Motorola 24-Bit Digital Signal Processor manual DSP56K Central Processing Module Programming Model

PROGRAMMING MODEL

DATA ARITHMETIC LOGIC UNIT

INPUT REGISTERS

47		X		0
		X1		X0
23	0	23	0

47	Y		0
	Y1		Y0
23	0	23	0

ACCUMULATOR REGISTERS

			55				A			0
			#		A2		A1			A0
		23	8 7		0	23		0 23		0
				55			B			0
			#		B2		B1			B0
		23	8 7		0	23		0 23		0
					ADDRESS GENERATION UNIT
23	16 15	0	23		16 15		0	23	16 15	0

*R7

*R6

*R5

*R4

*R3

*R2

*R1

*R0

POINTER

REGISTERS

*	N7	*	M7
				UPPER FILE
*	N6	*	M6
*	N5	*	M5
*	N4	*	M4
*	N3	*	M3
*	N2	*	M2
*	N1	*	M1	LOWER FILE
*	N0	*	M0
	OFFSET		MODIFIER
	REGISTERS		REGISTERS

PROGRAM CONTROL UNIT

23 16 15 0 23 16 15 0

*

LOOP ADDRESS REGISTER (LA)

*

LOOP COUNTER (LC)

23	16 15			0 23	16 15			8 7
*					*		MR		CCR
							STATUS
			PROGRAM
		COUNTER (PC)				REGISTER (SR)
31			SSH	16 15			SSL

0
		23				8	7	6	5	4	3	2	1	0
					*		*	SD	*	MC	YD	DE	MB	MA
			OPERATING MODE REGISTER (OMR)
0
				23	6	5								0
	1				*

STACK POINTER (SP)

* READ AS ZERO, SHOULD BE WRITTEN WITH ZERO FOR FUTURE COMPATIBILITY

# READ AS SIGN EXTENSION BITS,

SYSTEM STACK

15

WRITTEN AS DON’T CARE

Figure 5-9 DSP56K Central Processing Module Programming Model

5 - 18 PROGRAM CONTROL UNIT MOTOROLA