SpritesMind.Net

M-374 LX

A new version is now available. It features new music, now using DAC samples. Also, the audio issues on the real hardware and the bug that caused the game to run faster have been fixed.

I would like to thank Chilly Willy, who is now in the "Thanks to" section of the credits.

M-374 LX

I am not only a programmer, but also a music producer. Therefore, I present you my musical project: Positron Wave , whose musical style is inspired by the synthpop, italo disco and similar movements from the 1980s. The music is entirely available under the Creative Commons Attribution license.

The ...

M-374 LX

What should one do if the 68000 needs to write to the YM2612 while the Z80 runs a DAC sample driver (which seems to be the case of the games that use the 68000 version of the SMPS sound engine)?

M-374 LX

The audio on the real hardware is fine now. Thanks, Chilly Willy.

However, according to the Genesis Technical Overview document, the status of the YM2612 can be read from "any of the four locations". This seems to be another mistake in that document.

M-374 LX

Here are some of the functions related to the audio:

void z80_halt()
{
volatile ushort* z80 = (ushort*)Z80_RESET;
*z80 = 0x100;

z80 = (ushort*)Z80_BUSREQ;
*z80 = 0x100;

while(*z80 & 0x100);
}

void fm_write(uchar reg, uchar val, uchar part)
{
volatile uchar* ctrl;
volatile uchar* data ...

M-374 LX

I have finally had the opportunity to test the game on the real hardware.

The PSG notes are fine in the music, but random FM notes are played instead of the desired ones. Besides, the engine sound effect can be heard sometimes, but not always, and the crash sound effect seems to be never heard ...

M-374 LX

1. How can DAC samples be played at the correct speed/timing?
2. Are the DAC samples signed or unsigned?
3. Should music sequence data be copied to the Z80 RAM or read by banking when the playback is controlled by the Z80?
4. Does anyone know the sample rate of the Z80 sound driver found with ...

M-374 LX

nolddor wrote:how many levels are the game?

The level number is stored as a byte. As a result, the level number could be up to 255 and wrap back to 1.

However, the last playable level in my tests was around 20.

M-374 LX

Stef wrote:What tool do you use to compile your source ? the function should be included in sega.s boot file.

I use GCC under Linux.

The problem seems to be solved by linking one of the GCC libraries.

I found an "ldiv" label in the startup code.

M-374 LX

Crazy Driver is a simple homebrew driving game for Sega Genesis written mostly in C. Ports to Game Boy Advance and PC are also planned.

Gameplay
As the name suggests, you are a crazy driver in this game. All you want is to drive fast!

Crazy Driver is a simple driving game where you only need to ...

M-374 LX

If I try to do a division and compile, I get the following message:

Code: Select all

undefined reference to `__udivsi3'

What is the solution?

M-374 LX

Here is a simple tool to find hexadecimal color values for the Genesis I have written in JavaScript:

<html>
<head>
<script>
function getColor()
{
var r = parseInt(document.getElementById('r').value);
var g = parseInt(document.getElementById('g').value);
var b = parseInt(document.getElementById ...

M-374 LX

Thanks, Eke. It works now.
Optimizations were not needed, Chilly Willy.

M-374 LX

Do you mean I should add the volatile keyword before the declarations of the pointers (in the C files that have direct access to the hardware) and compile those files with -O1? If so, it did not work.

I had success accessing the VDP without the volatile keyword or optimizations.

M-374 LX

Here is my FM function to write a value to an FM register (part I only, as it is just a test):

void write_fm(uchar reg, uchar val)
{
uchar* ctrl = (uchar*)0xA04000;
uchar* data = (uchar*)0xA04001;

while(*ctrl & 0x80);
*ctrl = reg;

while(*ctrl & 0x80);
*data = val;

while(*ctrl & 0x80 ...

SpritesMind.Net

Search found 61 matches

Positron Wave (musical project)

Some questions about the Z80 and audio

Crazy Driver (simple but complete game)

"undefined reference to `__udivsi3'"

Simple JavaScript color tool

Unable to generate FM sound