Microcontroller User's Manual
3-12 MCF5282 User’s Manual MOTOROLA
EMAC Instruction Set Summary
3.5 EMAC Instruction Set Summary
Table 3-3 summarizes EMAC unit instructions.
3.5.1 EMAC Instruction Execution Times
The instruction execution times for the EMAC can be found in Section 2.12, “EMAC
Instruction Execution Times.”
The EMAC execution pipeline overlaps the AGEX stage of the OEP; that is, the first stage
of the EMAC pipeline is the last stage of the basic OEP. EMAC units are designed for
sustained, fully-pipelined operation on accumulator load, copy, and multiply-accumulate
instructions. However, instructions that store contents of the multiply-accumulate
programming model can generate OEP stalls that expose the EMAC execution pipeline
depth, as in the following:
mac.w Ry, Rx, Acc0
mov.l Acc0, Rz
Table 3-3. EMAC Instruction Summary
Command Mnemonic Description
Multiply Signed MULS <ea>y,Dx Multiplies two signed operands yielding a signed result
Multiply Unsigned MULU <ea>y,Dx Multiplies two unsigned operands yielding an unsigned result
Multiply Accumulate MAC Ry,RxSF,ACCx
MSAC Ry,RxSF,ACCx
Multiplies two operands and adds/subtracts the product to/from an
accumulator
Multiply Accumulate
with Load
MAC Ry,Rx,<ea>y,Rw,ACCx
MSAC Ry,Rx,<ea>y,Rw,ACCx
Multiplies two operands and combines the product to an
accumulator while loading a register with the memory operand
Load Accumulator MOV.L {Ry,#imm},ACCx Loads an accumulator with a 32-bit operand
Store Accumulator MOV.L ACCx,Rx Writes the contents of an accumulator to a CPU register
Copy Accumulator MOV.L ACCy,ACCx Copies a 48-bit accumulator
Load MACSR MOV.L {Ry,#imm},MACSR Writes a value to MACSR
Store MACSR MOV.L MACSR,Rx Write the contents of MACSR to a CPU register
Store MACSR to CCR MOV.L MACSR,CCR Write the contents of MACSR to the CCR
Load MAC Mask Reg MOV.L {Ry,#imm},MASK Writes a value to the MASK register
Store MAC Mask Reg MOV.L MASK,Rx Writes the contents of the MASK to a CPU register
Load AccExtensions01 MOV.L {Ry,#imm},ACCext01 Loads the accumulator 0,1 extension bytes with a 32-bit operand
Load AccExtensions23 MOV.L {Ry,#imm},ACCext23 Loads the accumulator 2,3 extension bytes with a 32-bit operand
Store AccExtensions01 MOV.L ACCext01,Rx Writes the contents of accumulator 0,1 extension bytes into a CPU
register
Store AccExtensions23 MOV.L ACCext23,Rx Writes the contents of accumulator 2,3 extension bytes into a CPU
register