Graphics Mode 2
This mode is concerned with both repeating bytes and conventional non-repeating bytes. The data bytes occur in groups of variable length. The first byte of a group indicates whether a repeated byte or a series of unrepeated bytes follow. If the first byte has a value from [00] to [7F] then it indicates a number of unrepeated bytes follow. A value of [00] represents one unrepeated byte, and a value of [7F] represents 128 unrepeated bytes. If the first byte has a value from [80] to [FF] then it indicates a repetition of the following byte. A value of [FF] represents one repetition (two occurrences), and a value of [80] represents 128 repetitions. If you wanted to print a pattern represented by the following thirteen data bytes in mode 0: [FF][FF][FF][FF][00][18][00][FF][FF][FF][FF] you could compress this data in mode 2 to just eight bytes: [FC][FF][02][00][18][00][FC][FF].
Bye...
Uwe
