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MCF5272 User’s Manual
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.
Table 3-1. MAC Instruction Summary
Instruction 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
MSAC Ry,RxSF
Multiplies two operands, then adds or subtracts the product
to/from the accumulator
Multiply Accumulate
with Load
MAC Ry,RxSF,Rw
MSAC Ry,RxSF,Rw
Multiplies two operands, then adds or subtracts the product
to/from the accumulator while loading a register with the
memory operand
Load Accumulator
MOV.L {Ry,#imm},ACC
Loads the accumulator with a 32-bit operand
Store Accumulator
MOV.L ACC,Rx
Writes the contents of the accumulator to a register
Load MACSR
MOV.L {Ry,#imm},MACSR
Writes a value to the MACSR
Store MACSR
MOV.L MACSR,Rx
Writes the contents of MACSR to a register
Store MACSR to CCR
MOV.L MACSR,CCR
Writes the contents of MACSR to the processor’s CCR register
Load MASK
MOV.L {Ry,#imm},MASK
Writes a value to MASK
Store MASK
MOV.L MASK,Rx
Writes the contents of MASK to a register
Содержание DigitalDNA ColdFire MCF5272
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Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
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Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
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Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...