Search found 1557 matches
- Tue Feb 25, 2020 7:46 pm
- Forum: Emulators
- Topic: A new ZX81 Emulator
- Replies: 13
- Views: 9207
Re: A new ZX81 Emulator
When we reach the RET of routine keyboard HL will be something of the following 1 - 2 - 3 - 4 - 5 -> register L = F7 0 - 9 - 8 - 7 - 6 -> register L = EF Q - W - E - R - T -> register L = FB P - O - I - U - Y -> register L = DF A - S - D - F - G -> register L = FD N/L- L - K - J - H -> register L = ...
- Sun Oct 13, 2019 4:09 pm
- Forum: Welcome Area
- Topic: Hello from Nottingham, UK.
- Replies: 21
- Views: 6274
Re: Hello from Nottingham, UK.
Welcome to the Forum, Lots of love for the humble machine. you can really do alot with it.
any questions just ask away.
Regard Andy
any questions just ask away.
Regard Andy
- Mon Oct 07, 2019 1:37 pm
- Forum: Hardware
- Topic: Mystery 330 ohm resistor connected to X1
- Replies: 4
- Views: 1912
Re: Mystery 330 ohm resistor connected to X1
I've seen similar on zx81 isue 3 boards with red solder mask but in my case they were 1K resistors
Andy
Andy
- Tue Oct 01, 2019 2:21 pm
- Forum: Hardware
- Topic: ZXPand vs ZXPand+ ?
- Replies: 2
- Views: 1752
Re: ZXPand vs ZXPand+ ?
put the sd in after powering on and see if it is recognised do a CAT
- Mon Sep 30, 2019 9:55 pm
- Forum: Development
- Topic: DOOM on ZX81?!
- Replies: 3
- Views: 2591
Re: DOOM on ZX81?!
awesome that preview looks really smooth, will download and try on real hardware... BOBS played with ray traced texture mapping in lo-res a long time ago... https://www.sinclairzxworld.com/viewtopic.php?f=4&t=548&p=4951&hilit=3d+rendering#p4951 the facebook video link https://www.facebook.com/bobs.s...
- Mon Sep 30, 2019 9:50 pm
- Forum: Hardware
- Topic: Re-enable ZXpand after CONFIG "X"
- Replies: 6
- Views: 2507
Re: Re-enable ZXpand after CONFIG "X"
Nice Trick, Thanks for sharing...
Andy
Andy
- Fri Sep 27, 2019 11:45 am
- Forum: Development
- Topic: Problem with TASM 3.2
- Replies: 10
- Views: 3774
Re: Problem with TASM 3.2
yes JR 4 bits lol nope..
JR and index offsets both 8bit SIGNED
JR and index offsets both 8bit SIGNED
- Fri Sep 27, 2019 11:29 am
- Forum: Development
- Topic: Problem with TASM 3.2
- Replies: 10
- Views: 3774
Re: Problem with TASM 3.2
quoted instead of edit
sorry

- Fri Sep 27, 2019 11:28 am
- Forum: Development
- Topic: Problem with TASM 3.2
- Replies: 10
- Views: 3774
Re: Problem with TASM 3.2
haha your right the IX and IY registers can't be negative but for example say they are holding the value $0000 and you add a negative offset it will roll round to $ffff for -1 $fffe for -2 $fffd fro -3 and so on... btw LD IY,-20000 ; is perfectly valid and results in the following bytes DD 21 E0 B1 ...
- Fri Sep 27, 2019 9:55 am
- Forum: Development
- Topic: Problem with TASM 3.2
- Replies: 10
- Views: 3774
Re: Problem with TASM 3.2
when using the index registers the offset byte is signed so -128 to +127 is the maximum range allowed.
same as relative jumps.
tasm allows you to enter negative numbers.
regards Andy
same as relative jumps.
tasm allows you to enter negative numbers.
regards Andy