mcf5272 Freescale Semiconductor, Inc, mcf5272 Datasheet - Page 105

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

MOTOROLA
3.1.4 Data Representation
The MAC unit supports three basic operand types:
3.2 MAC Instruction
For information on MAC instruction execution timings, refer to Section 2.7, “Instruction
Timing.”
• Two’s complement signed integer: In this format, an N-bit operand represents a
• Two’s complement unsigned integer: In this format, an N-bit operand represents a
• Two’s complement, signed fractional: In an N-bit number, the first bit is the sign bit.
number within the range -2
of the least significant bit.
number within the range 0 < operand < 2
least significant bit.
The remaining bits signify the first N-1 bits after the binary point. Given an N-bit
number, a
This format can represent numbers in the range -1 < operand < 1 - 2
For words and longwords, the greatest negative number that can be represented is -1,
whose internal representation is 0x8000 and 0x0x8000_0000, respectively. The
most positive word is 0x7FFF or (1 - 2
0x7FFF_FFFF or (1 - 2
N-1
+
a
Chapter 3. Hardware Multiply/Accumulate (MAC) Unit
N 2
N-2
i
'
=
–
a
0
N-3
2
(
... a
i
+
-31
1 N
2
).
(N-1)
a
–
1
Execution Timings
a
0
)
, its value is given by the following formula:
< operand < 2
&
ai
-15
N
); the most positive longword is
- 1. The binary point is to the right of the
(N-1)
- 1. The binary point is to the right
MAC Instruction Execution Timings
(N-1)
.
3-5