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HALT: Why always 4ts?Instruction breakdown of halt is like that: PC 4ts. That means it fetches instruction byte from ram which tooks 4 ts and then does nothing and read…
... believe the Z80 internally executes repeated NOP's until an interrupt is ... the NOP instruction needs to complete before the interrupt is handled.[/QUOTE ... value so the same HALT instruction is read and executed again ... -
HALT: Why always 4ts?Instruction breakdown of halt is like that: PC 4ts. That means it fetches instruction byte from ram which tooks 4 ts and then does nothing and read…
... the Z80 internally executes repeated NOP's until an interrupt is ... ignored and a NOP instruction is forced internally to ... then that intruction timings, interrupt sampling points, DRAM refresh ... fetched), or the next one (instruction after the HALT) ?
... -
HALT: Why always 4ts?Instruction breakdown of halt is like that: PC 4ts. That means it fetches instruction byte from ram which tooks 4 ts and then does nothing and read…
... /> After executing the HALT instruction the Z80 keeps doing an opcode fetch ... of the next instruction until there ... is a maskable interrupt (if enabled), a non-maskable interrupt ... -
HALT: Why always 4ts?Instruction breakdown of halt is like that: PC 4ts. That means it fetches instruction byte from ram which tooks 4 ts and then does nothing and read…
... even 30+ years after the Z80 was introduced, some tidbits about ... =TK90XFan;819956]One says that instruction like LDIR, LDDR, CPIR, CPDR ... copy will happily allow an interrupt routine to cut in halfway ... realize how 'dumb' a really Z80 is :lol: and how wasteful ... -
Vega ARM SOC?I read that the core of the new Vega was an ARM SOC. I thought it would have been an FPGA. But it seems it's an ARM running an emulator. Anyone kn…
... time each Z80 instruction spends on every instruction is documented ... Main halt ;wait until interrupt
ld bc,1000 ... 81FFh
dw Interrupt
Interrupt di ;here!
Emulator developmentHi, Could anyone explain or direct to a link that explains in not to technical terms how an emulator is developed. It has always blown my mind eve…
... few more variables representing the z80's registers - A, F, B ... done, you do whatever the z80 would do with that value ... how many T-States that instruction and its values represent. Keep ... Speccy) then you generate an interrupt, subtract 69888 from your T ...New game: SolarGun 1.0[img]https://dl.dropboxusercontent.com/u/75238938/solargun4.png[/img] [img]https://dl.dropboxusercontent.com/u/75238938/solargun5.gif[/img] (that g…
... to Z80 Manual, you have to re-enable interrupts inside the interrupt ... /> [quote]From Z80 Manual, Page 18
Section "Interrupt Response"
sub ... -section "Interrupt Enable/Disable"
The EI instruction ...Why doesnt this work???Simple piece of code wont do as it should, just want to fill the top 22 lines of screen with an attribute value (150) but it wont have any of it. Som…
... longer in total (1 for instruction and two extra data). In ... also doing it in his interrupt routine. So on those occasions ... was screwed up by the interrupt routine multiply.
I ... . Sometime in the 90s, the z80's production numbers reached 5 ...What should your speccy have come with ?:) I was thinking about this earlier. What changes should of been made to the Speccy when you purchased yours ? Realistically this topic really…
... clearly slower than either the z80 or 6809.
... around fewer clock cycles per instruction. This also means the ... onto the chip and sophisticated interrupt modes which fit into ... . So in the marketplace, z80 relative performance rose in comparison ...Help understanding the Z80.So I have a Z80 CPU and a 32k ram chip. I understand how they connect. (Data and address busses, chip select etc.) But how would i input information…
... which the z80 will read and interpret as an instruction. PC ... eg a JP instruction).
An instruction fetch is one ... , io reads, io writes, interrupt acknowledge, nmi acknowledge, halt, ... what the z80 will read as its first instruction or indeed ...shadow regs musingIn the process of optimising some assembler, it occurred to me how great it would have been if the Z80's shadow reg opcodes had been a bit more fully…
... the registers automatically switched on interrupt (along with an alternate stack ... the Z80 wasn't micro-coded. The LD r,r instruction just ... have added complexity around the instruction decode and probably impacted performance ...Need help with keyboard scanning ?After getting frustrated with learning ASM for a while I'm back into it. The little listing below is using the ROM's PRINT AT routine to draw me a sp…
... off) by issuing the DI instruction ([b]D[/b]isable [b ... handle) an interrupt.
On the Spectrum, the Z80 can use ... two interrupt modes, call very ... it as sneakily inserting the instruction JP $38 in the middle ...I introduce myself and my emulator.Hi! My name is Marta, and I've been a Speccy user for 30+ years now. During the past year I decided to write my own emulator, just to see if I cou…
... issue: I was sampling the interrupt line every T-state, while ... last M-cycle of each instruction.
I marvel at ... 'm going to rework the Z80 emulation, fix this, and then ...ZEsarUX Beta 8.1Hi! I have uploaded a new ZEsarUX 8.1 BETA version. You can download compiled versions for Windows, Mac, and the source code from: https://gith…
... interesting. [quote]
Improved accurate Z80 timing: IM mode 0 is ... [url="http://www.z80.info/z80inst.txt"]z80.info/z80inst.txt[/url ... hardware device generating the interrupt places an instruction on the data bus ...ZEsarUX Beta 8.1Hi! I have uploaded a new ZEsarUX 8.1 BETA version. You can download compiled versions for Windows, Mac, and the source code from: https://gith…
... interesting. [quote]
Improved accurate Z80 timing: IM mode 0 is ... [url="http://www.z80.info/z80inst.txt"]z80.info/z80inst.txt[/url ... hardware device generating the interrupt places an instruction on the data bus ...ZEsarUX Beta 8.1Hi! I have uploaded a new ZEsarUX 8.1 BETA version. You can download compiled versions for Windows, Mac, and the source code from: https://gith…
... Mostek Z80 datasheet, which includes a teardown of every instruction, cycle ... very likely wrong. The Z80 data sheets I have which ... great detail describe just single interrupt acknowledge cycle as a ... depending on the individual instruction would be just a ...Whats the smallest amount of time to precise emulate a Spectrum?Whats the smallest amount of time to completely emulate a Spectrum? Maybe the ULAs timings as mentioned here: [url="https://opencores.org/projects…
... non deterministic points because the Z80 instruction lengths aren't uniform.[/quote ... a ZX Spectrum then the Z80 might communicate along the lines ... was the state of the interrupt line a cycle ago", of ...Z80/SNA Compiler under Windows???Does anybody know anything about Z80/SNA compiler under Windows???
Does anybody know anything about Z80/SNA compiler under Windows???Z80 to DSK?Does anyone know if there is a prog that can convert z80,tzx or tap files to dsk format? I have access to a friends pc that has a 3 inch drive which …
... a prog that can convert z80,tzx or tap files to ... looked at a program called z80 snapshot loader at
[url ...Z80/SNA compiler under Windows???Does anybody know anything about Z80/SNA compiler under Windows???
Does anybody know anything about Z80/SNA compiler under Windows???Visible-Z80 - VISZ80 - by Miklos Patrubany Hi All ! Visible-Z80 - VISZ80 - by Miklos Patrubany Does anyone have this program ? Please help me. I want to learn Z80 and Assambler on Z8…
Hi All !
Visible-Z80 - VISZ80 - by Miklos Patrubany
< ... want to learn Z80 and Assambler on Z80 and I have a ...Converting TAP to Z80Is there an EXE out there that will convert *.TAP into any other snapshot (preverably Z80 or SNA) Please Help Oatesy
Is there an EXE out there that will convert *.TAP into any other snapshot (preverably Z80 or SNA)
Please Help
OatesySNA 2 Z80Hi Is there a difference between an sna file and a z80 file.Is it possible to rename the sna extension to z80 or do I need a conversion utility.
Hi
Is there a difference between an sna file and a z80 file.Is it possible to rename the sna extension to z80 or do I need a conversion utility.Z80 Stealth Emulator probsI have problems with my soundcard. I have an ESS1868 sound card and on most DOS programs I can use Adlib compatibility to get sound. Sometimes Soundb…
... to the problem:
Z80 stealth looks for Ess688 (or ... enable SBP support and boot Z80 stealth, but no go. Says ... . run it and then run z80 stealth. no luck. It still ...is Z80 by G.A. Lunter still going?I was thinking of registering Z80 v4 but I'm not sure if it is still being developed? Has anybody suceeded in registering recently? There is a websit…
I was thinking of registering Z80 v4 but I'm not ...Z80 Files Saved With M.G.T.I have some Z80 files which have been created by a X128 emulator on a PC. The files were saved using an M.G.T. Interface. I am using a mac and none …
I have some Z80 files which have been created ... convert these files to straightforward Z80 files so that I can ...
