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"Decoding z80 Opcodes" (http://www.z80.info/decoding.htm#intro) - Incorrect HALT Opcode?Apologies if this is a dupe but I searched within the forums and couldn't find anything. I've been working on a z80 emulator (for academic and rec…
... seems to incorrectly specify a HALT opcode as 0x7[i]7[/i ... .g. it says given an opcode, digits 7-6 should be ... -
Waiting for retraceHi. Is there any code available that performs a simple wait for the screen retrace thats callable from C? Thanks.
Use an asm block with the HALT opcode? -
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…
... external hardware that changes the opcode read @ some point ( ... repeatedly, is that the "HALT" opcode's location (PC unchanged from ... when the HALT opcode was first fetched), or ... next one (instruction after the HALT) ?
Any questions ... -
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 HALT instruction the Z80 keeps doing an opcode fetch ... external hardware that changes the opcode read @ some point (I ... repeatedly, is that the "HALT" opcode's location (PC unchanged from ... when the HALT opcode was first fetched), or the ... -
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…
... fetched repeatedly, is that the "HALT" opcode's location (PC unchanged from ... when the HALT opcode was first fetched), or the ... next one (instruction after the HALT) ?[/QUOTE]
I guess ... -
New version emulator ZEsarUX-4.0Hi I have uploaded a new version of my emulator ZEsarUX 4.0. You can download it from the project web page: http://sourceforge.net/projects/…
... . It got stuck in a halt opcode with interrupts disabled. I suppose ... it enters this halt opcode when it detects a loading ... -
Retro Virtual Machine is out!Fantastic emulator Retro Virtual Machine (@retrovm) is out today. It can emulates Amstrad/Sinclair models range. Give a try! http://www.retrovirt…
Forget my previous message, I think i found a bug in the Halt opcode thanks!!!! -
Address bus contents (i.e. PC) during execution of HALTI'm wondering if anyone can tell me what's placed on the address bus during execution of HALT, beyond the initial M1 cycle. The Z80 user manual state…
... executed, but that the opcode fetched from memory and NOP ... the opcode fetches were of the address of the HALT instruction ... contains the following code for HALT:
[CODE] case ... here is that the opcode fetch after a HALT could actually trigger ... -
Short Z80 QuizQ1) Which program gives different result ? A) XOR A ADD A,A B) XOR A ADC A,A C) SCF ADD A,A D) SCF ADC A,A Q2) What is the equivalent of NEG …
... Spectrum ?
DI
HALT
EI
RET
Opcode (10 Bonuspoints if you find ... -
A tidy loader for minigamesThe minigame competition doesn't permit the use of separate loaders like [code]10 LOAD "": RAND USR 32768[/code] The loader must be included in the b…
The minigame competition doesn't permit the use of separate loaders like
[code]10 LOAD "": RAND USR 32768[/code]
The loader must be included in the byte count.
In an attempt to save as many bytes as possible, people have written ... -
BEEPER music compo 10-11 July on Di:Halt partyoh yeah! public pressure organizers [B]Di:Halt [/B]which will take place [B]July 10-11[/B], agreed to hold the [B]beeper music compo[/B]. The rules…
... ! public pressure organizers [B]Di:Halt [/B]which will take place ... -
Opcode QuestionsHi all, I am an experienced LabVIEW progammer and also have fond memories of the spectrum. Thus I started to think about writing my own emulator an…
... know how to understand the OPcode imstructions correctly I should be ... -
Help pleeease "Proving Emulator OpCode flags are correct"So I had a cunning plan... I wanted to write a test harness for Emulators that could "prove" that all opcode flags were correct. I wanted something m…
... that could "prove" that all opcode flags were correct. I wanted ... program to "brute force" an opcode
Sent all results back ... of affected registers for every opcode)? Doing this BASIC/Assembly combo ... -
Is there an SNA halt bug?Hello all, I noticed that some SNAs don't work on my emulator but they do work in almost everyone else's, SPUD fails with them too which is a tad sp…
... to get stuck on the halt instruction. I can't find ... with regard to SNA and halt, does anyone have the details ... -
Top Telly Tip... Halt and Catch FireThe series is set in the early 1980s and depicts a fictionalized insider's view of the personal computer revolution. The show's title refers to the f…
... the fictitious machine code instruction Halt and Catch Fire, which would ... -
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…
Instruction breakdown of halt is like that:
... or interrupt.
if halt is already read by cpu ... and again to execute the HALT, why it still takes 4 ... /> I mean if cpu executed HALT at cycle 5, and if ... -
ZEsarUX 8.1 stableHi! I've uploaded a new ZEsarUX 8.1 stable version. Go to the github released webpage to download it: https://github.com/chernandezba/zesaru…
...
-added copper opcodes NOOP, HALT
-increased tbblue.mmc MMC ... when using breakpoints like peek/opcode in config file
Fixed ... a pronoun
Fixed undocumented opcode ED76: I had IM0 but ... -
Which Emulator has a menu option to enable Interrupts (EI) if emulated Speccy hangs after DI / HALT?Which Emulator has a menu option / debugger option to enable Interrupts (EI) if emulated Speccy hangs after DI / HALT? I tried SpecEmu and Fuse, b…
Which Emulator has a menu option / debugger option to enable Interrupts (EI) if emulated Speccy hangs after DI / HALT?
I tried SpecEmu and Fuse, but I can not find a option for doing this in their debugger. -
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:/…
... RZX bugs.
- Fixed monitor opcode not showing hex numbers (R ... snapshot (woody).
- Fixed incorrect HALT implementation (ZjoyKiler).
- Fixed incorrect ... -
Short Z80 QuizQ1) Which program gives different result ? A) XOR A ADD A,A B) XOR A ADC A,A C) SCF ADD A,A D) SCF ADC A,A Q2) What is the equivalent of NEG …
... ) B
6) The HALT state will continue until an ... the DI opcode so it will never exit the HALT. Barring an ... -
How does interrupts work?I am a little confused regarding the interrupts on the Spectrum. If I have some hundred bytes of machine code started with, say, [B]RANDOMIZE USR 300…
... itself?
Could the opcode have been "Clear A and ... /> One would not give the opcode "xor a" a different name ... notable exception being opcode 118 which is [B]HALT[/B] rather than ... ), (hl)[/I].
Calling opcode 175 anything other than [I ... -
68000 programming.Anyone here know anything about this? My question is: how does the programmer know how long hisinstructions are? Do determine the operands to branch …
... 0000
0004 7402 hlt ;halt processor.
0005
0006 ... .w (a0)+,d0 put current opcode into d0.
move d0 ... #9,D0
TRAP #15 Halt Simulator
END START ... -
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…
... are right about where the opcode is and where the registers ... /> [list]
[*] whether the LDIR opcode is running in contended memory ... screen rendering immediately after a HALT you can reduce the contention ... -
RAND USR that doesn't work in emulators and clonesEons ago, I "discovered" a strange RANDOMIZE USR. This is it: [b]RANDOMIZE USR 46578[/b] Using it on a genuine ZX Spectrum rubber key or Plus model,…
... PC register, so the first opcode fetch will be to location ... cycles must belong to the HALT (looped) opcode fetch. In my opinion ... satisfied:
1) the /HALT state is exited after the ... current fetch and executes the opcode.
I know that ... -
writing an emulator-newbie needs helpHi, this is my first post here. I decided to write a minimalistic emulator of ZX Spectrum-no emulation of advanced peripherals, no emulation of sound…
[QUOTE]
It's very easy to write to ROM - I can do it right now, with (as you stated) a simple LD (HL),n opcode with HL set to -
Code execution logging/profilingAs revealed in [url="http://www.worldofspectrum.org/forums/showthread.php?t=41666"]this thread[/url], I'm adding support for reading code execution l…
... ..6] [t-states] [opcode/operand]
The opcode/operand would be ... useful too.
Suggest that HALT is NOT expanded to 1000s ... -
Video generation using a CPUWe know it is possible to generate a video signal using a CPU, and this technique was often used on low-end computers in the early 1980's (for exampl…
... code 118 which is the opcode for HALT, and rather than a ...
