AMD Geode LX 800@0.9W - Manual (Page 524)

524 AMD Geode™ LX Processors Data Book
Security Block Register Descriptions 33234H
6.12.3.7 SB Source B (SB_SOURCE_B)
6.12.3.8 SB Destination B (SB_DEST_B)
SB Memory Offset 020h
Type
R/W
Reset Value 00000000h
SB_SOURCE_B 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
SOURCE_B RSVD
SB_SOURCE_B Register Bit Descriptions
Bit Name Description
31:4 SOURCE_B Source B. The Source field is a 32-bit pointer to system memory. It points to the start of
data to be encrypted or decrypted. The lower four bits must be written as zero and
always read zero. This forces the data fetching 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 regis-
ter 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 024h
Type
R/W
Reset Value 00000000h
SB_DEST_B 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
DEST_B RSVD
SB_DEST_B Register Bit Descriptions
Bit Name Description
31:4 DEST_B Destination B. 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 oper-
ation using the B pointer set (while STB is asserted, SB Memory Offset 004h[0] = 1).
3:0 RSVD Reserved. Set to 0.