-
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…
... fetch instructions while in the HALT state? (that is: repeated memory ... . Such instruction has 2-byte opcode (it's ED prefixed), so ... , the memory is read and opcode isn't discarded but interpreted ... -
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…
... fetch instructions while in the HALT state? (that is: repeated ... fetching the instruction following the HALT, but discards it.
< ... Such instruction has 2-byte opcode (it's ED prefixed), so ... , the memory is read and opcode isn't discarded but interpreted ... -
Startup colours of the Spectrum ROMHi Folks, Thought I would have a go at changing the startup colours of the Spectrum ROMs used within BasinC which ships with 48.rom (16384 bytes) …
... ;
// $ED Unused Opcode Trap for Keyboard (INKEY$)
// $ED Unused Opcode Trap for BREAK detection
// $ED Unused Opcode Trap for the Error Reconstruction ... trap is in the core, HALT instruction.
... -
Interrupt routineI have been trying to create an interrupt routine for playing AY music in the background but cant seem to get anything working. I have a music rou…
... (IX+04h),&C3 ; Z80 opcode for JP
LD (IX ... (IX+0Fh),&18 ; Z80 Opcode for JR
LD A ... interrupts again
LOOP: HALT ; Wait for interrupt
CALL ... -
endless runner project..So I'm thinking of writing a small tutorial series on writing games for the speccy in C, and figured that an endless runner would be an easy example …
... C,D
DI
HALT
Command explanations? Yes ... there you have it, one opcode, one clear and concise operation ... -
Need help from people with a +2A/+3Started a topic [url="https://www.worldofspectrum.org/forums/discussion/55141/need-help-from-people-with-a-2a-3"]here[/url] to get a broader reach, b…
... ,CST.Port
ei
halt
exx
out (c ... refers to Address, Op is Opcode, and the last two numbers ... /> 1. Try out the current opcode/combination thereof twice for all ... /> 2. Move to the next opcode/combination in the list and ... -
How can I make a UDG rotate?I designed a set of UDG's that can be used for making shapes or letters. Trouble is that my circle - for example - consists of 4 pieces and it would…
... /> ; Replace the old background
HALT
CALL restore_bgr
CALL ... $CB,$32 ; SLS D (undoc.opcode)
DEFB $CB,$33 ; SLS ... -
Kempston Mouse DriverHi Folks, Does anyone know the email of Chris Cowley who wrote the Kempston Mouse Driver in the WOS Archive? Many thanks Paddy
... /> ; Replace the old background
HALT
CALL restore_bgr
CALL ... $CB,$32 ; SLS D (undoc.opcode)
DEFB $CB,$33 ; SLS ... E (undoc.opcode)
; SET 0,D
New release of ZEsarUXFound today by chance on: [url]https://github.com/chernandezba/zesarux/releases/tag/10.1-13122021[/url] [quote]ZEsarUX-10.1 Beta1 Pre-release che…
... - Hardware type
Added Z80 Halt signal state support on zsf ... will be modified by the opcode at the cursor position
opcode decoding using key m (mode ... scripts
Fixed Z80 halt behavior and PC location
New release of ZEsarUXFound today by chance on: [url]https://github.com/chernandezba/zesarux/releases/tag/10.1-13122021[/url] [quote]ZEsarUX-10.1 Beta1 Pre-release che…
... tape setting
Added Z80 Halt signal state support on zsf ... will be modified by the opcode at the cursor position
opcode decoding using key m (mode ... zoom
Fixed Z80 halt behavior and PC location
Emulation and Debugging functionality[Cut n Paste from the original CSS post] Hi all, I'm currently working on SPIN's debugger, which is coming along nicely. Mostly, it's been devel…
... before or after the current opcode, which
allows any debugging ...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…
Anyone 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 support page and the CSS Faq, but I'm sure they're quite wrong in many cases.
...ANN: Issue 9 of Sam Revival magazine out now (Sam Coupe)Issue nine of Sam Revival magazine is out now, and this issue features the first cover disk! The magazine starts off with the usual Quazar News, as…
... quirk in an undocumented Z80 opcode in a newer revision of ...ANN: SpecEmu 2.3 - Minor UpdateHere's a minor update to the SpecEmu emulator - the emulator with an incredibly small filesize for a Win32 application, and backed up with an incredi…
... :
- Fixes to some overlooked opcode contention timings.
- Improved floating ...IM 2 interrupts and smooth scrolling - easy peasy!Okay, been fiddling around with IM 2 and have actually mastered (I think) how to use IM 2! Now I run my game Ragnar Revival in IM2 and use HALT to sy…
... Revival in IM2 and use HALT to sync screen drawing (dumping ... manipulation (a scrolling text) using HALT, and one without IM2 and ... HALT.
Here is the ...InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…
... /> Internally, the Z80 divides every opcode into M-cycles; each M ... /> * M1: 4 tstates: read the opcode (0x34).
* M2: 4 tstates ... bus value (0xff), coincidentally the opcode for RST 38, so the ... data bus means a random opcode could be executed, which makes ...Game loop design?Having some thoughts on how to design the game loop and could do with some hints and tips from folks who have done it before! It's all about how to …
... ,RET interrupt function, so that HALT can be used to time ... /> jr z,nosprdraw
halt ;Wait for interrupt
call ...Machine Code Sprites Example Code Using Char Based SystemBelow is my WIP code to do smooth screen wrapping sprites using char positions and offsets, as opposed to writing direct to a line (0-191) and shifti…
Smooth Color Masked Sprites using fast page flip on 48kHere is a quick demo of using char based sprites using the Page flip method: a) Background is copied to buffer b) Sprites drawn on buffer c) Buffer …
... waits till the next interrupt (HALT) so that it is in ... /> LD (OKTOFLIP),A
HALT
JP MAIN ...Techy Z80 questions****** Question 1 ****** Take the instruction SET b, (HL). This is broken down (in machine cycles) as follows (according to Microprocessor Technolo…
... (4T) [i.e. the actual opcode]
M2: MemoryRead(4T)
opcode that would have followed the ...Smooth Screen Scrolling RoutineHi everyone, this is a follow up to the thread on smooth screen scrolling. As promised here is the code for the routine. It's pretty long and fairl…
... /> LD A,0
MLOOP HALT
LD (SCRPOS),A ;SCROLL ...Zaf-forth to Z80 compiler Build 5This forth like complier is changing almost every day with new items been added. Here is a new Zaf-forth word add it the sptword.fth file - which is…
Sprites flickeringI am trying to write a Spectrum game in machine code. I am still a beginner in programming, however I did much progress recently, i believe. Now I am…
... with screen refeshing, interrupts and HALT command, but I still dont ...name that game It was definately a budget release a kind of future sports games with two robots maybe on wheels maybe floating where you had to shoot the ball int…
... you would slow to a halt and couldn't move till ...Battle ValleyHope someone can help. I used to love this game, but I've forgotten how you 'halt' the helicopter (or tank). I know you have to stop the helicopter -…
... I've forgotten how you 'halt' the helicopter (or tank). I ...ANNOUNCE: BASin Release 12 ready for downloadWell, after a rather large break, BASin's latest incarnation is ready for public use. Probably. BASin is a Sinclair Spectrum development environme…
... assembler, capable of assembling every opcode supported by the z80. Supports ...ANNOUNCE: BASin Release 12 ready for downloadWell, after a rather large break, BASin's latest incarnation is ready for public use. Probably. BASin is a Sinclair Spectrum development environme…
... assembler, capable of assembling every opcode supported by the z80. Supports ...Tape stopsHi, I'm trying to sample a tape, but it stops in the middle of the tape. I've tried it on 4 different players, and it stops on all of them. I've t…
... again it grinds to a halt almost immediately. It does this ...Machine Code QuestionHi All Not sure if this is the right place for this but it seems closest. Am starting to read the Toni Baker Intro to Machine Code book and its ver…
... the book plus the relevant Opcode listings...
Is Assembly ...
