AN2492 Freescale Semiconductor / Motorola, AN2492 Datasheet - Page 6

• Manufacturer Part Number: AN2492
• Description: MPC184 Descriptor Programmers Guide--PCI View
• Manufacturer: Freescale Semiconductor / Motorola

Execution Unit Mode Data
Execution Unit Mode Data
4.2 DEU Mode Register
The DEU mode register contains 3 bits which are used to program the DEU, as shown in Figure 6. It also
reflects the value of burst size, which is loaded by the crypto-channel during normal operation with the
MPC184 as an initiator. Burst size is not relevant to target mode operations, where an external host pushes
and pulls data from the execution units.
The mode register is cleared when the DEU is reset or re-initialized. Setting a reserved mode bit will
generate a data error. If the mode register is modified during processing, a context error will be generated.
6
1
Reserved
Clear memory
Modular exponentiation
R
R
F
F
F
F
F
F
F
F
F
F
MOD INV CMD
Modular addition
Modular subtraction
Modular multiplication with single reduction
Modular multiplication with double reduction
Polynomial addition
Polynomial multiplication with single reduction
Polynomial multiplication with double reduction
p
2
p
2
p
p
2
2
2
2
2
n
In this case, regAsel and regBsel refer to the specific segment of parameter memory A and B.
m affine point multiplication
m projective point multiplication
m point addition
m point doubling
m R
m INV CMD
R
affine point multiplication
projective point multiplication
point addition
point doubling
mod N
p
mod N
2
CMD
Routine
MPC184 Descriptor Programmer’s Guide— PCI View
Freescale Semiconductor, Inc.
Table 3. Mode Register Routine Definitions
For More Information On This Product,
Go to: www.freescale.com
Mode [6:4]
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
001
010
011
100
101
110
111
Mode [3:2]
regAsel
00 = A0
01 = A1
10 = A2
11 = A3
00
00
00
01
01
01
01
10
10
10
10
11
11
11
11
0
1
Mode [1:0]
regBsel
00 = B0
01 = B1
10 = B2
11 = B3
00
01
10
00
01
10
00
01
10
00
01
10
11
11
11
11
MOTOROLA
1