s3c2410a Samsung Semiconductor, Inc., s3c2410a Datasheet - Page 68

• Manufacturer Part Number: s3c2410a
• Description: 16/32-bit Risc Arm Microprocessor
• Manufacturer: Samsung Semiconductor, Inc.

PROGRAMMER'S MODEL
BIG-ENDIAN FORMAT
In Big-Endian format, the most significant byte of a word is stored at the lowest numbered byte and the least
significant byte at the highest numbered byte. Byte 0 of the memory system is therefore connected to data lines 31
through 24.
LITTLE-ENDIAN FORMAT
In Little-Endian format, the lowest numbered byte in a word is considered the word's least significant byte, and the
highest numbered byte the most significant. Byte 0 of the memory system is therefore connected to data lines 7
through 0.
INSTRUCTION LENGTH
Instructions are either 32 bits long (in ARM state) or 16 bits long (in THUMB state).
Data Types
ARM920T supports byte (8-bit), halfword (16-bit) and word (32-bit) data types. Words must be aligned to four-byte
boundaries and half words to two-byte boundaries.
2-2
Higher Address
Higher Address
Lower Address
Lower Address
Figure 2-2. Little-Endian Addresses of Bytes within Words
Figure 2-1. Big-Endian Addresses of Bytes within Words
31
8
4
0
31
11
7
3
Most significant byte is at lowest address.
Word is addressed by byte address of most significant byte.
Least significant byte is at lowest address.
Word is addressed by byte address of least significant byte.
24
24
23
9
5
1
23
10
6
2
16
16
15
10
6
2
15
9
5
1
8
8
7
11
7
3
7
8
4
0
0
0
Word Address
8
4
0
Word Address
8
4
0
S3C2410A