mcf5272 Freescale Semiconductor, Inc, mcf5272 Datasheet - Page 104

• Manufacturer Part Number: mcf5272
• Description: Mcf5272 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

Overview
The need to move large amounts of data quickly can limit throughput in DSP engines.
However, data can be moved efficiently by using the MOVEM instruction, which
automatically generates line-sized burst references and is ideal for filling registers quickly
with input data, filter coefficients, and output data. Loading an operand from memory into
a register during a MAC operation makes some DSP operations, especially filtering and
convolution, more manageable.
The MACSR has a 4-bit operational mode field and three condition flags. The operational
mode bits control the overflow/saturation mode, whether operands are signed or unsigned,
whether operands are treated as integers or fractions, and how rounding is performed.
Negative, zero and overflow flags are also provided.
The three program-visible MAC registers, a 32-bit accumulator (ACC), the MAC mask
register (MASK), and MACSR, are described in Section 3.1.1, “MAC Programming
Model.”
3.1.3 MAC Instruction Set Summary
The MAC unit supports the integer multiply operations defined by the baseline ColdFire
architecture, as well as the new multiply-accumulate instructions. Table 3-1 summarizes
the MAC unit instruction set.
Multiply Signed
Multiply Unsigned
Multiply Accumulate
Multiply Accumulate
with Load
Load Accumulator
Store Accumulator
Load MACSR
Store MACSR
Store MACSR to CCR
Load MASK
Store MASK
3-4
Instruction
MULS <ea>y,Dx
MULU <ea>y,Dx
MAC Ry,RxSF
MSAC Ry,RxSF
MAC Ry,RxSF,Rw
MSAC Ry,RxSF,Rw
MOV.L {Ry,#imm},ACC
MOV.L ACC,Rx
MOV.L {Ry,#imm},MACSR Writes a value to the MACSR
MOV.L MACSR,Rx
MOV.L MACSR,CCR
MOV.L {Ry,#imm},MASK
MOV.L MASK,Rx
Table 3-1. MAC Instruction Summary
Mnemonic
MCF5272 User’s Manual
Multiplies two signed operands yielding a signed result
Multiplies two unsigned operands yielding an unsigned result
Multiplies two operands, then adds or subtracts the product
to/from the accumulator
Multiplies two operands, then adds or subtracts the product
to/from the accumulator while loading a register with the
memory operand
Loads the accumulator with a 32-bit operand
Writes the contents of the accumulator to a register
Writes the contents of MACSR to a register
Writes the contents of MACSR to the processor’s CCR register
Writes a value to MASK
Writes the contents of MASK to a register
Description
MOTOROLA