Search found 490 matches

by djnzx48
Tue Oct 15, 2019 9:45 pm
Forum: Programming
Topic: Short beeper routines in assembly
Replies: 33
Views: 3613

Re: Short beeper routines in assembly

That makes more sense. But why is port 0x7fff not included in that range? Should 0x7ffe be changed to 0x7fff, or is that correct as it is?
by djnzx48
Mon Oct 14, 2019 7:00 am
Forum: Programming
Topic: Short beeper routines in assembly
Replies: 33
Views: 3613

Re: Short beeper routines in assembly

I rechecked the wiki page about I/O contention. Is it just me, or does it have a mistake? According to the description, "access to ports between 0x4000 and 0x7ffe with the low bit clear (i.e. when the ULA's own port is not being accessed) is subject to contention on every T state." This seems to be ...
by djnzx48
Tue Oct 08, 2019 6:56 am
Forum: Preservation
Topic: Programmers Development System (Dominion and some other sources)
Replies: 2
Views: 230

Re: Programmers Development System (Dominion and some other sources)

According to this interview, Paul Griffiths has (or used to have) the source code to Joe Blade IV, and considered finding it again. But it doesn't seem like he ever released it.
by djnzx48
Sat Oct 05, 2019 4:07 am
Forum: Games/Software
Topic: Miscellaneous game questions...
Replies: 16
Views: 622

Re: Miscellaneous game questions...

0:00 - 1:48 is from Visitors
1:48 - 2:49 is from Time
2:49 - 5:24 is from Dragon's Legend.
by djnzx48
Tue Oct 01, 2019 12:29 pm
Forum: Games/Software
Topic: Which Speccy game would you put in an arcade?
Replies: 50
Views: 2021

Re: Which Speccy game would you put in an arcade?

R-Tape wrote:
Tue Oct 01, 2019 12:11 pm
Joefish wrote:
Tue Oct 01, 2019 11:18 am
Aside, has anyone hacked it so it simply fires and drops bombs (where it can) when you hit FIRE?
This thread has the code fix, but the download link is dead. I have the thing somewhere but I can't find it!
If you mean the .tzx, I found a copy of it here.
by djnzx48
Fri Sep 27, 2019 11:17 pm
Forum: Programming
Topic: CPI / CPIR instruction
Replies: 14
Views: 512

Re: CPI / CPIR instruction

Those instructions sequences aren't exactly equivalent as CPI/LDI set flags if BC is equal to zero.

If LDI and CPI take the same number of T-states, my guess is that CPI uses the same circuitry but doesn't output the value to memory, or maybe just writes it back to HL.
by djnzx48
Tue Sep 24, 2019 10:28 pm
Forum: Emulators
Topic: QtSpecem v0.80
Replies: 2
Views: 296

Re: QtSpecem v0.80

Looks cool, I'll have to try this later.

What license does the emulator use? The main LICENSE file says MIT but inout.c contains a GPL2 notice.
by djnzx48
Sat Sep 21, 2019 1:11 am
Forum: Programming
Topic: EX (SP),HL
Replies: 10
Views: 615

Re: EX (SP),HL

You can use it as an easy way to swap HL and IX.

PUSH HL
EX (SP), IX
POP HL