A bit of all, H is (re)stored after this instruction.
Charlie's Red Ant - a ROM instruction that reads throughout memory
Re: Charlie's Red Ant - a ROM instruction that reads throughout memory
Thinking about a "claire.p" that shows a "thumbs up" path in the Live Memory View...
Re: Charlie's Red Ant - a ROM instruction that reads throughout memory
Hi,
Zsolt
Why is this the solution? This is same memory reading.dr beep wrote: ↑Sun Sep 10, 2017 10:22 pmSo the fix should be LD H, (HL)sirmorris wrote: ↑Sun Sep 10, 2017 6:59 pm Also,Is exactly itCode: Select all
L0237: LD B,(HL) ; (7) Note. Harmless Nonsensical Timing weight.
Zsolt
ZX81 (8K), ENTERPRISE 128, [ZX SPECTRUM (48K,+,+128K,+2,+2A), TS1000, TS1500, TS2068, Cambridge Z88, PRIMO A64 (red)]
Re: Charlie's Red Ant - a ROM instruction that reads throughout memory
The timing must be the same, but B gets a value that is not allowed.zsolt wrote: ↑Tue Sep 12, 2017 4:58 pm Hi,Why is this the solution? This is same memory reading.dr beep wrote: ↑Sun Sep 10, 2017 10:22 pmSo the fix should be LD H, (HL)sirmorris wrote: ↑Sun Sep 10, 2017 6:59 pm Also,Is exactly itCode: Select all
L0237: LD B,(HL) ; (7) Note. Harmless Nonsensical Timing weight.
Zsolt
CP (HL) might work too, but it does effect the Z-flag where LD H,(HL) has no effect on flags but still use 7 tstates in 1 command and 1 byte.
Re: Charlie's Red Ant - a ROM instruction that reads throughout memory
Just for fun....
regards Andy .
regards Andy .
what's that Smell.... smells like fresh flux and solder fumes...
Re: Charlie's Red Ant - a ROM instruction that reads throughout memory
Thanks I think I'll have it running all night on real hardware - it works quite well even with monitor switched off and eyes closed
Re: Charlie's Red Ant - a ROM instruction that reads throughout memory
did i forget to mention it works very well on eightyone V1.7
what's that Smell.... smells like fresh flux and solder fumes...
Re: Charlie's Red Ant - a ROM instruction that reads throughout memory
OK, it is time-correct, but does not solve the original "problem":
(if it is a real problem)sirmorris wrote: * Yes, the ZX81 appears to have a pet - a restless red 'ant' (escaped from the classic game?) which relentlessly patrols RAM from the end to the start. It's (most likely) a read instruction in the display routine.
Andy, what should I see there?
ZX81 (8K), ENTERPRISE 128, [ZX SPECTRUM (48K,+,+128K,+2,+2A), TS1000, TS1500, TS2068, Cambridge Z88, PRIMO A64 (red)]
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Re: Charlie's Red Ant - a ROM instruction that reads throughout memory
Well, it's been in the ROM since 1981...
Mark
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: Charlie's Red Ant - a ROM instruction that reads throughout memory
It's not a problem! It's a pet!