1802 HHC software

the original software in the HHC was based on the Forth Inc dictionary structure (names stored as 1 length byte and 1st 3 bytes of name) - this compact method allowed for more code to be squeezed into the available RAM

the initial system software included a Forth code word set, a Forth threaded word set, Forth compiler, a 'Block' screen editor, cassette 'Block' I/O, serial printer,  and low-level monitor for installation support, using a total of 10Kb of memory

this was initially hand-coded and then loaded using a multi-stage bootstrapping process:-
 - a DMA loader routine was entered using the loader switches
 - a Forth monitor routine was loaded using the DMA loader routine & switches
 - sufficient code was entered as hex values using the monitor  &
       keyboard to provide an operational Forth compiler
 - subsequent software was then entered as Forth source, using the keyboard
 - the system software was then saved to cassette tape as 1Kb blocks for backup

a few years ago i upgraded the code from the original Forth Inc style to a combination of Forth-79 and FIG Forth and upgraded the bootstrapping process to load software from a PC using either the serial connection or the bootloader board adapted for a parallel port connection

i wrote cross-assembly / cross compilation software for the 1802 using a DOS-window  version of Forth 83, but i've now updated that cross-development code to operate with Win32Forth, the full Windows and ANSI version of Forth

i've been experimenting recently with an MMC / SD card interface for the HHC - a minimal hardware circuit and source code in my version of Forth 79 / FIG Forth is available via the 'mmc card' menu item on the left