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Help with 1-bit sampled soundHi all, I've been sent over this way from the CPC Wiki forums as you guys may be able to help me more specifically with a programming query. Firstly…
... 's around 8-10 T-states of operation in part-prepping the ... new value roughly every 31 T-States.
The sample ... around 7000 bytes per second, with two samples per byte, allowing reproduction ... actually replay each table entry two or four times, thus ... -
How many T-states takes PUSH DE ?Hi. Just a quick one. According to z80.info docs, a PUSH DE should take 11 T-States to be executed. But WHAT if SP is pointing to Contended Memory,…
... PUSH DE should take 11 T-States to be executed.
T states looks OK, but shouldn't it take longer ... interrupts disabled but that shouldn't change the fact that the ... />
I think this 11 T states info is normal situation and ... -
Using the stack to copy memory blocksA [b]PUSH[/b] and a [b]POP[/b] instruction together take less time than two [b]LDI[/b], so long [b]POP/PUSH[/b] sequences are sometimes used to copy …
... together take less time than two [b]LDI[/b], so ... br /> ret
; Total = 148 T-states per iteration.[/code]
The ... ; 10
; Total = 138 T-states per iteration.[/code]
The ... -
Tinkering with DMASo, some afternoon tinkering... [img]http://photo.alioth.net/tmp/dma_small.jpg[/img] The purpose of this all is to see what's possible using the Xi…
... PUSH HL, which takes 11 T-states per two bytes.
With DMA ... , this is reduced to 6 T-states per two bytes.
* ... memory timings would take 6 T-states per byte copied.
T-states per byte!
Also ... -
Scrolling loader counter in 85 T-States?Would it be possible to write a scrolling loader counter in 85 T-States? I have a custom screen load routine that loads attribute first, then the …
... scrolling loader counter in 85 T-States?
I have a ... scrolling load counter in 85 t-states. Should be possible to update ... stack useage. My loader doesn't touch the stack, no calls ... -
Help needed to speed up functionCan anyone help me to re-factor this code snippet. The "MAP" section holds information about which tiles go where on the screen (handled by another f…
The two INC HL after eachother can ... L
saving another 4 T-states per run.
The POP ... 16 * 8 * 4 - 8 * 4 T States
Help needed to speed up functionCan anyone help me to re-factor this code snippet. The "MAP" section holds information about which tiles go where on the screen (handled by another f…
... , Dr BEEP wrote:
The two INC HL after eachother can ... L
saving another 4 T-states per run.
The POP ... 16 * 8 * 4 - 8 * 4 T States
[/quote]
I haven't tested the code, but HL ...The So What's This Buzzsaw All About Then? Thread.Erm. This: [URL="http://www.joefish.co.uk/speccy/Joefish_Buzzsaw_Demo_1.tap"]http://www.joefish.co.uk/speccy/Joefish_Buzzsaw_Demo_1.tap[/URL] Keys…
... to tell with just the two sprites. But if it ... takes (I think) 215 T-states to copy each line, allowing ... Pentagon version takes exactly 224 T-states per line, without contention.
< ... demo. Although it now has two different custom rainbow generators in ...Which Speccy game had best border effectsIn truth, I'm just trying to remember a game from my youth, and the amazing border effect during pause is the only thing I can clearly recall about i…
... more useful total of 16 T-States.
[/QUOTE]
< ... instructions then you don't need to copy values ... C),E, giving you 12 T-states per colour change, i.e. ... A which completes 11 T-states later just in time ... colour, giving you a two-character wide band. You ...FUSE serial communication sample anyone?Hi, in [URL="http://manpages.ubuntu.com/manpages/precise/man1/fuse.1.html"]FUSE man pages[/URL] one finds switches for serial comms. By using --inte…
... line a fixed number of t-states after the start bit, and ... ... there are cca. 29.36 t-states per bit which is sufficient if ... requires almost no wait states - perhaps two nop instructions per bit. So no ... 32 bytes=1600 theoretical bytes per second or around 14.400 ...Interface 1 - RS232 question.I am thinking about doing some Spectrum stuff based around the RS232 port used on the Interface 1. Has anyone had any joy doing this with an emulator…
... I am adding interrupt mode operation this week. Will publish ... time while maintaining normal Spectrum operation.
Still am ... i.e. out of 70k t-states per interrupt. That is approx. ... Note that even with background operation it is still faster then ...How would you approach parallax?So ... there is this trick by Joffa that we all know...of waiting for the ULA to reach certain pattern on the screen using the IN command. And then s…
... ]
Should be only 19 t-states per byte, as opposed to your ... /> RL (HL) ; 15 t-states
DEC HL ; 6 t-states
32 times ... /> Timings are 21 t-states x 32 cols = 672 per scan line. Scrolling ... . And you scroll mid part two times for each scroll of ...off screen bufferwhen using an offscreen buffer is the memory copied to the screen in a way that makes it easier to draw sprites to the buffer? E.g. Lets say you…
... quote]
You don’t need to PUSH and POP ... ]. That way you save 21 T states per loop iteration.
t need to reset the ... the sprite. You won’t benefit from LDI when ... of loop iterations by two and not wasting time ...Fast Binary to Text DisplayI've done this thing that takes some memory contents and converts it to a Binary version of 0's and 1's on screen. However, I've no idea what to use …
... kidding. RL C is 8 T states; RRD 18!
You ... register somewhere and replace the two SETs with a single OR ... h
[/code]
(1 T state faster at the expense ... />
Better yet. Save 5 T states per iteration by replacing PUSH/POP ...Raster effects - quick questionHi Guys Just a quick question regards what the ULA is doing as its drawing each scan line. Assuming the beam has finished drawing the border, am I…
There's actually 224T per line (228T on a 128 ... left. So for 96 T-states per line there is no memory ... a PUSH instruction can write two bytes in 11T if you ... tick in a multi-T-state instruction the read ...
Nirvana etc. engine doesn't use a linear buffer of ...Understanding tape edgesI've never done any tape reading code. But I've read about these "edges" on multiple occasions. Trouble is I don't understand what they heck they are…
Incredibly, after two years, I have just four ... seconds? After that there are two control pulses: first sync pulse ... 855 and 1710 t-states per bit i.e. 11542.5 t-states per byte or ... not, because if you have two control pulses (667 and 753 ...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…
... cycle 3 will take 3 T-states to read the contents of ... ] gap in the ULA wait states before it can write to ... start either 7 or 8 T-states after M3: the Z80 must ... in the wait states, it will take 32 T-states per byte.
Timing of Timex Computer 2068Is the timing of the Timex Computer 2068 fully documented yet? I have one here with the ZX Spectrum Emulator cartridge and have downloaded a few test…
... . There are 224 t-states per line and 312 lines per frame. The screen ... the data buses. I haven't checked if this is the ...A sped up pixel-shift routine for 1-byte–wide spritesHere’s an optimized (for speed) real-time sprite shifting routine for sprites that are one byte wide. It uses no memory variables for storage of inte…
... ]inc hl[/b], which is two T states slower.
Note the ... /> (The routine is shared between two sprites, hence the [b]ld ...Fixing a ZX Clone from .ru - 27 years late.Hi there, I've currently assembled another russian clone a "Compact 256 Turbo" from a PCB I bought. The machine appears to be fully functional and o…
... to be largely compatible (69888 T-States per INT, 295/312 Lines on ...ZX Spin 0.4 available for Download.Standard Cut-n-Paste from the CSS post: If all goes well, I'll upload it to WOS on monday. ----------------------------------------- Okay, it's th…
... are more interested in more T states per frame and hence less partially ... contended memory and processor wait states/clock halting.
Fraser ...Help needed to speed up functionCan anyone help me to re-factor this code snippet. The "MAP" section holds information about which tiles go where on the screen (handled by another f…
... save a significant number of T-States per cycle (given that indexing instructions ...Method to read byte as binary string rather than dec?Hi all Am fiddling around with the screen buffer and have written a routine to scan the screenbuffer into upper ram and then write it back in upside…
... :32, cyborg wrote:
Can't do that on a Spectrum ... data would take about 5000 T-States or so (clock cycles basically ... /> The ZX has approx 70000 T-States per frame, but this depends in ... would take about over 40000 T-States, and that's not taking ...Contention and floating bus timingHello, I was recently playing a bit with memory contention and floating bus stuff in ZXDS and there is one thing which puzzles me a bit. It is the d…
... the contention during the following two T states, but this extending is what ... I haven't got from the schematics (yes ...another c64 vs. Speccy site...[url]http://c64vsspectrum.com/[/url] 25 years and we are still brawling.. ;)
... !)
There's 224 T-states per scanline, so by the rough ... envelope calculation, something like 7 T-states per 8 pixel long memory cell ... d have less that 1 T-state per memory read from screen ... cycle takes 3 T-states, and there wouldn't be 1 T-state to ...AY tracker routineHi. Yesterday i played with some ay tracks and was surprised how big are tracker routines and music data (over 1.5KB for Pro Tracker routine and 4-6 …
... and less than a thousand t-states per interrupt.
On the ...Real 60Hz NTSC 48K ZX SpectrumNot a 3rd party mod. The joystick mod was added by the user, but the board and the computer is exactly what was sold in Chile, South America. We migh…
... convinced myself that it wouldn't work because the time measured ... we know the number of T-states per frame, then we can work ... know precisely how long a T-state is, given any arbitrary ...Real 60Hz NTSC 48K ZX SpectrumNot a 3rd party mod. The joystick mod was added by the user, but the board and the computer is exactly what was sold in Chile, South America. We migh…
... convinced myself that it wouldn't work because the time measured ... we know the number of T-states per frame, then we can work ... know precisely how long a T-state is, given any arbitrary ...The So What's This Buzzsaw All About Then? Thread.Erm. This: [URL="http://www.joefish.co.uk/speccy/Joefish_Buzzsaw_Demo_1.tap"]http://www.joefish.co.uk/speccy/Joefish_Buzzsaw_Demo_1.tap[/URL] Keys…
... of the code with 219 T-States per line, somewhere betweeen the 48k ...
