from Dr Ian Logan, 4th September1984
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SINCLAIR  LOGO

Notes on interfacing to  ROBOT  BIN  files .

The command  STARTROBOT  looks in memory for a suitable
file, if this is not found then an attempt is made to load a
machine code file from the current default device. The file
has to be called  ROBOT  BIN   (ten characters) and  must  have
as its first two bytes the load address of the code, no notice 
is taken of the load address supplied by the normal Sinclair
file header. These first bytes may be corrupted once the code 
has loaded so before making a copy from within Logo they must be 
replaced. The bytes occur in the order Low byte, High byte.

In the case of a ROBOT  BIN  file which wishes to make
use of the automatic parameter passing facilities built into 
Logo  the file must reside at  64623 (decimal), and so the 
first two bytes are  64621  111  and  64622  252.

The first block of the code must then consist of a jump
table to deal with all turtle related commands.

If these parameter passing facilities are not required 
the STOPTURTLE command must be used immediately after loading 
and the code can be placed elsewhere in memory.

STARTROBOT automatically moves the pointers to the top 
of available workspace, using PRINT .RESERVED before and
after loading ROBOT BIN will show this .

STARTROBOT   must be used before any procedures are 
written othewise the Logo error message LOGO not fresh !!! will
be produced.

In version 1.6 of Logo (the current release version ) any 
attempt to break out of searching for a ROBOT BIN file from 
cassette (default drive O) will result, unfortunately in a 
total system restart, which can be annoying. This feature does 
not occur when using Microdrive.

This is the jump table required

JP	INIT		:0 - INIT	ARG	--)HL
JP	FD		:1 - FD 	HL	(--ARG
JP	BK		:2 - BK 	HL	(--ARG
JP	RT		:3 - RT 	HL	(--ARG
JP	LT		:4 - LT 	HL	(--ARG
JP	PU		:5 - PU		NO  ARG
JP	PD		:6 - PD		NO  ARG
JP	RETURN		:7 - PX		NO  ARG
JP	RETURN		:8 - PE		NO  ARG
JP	RETURN		:9 - SETH 	HL    (--ARG
JP	RETURN		:10- SETSCRUNCH	HL (--ARG1 DE (--ARG2
JP	RETURN		:11- SETPC	HL	(--ARG
JP	RETURN		:12- SETPOS	HL (--ARG1 DE (--ARG2
JP	RETURN		:13- CLEAN	NO  ARG
JP	RETURN		:14- HEADING	ARG   --)HL
JP	RETURN		:15- POS	ARG1  --)HL ARG2 --)DE
JP	RETURN		:16- PC		ARG   --)HL
JP	RETURN		:17- SETBG	HL     (--ARG
JP	RETURN		:18- BG		ARG	--)HL
JP	BEEP		:19- BEEP	HL   (--ARG1 DE (--ARG2

A RETURN in column two indicates that this command is not 
implemented in the turtle driver code, any command could be 
used or not as desired. It is desirable that keyboard reads are 
included at suitable points to allow an abort of the code if for 
any reason the turtle hangs up and cannot complete a movement.
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Supplementary notes
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"ROBOT  BIN" file relocated by LOGO to end at 65000-1
at start of file are 20 C3 (195 dec) separated by two bytes apiece
this is the jump table.
The raw file must have at the start before the first C3 the low and 
high bytes of the address of the first C3 so LOGO knows where to put 
it, these are discarded on loading.