1K lowres games in machinecode on a Lambda

[David G]

Good idea

On the emulators, poking a 127 [opcode for ld a,a] to the screen

Code: Select all

POKE 16576,127

• On EightyOne it prints a space

• On NO$ZX it prints a 'Z'

7Fh 127
3Fh 'Z'
So maybe NO$ZX is disregarding BIT 6

[mrtinb]

If you make small programs I can test them on both ROMs, on real hardware, when I have my setup running.

[dr beep]

Good idea

On the emulators, poking a 127 [opcode for ld a,a] to the screen

Code: Select all

POKE 16576,127

• On EightyOne it prints a space

• On NO$ZX it prints a 'Z'

7Fh 127
3Fh 'Z'
So maybe NO$ZX is disregarding BIT 6

What NO$ZX is doing is the same what my 1997 emulator did.
That is why I coded the 2020 emulator
1) speeding up
2) adding my games to run on the emulator.

Those opcodes can be quite handy in games.
See my game DIGG-IT.
When you jump the player will not go too high. That is because above the player are hidden opcodes to prevent going up.
On dropping only a platform is allowed under the player.

[David G]

"the 2020 emulator" is SP-2-ZX81 for the 48K ZX Spectrum. What was the 1997 emulator called?

[dr beep]

"the 2020 emulator" is SP-2-ZX81 for the 48K ZX Spectrum. What was the 1997 emulator called?

ZX81EMULATOR

https://spectrumcomputing.co.uk/entry/1 ... 1-Emulator

The 2020 was called so it also had the nr 2 in the name, indicating a second emulator.

[David G]

If you make small programs I can test them on both ROMs, on real hardware, when I have my setup running.

Here is the small program

Code: Select all

POKE 16576,127

This pokes a 127 [opcode for ld a,a] to the screen. On a ZX81 this simply appears as a space, on some emulators it prints a 'Z'

[mrtinb]

So I've typed the POKE on both ROMs on real hardware.

"Original" ROM gives blank screen with OK.



And the "updated" ROM gives also a blank screen with OK.