Please don't just vote but give reasons why.

    ... ... passed
    Contended memory... passed
    High port contention 1... passed
    Contended memory... passed
    High port contention 1... passed
    Contended memory... passed
    High port contention 1... passed
    rich_chandler rich_chandler June 2009 Emulators
  • Has any programmers recently pushed the spectrum to the limits?Hi there. Ive just discovered this great forum and I was brought up with the speccy 16,48 and then 128k. Im just wanting to know if there are any re…

    ... code, modifying the code in memory on the fly, and ... having a slightly peculiar attribute memory map (because the instructions holding ... it trivially by using more memory) which seems to work ... ; Hit here just as the contention-free period starts - start pushing ...
    AMW AMW August 2009 Development
  • Some ever noticed that +2A/+3 halts Z80 using WAIT?I mean: Anyone ever noticed that the +2A/+3 halts the Z80 using WAIT? All documentation I've read about contention state that the ULA halts the Z80 …

    ... kind of contention. A program run within the RAM memory executes as ... program were running in high memory. In both cases the CPU ... Instead of having two different memory banks, the Inves has only ... bank composed by two 41464 memory chips.

    However, ...
    mcleod_ideafix mcleod_ideafix October 2009 Hardware
  • Some ever noticed that +2A/+3 halts Z80 using WAIT?I mean: Anyone ever noticed that the +2A/+3 halts the Z80 using WAIT? All documentation I've read about contention state that the ULA halts the Z80 …

    ... CPU can be kept supplied / memory writes can be delayed while ... Micro worked without contention was interesting. The 6502, if memory serves, has ... much more regular pattern of memory access than the Z80, and ... t be accessing it. The memory used was only just fast ...
    Winston Winston October 2009 Hardware
  • Tutorial - learn machine code in 30mins[B][I]Message from the moderators[/I] - bigjon has requested that readers' attention be drawn to a better version of this tutorial, one which is easi…

    ... address spaces -- one where memory lies and one where ... Then they are known as memory-mapped peripherals. The reason ... (known as contention). Having the display file memory mapped allows the ... This means peripherals are always memory-mapped, the downside of ...
    Alcoholics Anonymous Alcoholics Anonymous November 2009 Development
  • More colours II (Was: Most popular new features?)The suggested 4xCLUT multi-colour solution never took off.

    ... a contention cycle if the ULA is busy reading lower memory, if ... means every time it changes memory pages the pallette will change ...
    Winston Winston November 2009 Emulators
  • More colours II (Was: Most popular new features?)The suggested 4xCLUT multi-colour solution never took off.

    ... means every time it changes memory pages the pallette will change ... CPU might be accessing the memory will be a really problem ... of using some off-chip memory for the palette. Of course ... is significantly easier to handle contention etc (of which there will ...
    csmith csmith November 2009 Emulators
  • More colours II (Was: Most popular new features?)The suggested 4xCLUT multi-colour solution never took off.

    ... of using some off-chip memory for the palette. Of course ... is significantly easier to handle contention etc (of which there will ...
    Winston Winston November 2009 Emulators
  • just thinking about ...compo for zx 16k ? anyone ?

    ... ]You could call it the Contention Competition, since all the lower ... interesting even without it, whole memory is contended, you really have ... sprites are shifted and placed memory and finally your code builder ...
    Fikee Fikee November 2009 Development
  • Need help with interrupts againI'm fighting to understand how interrupts code handling works I'm trying to set my simple own interrupt routine, as I don't want to be dependent on …

    ... I to point into contended memory can cause snow in the ... memory refresh cycles which can fool the ula into thinking bus contention ...
    Alcoholics Anonymous Alcoholics Anonymous November 2009 Development
  • More colours in existing games?I have been trying to follow the various threads about the new ULA and more colours. I don't understand quiet a lot of it as back in the day all I di…

    ... It will use off-chip memory, and the real trick will ... as required from the palette memory on demand without affecting the ... normal ULA timing. Thankfully memory is fast these days, so ... too. Currently documenting the CPU contention, which is proving tricky to ...
    csmith csmith December 2009 Emulators
  • Games not compatible with real grey +2There are many threads about Spectrum+3/2A incompatibility issues but what about grey +2? I've found that games like Marauder and Skate Crazy don't w…

    ... values when reading from contended memory which causes rubbish to be ... fetch by the program causes contention while the screen draws and ... one (during the auto-inserted memory refresh cycle) but I find ... t properly deal with two contention events close together if ...
    Alcoholics Anonymous Alcoholics Anonymous January 2010 Games
  • Spectrum 2-3 times more powerfull than MSX?![url]http://www.youtube.com/watch?v=2-kI0urN9tI#t=8m18s[/url]

    ... part of the Z80's memory map, but fully controlled by ... is quicker even allowing for contention. The MSX also has a ...
    joefish joefish March 2010 Sinclair Miscellaneous
  • Resolution & Memory Question ...Hi, I'm hoping someone with some experience writing an emulator, or a vast knowledge of all things Spectrum can help me answer the following questio…

    ... screen data from this particular memory chip (or chips), which ... times. This is the 'contended memory'.

    The remaining ... RAM, but without the interfering contention.

    The ... stored just after the screen memory, then the BASIC program, ...
    joefish joefish April 2010 Emulators
  • DivIDEo - streaming video on the DivIDEThis has been a bit of a personal holy grail for years and years, so I'm very pleased to announce the release of DivIDEo, my streaming video system f…

    ... I run into contention is when writing to screen memory, and there ...
    gasman gasman May 2010 Announcements
  • LDIR timings in contended RAM?The 48K Spectrum technical reference page ([URL="http://www.worldofspectrum.org/faq/reference/48kreference.htm"]here[/URL]) describes the detailed ti…

    ... opcode is running in contended memory or not;
    [*] ... HL) is pointing to contended memory or not;
    [*] whether ... DE) is pointing to contended memory or not;
    [/list ... note is that contended memory is not actually contended ... can reduce the contention.
    BloodBaz BloodBaz June 2010 Development
  • LDIR timings in contended RAM?The 48K Spectrum technical reference page ([URL="http://www.worldofspectrum.org/faq/reference/48kreference.htm"]here[/URL]) describes the detailed ti…

    ... to note is that contended memory is not actually contended until ... HALT you can reduce the contention.[/QUOTE]
    Or to save ...
    mcleod_ideafix mcleod_ideafix June 2010 Development
  • RGB to VGA convertor for ZX128/+2/+2A/+3David Luftner release source code (VHDL) of SCANDOUBLER for ZX128/ZX128+2/+2A/+3: [url]http://velesoft.speccy.cz/other/scandoubler-for-zx128_fixed_by…

    ... up to 100Hz refresh, if memory bandwidth allows) and selectable line ... CPLD though (with the internal memory of the FPGA, I've ... possible ways to reduce the memory bandwidth requirements on the external ... CPU clock while in ULA contention. (Actually for a double ...
    Winston Winston July 2010 Hardware
  • Recent talk of developing new SpectrumsHi all, I can see from a few threads on here that some Wossers like Vasil and Aien 8 are interested in developing more powerful Spectrums or improvi…

    ... gonna lose a lot to contention. Unless the CPU is fast ... pretty much directly proportional to memory bandwidth. Part of the ARM ... and waste as little available memory bandwidth as possible, nearly all ... comparison is very wasteful of memory bandwidth.
    Winston Winston December 2010 Hardware
  • contended memory...so memory contention on the toastrack and the grey +2 is in the wrong place compared to the documentation, yet the +2a/b and +3 it is in the correct …

    So the question for games not running properly is not that the CPU contention timing is different, but that contention is applied differently to memory banks on the toastrack/+2 and the +2a/b/3.

    Which runs the most games?
    csmith csmith January 2011 Hardware
  • contended memory...so memory contention on the toastrack and the grey +2 is in the wrong place compared to the documentation, yet the +2a/b and +3 it is in the correct …

    ... different, but that contention is applied differently to memory banks on the ...
    BiNMaN BiNMaN January 2011 Hardware
  • contended memory...so memory contention on the toastrack and the grey +2 is in the wrong place compared to the documentation, yet the +2a/b and +3 it is in the correct …

    ... different, but that contention is applied differently to memory banks on the ... /+2B, or written assuming the contention in the manual will work ...
    guesser guesser January 2011 Hardware
  • Contention: LDI vs LD (ss), rAccording c.s.s. FAQ: instruction LD (ss),r breakdowns as pc:4,[b]ss:3[/b] and LDI as pc:4,pc+1:4,hl:3,[b]de:3,de:1 x 2[/b] can anyone explain why …

    ... that DE pointing to contended memory introduces 3 delays ?[/QUOTE]
    contention pattern.
    Philip Kendall Philip Kendall February 2011 Development
  • A thousand core CPU?Maybe this is old news to most people on here, but according to: [url]http://www.zdnet.co.uk/news/emerging-tech/2010/12/25/intel-why-a-1000-core-chi…

    ... case of gaming) texture memory. The more memory the graphics card has ... graphics card that had the memory to cope with it. The ... to be some shared resource contention going on. It's a ...
    ewgf ewgf February 2011 Chit chat
  • A thousand core CPU?Maybe this is old news to most people on here, but according to: [url]http://www.zdnet.co.uk/news/emerging-tech/2010/12/25/intel-why-a-1000-core-chi…

    ... relied upon to have more memory and CPU/GFX power for ... apples vs oranges here - my contention is that the XBox runs ... the GFX and the program memory, if you take the games ... game performance up while other memory resident drivers and programs are ...
    ewgf ewgf February 2011 Chit chat
  • A thousand core CPU?Maybe this is old news to most people on here, but according to: [url]http://www.zdnet.co.uk/news/emerging-tech/2010/12/25/intel-why-a-1000-core-chi…

    ... relied upon to have more memory and CPU/GFX power for ... apples vs oranges here - my contention is that the XBox runs ... the GFX and the program memory, if you take the games ...
    The Starglider The Starglider February 2011 Chit chat
  • Recent talk of developing new SpectrumsHi all, I can see from a few threads on here that some Wossers like Vasil and Aien 8 are interested in developing more powerful Spectrums or improvi…

    ... (0xff)
    Contended memory? passed
    High port contention 1? passed
    memory? failed (0x02)
    High port contention 1? passed
    High port contention ... =0x01)
    Contended memory? passed
    High port contention 1? passed
    gasman gasman February 2011 Hardware
  • Push/Pop data copyingWe all know that stack pointer cheese and push/pop is faster to move data than LDIR - which in turn is slower than unrolled LDI's anyway. I rewrote …

    ... to synchronise with the contended memory cycles, so as not to ... /> push hl ; 4T lost to contention
    push de ; 5T lost ... to contention
    push bc ; 5T lost ... to contention
    ld a,0 ; 7T ...
    gasman gasman March 2011 Development
<1…16171819202122…34>

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