XTRAN Example — Translate HP (Compaq, Digital) MACRO-11 Assembler to C

This example uses the following XTRAN rules:

• The standard set of rules for parsing MACRO-11
• A rule for parsing invocations of the CALLNZ macro
• The standard set of rules for parsing C
• The standard set of rules for translating MACRO-11 to C
• A translation rule for the CALLNZ user macro that specifies the C code to which it should translate
• A standard set of rules for structuring C code
• The standard set of rules for rendering C
• The standard set of rules for styling rendered C code

NOTE that otherwise the translation shown below was done with default conditions.  XTRAN provides many options for controlling the way it translates.

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Process Flowchart

Here is a flowchart for this process, in which the elements are color coded:

• BLUE for XTRAN versions (runnable programs)
• ORANGE for XTRAN rules (text files)
• RED for code

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Input to XTRAN:

XFLGS	=	12		;SOME FLAGS
WARRNE	=	4		;WORD ARRAY NO. OF ELEMENTS
;
ENTRY:				;ENTRY POINT
	MOV	#BWS,R4		;PT TO BYTE WS
	CLR	R5		;INIT BYTE ARRAY SUBSCRIPT
	CLR	R3		;INIT WORD ARRAY SUBSCRIPT
	MOV	#WARRNE,R2	;LENGTH OF WORD ARRAY
LOOP:	MOV	(R0),WWS	;REMEMBER LAST WORD VALUE
	ADD	(R0)+,WARR(R3)	;UPDATE WORD ARRAY ELEMENT
	BLT	DONE		;IF NEG, QUIT
	BEQ	10$		;IF ZERO, DON'T CLEAR BYTE
	CLRB	BARR(R5)	;CLEAR BYTE ARRAY ELEMENT
	BICB	#XFLGS,(R4)	;CLEAR SOME FLAGS TOO
10$:
	ADD	#2,R3		;NEXT WORD ARRAY ELEMENT
	INC	R5		;NEXT BYTE ARRAY ELEMENT
	SOB	R2,LOOP		;IF MORE TO DO
	CALLNZ	@R1,SUBR,DONE	;CALL IF NONZERO
	BISB	#XFLGS,(R4)	;ADD FLAGS TO BYTE WS
	MOV	R1,@#A2		;SET ENTRY ADDR
	CLR	R0		;INIT RETURN VALUE
	BIS #<^C^D<12&14>!<25!13.>>,R0 ;ADD SOME FLAGS
DONE:	RTS	PC		;BACK TO CALLER
WARR:	.WORD	9.,8.		;WORD ARRAY OF VALUES
	.WORD	7
	.WORD	6
BARR:	.BYTE	1		;BYTE ARRAY OF VALUES
	.BYTE	2,3
	.BYTE	4
STR:	.ASCII	?String with?<15><12>/embedded/<14>
	.ASCIZ	+control characters+
BWS:	.BYTE	22.		;BYTE WORKING STORAGE
WWS:	.WORD	0		;WORD WORKING STORAGE
	.END

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Output from XTRAN:

	extern short a2;
	extern short *tmp0;
	extern short *tmp1;
	extern short tmp2;
	extern short tmp3;
	extern char *tmp4;
	extern short tmp5;
	extern unsigned short subr();

	static short warr[4] = {9, 8, 7, 6};	/*word array of values*/
	static char barr[4] = {1, 2, 3, 4};	/*byte array of values*/
	static char str[41] =
	  "String with\r\nembedded\fcontrol characters";
	char bws = 22;				/*byte working storage*/
	short wws = 0;				/*word working storage*/

#define XFLGS 012				/*some flags*/
#define WARRNE 4				/*word array no. of elements*/

entry:						/*entry point*/
	tmp4 = &bws;				/*pt to byte ws*/
	tmp5 = 0;				/*init byte array subscript*/
	tmp3 = 0;				/*init word array subscript*/
	tmp2 = WARRNE;				/*length of word array*/
loop:
	wws = *tmp0;				/*remember last word value*/
						/*update word array element*/
	if ((warr[tmp3 / 2] += *(tmp0++)) >= 0)	/*(XTR: rvsed) if neg, quit*/
	    {
	    if (warr[tmp3 / 2] != 0)		/*(XTR: rvsed) if zero, don't clear byte*/
		{
		barr[tmp5] = 0;			/*clear byte array element*/
		*tmp4 &= ~XFLGS;		/*clear some flags too*/
		}
	    tmp3 += 2;				/*next word array element*/
	    ++tmp5;				/*next byte array element*/
	    if (--tmp2 != 0)			/*if more to do*/
		goto loop;
	    if (!*tmp1)				/*call if nonzero*/
		{
		if (!subr())
		    goto done;
		}
	    *tmp4 |= XFLGS;			/*add flags to byte ws*/
	    a2 = tmp1;				/*set entry addr*/
	    tmp0 = 0;				/*init return value*/
	    tmp0 |= ~(12 & 14) | (025 | 13);	/*add some flags*/
	    }
done:
	return;					/*back to caller*/