.TITLE	SWPBYT
	.GLOBL	SWPBYT,WRDSWP
;SWAP BYTES  -  SWPBYT
;CALL SWPBYT(ADDR, NBYTES)
;
;SWAP WORD PAIRS - WRDSWP
;CALL WRDSWP(ADDR, NBYTES)
SWPBYT:	MOV	R0,-(SP)
	MOV	R1,-(SP)	;SAVE REGS USED
	MOV	2(R5),R0	;GET ADDR
	BEQ	1$		;0 ILLEGAL
	BIT	#1,R0
	BNE	1$		;ALSO ODD ILLEGAL
	MOV	@4(R5),R1	;GET NBYTES
	BEQ	1$		;ZERO ILLEGAL
	ASR	R1		;DIVIDE BY 2
	TST	R1
	BLE	1$		;MUST BE POSITIVE
2$:	SWAB	(R0)+		;MUNG STUFF
	DEC	R1
	BGT	2$		;DO ALL WE MUST
1$:
	MOV	(SP)+,R1
	MOV	(SP)+,R0
	RTS	PC
WRDSWP:	MOV	R0,-(SP)
	MOV	R1,-(SP)
	MOV	R2,-(SP)	;SWAP WRD PAIRS
	MOV	2(R5),R0	;GET ADDR
	BEQ	1$		;0 ILLEGAL
	BIT	#1,R0
	BNE	1$		;ALSO ODD ILLEGAL
	MOV	@4(R5),R1	;GET NBYTES
	BEQ	1$		;ZERO ILLEGAL
	ASR	R1		;DIVIDE BY 2
	ASR	R1		;DIVIDE BY 2
	TST	R1
	BLE	1$		;MUST BE POSITIVE
2$:	MOV	(R0)+,R2	;SAVE 1ST WORD
	MOV	@R0,-2(R0)	;COPY DOWN
	MOV	R2,(R0)+	;THEN COPY UP
	DEC	R1		;COUNT LOOP DOWN
	BGT	2$
1$:	MOV	(SP)+,R2
	MOV	(SP)+,R1
	MOV	(SP)+,R0
	RTS	PC
	.END