Analog Devices ADSP-BF535 Blackfin, Hardware Reference Manual

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Arithmetic Logic Unit (ALU)
2-24 ADSP-BF535 Blackfin Processor Hardware Reference
Arithmetic Logic Unit (ALU)
The two ALUs perform arithmetic and logical operations on fixed-point
data. ALU fixed-point instructions operate on 16-bit, 32-bit, and 40-bit
fixed-point operands and output 16-bit, 32-bit, or 40-bit fixed-point
results. ALU instructions include:
• Fixed-point addition and subtraction of registers
• Addition and subtraction of immediate values
• Accumulator and subtraction of multiplier results
• Logical AND, OR, NOT, XOR, bitwise XOR, Negate
• Functions: ABS, MAX, MIN, Round, division primitives
ALU Operations
Primary ALU operations occur on ALU0, while parallel operations occur
on ALU1, which performs a subset of ALU0 operations.
Table 2-7 describes the possible inputs and outputs of each ALU.
Combining operations in both ALUs can result in four 16-bit results, two
32-bit results, or two 40-bit results generated in a single instruction.
Table 2-7. Inputs and Outputs of Each ALU
Input Output
Two or four 16-bit operands One or two 16-bit results
Two 32-bit operands One 32-bit result
32-bit result from the multiplier Combination of 32-bit result from the multiplier
with a 40-bit accumulation result