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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Exponentiation
Acceleration Unit
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
916
Order Number: 306262-004US
Register
EAU Command Register
Bits
Name
Description
Reset
Value
Access
31:3
0
(Reserved)
0x00
29
SE
EAU Short Exponent Enabled
• 0: do NOT skip leading zeros in modular exponentiation operation
• 1: skip leading zeros in modular exponentiation operation
(overrides FE=0)
0x0
RW
28
FE
EAU Fast Exponent Enabled
• 0: do not skip zeros in modular exponentiation operation
• 1: skip ALL zeros in modular exponentiation operation
0x0
RW
27:2
4
CMD
EAU Command Bits have special encoding for EAU commands. EAU
starts execution when the high byte of the Control Register is written.
‘0000 NOP/Idle
‘0001 Modular Exponential (C=Me mod n)
‘0010 Large Number Multiplication (A*B)
‘0011 Large Number Addition (A+B)
‘0100 Modular Reduction (A MOD n)
‘0101 Large Number Subtraction (A-B)
‘0110 Clear EAU RAM
‘0111 Reserved
‘1000 MonPro (R= a_bar * b_bar * r-1 mod n)
‘1001 Reserved for EAU RAM reads
‘1010 Reserved for EAU RAM writes
‘1011 RAM Fill (Reg Dst < FILL)
‘1100 EAU RAM Register Clear (Reg Dst < 0)
‘1101 EAU RAM Register Copy (Reg Dst < Reg Src)
‘1110 Reserved for RAM BIST
‘1111 Reserved
0x000
RW
23
(Reserved)
0x0
22:1
6
SIZE
Operand Size bits: This field defines the length of operands to be
operated on (# of 32-bit words). Valid values for these bits are 8, 16,
24, 32, 40, 48, 56 and 64. The value of 2 is illegal due to architectural
pipeline limitations.
This field is applicable to Modular Exponentiation, Multiplication,
Modular Reduction, Add, Subtract, Copy, Clear, and Fill commands.
0x1
RW
15
(Reserved)
0x0
14:1
2
DST
EAU Destination Field
This field contains the destination register number for copy, clear, and
fill commands.
0x0
RW
11
(Reserved)
0x0
10:8
SRC
EAU Source Field
This field contains the source register number for copy commands.
0x0
RW
7:0
FILL
EAU Fill Value
This byte contains the value to be written into the EAU RAM using the
FILL command. It fills the EAU register defined in the DST field of the
EAU Command Register. The number of double words that are filled is
defined in the SIZE field of the EAU Command Register.
0x0
RW