Binary file

A CoCo binary file can contain sheer data or one or more executable machine language programs. They can be loaded into memory from disk using the LOADM command or from tape using the CLOADM command. Included in the format is the load address of the binary as well as an execution address. They may contain multiple loadable sections each having its own load address. A section starts with a five byte long preamble of which the first byte is $00, the following two bytes specify the length of the data block to be loaded, and the last two bytes specify the start address in RAM the data block is to be loaded at. This is then followed by the actual bytes comprising ML code and/or any data. The data block can be followed by another preamble to a new section with more data/code or is terminated with a postamble. The postamble is also five bytes in length, with the first one being $FF, the next two being $00, and the last two forming the execution address for the ML program in the binary file, if any. Pure data blocks are typically 256 bytes long, whereas a ML program usually is a single block the size of the program, depending on how it was assembled.

00	length	start address
program/data block
FF	00 00	execution address

Loading from tape

Tape files have a slightly different format:

1. A leader of 128 bytes of $55

1. Namefile block

1. 0.5 sec blank

1. 128 bytes $55

1. data blocks

1. end of file block

Namefile block 15 bytes of data

1. 8 bytes for name

1. file type byte; Basic=0, data=1, ML=2

1. ascii flag; binary=0, ascii=$FF

1. gap flag byte; continuous=1, gaps=$FF - this byte may not be used

1. 2 bytes; start address

1. 2 bytes; load address

Block headers

1. $55

1. $3C sync byte

1. block type; name=0, data=1, EOF=$FF

1. block length byte; value 0-255

1. data; 0-255 bytes

1. checksum

1. $55

EOF block

1. No data bytes