Freescale Semiconductor MCF5480 - Manual (Page 159)

EMAC Instruction Set Summary
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 4-11
4.3 EMAC Instruction Set Summary
Table 4-3 summarizes EMAC unit instructions.
4.3.1 EMAC Instruction Execution Timing
The instruction execution times for the EMAC can be found in Section 3.7, “Instruction Execution
Timing.”
The ColdFire family supports two multiply-accumulate implementations that provide different levels of
performance and capability for differing silicon costs. The EMAC features a four-stage execution pipeline,
optimized for 32-bit operands with a fully-pipelined 32 × 32 multiply array and four 48-bit accumulators.
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
move.l Acc0, Rz
Table 4-3. 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