--------------------------------------------------------------------
    -- Copyright (C) 2002,2003  Allen Brown
    -- 
    -- This program is free software; you can redistribute it and/or modify
    -- it under the terms of the GNU General Public License version 2 as
    -- published by the Free Software Foundation.
    -- 
    -- This program is distributed in the hope that it will be useful,
    -- but WITHOUT ANY WARRANTY; without even the implied warranty of
    -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    -- GNU General Public License for more details.
    -- 
    -- You should have received a copy of the GNU General Public License
    -- along with this program; if not, write to the
    --   Free Software Foundation, Inc.
    --   59 Temple Place, Suite 330
    --   Boston, MA  02111-1307  USA
    -- 
    -- To contact the author of this software:
    --   Allen Brown
    --   PO Box J
    --   Corvallis, OR
    -- 
    --   http://brown.armoredpenguin.com/~abrown/contact.html
    --------------------------------------------------------------------

Pbasic simulation translator:


Pbasic is case insensitive.
Translate all variables and addresses to lower case.

Use the following shorthand:
  define $an = \([a-z][a-z0-9_]+\)
  define $nu = \(-?[0-9].?[0-9]+\)

from pbasic		to C				comment
------------		-----				----------------
'\(.*\)			//\1				PBasic comments are
							directly converted
							to C comments.
$an var byte
$an var $an.$an						Too complex to summarize.
							But the upshot is that
							all var declarations
							are handled.
$an con <expr>		#define \1 <expr>

output			pboutput();			Currently stubbed.
input			pbinput();			"
high			pbhigh();			"
low			pblow();			"

$an = <expr>		pblet(&\1,<expr>);

if <expr1> = <expr2> then $an:
			if( pbeq(<expr1>,<expr2>) ) goto \3;
							All if compares, not
							just = supported.
							if/then/else/endif
							supported.
put $nu,$nu		pbput(pbconst(\1),pbconst(\2);
put $nu,$an		pbput(pbconst(\1),\2);
get $nu,$an		pbget(&\2,pbconst(\1));
gosub $an:						Complex.  See the code.
return			goto gosubreturnc;		Unwind the stack that
							was pushed at the
							gosub call.
goto $an:		goto \1

serin			pbserin				Complex.  See the code.
serout			pbserout			"
shiftout		pbshiftout			"
lookup							Complex.  See the code.
debug			printf("DEBUG: ...",...)	Must end with CR.
							Ignores DEC/HEX, but
							always outputs both.

----------------------------------------------------------
		Parts of Expressions

abs(<expr>)		pbabs(<expr>)
not(<expr>)		pbnot(<expr>)

<expr> MAX <expr>	pbmax(<expr>,<expr>)
<expr> MIN <expr>	pbmin(<expr>,<expr>)
<expr> + <expr>		pbadd(<expr>,<expr>)
<expr> - <expr>		pbsub(<expr>,<expr>)
<expr> * <expr>		pbmul(<expr>,<expr>)
<expr> / <expr>		pbdiv(<expr>,<expr>)
<expr> \ <expr>		pbmod(<expr>,<expr>)
<expr> << <expr>	pbshl(<expr>,<expr>)	shift left
<expr> >> <expr>	pbshr(<expr>,<expr>)	shift right
<expr> = <expr>		pbeq(<expr>,<expr>)
<expr> <> <expr>	pbne(<expr>,<expr>)
<expr> > <expr>		pbgt(<expr>,<expr>)
<expr> < <expr>		pblt(<expr>,<expr>)
<expr> >= <expr>	pbge(<expr>,<expr>)
<expr> <= <expr>	pble(<expr>,<expr>)
<expr> and <expr>	pbland(<expr>,<expr>)	Logical
<expr> or <expr>	pblor(<expr>,<expr>)
<expr> xor <expr>	pblxor(<expr>,<expr>)
<expr> & <expr>		pbband(<expr>,<expr>)	Bitwise
<expr> | <expr>		pbbor(<expr>,<expr>)
<expr> ^ <expr>		pbbxor(<expr>,<expr>)
~ <expr>		pbbnot(<expr>)
(<expr>)						Parenthesis supported.

----------------------------------------------------------
	Not implemented

[]			Brackets don't seem to provide useful information.

Also, full syntax checking of the .bsx source file is not done.
It is possible to write code that works on this simulator but
which is not valid .bsx.

OTOH, some valid .bsx will not compile.  In particular, .bsx
is cavalier about where variables may be declared.  C is far
more restrictive.  If you place all of your declarations at
the beginning of the .bsx file, you will not have trouble with
either the simulator or the Basic Stamp.

----------------------------------------------------------