DSP Core Reference Manual

Memory Interface

SC140 DSP Core Reference Manual 2-59

Figure 2-22. Data Transfer in Big and Little Endian Modes

For single-register moves, assuming an equivalent memory map in big and little endian modes, the byte

organization on the buses is identical in both modes. However, the memory subsystem must route the data

bus bytes to different memory addresses for each supported endian mode.

Big Endian

Little Endian

MOVE.B (A0), D0

MOVE.B (A2), D0

MOVE.W (A8), D0

MOVE.L (A16), D0

xxxx xxxx xxxx xx0a

xxxx xxxx xxxx xx0c

xxxx xxxx xxxx 0102

xxxx xxxx 1122 3344

64-bit XB-BUS

64-bit XA-BUS

SC140 Core

Memory

Instructions Data Bus Contents

16 ($10)

24 ($18)

32 ($20)

34567

0a 0b 0c 0d 0e 0f

01 02 03 04 05 06 07 08

11 22 33 44 cc dd ee ff

16 ($10)

24 ($18)

32 ($20)

76543210

0f 0e 0d 0c 0b 0a

07 08 05 06 03 04 01 02

cc dd ee ff 11 22 33 44