AMD Geode LX 800@0.9W - Manual (Page 523)

AMD Geode™ LX Processors Data Book 523
Security Block Register Descriptions 33234H
6.12.3.5 SB Destination A (SB_DEST_A)
6.12.3.6 SB Length A (SB_LENGTH_A)
SB Memory Offset 014h
Type
R/W
Reset Value 00000000h
SB_DEST_A Register Map
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Destination A RSVD
SB_DEST_A Register Bit Descriptions
Bit Name Description
31:4 DEST_A Destination A. The Destination field is a 32-bit pointer to system memory. It points to
the start of memory where the results of encryption or decryption operation are to be
written. The lower four bits must be written as zero and always read zero. This forces
the data writing to begin on a 16-byte boundary. This register should not be changed
during an AES encryption or decryption operation using the A pointer set (i.e., while
STA is asserted, SB Memory Offset 000h[0] = 1). This register can be modified during
an operation using the B pointer set (while STB is asserted, SB Memory Offset 004h[0]
= 1).
3:0 RSVD Reserved. Set to 0.
SB Memory Offset 018h
Type
R/W
Reset Value 00000000h
SB_LENGTH_A Register Map
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
LENGTH_A RSVD
SB_LENGTH_A Register Bit Descriptions
Bit Name Description
31:4 LENGTH_A Length A. The Length field is a 32-bit value that describes the number of bytes to be
encrypted or decrypted in the next operation using pointer set A. The lower four bits
must be written as zero and always read zero. This forces the data length to be an inte-
ger number of 16-byte blocks. This register should not be changed during an AES
encryption or decryption operation using the A pointer set (i.e., while STA is asserted,
SB Memory Offset 000h[0] = 1). This register can be modified during an operation using
the B pointer set (while STB is asserted, SB Memory Offset 004h[0] = 1).
3:0 RSVD Reserved.