Motorola ColdFire MCF5281 - Manual (Page 90)

Enhanced Multiply-Accumulate Unit (EMAC)
3-12 Freescale Semiconductor
movem.l (a7),#0x00ff ; restore the state from memory
move.l #0,macsr ; disable rounding in the macsr
move.l d0,acc0 ; restore the accumulators
move.l d1,acc1
move.l d2,acc2
move.l d3,acc3
move.l d4,accext01 ; restore the accumulator extensions
move.l d5,accext23
move.l d6,mask ; restore the address mask
move.l d7,macsr ; restore the macsr
Executing this sequence type can correctly save and restore the exact state of the EMAC programming
model.
3.3.1.3 MULS/MULU
MULS and MULU are unaffected by fractional-mode operation; operands remain assumed to be integers.
3.3.1.4 Scale Factor in MAC or MSAC Instructions
The scale factor is ignored while the MAC is in fractional mode.
3.3.2 EMAC Instruction Set Summary
Table 3-8 summarizes EMAC unit instructions.
Table 3-8. EMAC Instruction Summary
Command Mnemonic Description
Multiply Signed muls y,Dx Multiplies two signed operands yielding a signed result
Multiply Unsigned mulu 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,y,Rw,ACCx
msac Ry,Rx,y,Rw,ACCx
Multiplies two operands and combines the product to an
accumulator while loading a register with the memory operand
Load Accumulator move.l {Ry,#imm},ACCx Loads an accumulator with a 32-bit operand
Store Accumulator move.l ACCx,Rx Writes the contents of an accumulator to a CPU register
Copy Accumulator move.l ACCy,ACCx Copies a 48-bit accumulator
Load MACSR move.l {Ry,#imm},MACSR Writes a value to MACSR
Store MACSR move.l MACSR,Rx Write the contents of MACSR to a CPU register
Store MACSR to CCR move.l MACSR,CCR Write the contents of MACSR to the CCR
Load MAC Mask Reg move.l {Ry,#imm},MASK Writes a value to the MASK register
Store MAC Mask Reg move.l MASK,Rx Writes the contents of the MASK to a CPU register
Load Accumulator
Extensions 01 move.l {Ry,#imm},ACCext01 Loads the accumulator 0,1 extension bytes with a 32-bit
operand
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3