ASSEMBLY LANGUAGE EXTENSION PREPROCESSOR

This application of STAGE2 to enhance assembly language programs with a few
control structures is included with this STAGE2 package mainly for example.
No user documentation is provided but it should not be difficult to see how
to use it by trying the examples provided.

	Examples:
		STAGE2 ALXTEST.ASM,ALXTEST.LST=ALX.MAC,ALXTEST.ALX

		STAGE2 BOUT.ASM,BOUT.LST=ALX.MAC,BOUT.ALX


IMPLEMENTATION NOTES:

	> means push   ^ means pop   C means condition

	Stack		Source Statements	Generated Code

	>n >K		IF ( C )			JCF	n

	^K ^n		    FIN			n:

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

	>n >n+1 >W	WHEN ( C )			JCF	n+1

	^W >E		    FIN				JMP	n

	^E ^n+1 >K	ELSE			n+1:

	^K ^n		    FIN			n:

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

	>B		BRANCH

			    ( V1 )  L1			CPI	V1
							JZ	L1

			    ( V2 | V3 | V4 )  L2	CPI	V2
							JZ	L2
							CPI	V3
							JZ	L2
							CPI	V4
							JZ	L2

			    ( OTHERWISE )  L3		JMP	L3

	^B		    FIN

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

	>n >S		SELECT

	>n+1 >I		    ( V1 )			CPI	V1
							JNZ	n+1

	^I ^n+1			FIN			JMP	n
						n+1:

	>n+3 >I		    ( V2 | V3 | V4 )		CPI	V2
							JZ	n+2
							CPI	V3
							JZ	n+2
							CPI	V4
							JNZ	n+3
						n+2:

	^I ^n+3			FIN			JMP	n
						n+3:

	>O		    ( OTHERWISE )

	^O			FIN

	^S ^n		    FIN			n:

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

	>n >n+1 >L	WHILE ( C )		n+1:	JCF	n

	^L ^n+1 ^n	    FIN				JMP	n+1
						n:

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

	>n >R		REPEAT			n:

	^R ^n		    UNTIL ( C )			JCF	n

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

	Statement is allowed if top of stack is one of the following:
	I,K,L,O,R,W,*.  Otherwise particular control statements are
	expected.

		I,K,L,O,W	statement or FIN

		R		statement or UNTIL

		E		ELSE only

		S		SELECT ITEM or FIN

		B		BRANCH ITEM or FIN