Table of Contents
Advertisement
General Operation
For all operations, the resulting 40-bit product is extended to a 48-bit value (using
sign-extension for signed integer and fractional operands, zero-fill for unsigned integer
operands) before being combined with the 48-bit destination accumulator.
Figure 3-4 and Figure 3-5 show relative alignment of input operands, the full 64-bit
product, the resulting 40-bit product used for accumulation, and 48-bit accumulator
formats.
Product
Extended Product
+
Accumulator
Product
Extended Product
Accumulator
Figure 3-5. Signed and Unsigned Integer Alignment
3-4
OperandY
X
OperandX
40
8
8
Extension Byte Upper [7:0]
Figure 3-4. Fractional Alignment
OperandY
X
OperandX
24
+
Extension Byte Upper [7:0]
MCF5282 User's Manual
32
32
23
40
40
Accumulator [31:0]
32
32
32
8
8
8
32
8
8
32
Accumulator [31:0]
Extension Byte Lower [7:0]
"0"
8
Extension Byte Lower [7:0]
MOTOROLA
Advertisement
Table of Contents
