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Z80 opcode breakdownAnyone knows if there's a document on the net covering all the Z80 instruction breakdown by machine cycles? All I could find was that one on the Z80…
... the net covering all the Z80 instruction breakdown by machine cycles?
Z80 support page and the CSS ... -
Question about CP Z80 instructionSorry if this is the wrong folder, but it seems the most appropriate. When performing a CP instruction, is the P flag set when the compared values …
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When performing a CP instruction, is the P flag set ... -
Z80 Emulator Source?Found a link to this on comp.sys.amstrad.8bit. i havent been with the discussion long but supposedly this is the source for a Z80 emulator. Forgive m…
... is the source for a Z80 emulator. Forgive my ignorance ... if it's a Z80 emulator for Spectrum or ... ds 08400h - fetchend
;instruction jump table
jumpb ... , ins_rst_38h
;instruction implementation
ins_nop:
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 ...Techy Z80 questions****** Question 1 ****** Take the instruction SET b, (HL). This is broken down (in machine cycles) as follows (according to Microprocessor Technolo…
... 've seen in many Z80 docs. My question: ... when does the Z80 read the opcode that ... ?? And if the Z80 could access the memory while ... br />
How is this instruction broken down ?
... every (IX+d) instruction is exactly 12T longer than ...Noob to Z80 needing +3 helpI'm quite new to z80 programming, but i'm attempting to write some kind of windowing system that will run alongside BASIC on my +3 with Kempston mous…
I'm quite new to z80 programming, but i'm attempting ... be calling +3DOS and running interrupt code here, so i think ...How does the Z80 work internaly?How does the Z80 work internaly, i.e. how does it actually execute a machine code instruction? When it fetches a byte from the memory and finds, for…
How does the Z80 work internaly, i.e. how ... actually execute a machine code instruction?
When it fetches ... 00111100) which would mean the instruction "[B]INC A[/B]", how ...It's a trap!So I got a CPLD (not the eventual one I want to use for the ethernet project - rather, one I actually have here and now, an XC9536 in a PLCC44). And…
... is set to trap instruction fetches at the following ... *our* device has caused an interrupt (otherwise ignored)
- 0x0066 ... trap before the Z80 actually fetches the instruction, and prevent the ... released until *after* the instruction at 0x007C gets fetched. ...Dangerous Z80 Assembly CommandHave been reading Toni Bakers' "Mastering MC On Ya Speccy" book and came across the list of Z80 commands in the dictionary section. Page 102 "[b]IM…
... came across the list of Z80 commands in the dictionary section ... ] Under no circumstances use this instruction."
Er OK Toni ...Spin problems/issuesI am running Spin 0.666 and have noticed a few issues (some are bugs, some might be just me). I am using Vista sp1 (yeah I know!), and I've seen Dunn…
... "run". The Z80 will now freeze at the HALT instruction because no ... is stuck on the HALT instruction. Press "step over". It's ... I get past the HALT instruction is to remove the breakpoint ... register window. If you interrupt the Z80 at a random point, and ...InterruptsI need help emulating interrupts. My z80 core currently emulates all un-prefixed opcodes and the CB opcodes. I thought I would start on emulating co…
... emulating interrupts.
My z80 core currently emulates all un ... I check for an interrupt after each instruction execution in my main ... loop? When an interrupt occurs, what ...Tips on (dis-)assembling Z80 instructionsedit: Naturally I managed to post this in the wrong forum. I'd much appreciate it if any moderator would move it to the development section. For the…
... beginner when it comes to Z80 assembly (not to mention a ... dealing with the Z80's less than orthogonal instruction set while still ...A question about M1 cyclesI'm writing an interrupt routine that, after the usual register pushes, will jump to a location of my choice with a [b]JP (IY)[/b] instruction. If I…
... only manifest itself if an interrupt pulse occurred [b][i ... ]LD IY, nn[/b] instruction. I'd better double- ... of M1 cycles inside the Z80.
Is ... nn[/b] is an atomic instruction -- once started, is it ... [/b] -- just the one instruction -- with [b]DI[/b] ...Z80 Machine Code Question...Hi Folks, I know not strictly a BASIC question but I have started to learn Z80 machine code - 25 years too late! :smile: I have been reading a book…
... I have started to learn Z80 machine code - 25 years too ... stuck with the JR NZ instruction. My little test program is ...Z80 sound enginesI'm looking for a decent sound engine to use in a Z80 program I'm writing, but I've no idea which is the best/fastest/easiest to use. I could do wit…
... engine to use in a Z80 program I'm writing, but ... least amount of time every interrupt.
I tried Romford from ...Hex editor with z80 disassemblyAnnouncing 'he', a curses-based hex editor. Among its features is the ability to disassemble the byte under the cursor (and succeeding bytes if nece…
... bytes if necessary) as a Z80 instruction.
[url]https://github ...Simple explanation of interrupts (in the context of Z80/Speccy)I wondered if somebody on here could explain in simple terms how interrupts work on the Speccy and where interrupts are source from. Are they a natur…
... a natural feature of the Z80, or are they instigated via ... -frame, can you schedule an interrupt or trigger one manually? Are ... own handler, or does each interrupt go through a list (or ...Is there a DD40 instruction?On this page: [URL="http://mdfs.net/Software/Z80/Exerciser/Spectrum/zexall.src"]Z80 instruction set exerciser for Spectrum[/URL] I noticed the belo…
... ://mdfs.net/Software/Z80/Exerciser/Spectrum/zexall.src"]Z80 instruction set exerciser for ... /> but in the The Undocumented Z80 Documented (Sean Young) I don ... in ZeXall or is the instruction missed from Sean Youngs doc ...Fantasy Z80 instructions?This follows on from something catmeows said in another thread, and that I've been meaning to ask for a while. This may sound daft to people with mo…
... talk to think of these instruction?
If other, potentially ... which current ones in the Z80 set would you replace?Optimisations in Exomizer Z80 decrunch codeThis is the 163 bytes old code (simple and optimized): [CODE] ld iy, exo_mapbasebits ld a, 128 ld b, 52 push de exo…
... ). Change the INC IY instruction by the IYl one and ... s used by Amstrad CPC interrupt routine. Also there is a ... the "ld iyl, c" (first instruction) of the exo_getpair routine before ... /> and inserting a "dec ixl" instruction before "djnz exo_initbits" one.
Compiling Lisp to Z80.I am doing some thought experiments on this. Here is an example of a Lisp program. It adds two numbers together. [code] (define (add x y) (if (= …
... code translated by me to Z80 (there could well be many ... , I've not done much Z80 before at all so bear ... . Then, move the "pop b" instruction to the beginning of the ...Fast Z80Todays Spectrums are fast as hell and few software utilises this. Z80 in ReVerSE runs at 42 MHz, in Speccy2010 at 28 MHz, in Pentagon 2.666 and in N…
... software utilises this.
Z80 in ReVerSE runs at 42 ... MHz (comparable to 70 MHz Z80).
Two options:< ... br /> 1. Fast Z80 on the mainboard. Plusses: easy ... instructions may be added to Z80 instruction set, 2 MB RAM guaranteed ...Adding a pause key to ArkanoidHaving rediscovered the simple pleasure of playing 1980s games on genuine 1980s hardware, I've also remembered that emulation can provide a feature m…
... contains the three-byte instruction LD BC,0xF7FE, preparing ...
ei ; restore interrupt handler
jr .return_to_game ... br /> (Arkanoid installs an interrupt handler. I don't know ... such as me whose z80-fu is still ...z88dk and im2I set up a minimal IM2 mode so I can draw sprites for a laff [code] #include <string.h> #include <stdio.h> #include <im2.h> #include <stdlib.h> #in…
... im2_Init(0xd300); // place z80 in im2 mode with interrupt vector table located ... ); // POKE jump instruction at address 0xd4d4 (interrupt service routine entry)
instruction
printf(" ...Hacker Chris' Christmas Demo doesn't work[url=http://www.worldofspectrum.org/infoseekid.cgi?id=0007314]Christmas Demo[/url] .z80 file from WOS doesn't work for me. I tested in Fuse and SpecE…
... ?id=0007314]Christmas Demo[/url] .z80 file from WOS doesn't ... stuck in a HALT instruction with maskable interrupt disabled.
Is ...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…
... return address of the interrupt handler. Firstly, if ... address of the HALT instruction each time, what need ... seem simpler in the interrupt acknowledgement not to deal ... interrupt acknowledgement, it contains:
[CODE] if( z80.halted ) { PC++; z80 ...z80 assembly helpEver since I was a child I wanted to program my zx81 then my zx spectrum + 2. However, it was such a mystical beast and I only ever used BASIC not kn…
... started reading numerous books around z80 assembly. It's slow going ... /> delay0 halt ; wait for an interrupt.
djnz delay0 ; loop.
z80 assembly!Key repeat weirdness with EI & IYI finally (after 35 years!) decided to write something a) for 48k speccy b) in z80 assembler. It's been over 20 years since I've written anything in …
... ) for 48k speccy b) in z80 assembler. It's been over ... memory layout and b) that z80 has more registers than 6502 ... of that I use HALT instruction to wait for vertical retrace ... piece of code in some interrupt still seems to do "ld ...
