Search found 124 matches

by Jo Even
Fri Sep 27, 2019 11:45 am
Forum: Other
Topic: MZ-80A / MZ-80K extra RAM
Replies: 22
Views: 1866

Re: MZ-80A / MZ-80K extra RAM

Yes, the HBL is used as "master clock" for the timer interrupt, so it's possible to get one interrupt per VBL by dividing the clock by the number of lines per frame. If you time the initialisation of the timer to the VBL signal it should be possible to get a reliable interrupt when the last line of ...
by Jo Even
Fri Sep 27, 2019 10:18 am
Forum: Games
Topic: A small preview
Replies: 9
Views: 1071

Re: A small preview

Yes, this is a 700 game and only use stock 700 features.
by Jo Even
Fri Sep 27, 2019 8:32 am
Forum: Other
Topic: MZ-80A / MZ-80K extra RAM
Replies: 22
Views: 1866

Re: MZ-80A / MZ-80K extra RAM

Ahh... That's a bit diappointing, I've always believed that the 700 had hardware scrolling. Not that much use in the extra VRAM then. Isn't access to VRAM slower than RAM too? It looks like it's only accessed during blanking periods?
by Jo Even
Fri Sep 27, 2019 6:56 am
Forum: Other
Topic: MZ-80A / MZ-80K extra RAM
Replies: 22
Views: 1866

Re: MZ-80A / MZ-80K extra RAM

MZ-700 games could also effectively use that "second" memory to store a background to be restored when redrawing software sprites for instance. That's what I've been using it for in my current game project, but if I understand it correctly you should be able to use the second page for scrolling too...
by Jo Even
Thu Sep 26, 2019 10:01 pm
Forum: Games
Topic: A small preview
Replies: 9
Views: 1071

Re: A small preview

Yes, a Tetris-game with both one- and two-player modes.
by Jo Even
Wed Sep 25, 2019 4:44 pm
Forum: Games
Topic: A small preview
Replies: 9
Views: 1071

A small preview

A small preview of a game Geir and myself has been working on for the last couple of weeks.
preview.jpg
preview.jpg (115.21 KiB) Viewed 1071 times
The game is written in C using z88dk.
by Jo Even
Tue Sep 24, 2019 10:03 am
Forum: Other
Topic: [MZF] MZ7: MZF file compressor using ZX7 algorithms
Replies: 16
Views: 1552

Re: [MZF] MZ7: MZF file compressor using ZX7 algorithms

Tested this quickly today, it compressed my mzt-file to less than a third. Thanks a lot for this brilliant tool :)
by Jo Even
Mon Sep 23, 2019 9:28 am
Forum: Other
Topic: Detecting VBL on 800 in 700-mode
Replies: 24
Views: 1778

Re: Detecting VBL on 800 in 700-mode

This piece of code stolen from the monitor works. __asm push af wait1: ld a,(0e002h) rlca jr nc,wait1 wait2: ld a,(0e002h) rlca jr c,wait2 pop af __endasm Maybe the compiled C code isn't fast enough. VBL is low for less than 3ms, but it should take some pretty inefficient code to miss that. Edit: Ju...
by Jo Even
Sun Sep 22, 2019 9:39 pm
Forum: Other
Topic: Detecting VBL on 800 in 700-mode
Replies: 24
Views: 1778

Re: Detecting VBL on 800 in 700-mode

while (*(unsigned char *)0xe002 & 0x80); This is working on the 700 but always returns immediately on the 800 emulator in 700 mode. Why did I write "700" and not "700 emulator"? Because when I finally managed to test this on a REAL 700 it shows exactly the same behaviour. So the problem *is* with t...
by Jo Even
Sun Sep 22, 2019 8:03 pm
Forum: Other
Topic: [MZF] MZ7: MZF file compressor using ZX7 algorithms
Replies: 16
Views: 1552

Re: [MZF] MZ7: MZF file compressor using ZX7 algorithms

This is very interesting! I will definitely test this with my current project.