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Machine code optimisationI'm geting back into z80 coding and wonder what the best way of showing how efficient the code is. I've got Rodney Zaks book and see there are timin…
... each instruction - ie M Cycles. T States and time @ 2 MHz.
Unless you're doing t-state critical stuff like border ... onto the screen (and don't bother using a back-buffer ... -
Machine code optimisationI'm geting back into z80 coding and wonder what the best way of showing how efficient the code is. I've got Rodney Zaks book and see there are timin…
What are M Cycles and T states?
Looking through the ... has 2 M and 9 T sugesting 4.5 Ts = 1 ... ,(BC) is 2M and 7 T or 3.5 Ts to ... -
Machine code optimisationI'm geting back into z80 coding and wonder what the best way of showing how efficient the code is. I've got Rodney Zaks book and see there are timin…
... (in bytes) and time (in T-states) for all instructions (although I ... don't recall anymore as many opcodes ... to know exactly how many T-states the code will take, so ... -
Experimenting with turboloadersHello, My first post, having lurked here for a while. I'm a lifelong computer nerd, Spectrum fan since childhood in the eighties, and have recently…
... ve only got about 300 T-states to do it, and ... since the main loader doesn't need them for anything; ... as if timings weren't already tricky enough when writing ... long as you don't hack them too much[/QUOTE ... . The games themselves wouldn't be hacked at all, ... -
Experimenting with turboloadersHello, My first post, having lurked here for a while. I'm a lifelong computer nerd, Spectrum fan since childhood in the eighties, and have recently…
... for; as if timings weren't already tricky enough when writing ... extra delay of 0-7 T-states for each read or write ... delay is unpredictable. You won't see it when the border ... and beeper sound routines can't be done on a 16K ... -
Experimenting with turboloadersHello, My first post, having lurked here for a while. I'm a lifelong computer nerd, Spectrum fan since childhood in the eighties, and have recently…
... loading screen, but I can't deny its a tempting thought ... .[/QUOTE]If you have the T-states to spare for a loadagame ... agree, that loading screen shouldn't be messed with. I do ... -
Experimenting with turboloadersHello, My first post, having lurked here for a while. I'm a lifelong computer nerd, Spectrum fan since childhood in the eighties, and have recently…
... ROM style encoding. 583/1166 T states.
[QUOTE=stephenw32768;724130 ... on Github, but I don't think you've checked that ... at the weekend. It won't be as fancy an experience ... as Versaload because I won't have time to implement a ... -
RCS (Reverse Computer Screen)[B]RCS[/B] ("Reverse Computer Screen", or simply SCR written backwards) is a small utility I'm about to release, that reorders bytes from the ZX-Spec…
... still 27 bytes but 13824 t-states shorter.
[CODE]Smallest ... -
RCS (Reverse Computer Screen)[B]RCS[/B] ("Reverse Computer Screen", or simply SCR written backwards) is a small utility I'm about to release, that reorders bytes from the ZX-Spec…
... still 27 bytes but 13824 t-states shorter.
[CODE]Smallest ... ][/QUOTE]
It doesn't work :( -
Experimenting with turboloadersHello, My first post, having lurked here for a while. I'm a lifelong computer nerd, Spectrum fan since childhood in the eighties, and have recently…
... that would leave you fewer T-states in which to do tricks ... -
LZ4 decoderI encountered the [URL="http://code.google.com/p/lz4/"]LZ4 compressor[/URL] a few weeks ago. Reading the [URL="http://fastcompression.blogspot.co.uk…
... reading this correctly (and counting T-states from memory), that saves 8T ... -
SE Basic IV Buffy v4.1 source (WIP)I've been doing a major refactor on the SE Basic source and I'd appreciate a code review from anyone who has time to look at it. I've almost certainl…
... /> be_ix_plus_3:
nop ; 12 t-state delay
nop ; 8 ... be_h_and_l_lp ; 12 or 7 t-state jump
dec b ... /> jp nz, be_h_and_l_lp ; 10 t-state jump
xor %00010000 ... br /> inc c ; add 16 t-states
jp (ix) ; jump ... -
Experimenting with turboloadersHello, My first post, having lurked here for a while. I'm a lifelong computer nerd, Spectrum fan since childhood in the eighties, and have recently…
... and friends using their spare T-states to display countdown timers, but ... possible.
47loader isn't nearly clever enough to do ... -
Timex 2068 hi-color / hi-res modes.Hello. I know this is not a Timex forum but since it is a very close relative of the Speccy I thought I'd ask my question here. Does anyone know …
... QUOTE=memrah;733821]But wasn't the 2068 ULA very compatible ... a video signal that doesn't work on a lot ... s no reason you couldn't make an SCLD (the ... different, both in the t-states before the screen blank and ... the US).[quote]I don't think software could tell ... -
Experimenting with turboloadersHello, My first post, having lurked here for a while. I'm a lifelong computer nerd, Spectrum fan since childhood in the eighties, and have recently…
... 'd need to leave enough T-states to update a counter, but ... hex.
It wouldn't be as elegant as, say ... -
128k programmingOk, I have had the normal man look (ie. not really), I want a good resource for 128k asm programming. Mostly just to find out how the RAM bank switc…
what advantage is there in using the shadow screen?
you still have to write bytes to both screens to erase them dont you? (which takes up valuable processor T-States) -
idea: new gaming interface for ZX Spectrum (48k)First of all, I am not an expert this is just an idea of what I would like to see happening in the modern era of the ZX Spectrum. A compact, small, …
... Arduino Nano (although don't quote me on that, ... bus) is 2.5 Z80 T-states. The Arduino Nano running ... will therefore have 11 AVR T-states to respond to the ... it'll take 7 AVR T-states to begin executing your ... leaving you only 5 AVR T-states to get the data you ... -
Cross platform developmentI'm just vaguely considering supporting a few more retro 8 bit platforms for something I have in mind to do. Just Z80 and 6502 really, but that cove…
... page + index register is 4 T-states). You might not be able ... ).
What it doesn't have is register pairing and ... -
bit manipulation conundrumWhat's a neat way to change this bit pattern in registers BCDE: [code]Loop0: ;change B:00000000 C:abcdefgh D:ijklmnop E:qrstuvwx[/code] to this bit …
... bytes, run time about 400 t-states. Of course, I would love ... E ;E=uvwx qr0s; CF=t
RL E ;E=vwxq ... -
Assembly code auto optimiserFor my Finders Keepers Plus project I'm considering writing an Assembly code auto optimiser. Way back when I wrote the original FK I considered optim…
... take 10 T-states, whereas a JR (unconditional) takes 12 T-states, and conditional ... 7 (if condition is false) T-states.
This can be ... (HL) [4 T-states], JP (IX), JP (IY) [8 T-states] and finally DJNZ ... -
Assembly code auto optimiserFor my Finders Keepers Plus project I'm considering writing an Assembly code auto optimiser. Way back when I wrote the original FK I considered optim…
Well you should be looking for a profiler at least... Surely emulators should know how many T states each instruction takes and it would be easy for them to track it. -
Aspartame "is safe"In case there's anyone remaining on WoS who believes in the nonsensical "aspartame is toxic" hoax, here is a link to a reputable source which refutes…
... ago - the guy wasn't blue per se, but was a worrying ... -
IF1bis vs SpectranetSince I will shortly have access to both an IF1bis (which I've bought) and a Spectranet (thanks to a loan from cmonkey), I will be in a position to g…
... coding you don't need all that many T-states to do it ... -
IF1bis vs SpectranetSince I will shortly have access to both an IF1bis (which I've bought) and a Spectranet (thanks to a loan from cmonkey), I will be in a position to g…
... the sense that it doesn't need to be known in ... trivial number of T-states.
I don't think Gasman's ... -
A new full-screen bicolor engine called NIRVANA[I]OK, there's something I need to clarify first: Nowadays if you write [B]"multicolor"[/B] everyone assumes it refers to "multicolor 8x1" (an attri…
... takes exactly [B]14100[/B] T-states.
If you want ... take exactly [B]14100[/B] T-states also, before it reaches address ... -
A new full-screen bicolor engine called NIRVANA[I]OK, there's something I need to clarify first: Nowadays if you write [B]"multicolor"[/B] everyone assumes it refers to "multicolor 8x1" (an attri…
What do you mean, count the T-states? Are you mad? Have you nothing better to do? :lol: -
A new full-screen bicolor engine called NIRVANA[I]OK, there's something I need to clarify first: Nowadays if you write [B]"multicolor"[/B] everyone assumes it refers to "multicolor 8x1" (an attri…
[QUOTE=joefish;746108]What do you mean, count the T-states? Are you mad? Have you nothing better to do? :lol:[/QUOTE]
It's just a strange habit I acquired in recent years :) -
ULA snow effectIt's wintertime, you know. [quote="http://ramsoft.bbk.org.omegahg.com/floatingbus.html"]when the I register falls in the range 0x40-0x7F then the UL…
... 1-TState accuracy. I don't know if Woody improved the ... i,a which is 9 T-states? -
A new full-screen bicolor engine called NIRVANA[I]OK, there's something I need to clarify first: Nowadays if you write [B]"multicolor"[/B] everyone assumes it refers to "multicolor 8x1" (an attri…
... 448 T-states. Also it has a "tolerance" of about 35 T-states ... executing a NOP instruction (4 T-states) for instance, you will ... a maximum delay of 3 T-states (if the computer has ... instructions take more than 20 T-states, thus causing longer interrupt delays ...
