Data Types And Endianness - Xilinx MicroBlaze Reference Manual

Data Types and Endianness

MicroBlaze uses Big-Endian or Little-Endian format to represent data, depending on the
selected endianness. The parameter C_ENDIANNESS is fixed to 1 (little-endian).
The hardware supported data types for MicroBlaze are word, half word, and byte. When
using the reversed load and store instructions LHUR, LWR, SHR and SWR, the bytes in the
data are reversed, as indicated by the byte-reversed order.
The bit and byte organization for each type is shown in the following tables.
Table 2-2: Word Data Type
Big-Endian Byte Address
Big-Endian Byte Significance
Big-Endian Byte Order
Big-Endian Byte-Reversed Order
Little-Endian Byte Address
Little-Endian Byte Significance
Little-Endian Byte Order
Little-Endian Byte-Reversed Order n
Bit Label
Bit Significance
Table 2-3: Half Word Data Type
Big-Endian Byte Address
Big-Endian Byte Significance
Big-Endian Byte Order
Big-Endian Byte-Reversed Order
Little-Endian Byte Address
Little-Endian Byte Significance
Little-Endian Byte Order
Little-Endian Byte-Reversed Order n
Bit Label
Bit Significance
Table 2-4: Byte Data Type
Byte Address
Bit Label
Bit Significance
MicroBlaze Processor Reference Guide
UG984 (v2016.2) June 8, 2016
UG984 (v2016.1) April 6, 2016
n n+1 n+2
MSByte
n n+1 n+2
n+3 n+2 n+1
n+3 n+2 n+1
MSByte
n+3 n+2 n+1
n+1 n+2
0
MSBit
n n+1
MSByte LSByte
n n+1
n+1 n
n+1 n
MSByte LSByte
n+1 n
n+1
0 15
MSBit LSBit
n
0 7
MSBit LSBit
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Chapter 2: MicroBlaze Architecture
n+3
LSByte
n+3
n
n
LSByte
n
n+3
31
LSBit
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