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+3 dead(!)Hi, When I turn on my +3 I see only white and black strips (vertical) on screen any idea on how to fix it? Thank you in advance Chris [IMG]http:…
... executed a DI, then a HALT instruction, so the CPU stops ... instructions from external memory. The HALT instruction continues to issue M1 cycles ... is halted, but the "instruction" read at that M1 cycle ... it does not execute a HALT...
BTW: check ... -
Framerate of Spectrum gamesI was reading a bit about framerates in modern games and it got me wondering about the Speccy. First off I'd hoped to find what framerate my old gam…
... have to add an extra HALT in 'cos 50fps is too ... in the end adding a HALT instruction was the best solution.
Zon xDid anyone ever use a ZON X sound generator? I've been rummaging around in the loft and found it (along with Machine Language for the absolute beginn…
... , which was signalled by a HALT instruction (which actually executed, to make ...Adjusting your code for screen refreshingOk, I'm aware that I should know it already after writing 5 Spectrum games in machine code but interrupts and screen refreshes were always my weaker …
... Interrupt signal that makes a HALT instruction end,
invoke a ... allow interrupts (normal = IM1)
HALT ;does make the test!
HALT is executed also a MASK ... screen memory after issueing a HALT
for synchronizing, how ...Tricks with IN 31It's generally considered unwise to use a Kempston joystick's fire button to start a game, because the floating bus effect can make arbitrary data ap…
... :
- read port 31 after HALT instruction (or at begin of IM2 ...Tricks with IN 31It's generally considered unwise to use a Kempston joystick's fire button to start a game, because the floating bus effect can make arbitrary data ap…
... :
- read port 31 after HALT instruction (or at begin of IM2 ...1K ZX81 "Chariddy" games competition mate..I'm trying to put together a Cronosoft 1K ZX81 gamestape in the style of the old "JK GREYE" 10 games tape that I remember owning about 28 years ago. …
... would be executed as a HALT instruction. It's a fairly simple ...Help! Reverse engineering a Spectrum game[deleted]
... , and (3) is just a HALT instruction, and could be considered as ...Help! Reverse engineering a Spectrum game[deleted]
... , and (3) is just a HALT instruction, and could be considered as ...Help! Reverse engineering a Spectrum game[deleted]
... , and (3) is just a HALT instruction, and could be considered as ...How to Write ZX Spectrum Games As some of you may know, it has long been my intention to produce a document which explains pretty much everything I have learned - and am still lea…
... /> Chapter Twelve - Timing
The Halt Instruction
The Spectrum's Clock ...Opinion on new 128K only gamesHello, Being new to the WOS community, I am unclear on the attitude towards 128K only software, that is; Is there a strong need to support the 48K m…
... read it just after a HALT instruction, as the ULA will be ...Assembly Programming for IDIOTSOk are there any websites guides for what opcodes do in a z80 or books... but for really really thick people like me :-) Something along the lines …
... . This is done using the HALT instruction to make the Z80 wait ... next interrupt occurs. After the HALT instruction has executed you know the ...Assembly Programming for IDIOTSOk are there any websites guides for what opcodes do in a z80 or books... but for really really thick people like me :-) Something along the lines …
... TV display. The 'HALT' instruction becomes a 'NOP' instruction that is repeated over ... of your program once the 'HALT' instruction has found the interrupt signal ... magic 'CALL' instruction between the 'HALT' instruction and the next instruction that would follow ...That minigame at the start of EurekaDoes anyone else think that minigame thing you have to play before you get into Eureka is really annoying? I've had it for years but I haven't played…
... lot! This POKE removes the HALT instruction and makes the game a ...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,…
... . So, every time the HALT instruction is executed (at the very ... set to 0000? The instruction inmediately following HALT is PUSH DE, ... . [B]The PUSH DE instruction was indeed executed... after a ... !!??!![/B]
The instruction following PUSH DE is LD ...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,…
... PUSH DE, isn't the HALT instruction spread over two M cycles ... so that in reality /HALT is only asserted in T2 ... PUSH DE's M1 cycle (instruction overlap)? Perhaps this might ... on real hardware and /HALT goes low just after the ... clock in T4 of HALT's M1 cycle.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…
... of DAA tests) and 76 (HALT), but I don't really ... AF=9a02 right before DAA instruction, so I think this test ... implementation is correct. As for HALT instruction, I simply don't signal ... /port/flag values after every instruction are correct according to tests ...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…
... of DAA tests) and 76 (HALT), but I don't really ... AF=9a02 right before DAA instruction, so I think this test ... implementation is correct. As for HALT instruction, I simply don't signal ... /port/flag values after every instruction are correct according to tests ...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…
Yes, I redraw screen once every 69888 T-states. Isn't that the right thing to do?
I'm trying to eliminate potential causes and so:
- it can't be display_screen() routine, otherwise at least one game I tested would display garbage ...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…
... had interrupts disabled and a HALT instruction was executed, then the game ... right in assuming that your HALT emulation simply increments T_states by ...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…
... check if PC points to HALT instruction and, in such case, increment ... and HALT. Of course LD causes PC to move to next instruction ... to a byte past a HALT instruction which was just skipped.
instruction executed before an INT was HALT, then add ...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…
... check if PC points to HALT instruction[/quote]
No, you ...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 towriting 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] if there is a HALT instruction immediately after return from interrupt ... /> Obviously you would execute the HALT. What else could a z80 ...Authored with ZXodus EngineIMHO the [URL="http://www.worldofspectrum.org/infoseekid.cgi?id=0026639"]ZXodus Engine[/URL] entry should have a list like "The following games are k…
... - try to get into a HALT instruction to wait for the interrupt ... the middle of a long instruction when the interrupt kicks in ...
