BBC BASIC for the Commodore 64
==============================
Uses standard BBC HiBASIC II relocated to &B800.
Host interface code at &B000-&B700 and &F800-&FFFF.

26-Feb-2013, v0.23:
- Screen moved to top of memory, allows standard 6502 BBC BASIC with
  workspace at &400 to be dropped straight in. Also allows different screen
  modes to be used with free memory at the top of BASIC's memory being used,
  as in other environments.

20-Feb-2013, v0.22:
- SAVE implemented.

15-Feb-2013, v0.21:
- OSBYTE, OSWORD, OSRDCH in high memory.
- VDU queue and dispatch.
- COLOUR, VDU 20, TAB, MODE (all MODEs are MODE 1).
- OSWORD &05 (RdMem), OSWORD &06 (WrMem), OSBYTE &80 (ADVAL) (currently
  just reads Kernal/IO memory).
- Flashing cursor enabled, removed during character output.

10-Feb-2013, v0.20:
- Seperated Host Interface code from BASIC source, can now develop
  seperately without interdependencies.
- LOAD calls OPEN with secondary address=0 (reading) instead of 2 (writing).

04-Feb-2013, v0.15:
- OSWORD &01 (=TIME) returns count in 1/100s.
- LOAD and LOAD (notfound) works, READST needed to be checked before
  entering load loop.
- C64 error values translated into BBC errors.
- "d:filename" filenames implemented.
- If loading from tape, prompts to RECORD instead of PLAY. Also, if
  Stop/Escape pressed, leaves channel open and can't load from a
  different device.

03-Feb-2013, v0.14:
- Code has "BBCBASIC" title.
- OSWORD dispatch integrated into OSBYTE dispatch.
- OSWORD &00 (RDLINE).
- OSWORD &01 (=TIME) - returns in 1/60s, needs converting to 1/100s.
- CALL/USR to &64xxxx calls with C64 Kernal and I/O paged in.
- Made a start on OSFILE for loading. LOAD works, but LOAD (notfound)
  reads a single byte before giving an error, causing Bad program if
  loading a program.

02-Feb-2013, v0.13:
- OSBYTE dispatch code.
- Minimal OSBYTE implemented, calls &00, &7C-&87 return minimal results.

01-Feb-2013, v0.12:
- BBC API at &FFxx when Kernal switched out. NMI also pages in C64 Kernal.

31-Jan-2013, v0.11:
- Worked out how to switch out active Kernal, full 64K RAM used, IRQs page
  in C64 Kernal. Code moved up to &B000-&FFFF.

28-Jan-2013, v0.10:
- OSWRCH, OSRDCH, BRK error blocks implemented. Keyboard input and screen
  output characters are translated to regular ASCII. Only one-byte control
  characters implemented so far.