Search found 92 matches

by GManiac
Wed Oct 03, 2012 4:14 pm
Forum: SGDK
Topic: How to declare boolean on SGDK?
Replies: 6
Views: 2514

And in C it's well known that FALSE is 0 and TRUE is not 0 :) AFAIR, C defines TRUE as 1. But with 68k it's better to use -1 (#$FF, 255). Why? Because value -1 is invariant in logical and bitwise operators: not( 0 ) = -1 not( FALSE ) = TRUE 68k has even special instructions Scc which set byte to 0 ...
by GManiac
Fri Jun 01, 2012 3:06 pm
Forum: Megadrive/Genesis
Topic: Good books for learning Assembly Language?
Replies: 14
Views: 5170

Once I learned programming in asm for Genesis reading these docs
http://www.ticalc.org/pub/text/68k/
You may read "68kguide.txt" first.
by GManiac
Tue Apr 17, 2012 6:06 pm
Forum: Hardware
Topic: Undocumented YM2612 register $2C
Replies: 13
Views: 9455

Everything okay:
When I wrote this they really didn't work :)
by GManiac
Tue Apr 17, 2012 5:41 pm
Forum: Hardware
Topic: Undocumented YM2612 register $2C
Replies: 13
Views: 9455

Bits 6 and 7 are very useful, as they allow the internal 14-bit output data from the operator unit to be read out over the status register
Awesome! I would like to know this in 2009 :) Regretfully, now I'm not very interested in all this stuff about YM.

Your links don't work...
by GManiac
Mon Apr 16, 2012 4:29 pm
Forum: Hardware
Topic: Undocumented YM2612 register $2C
Replies: 13
Views: 9455

Heh, in my tests I discovered that bit 5 in $2C makes channels silent. I tested Channel 1 in Alg 7. I didn't guess to test DAC mode :) The FM test register at 0x21 has the upper 6 bits with a known function, with the lower 2 bits with no know function. What are these functions excatly? I made tests ...
by GManiac
Fri Apr 13, 2012 4:25 pm
Forum: Blabla
Topic: New game Mr. Nutz 2 [SMD]
Replies: 3
Views: 3660

It's not released, it was compiled by MetalliC from emu-land
http://www.emu-land.net/forum/index.php ... #msg838076
by GManiac
Tue Oct 25, 2011 7:32 pm
Forum: Megadrive/Genesis
Topic: New idea for a cart dumper, would it be useful?
Replies: 31
Views: 8149

This idea is not new :) Not hot-switching of carts nor "audio dumping". For example,
http://www.emu-land.net/forum/index.php ... 1753.0;all
(in Russian).
by GManiac
Fri Oct 21, 2011 4:21 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 406016

Hmm - does the FM channel still update even if it is set to PCM? Yes, it does. FM Channel 6 and Reg $2A are independent of each other. "DAC mode" (Reg $2B) only chose output of one of them. If it is in "FM Mode" it outputs Channel 6 output. If it is in "DAC Mode", it outputs value stored in Reg $2A...
by GManiac
Thu Aug 11, 2011 5:31 am
Forum: Sound
Topic: YM2612 - prescaler init question
Replies: 4
Views: 1834

Hmm, my first thought was about real prescaler (regs $2D-2F)... Example: clock_rate = 7 670 000 channels = 6 operators per channel = 4 cycles per operator = 6 Channel_freq = 7670000 / 6 / 4 / 6 = 53263 If you increase number of channels without changing clock_rate, Channel_freq will decrease and sou...
by GManiac
Sun May 29, 2011 10:42 am
Forum: Sound
Topic: YM2612 shape of envelope attack
Replies: 7
Views: 3866

For values > 1 the formula should be att += template_step * (not (att)) >> 4 Maybe it's a bit incorrect. It's hard to test increasings when template_step is 2 or more, because of pretty high values of AR to get it and pretty short periods between ATTACK steps. template_step is taken from EG_TEMPLATE...
by GManiac
Sun May 29, 2011 10:33 am
Forum: Blabla
Topic: The death march
Replies: 11
Views: 3701

they are paid at least $24K (in California, at least $34K, I believe)
For month or for year? :) In first case it's very high cost, but in second case it's not normal for such loaded work, imho.
by GManiac
Sat May 28, 2011 12:41 pm
Forum: Sound
Topic: YM2612 shape of envelope attack
Replies: 7
Views: 3866

EG uses next formula for ATTACK RATE = 1 att += not(att) asr 4 When I tried to get template of EG attack values on hardware I used modualtion of oscillator by sum of 2 operators (algo 5, as far as I remember). Modulators were at sin256 phase (maximum), frequency = 0, TL = 0, amplitude at start = 0. ...
by GManiac
Sat Mar 19, 2011 4:39 pm
Forum: Tools
Topic: Disassembly
Replies: 12
Views: 6318

I moved to another OS and another HDDs :) All in mess, so now I "lost" some of my tools. Here is nlz of MUSHA by old version of Analyzer (which I found in one of my numerous folders; new version is somewhere in archives). http://shedevr.org.ru/ghost/musha.rar Simply disasm this ROM. My disassembler ...
by GManiac
Sat Mar 19, 2011 4:17 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 406016

No, we've discussed this. Glitch in DAC. Sine table is normal, I tested it using phase modulation.
by GManiac
Sat Mar 19, 2011 12:56 pm
Forum: Sound
Topic: New Documentation: An authoritative reference on the YM2612
Replies: 859
Views: 406016

Okay, I understand. And if you run this test on MD1 you should see only 2 steps: from -1 to 0 and from 0 to +1. You won't see step from -2 from -1 because of glitch, so level "-1" will be last longer on X axis. And step -1 to 0 will be HUGE (that is ladder effect). Also, I noticed another glitch in ...