3 ms·
Something here: https://www.c64-wiki.com/wiki/Transwarp https://www.c64-wiki.com/wiki/Transwarp Also: "Plain Commodore GCR encodes 4 bytes raw to 5 bytes on di
by bonzini 4y ago
Something here: https://www.c64-wiki.com/wiki/Transwarp https://www.c64-wiki.com/wiki/Transwarp
Also: "Plain Commodore GCR encodes 4 bytes raw to 5 bytes on disk, Transwarp encodes 3.5 bytes raw to 5 bytes on disk. (Thus only 223 = $df instead of 256 bytes per block, the 224th byte is the checksum.)
One trick is to encode those 3.5 bytes using a subset of plain Commodore GCR, such that it works just fine with d64 and regular transfer/copy solutions. Part of that trick is that decoding a GCR byte drive-side just takes a table lookup (4 cycles). =)"