Search found 137 matches

by thewiz
02 Nov 2017 15:33
Forum: PROGRAMMING
Topic: Generating a 60Hz Interrupt
Replies: 3
Views: 6126

Re: Generating a 60Hz Interrupt

Thanks Martin,

Hadn't thought of counting interrupts in the ISR routine too.

Your first idea would be a simple flip/flop affair.

LD A, (ISR_FF)
INC A
AND 1
LD (ISR_FF), A
JR ????
by thewiz
01 Nov 2017 15:42
Forum: PROGRAMMING
Topic: Generating a 60Hz Interrupt
Replies: 3
Views: 6126

Generating a 60Hz Interrupt

Ok I've been looking into generating a 60Hz interrupt using the CTC as a large number of VGM's have been captured at this rate. I am using channel 1 for this to avoid the VDP interrupt on channel 0. So my first attempt got a 61Hz interrupt by programming the CTC in Timer mode, with a prescaler of 25...
by thewiz
20 Oct 2017 14:44
Forum: PROGRAMMING
Topic: Memotest 2017 - Z80 coding contest
Replies: 27
Views: 31835

Re: Memotest 2017 - Z80 coding contest

I've still been tinkering with my code and seen how I can get it to 37 bytes. By making ED = p xor q and moving the ADD HL,HL instructions so that the next XOR can be combined got it down to 38 bytes. Which just left shaving a byte off the p ROL a bit. Well done Tony, I can see my Z80 skills are rus...
by thewiz
19 Oct 2017 14:20
Forum: PROGRAMMING
Topic: Memotest 2017 - Z80 coding contest
Replies: 27
Views: 31835

Re: Memotest 2017 - Z80 coding contest

I know the competition is over but I've been tinkering with my code I made and just by using BC and DE as p and q, one of the points made already, I've got my code down to 44 bytes. A saving of 8 bytes.

Regards
by thewiz
16 Oct 2017 22:00
Forum: MEMOFEST 2017
Topic: Memofest 2017 Photos
Replies: 13
Views: 20233

Re: Memofest 2017 Photos

Another group photo.
Group Photo
Group Photo
MTX2017 Group Photo.jpg (246.2 KiB) Viewed 7505 times
by thewiz
16 Oct 2017 14:22
Forum: PROGRAMMING
Topic: Memotest 2017 - Z80 coding contest
Replies: 27
Views: 31835

Re: Memotest 2017 - Z80 coding contest

Here was my attempt at 52 bytes. CALC_PRNG ;* p := p XOR q XOR (p ROL a) XOR ((p XOR q) SHL b) ;* 1111111 1111111 ;* q := ((p XOR q) ROL c) ;* 1111111 LD A, L ; BC = DE = (HL XOR DE) XOR E ; HL = old p LD C, A LD E, A LD A, H XOR D LD B, A LD D, A ; ????????????? SWAP BC and DE USAGE ???????????????...
by thewiz
07 Oct 2017 17:55
Forum: MEMOFEST 2017
Topic: ROM Upgrades
Replies: 4
Views: 6534

Re: ROM Upgrades

Great, I'll bring my CFX.
by thewiz
25 Sep 2017 17:44
Forum: PROGRAMMING
Topic: Memotest 2017 - Z80 coding contest
Replies: 27
Views: 31835

Re: Memotest 2017 - Z80 coding contest

Is there any restriction on self modifying code?
by thewiz
18 Aug 2017 13:47
Forum: MEMOFEST 2017
Topic: What to DO at Memofest 2017
Replies: 17
Views: 19133

Re: What to DO at Memofest 2017

I should have a new game finished to show off, a conversion of a 1979 arcade game.

Just High score (which is a bitch to do), title screen and sound to do.

Is there going to be a surgery for poorly MTX's?
by thewiz
18 Aug 2017 13:42
Forum: PROGRAMMING
Topic: MTX BASIC / Assembly Interface
Replies: 2
Views: 5647

Re: MTX BASIC / Assembly Interface

For development, Memu can be used to show what blocks of data are being loaded. On a real MTX, if its loaded by Basic, then the sysvars will. Basic starts at BASBOT ($FAA7), i.e. $4000 or $8000. Basic ends at ARRTOP (includes memory for arrays) ($FACC) Noddy ends at NBTOP. ($FAA4) So size of data lo...