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Zero v0.8Pigs can apparently fly because it's the v0.8 update of Zero that no one asked for but is out for public consumption anyway. Grab it [url="https:/…
... Fixed loading of some 128k Z80 files with trailing zeros (Damien ... Res(6, IY/IX+n) instruction. (woody)
- Fixed ... flag being incorrectly reset during interrupt (woody).
- Fixed ... br /> - Fixed loading of z80 snapshots with invalid tstate values ... -
Easiest way to figure instruction lengthGiven a start address, what is the easiest way to find out instruction length at that address in Z80? I found [url="http://www.z80.info/decoding.htm"…
... instruction length at that address in Z80? I found [url="http://www.z80 ... -
My own Home Computer It's true. My company are planning to build a new Home Computer. It will use a Z80 CPU running at 6mhz, 128k Ram and will run all Spectrum and ZX81 …
... compiler performance from BASIC to z80, I'd be surprised ... 90% z80 asm. These took full advantage of their hardware - interrupt lengths ... Knowledge of how long an instruction would take in machine cycles ... except for a fully clocked z80 (which would render most ... -
Here's a christmas present for you!SE Basic is no longer being developed.
... timings (TSTates per instruction) and just taken the interrupt from the PC ... BASIC from a .sna or .z80 is possible. It wouldn't ... -
Sync-buzzer, interrupts and general confusionBeen wittering on about this in the Misc group, but thought it was best discussed here. Basically been trying to recreate the Sid-Sound effect from A…
... . Execute the 'DI' instruction and the Z80 will ignore interrupt signals on the ... 'ret' instruction so that external devices can see when interrupt service routines ... an interrupt occurs in the last machine cycle of an instruction. Instructions ... -
Sync-buzzer, interrupts and general confusionBeen wittering on about this in the Misc group, but thought it was best discussed here. Basically been trying to recreate the Sid-Sound effect from A…
... "The Programming Guide to the Z80 Chip" by Philip R. Robinson ... that this instruction does not return the processor to the interrupt recognition ... of the *next* instruction. That means no interrupt can happen until after ... -
Sync-buzzer, interrupts and general confusionBeen wittering on about this in the Misc group, but thought it was best discussed here. Basically been trying to recreate the Sid-Sound effect from A…
... device know that its interrupt service routine is finished ... interrupt? It watches the Z80 data bus to see if a 'reti' instruction ... allow lower priority peripherals to interrupt again.
... vain for a 'reti' instruction that never gets executed. ( ... -
Any Errors?Any errors you feel Sinclair Research or even Amstrad made with the speccy??
... ]
NMI == "non-maskable interrupt". 'Normal' interrupts (those generated by ... ') by the DI instruction. The non-maskable interrupt, as you may be ... IFF1).
When the Z80 receives an NMI, it immediately ... -
Any Errors?Any errors you feel Sinclair Research or even Amstrad made with the speccy??
... br /> NMI == "non-maskable interrupt". 'Normal' interrupts (those generated by ... ') by the DI instruction. The non-maskable interrupt, as you may ... ).
When the Z80 receives an NMI, it immediately ... allow you to force an interrupt whenever you want, and ... -
VSYNC FunctionI have written a VSYNC function, so that I can clear the screen before redraw without flicker on the screen, I do this by peeking at the address 2367…
... the z80 in im1 mode, which means an interrupt ... always run if the z80 is in im1 mode, ... the z80 in im2 mode and write an interrupt ... routine that simply does an "ei; reti". This way the instruction ... around 19 cycles following the interrupt.
... -
InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…
... reasons: firstly, if the instruction before the interrupt is longer than 34 ... M-cycle of every every instruction, the Z80 will sample the /INT ... interrupt (NMI)
The Z80 has a second interrupt, the non-maskable interrupt ... -
InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…
... M-cycle of every every instruction, the Z80 will sample the /INT ... straight out of the Mostek Z80 manual.
[quote]< ... in agreement with the Mostek Z80 manual.
[quote]< ... EI/RET and the instruction before the interrupt finished just as the ... -
InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…
Considering the plain Z80, RET and RETI works exactly ... reason for using the RETI instruction is if you use the ... through PIO, that uses different interrupt service routines. The PIO by ... for ending the ULA generated interrupt by RETI.
[url ... -
InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…
... /> According to Programming the Z80 RST instructions take 11 T ... performed in an interrupt acknowledge -- the instruction is obtained from ... These interrupt responses are documented in [url="http://www.z80.info ... . I also have the Z80 Mostek Manual which has an ... -
InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…
... wrote:
Considering the plain Z80, RET and RETI works exactly ... reason for using the RETI instruction is if you use the ... through PIO, that uses different interrupt service routines. The PIO by ... for ending the ULA generated interrupt by RETI.
[/quote]< ... -
InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…
... document by Zilog available. The interrupt request/acknowledge cycle description says ... mode 2 because placing an instruction opcode on the bus is ... />
It is the Z80 CPU DATASHEET at [url="http ... ://z80.info/zip/z80data.zip"]http://z80.info/zip/ ... -
I would like to write emulatorHi guys, I'm new to this forum but I realise that you must get loads of posts from people asking "how do I write an emulator" so I'll try and be spe…
... to the structure of the Z80. It's all very interesting ... memory address of the next instruction, right?).
[quote] ... some method of timing the interrupt frequency - and handily enough, ... excellent e-book ("Programming the Z80" by Rodnay Zaks) which I ... -
Cool BASIC tricks and tips!Following on from Dunny's excellent suggestion of a compendium of BASIC tips + tricks, I believe it would be better to have a topic dedicated to it. …
... reset (effectively a RST 0h instruction).
[/quote]
... asserting the Z80's /RESET line) "resets the interrupt enable flip-flop ... and R and sets the interrupt status to mode 0." Of ... (equivalent of an RST 0 instruction), if for instance I want ... -
MEMPTR finally crackedThis post is mainly for emulator developers. As you may be well know there is a misterious internal register in Z80 CPU (MEMPTR) which value is set …
... suggested? There is not ONE instruction tested but all the instructions ... .info), then in IM0 mode interrupt length is 12 tacts (on ... . And, at least 4 different Z80 clones found which gives different ... A and F before DAA instruction. (This also gives a good ... -
ANN: SP1 for Z88DK (aka splib3, Sprite Pack v3.0)Well it's finally arrived, after a month of "a few days from now" release deadlines. SP1 is the lastest version of splib, a flicker-free software sp…
... . Once the current instruction is complete the z80 effectively calls a subroutine ... that the z80 will ignore maskable interrupts. The "ei" instruction re-enables ... generated the interrupt is expected to supply an instruction for the z80 to ... -
Z80 vs. 8080.[QUOTE=obo]... because 8080 is pretty much just a cut down Z80.[/QUOTE] Really? So what's been cut, and why? Hang on, didn't the 808 evolve from the…
... that 8080 is cut Z80 is misleading.[/QUOTE]
Z80. I only claimed that ... subset of what the Z80 provides (which is kinda ... only a single interrupt mode (equivalent to Z80's mode ... startup mode). The 8080 instruction set also uses a ... -
for a stupid: what?s NMI?erhm, yes, I?m not familiar with it... :rolleyes: I know the function of a hardware ?snapshot? button from Didaktik M/Kompakt, but I?m not familiar…
... interrupt mechanism is ignored (or "masked") by the DI instruction ... .
If the /NMI pin on the Z80 ... is high at the end of an instruction ... triggering here), the Z80 will abandon whatever it ... system variable and the Z80 would jump to ... -
for a stupid: what?s NMI?erhm, yes, I?m not familiar with it... :rolleyes: I know the function of a hardware ?snapshot? button from Didaktik M/Kompakt, but I?m not familiar…
... will cause the Z80 to do its dirty [B]interrupt[/B] chores ... interrupt routine should end up with a [B]RETN[/B] instruction as ... tell the Z80 whether to accept an ordinary maskable interrupt or not ... -
for a stupid: what?s NMI?erhm, yes, I?m not familiar with it... :rolleyes: I know the function of a hardware ?snapshot? button from Didaktik M/Kompakt, but I?m not familiar…
... . Compare this to the usual interrupt routine.
Some ... the execution of a complete instruction (ie the state of the ... state of an instruction) whereas BUSRQ can cause the z80 to relinquish ... in the middle of an instruction's execution. Why this gets ... -
The Only Reason Sinclair Succeeded (Provoking Controversy)Although I love my Sinclairs dearly, I think that the only reason they succeeded was because at the time most people did not know any better (factori…
... and things like return from interrupt are 6. I think the ... you can with 1 instruction on the Z80.
Yes, it' ... the instruction set directly in hardware.
The ZWorld Rabbit Z80 ... fixed major shortcommings in the Z80 instruction set.
If ... -
The Only Reason Sinclair Succeeded (Provoking Controversy)Although I love my Sinclairs dearly, I think that the only reason they succeeded was because at the time most people did not know any better (factori…
... and things like return from interrupt are 6. I think the ... you can with 1 instruction on the Z80.
Yes, it' ... the instruction set directly in hardware.
The ZWorld Rabbit Z80 ... fixed major shortcommings in the Z80 instruction set.
If ... -
The Only Reason Sinclair Succeeded (Provoking Controversy)Although I love my Sinclairs dearly, I think that the only reason they succeeded was because at the time most people did not know any better (factori…
... and things like return from interrupt are 6. I think the ... 4 for any instruction and probably half the instruction set takes over ... you can with 1 instruction on the Z80.
Yes, it's ... />
The slowest commonly used instruction is LDIR at 21 t ... -
The 150 pound home computerWe missing out on this still ... I think. I know the PC market has wrecked all chance for any alternatives to ever have a hope but ... what if. :lol:…
... and included in the ez80 instruction set. So that takes care ... be a "compatible z80" but an improved z80, so there will ... behaviour correct and getting the z80 timing versus raster position correct ... execution speed to the vbi interrupt); however this can only be ... -
My emulator doesn't take "commands"Hi This is probably a question that is very hard to answer, but perhaps some of you have/had the same problem. In my own emulator (that I have built)…
... a problem, The BIT instruction how does it handle flags ... to have changed during the z80's lifetime as it ...
[url]http://www.z80.info/zip/z80-documented.pdf[/url]
interrupt response across z80 versions, the internal memptr ...
