SuperH (SH) 64-bit RISC Series SH-5 System Architecture, Volume ...

PRELIMINARY DATA
230 DBUS protocol
3.6.6 Endian-specific behavior
Data
size
The msk field determines which bytes in the data field are significant. The manner
in which the bytes within the data field correspond to offsets from the address field
is dependant on the endianness of the target system.
This is illustrated in Table 81.
Mask
Byte positions within 8-byte data field
D R A FT
Address offset in
endian mode:
7 6 5 4 3 2 1 0 Big Little
8 0xFF MSB LSB 0 0
4 0x0F MSB LSB 4 0
4 0xF0 MSB LSB 0 4
2 0x03 MSB LSB 6 0
2 0x0C MSB LSB 4 2
2 0x30 MSB LSB 2 4
2 0xC0 MSB LSB 0 6
1 0x1 7 0
1 0x2 6 1
1 0x4 5 2
1 0x8 4 3
1 0x10 3 4
1 0x20 2 5
1 0x40 1 6
1 0x80 0 7
Table 81: DBUS mask/address mapping for big and little endian modes
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SH-5 System Architecture, Volume 3: Debug 05-SA-10003 v1.0