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New discovery on Z80 interrupts.This is to announce the discovery of a new, hitherto unknown, behavior of the RETI and RETN instructions. As everyone knows, the maskable interrup…
... can be tested on Visual Z80 Remix: https://floooh.github.io ... -
Emulator compatibility with real SpectrumHi emulator programmers... Having spotted for the last 6 months that my iPAQ is still missing a Spectrum emulator I started typing last tuesday - an…
... and they both have a Z80-inside (TM) you can't ... A,R (however do set flags correctly). -
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…
... make sure you understand the flags register (register F of the ... .
Again, see the z80 CPU page I listed above ... -
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…
... a small error above. The Z80 doesn't use signed binary ... be 15. As for the flags, well it depends upon [I ... of individual instructions on the flags. If you want a reasonable ... needs to include the "undocumented" flags (bits 3 and 5) as ... -
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…
... this always true? If the Z80 uses two's complement then ... patterns are consistant and the flags are updated correctly.
z80 deals with binary numbers (not ... emulator :(. [/quote]
The Z80 doesn't care - only humans ... -
There's a bug in my Speccy, Dear Liza, Dear Liza...Hi guys, Just me being annoying again - Can anyone out there in 'Internetland' help me with ideas about what could be causing a bug in my Speccy em…
... )) would be some kind of .Z80 or .SNA file - you load ... look to make sure your flags are sticking up OK.
ADCI'm a little confused about how the Z80 manages the ADC instruction. I'm assuming two ADD instructions are performed (am I wrong?!) I can think of 3 …
... -bit adder (as in a z80 8-bit add instruction), you ... you did ask how the z80 does it :)
[quote ... sets Carry and Half-Carry flags fine but how is the ...divIDE issuesI discovered a few issues with the divIDE hardware and FATware software that may be of interest to some people. 1. ROM paging If your Spectrum is a…
... "extended" ones (maybe just using flags or different set of block ... format like it is in Z80.
Basically we talk ...Has this been done before?Are there any emulators whose speed can be adjusted by the Spectrum program that the emulator itself is running? So that, say the Spectrum program ca…
... to be embedded in the z80. Maybe you should have a ... ? I was thinking of having flags (that the emulator would read ... in an existing Spectrum program) Z80 instructions.
It's ...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 …
... a misterious internal register in Z80 CPU (MEMPTR) which value is ... set or changed by some Z80 instructions and 2 bits of ... 3 and 5 of the Flags register after the instruction BIT ... was not exactly known which Z80 instructions initialize the MEMPTR and ...Sprite adviceHello. So, I'm slowly getting to grips with Z80 assembly - currently equal parts frustration and enjoyment. Now looking for some advice to help shift…
... I converted
; them to Z80.
; My generators were kind ... PC, but acceptable on
; Z80. Their advantage was their small ... size, but on Z80-assembler they are
; ... , quite a gonzo-routine on Z80. This
; could be considered ...The new GP2Xpectrum releases threadYeah, I know the thread title isn't exactly too original, but I've decided that just one post to hold all updates makes more sense than a lot of smal…
... /Software/Z80/Exerciser/Spectrum/]Z80 Exerciser[/URL], and fixed several flags bugs ... even a bug loading the z80 file from that page. ... bug when loading some .z80 files with version 1.45 ... DAA instruction.
- Fixed flags behaviour for several instructions: BIT ...ZXSpin 0.61 Available nowHi all! Well, after a lengthy few testing cycles, I'm taking the plunge and uploading the latest version of ZXSpin, to replace the rather aged old 0…
According to the [URL=http://www.mdfs.net/Software/Z80/Exerciser/Spectrum/]Z80 Exerciser[/URL], some flags are wrong.
The failed tests are:
hl,
add hl,
add ix,
add iy,
bit n,ZXSpin 0.61 Available nowHi all! Well, after a lengthy few testing cycles, I'm taking the plunge and uploading the latest version of ZXSpin, to replace the rather aged old 0…
... .mdfs.net/Software/Z80/Exerciser/Spectrum/]Z80 Exerciser[/URL], some flags are wrong ...ZXSpin 0.61 Available nowHi all! Well, after a lengthy few testing cycles, I'm taking the plunge and uploading the latest version of ZXSpin, to replace the rather aged old 0…
... than one version of the z80 used? It may only ... ://www.mdfs.net/Software/Z80/Exerciser/Spectrum/outall.txt[/ ... just flag effects. The .z80 file is in 48k mode ... them thanks to The Undocumented Z80 Documented, by Sean Young ... out to be related to flags 5 and 3, so ...ZXSpin 0.61 Available nowHi all! Well, after a lengthy few testing cycles, I'm taking the plunge and uploading the latest version of ZXSpin, to replace the rather aged old 0…
... ]http://www.mdfs.net/Software/Z80/Exerciser/Spectrum/outall.txt[/url ... out to be related to flags 5 and 3, so they ... 'm not interested. 5+3 flags are emulated as per the ...ZXSpin 0.61 Available nowHi all! Well, after a lengthy few testing cycles, I'm taking the plunge and uploading the latest version of ZXSpin, to replace the rather aged old 0…
... =Dunny]Well, as MEMPTR *is* flags 5+3, I'd say ... ?[/QUOTE]
MEMPTR is flags 5+3 for the instruction ... Z80 Exerciser to be an interesting way to find bugs in flags ...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:…
... behaviour correct and getting the z80 timing versus raster position correct ... speed between the ez80 and z80 changes with the sequence of ... even with a Z80.
The flags and timing will sacrifice ...C# emulatorHi, I wanted to branch out and get a little better with C# so I think I need something meaty to do to keep me going....so an emulator seemed a reaso…
... adding z80 instructions.. :) Still not sure how to deal with the flags ...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)…
... instruction how does it handle flags?
I?ve search the ... here.
[url]http://www.z80.info/z80href.txt[/url]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)…
... instruction how does it handle flags?
I?ve search the ... to have changed during the z80's lifetime as it has ... />
[url]http://www.z80.info/zip/z80-documented.pdf[/url]
z80 versions, the internal memptr register and how it affects flags ...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)…
... when I wrote them of Z80 behaviour.
As a ... , LDIR, everything works exept for flags, could that be the "same ...Z80 Developer ConsoleHi, This is a project I have meaning to do for ages, recently had a kid, had some time off work (as a software developer) and surprisingly had a bit…
... fan, but I think this Z80 developer console would more closely ... taken from the Rodney Zaks Z80 book. So then you know ... effect it has on the flags and registers.
The hint ...He's back......and he's got a new trick! AY Chip here. I've been away far too long. I would like to announce 'HatStand': for no adequately explored reason, I h…
... , yes? So... how does the Z80 know that the interrupt should ... 've done all of the flags right (especially 5 and 3 ...super-quick games in BASIC?do you think, games written in BASIC could run flawlessly at high speed when run in a speccy emulator at, say, 1000% speed? (i wonder, speccy is rare…
... [I]Normal Speed[/I] type flags, via unused op-codes, then ... at the end of the Z80-CPU intensive routines, the [I ...Fuse for Mac OS X beta releasesA beta version of Fuse for Mac OS X has been released at the dedicated sourceforge project: [url]http://sourceforge.net/projects/fuse-for-macosx/[/u…
... , Mark Woodmass).
[*] Fix undocumented flags after BIT n,(IX+d ... the reset line on the Z80) and "hard" resets (pulling the ... Interface I state information to z80 and szx snapshots (Fredrick Meunier ...Bizarre stuff in Interface 1's shadow ROMAccording to the Complete Shadow ROM disassembly, the function that exits back to the BASIC interpreter after interpreting IF1 commands is this: [co…
... ...but - BIT 7, (FLAGS) is not a valid Z80 instruction. You can ...
