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z80 Startuphi everyone, does the z80 upon start up reset all registers (including A) to 0? Many thanks, Robin
Higher memory is not being accessed but you may be seeing memory refresh cycles which occur after every opcode fetch. That has the address IR (I register, R register) placed on the bus. -
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…
... Atic Atac a series of HALT instructions is performed until I ... -
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…
... Atic Atac a series of HALT instructions is performed until I ... -
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 ... 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…
... 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…
... for branching to the correct opcode to execute) that displays or ... a message when an unimplemented opcode is executed, instead of (presumably ... -
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…
... for branching to the correct opcode to execute) that displays or ... a message when an unimplemented opcode is executed, instead of (presumably ... -
BEEPER Demo: "9 CHANNELS" (ZX48)Hi my friends. Another year, another demo for Spectrum 48K. :) This time - "9 channels" demo, for BEEPER fans. [url]http://pouet.net/prod.php?wh…
... game in place of a HALT after the main loop has ... -
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 ... -
Inlay Project DiscussionAll, It's time this project was actually started in anger. The aim of this thread is to find out what every wants from it and the standards that sh…
... will swiftly grind to a halt, as I can't take ... -
Inlay Project DiscussionAll, It's time this project was actually started in anger. The aim of this thread is to find out what every wants from it and the standards that sh…
... will swiftly grind to a halt, as I can't take ... -
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…
... devices to recognize the RETI opcode to know that their interrupt ... -
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…
... if PC points to HALT instruction and, in such ... CURRENTLY PC does point to HALT, it gets incremented by ... a byte past a HALT instruction which was just ... now it also prevents HALT from going on forever, ... but always skips a HALT that could occur immediately after ... -
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 ... -
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] if there is a HALT instruction immediately after return from ... /> Obviously you would execute the HALT. What else could a z80 ... -
if you liked the bomb question, here's another one for you...which is worse ? You're in a car, travelling at 50mph, and have a head on collision with another car going in the opposite direction, at the same sp…
... 't come to an instant halt, they'll deflect off each ... -
Fastest way to mirror a byte?I.E. turning 01100000 into 00000110, in assembly. I'm trying but I suck at stuff with rotation and the carry bit. Any pointers?
... with BC',DE',HL'.
HALT Halt computer and wait for interrupt ... -
Books for BASICIs there any godo books out there to learn BASIC ? I want to go from begininer to advanced really even though back in the day I used to write games …
... all actually works at the opcode level.
D ... -
Getting the contents of tablesHi All, I'm risking a potentially daft question here as it seems pretty fundamental but here goes: What's the best way of pointing register pairs a…
... (but you can't use HALT command then)
-write ... -
Fastest way to mirror a byte?I.E. turning 01100000 into 00000110, in assembly. I'm trying but I suck at stuff with rotation and the carry bit. Any pointers?
... listing of instructions with descriptions, opcode bytes, timing and flags affected ... -
Fastest way to mirror a byte?I.E. turning 01100000 into 00000110, in assembly. I'm trying but I suck at stuff with rotation and the carry bit. Any pointers?
... instruction is once for each opcode fetch. Almost exclusively this is ... -
IN or INKEY ?just curious which is better to use.. I have a menu done.. and use 6/7 to go up down it + space to cycle thru the options (using inkey).. obv. if I w…
...
add a,$A0 ;}opcode
ld (OPCODE),a
call FPTOA ... bc ;B =2nd variable
OPCODE: nop ;operator goes here: AND ... -
Fastest way to mirror a byte?I.E. turning 01100000 into 00000110, in assembly. I'm trying but I suck at stuff with rotation and the carry bit. Any pointers?
... listing of instructions with descriptions, opcode bytes, timing and flags affected ... -
Fastest way to mirror a byte?I.E. turning 01100000 into 00000110, in assembly. I'm trying but I suck at stuff with rotation and the carry bit. Any pointers?
... /> jr c,loop
halt
defs (-$)%256 ; 256 ...
