-
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…
... have added complexity around the instruction decode and probably impacted performance ...
We can look to HALT to get some idea of ... random logic is dedicated to HALT decoding. Still, I think ... of possibility. And like HALT they could have been decoded ... -
A Neat Redefine Keys RoutinePreviously, I’ve only shared this routine with a couple of people via PM, but I’ve now decided to make it public. I optimized it for size, so it uses…
... ;a short pause
3$ halt ;before
djnz 3$ ;leaving ... ,controls_i ;location of the first instruction for SMC injection
ld ... -
Detecting +3 / +2AWhat's a simple but reliable way to detect if code is running on a +2A/+3? My first though was to try switching to ROM2 and then checking for the …
... code:
[code]
halt ;wait for top border
[/code]
The instruction LD A,($5800) might look ... -
Witchcraft: Nirvana, Bifröst and such[url="http://www.rgcd.co.uk/2011/10/buzzsaw-zx-spectrum.html"]"When considering this next to nearly every other ZX Spectrum game though, Buzzsaw is l…
... routine consist of one RET instruction - or at most an EI ... you just use EI and HALT whenever you need your code ... -
[Asm] Is this nested loop faster than LDIR or a bunch of unrolled LDI's?Hi all. I'm learning Z80 asm on Speccy 48K, and to start with I decided to write my own "CLS" routine (without relying on ROM calls or LDIR) as a lea…
... :
[code]
start halt
xor a
instruction and overall?[/quote]
I ... -
50Hurts - Full-screen 50Hz 1-pixel scrolling on a 128K Speccy50Hurts - Full-screen 50Hz 1-pixel horizontal scrolling on a 128K Speccy. Graphics are an obvious nod to Joffa, whose games and banter were a big ins…
... /> org $8000 ;
Start:
halt
di
; pasmo -d ... /> l3: dec hl ; [6]padding instruction
ld a,e ; [4 ... -
The latest build of Specemu?The latest version of Specemu (a fantastic emulator, BTW) I have is SpecEmu-3.1.b150912.zip, which is a year old now, but knowing Woody he's probably…
... support for LDxR / CPxR block instruction interruption (INxR / OTxR coming after ... real hardware too)
Fixed HALT behaviour
Fixed screen flip ... -
The latest build of Specemu?The latest version of Specemu (a fantastic emulator, BTW) I have is SpecEmu-3.1.b150912.zip, which is a year old now, but knowing Woody he's probably…
... support for INxR / OTxR block instruction interruption (thanks, David Banks, ZJoyKiler ... files with an incorrectly set HALT flag state[/quote] -
How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... /> push hl ;these four push instruction stores 8 bytes on stack ... /> push hl ;these four push instruction stores 8 bytes on stack ... /> push hl ;these four push instruction stores 8 bytes on stack ... -
How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... /> push hl ;these four push instruction stores 8 bytes on stack ... /> push hl ;these four push instruction stores 8 bytes on stack ... /> push hl ;these four push instruction stores 8 bytes on stack ... -
How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... /> push hl ;these four push instruction stores 8 bytes on stack ... /> push hl ;these four push instruction stores 8 bytes on stack ... /> push hl ;these four push instruction stores 8 bytes on stack ... -
How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... Spin disassembler dissassemble first real instruction correctly
nop
delay0 halt
djnz delay0
instruction stores 8 bytes on stack ... hl ;these four push instruction stores 8 bytes on ... -
How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... /> push hl ;these four push instruction stores 8 bytes on stack ... /> push hl ;these four push instruction stores 8 bytes on stack ... /> push hl ;these four push instruction stores 8 bytes on stack ... -
Console frameworkStill working on Specotron, but at the point where working out the diagonal lines collision is not good at beer o'clock. In the meantime I've knoc…
... /> call drawcursor
.loop
halt
call scankeys
call ...
eval_ptr dw 0 ; first instruction to process during eval
Console frameworkStill working on Specotron, but at the point where working out the diagonal lines collision is not good at beer o'clock. In the meantime I've knoc…
... /> call drawcursor
.loop
halt
call scankeys
call ...
eval_ptr dw 0 ; first instruction to process during eval
Console frameworkStill working on Specotron, but at the point where working out the diagonal lines collision is not good at beer o'clock. In the meantime I've knoc…
... /> call drawcursor
.loop
halt
call scankeys
call ... !
eval_ptr dw 0 ; first instruction to process during eval
Console frameworkStill working on Specotron, but at the point where working out the diagonal lines collision is not good at beer o'clock. In the meantime I've knoc…
... /> call drawcursor
.loop
halt
call scankeys
call ... !
eval_ptr dw 0 ; first instruction to process during eval
SCF/CCF flags - new discoveryI can't believe that no one is interested in discussing the additional, previously undocumented internal state of the Z80 CPU I have discovered recen…
... Patrik Rak;668337]If an instruction modifies the flags, the ... F, whereas if an instruction doesn't modify the flags ... bits as part of the instruction operation. The EX AF, ... two-instruction sequences, excluding conditional and DD/FD-prefixed ones and halt ...LINE-routine and other nice pieces of codeThe line-topic came in the end with a nice piece of fast coding. I think that there might be more of these routines out there (where-ever-u-r). Isn…
BMP2SCR utilityI can't get this to work. In the PDF instruction file, it says "After loading BMP2SCR" you will see the logo and a menu. Well I can see the logo, but…
I can't get this to work.
In the PDF instruction file, it says
"After loading BMP2SCR" you will see the logo and a menu.
Well I can see the logo, but there is no menu there: it's just Microsoft Paint.
Anyone get it working?Spectrum stuff for saleSpectrum 128with colour monitorPRSM ql14 in black case cruiser joy stick Opus Discovery double disc drive with box Organ master in box with inst Saga…
...
A dozen or more instruction books on spectrum i e ...learning with the spectrumHello friends! When you load a game into the spectrum (i.e a game for the 48k), how can you guess where is stored its first and its last instructio…
... its first and its last instruction in RAM?? I know from ...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 …
Jericho Road and GalileeHi All, I'm looking for information on two Adventure Games written by Peter Goodlad which were released by Shards Software. The first is called Jer…
... from 1983. According to the instruction sheet there was a set ... also a copy of the instruction sheet?
Failing that ...Instruction Manual for FIST IIThe title says it! Where do I get it?
The title says it! Where do I get it?Vulcan instruction manual, and cover scans uploaded.Hi, I can't remember who asked for it now, but here is a url to a directory on my web-space with scans of the instructions for VULCAN. [url="http:…
Hi,
I can't remember who asked for it now, but here is a url to a directory on my web-space with scans of the instructions for VULCAN.
[url="http://homepage.ntlworld.com/thx1138/Vulcan/"]http://homepage.ntlworld.com/thx1138 ...
