Hector cassette format (Victor Interact Micronique)

gistfile1.txt

# Interact cassette format

The cassette content is made of successive records, each starting by a header, optionally followed
by some payload. Each record's action is determined by a type byte.

record header: [00 40 A0 A9 FE]
                |  |  |  |  ^ Tape record data type identifier
                |  |  `--+--> Bytes to read/fill [TPBYTS=(5FD6)]
                `--+--------> Dest memory address [TPSTRT=(5FD4)]

Record data type flags:
	0xFD: end of file. Call program at 0x4C00, must start with 0x31 (LD sp, #xxxx) (see 0x01CF)
	0xFE: bulk memory data (erase a memory region).
	0xFF(or anything else): tape data

Bulk memory data: expects one byte payload and fills memory with it. (see 0x027B)
  BulkByte -> [TPSTRT, TPSTRT + TPBYTS[
  
  Example: 00 40 A0 A9 FE 00
    Zeroes 0xA9A0 bytes starting from 0x4000

Tape data: expects a data block of size TPBYTS and copy to memory at TPSTRT. (see 0x02AE)

# .k7 file encoding

The k7 file data is cut into chunks, prefixed by one byte storing the size of the chunk.

[size1][data1 of size size1][size2][data2 of size size2]...

Note1: when size is 0, then the block is 256 bytes long

Note2: Mame uses the last byte of a block to detect bulk records and insert waiting time.
  Thus it is important to put bulk records in their own k7 chunk.

Example: [05] DB 5F 02 00 FF [02] E0 39
                     ---  ^        \ actual data
                      |   | 
                      |   ` tape data
                       ̀ length: 2 bytes
  Copy 2 bytes at 0x5FDB