-
Ensure my interrupt handler begins at the same T-stateHi! Is there a way to ensure that an IM 2 interrupt handler starts always at the same T-state (related to the moment the ULA triggers the INT line, w…
... main loop is full of HALT instructions, with some instructions to ... of instructions that aren't HALT last a number of cycles ... -
SpecBAS 0.830 Released!Hi guys - A new official release of SpecBAS has been released. The full changelog is below, but for now here's the download: [url]https://sites.goo…
... messages (including 0:OK) would halt all sound when displayed - now ... -
Playing AY music on the SpeccyCan anyone help with playing AY ripped music on the Speccy? So, let's say I want to play some ripped AY music, such as: [url]ftp://ftp.worldofspect…
... data in tra_0_2.BIN per HALT command (every 50th sec) to ...
EI
LOOP:
HALT
CALL 51802
JR ... -
Understanding contentionI'm trying to understand contention and its implications when some "weird" bus cycles (such as I/O cycles with I/O addresses in the contended memory …
... /O addresses in the contended memory area) are issued ... TW, but memory is always contended in T1?
contended period has just begun, ... O bus cycle to a contended port (port $00FE ... at the start of contended area too would enlarge ... -
New 48K Spectum emulator on the Windows StoreHi, I've just uploaded a new "Free" Spectrum 48K emulator to the Windows Store, see: http://apps.microsoft.com/windows/en-gb/app/specwin48/4d54…
... /> I've read all about contended memory but as yet haven ... -
TV Pal, odd and even framesI have been researching, but haven't found any real interesting information on this subject, so far. What I mean is, since TV PAL signal is interl…
... ) frame, since they just use HALT to sync on the Spectrum ... -
I feel they could have done this.After reading the ZX Spectrum ULA, I learned about how the ULA detects if the Z80 if going to access memory in the next cycle and stops it if the ULA…
... part of the memory is contended.
Alternatively, the ULA could ... -
[NEW] Retro Virtual Machine v1.0.0 for OSX released!!!!Here it is! Retro Virtual Machine v1.0.0 RELEASED!!!! Many thanks first to Patrik Rak for the PZX format and for their Z80 tests without which RVM…
... bus’
Emulation of the contended memory timings.
Pixel to ... -
z80 assembly helpEver since I was a child I wanted to program my zx81 then my zx spectrum + 2. However, it was such a mystical beast and I only ever used BASIC not kn…
... ; length of delay.
delay0 halt ; wait for an interrupt.
delay0 halt ??
djnz delay0 ??
ret ... -
No contended memory?Sorry if this is a stupid question. But I'm trying to learn more about the ZX Spectrum. If I had a stock 48k Speccy and I could wave a magic wa…
Sorry if this is a stupid question. But I'm trying to learn more about the ZX Spectrum.
If I had a stock 48k Speccy and I could wave a magic wand to remove the memory contention, what software would break?
Would games still ... -
Text scroller and custom fontYesterday I was testing this text scroll routine taken from Jonathan Cauldwell's Intro Maker (labels have been inserted to allow partial code relocab…
... /> JR NZ, L_35381
L_35387: HALT
CALL 00654
INC ... -
Shadow of the Unicorn loader for +2A / +3hi, i have tried to load SotU with the [url="http://www.worldofspectrum.org/infoseekid.cgi?id=0023000"]RAM loader from Fraser Ross[/url], which is l…
... ram page #4 should be contended on the +2A/+3, to ... whether the WoS page about contended ram pages on +2A/+3 ... paged in at 0x0000, not contended on the real machine?
New version emulator ZEsarUX-4.0Hi I have uploaded a new version of my emulator ZEsarUX 4.0. You can download it from the project web page: http://sourceforge.net/projects/…
... Timex mode 512x192
Fixed contended memory timings on Spectrum 128k ...20+ years of X128!Hard to believe, but it's true! I was inspired by Gerton Lunter's Z80 (which I had used for years) and I wanted to make my own Spectrum emulator. …
... proper releases ground to a halt with V0.94 on 02 ...New Game - Cuboid CaptorWell, here it is, the (somewhat underwhelming) Cuboid Captor! This game was written for the ZX DEV 2015 competition and (to my knowledge) was the …
... and for good reason: the contended memory makes it sound like ...ZX Diagnostics v0.33 releasedHi everyone, I'm pleased to announce the release of v0.33 of zx-diagnostics. This release contains the following changes: - ULATest: Detect …
... +2A/+3 were also triggering contended fail notifications
- Bugfix: Memory ...Let's copy buffers!Figured I'd do some double buffered graphics, so I can render for several frames before displaying stuff. Yes, I mean on a 48k speccy, so no 128k spe…
... particular emulator doesn't handle contended memory correctly, but relative differences ...+2 Gray ProblemI'm trying to repair a +2 gray that behaves differently at every boot up. Some rare times I can get the selection window but pretty soon the characte…
... ? It must be on the contended RAM part since its causing ...ZX-Uno first impressionsZX-Uno first impressions Hello: I received my ZX-Uno last Saturday and I wanted to give everyone my first impressions of this latest ZX Spectru…
...
Keyboard
Timing
Contended RAM
DIVMMC
NMI ...help with broken +2 greyHello, the other day I was trying to record sounds from my grey +2 "sound" socket to an old cassette recorder. Suddenly the screen went to a solid…
... clock is also missing the "contended memory" pauses which I've ...Contended Memory, literallyDoes anyone else have the sort of memory where they have trouble just picking out info cold? I know we had a discussion about memory sometime last mo…
Does anyone else have the sort of memory where they have trouble just picking out info cold? I know we had a discussion about memory sometime last month, but...
For example, I like to think I'm a fairly competent developer, well the company ...Contended memory article on WikipediaYeah, apparently there's one. https://en.m.wikipedia.org/wiki/ZX_Spectrum_Contended_Memory [quote] However, the ULA must wait for a Z80 read or wr…
Yeah, apparently there's one. https://en.m.wikipedia.org/wiki/ZX_Spectrum_Contended_Memory
[quote] However, the ULA must wait for a Z80 read or write to complete before it can stop the Z80's clock and access the memory. As the ULA has no ...ZXDS 1.3.4Hello, to celebrate the 35th Spectrum (and 10th ZXDS) anniversary, I have prepared [url="http://zxds.raxoft.cz/"]new ZXDS release[/url]. It fixes …
... very subtle contention bug in HALT emulation, which no one will ...128k memory musingI've been pondering on the 128k memory thing a bit, and it's just bloody stupid. The 64k memory space is divided in four chunks. One is always los…
... 6 as they aren't contended) along with all the needed ...Double Buffering Artefacts on Real HardwareI have a project that I've played around with for a while and always tested using emulators, either ZX Spin or Spectaculator. It is a 128k game th…
... switch the screen after a HALT instruction.
Of course ...128K memory bank selection to avoid contention issuesI'm currently developing a game and I'm trying to get my head around the memory contention issues of the various 128K/+2/+2A/+3 spectrum models in or…
... ,3,5 and 7 are contended and that for models +2A ... ,5,6 and 7 are contended. I can see why banks ... 5 & 7 are contended as they relate to the ...Key repeat weirdness with EI & IYI finally (after 35 years!) decided to write something a) for 48k speccy b) in z80 assembler. It's been over 20 years since I've written anything in …
... because of that I use HALT instruction to wait for vertical ... retrace. And HALT does not seem to work ... wait for vertical retrace without HALT & EI?
Memory Contention: A Hypothetical Fix?I have just had this crazy thought: If one were to wire an additional memory chip, say a 6264 8Kx8 SRAM, in parallel with the main memory so that it …
... ULA is reading from, would halt the Z80 only if the ...A Neat Redefine Keys RoutinePreviously, I’ve only shared this routine with a couple of people via PM, but I’ve now decided to make it public. I optimized it for size, so it uses…
... ;a short pause
3$ halt ;before
djnz 3$ ;leaving ...
