Note: One of the algorithms is incorrect due to a missing operator. Need to update the image. Will have to get on that soon.
These are the original 32 algorithms as used in Yamaha DX7.
The later Yamaha FS1R and Yamaha SY77 may have compatibility with these algorithms, but that's beyond the current scope. The FS1R contains 88 algorithms, while the SY77 contains 45 algorithms.
| // Adler-32 | |
| // Appears simpler than Fletcher, yet even better (possibly due to a = 1). | |
| function adler32(data) { | |
| var a = 1, b = 0; | |
| for (var i = 0; i < data.length; i++) { | |
| a = (a + data[i]) % 65521; | |
| b = (b + a) % 65521; | |
| } | |
| return a | (b << 16); | |
| } |
| // #### ARRAY <-> STRING CONVERSION #### | |
| // b62 - reversible base62 encoder/decoder in two lines. | |
| function b62(n,c="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"){var r="",l=c.length,i=0; | |
| if(n.trim)while(i<n.length)r=l*r+c.indexOf(n[i++]);else while(n>0)r=c[n%l]+r,n=Math.floor(n/l);return r} | |
| // arst is a reversible string<>array utility in one line. It converts a string to an array of integers and back. | |
| // ES6 (shorter) | |
| arst=a=>{return a.trim?[...a].map(a=>a.charCodeAt()):String.fromCharCode.apply(0,a)} |
| Scream Tracker | |
| <<<<< USERS MANUAL >>>>> | |
| (C) 1990 Sami Tammilehto | |
| ============================================================================== |
| <links> | |
| <entry name="Project 2612 - Mega Drive Music Archive" url="http://project2612.org/"/> | |
| <entry name="SMSPower/VGM - Sega 8-bit Music Archive" url="http://www.smspower.org/Music/VGMs"/> | |
| <entry name="SNES Music - SNES Music Music Archive" url="http://snesmusic.org/v2/"/> | |
| <entry name="NSF Directory - Nintendo Music" url="http://nsf.joshw.info/"/> | |
| <entry name="Zophar/disch - NSFE Archive" url="http://disch.zophar.net/nsfe.php"/> | |
| <entry name="melcom's Chiptune Archive - YM, MOD, Adlib" url="http://chiptunes.back2roots.org"/> | |
| <entry name="USF @ hcs64 - Nintendo 64 Music" url="http://usf.hcs64.com/"/> | |
| <entry name="" url="http://kss.joshw.info/"/> | |
| <entry name="" url="http://hes.joshw.info/"/> |
| /* | |
| Optimized CRC-16 for 0x1021 (unreflected) | |
| ---- | |
| With this code, (5) CRC-16 variants can be modelled: | |
| crc=0x0000, xorout=0x0000 = CRC-16/XMODEM (default) | |
| crc=0xFFFF, xorout=0x0000 = CRC-16/IBM-3740 | |
| crc=0xFFFF, xorout=0xFFFF = CRC-16/GENIBUS | |
| crc=0x0000, xorout=0xFFFF = CRC-16/GSM |
| // BSD-16 | |
| // From: en.wikipedia.org/wiki/BSD_checksum | |
| function bsd16(data) { | |
| for(var i = 0, c = 0; i < data.length; i++) { | |
| c = (c>>1) + ((c&1) << 15); | |
| c += data[i]; | |
| c &= 0xffff; | |
| } | |
| return c; | |
| } |
| /* | |
| Cyclic redundancy check (CRC-4, CRC-8, CRC-16, CRC-32) | |
| Common CRC implementation supporting wide range of configurations: | |
| http://reveng.sourceforge.net/crc-catalogue/all.htm | |
| NOTE: These common polynomials are likely suboptimal. | |
| In the future I should make a page of Koopman's best general purpose polynomials. | |
| http://github.com/bryc |
| /* | |
| Optimized Alea | |
| ---------------------- | |
| Based on Alea by Johannes Baagøe (2010) which is based on MWC by George Marsaglia and Arif Zaman (1991). | |
| Should be fast and pass BigCrush statistical test suite. It's quite fast but the quality is unverified. | |
| Used like so: | |
| var rand = Alea("test123"); | |
| rand(); // 0.7390809920616448 | |
| rand(); // 0.3916741746943444 |