Analog Devices ADSP-21020 manual Mrf Mrb = Mrf, = Mrb Mrf = Mrf = Sat Mrf = Sat Mrb

ADSP-21020

				Table V. Multiplier Compute Operations
Rn	= Rx * Ry (	S	S	F	)	Fn	= Fx * Fy
MRF		U	U	I
MRB				FR

Rn	= MRF	+ Rx * Ry (		S	S	F	)
Rn	= MRB			U	U	I
MRF	= MRF					FR
MRB	= MRB
Rn	= SAT MRF		(SI)
Rn	= SAT MRB		(UI)
MRF	= SAT MRF		(SF)
MRB	= SAT MRB		(UF)
MRF	= 0
MRB

Rn	= MRF	– Rx * Ry (		S
Rn	= MRB			U
MRF	= MRF
MRB	= MRB
Rn	= RND MRF		(SF)
Rn	= RND MRB		(UF)
MRF	= RND MRF
MRB	= RND MRB

S F )

UI FR

	MRxF		= Rn		Rn	=	MRxF
	MRxB						MRxB
Rn, Rx, Ry			R15–R0; register file location, fixed-point
Fn, Fx, Fy			F15–F0; register file location, floating-point
MRxF			MR2F, MR1F; MR0F; multiplier result accumulators, foreground
MRxB			MR2B, MR1B, MR0B; multiplier result accumulators, background
(		x-input	y-input	data format,	)
				rounding

SSigned input

U Unsigned input

I Integer input(s)

F Fractional input(s)

FR	Fractional inputs, Rounded output
(SF)	Default format for 1-input operations
(SSF)	Default format for 2-input operations

Table VI. Shifter and Shifter Immediate Compute Operations

Shifter	Shifter Immediate
Rn = LSHIFT Rx BY Ry	Rn = LSHIFT Rx BY<data8>
Rn = Rn OR LSHIFT Rx BY Ry	Rn = Rn OR LSHIFT Rx BY<data8>
Rn = ASHIFT Rx BY Ry	Rn = ASHIFT Rx BY<data8>
Rn = Rn OR ASHIFT Rx BY Ry	Rn = Rn OR ASHIFT Rx BY<data8>
Rn = ROT Rx BY RY	Rn = ROT Rx BY<data8>
Rn = BCLR Rx BY Ry	Rn = BCLR Rx BY<data8>
Rn = BSET Rx BY Ry	Rn = BSET Rx BY<data8>
Rn = BTGL Rx BY Ry	Rn = BTGL Rx BY<data8>
BTST Rx BY Ry	BTST Rx BY<data8>
Rn = FDEP Rx BY Ry	Rn = FDEP Rx BY <bit6>: <len6>
Rn = Rn OR FDEP Rx BY Ry	Rn = Rn OR FDEP Rx BY <bit6>:<1en6>
Rn = FDEP Rx BY Ry (SE)	Rn = FDEP Rx BY <bit6>:<1en6> (SE)
Rn = Rn OR FDEP Rx BY Ry (SE)	Rn = Rn OR FDEP Rx BY <bit6>:<1en6> (SE)
Rn = FEXT Rx BY Ry	Rn = FEXT Rx BY <bit6>:<1en6>
Rn = FEXT Rx BY Ry (SE)	Rn = FEXT Rx BY <bit6>:<1en6> (SE)
Rn = EXP Rx
Rn = EXP Rx (EX)
Rn = LEFTZ Rx
Rn = LEFTO Rx

Rn, Rx, Ry R15-R0; register file location, fixed-point

<bit6>:<len6> 6-bit immediate bit position and length values (for shifter immediate operations)

–10– REV. C