![Freescale Semiconductor MCF54455 Reference Manual Download Page 605](http://html1.mh-extra.com/html/freescale-semiconductor/mcf54455/mcf54455_reference-manual_2330541605.webp)
Cryptographic Acceleration Unit (CAU)
24-5
Freescale Semiconductor
24.2.3
CAU General Purpose Registers (CA
n
)
The nine CAU general purpose registers are used in the CAU commands for storage of results and as
operands for the various cryptographic algorithms.
24.3
Functional Description
24.3.1
Programming Model
The CAU is an instruction-level coprocessor. It has a dedicated register file, a specialized ALU, and
specialized units for performing cryptographic operations. The CAU design uses a simple, flexible
accumulator-based architecture. Most commands, including load and store, can specify any register in the
register file. Some cryptographic operations work with specific registers.
24.3.2
Coprocessor Instructions
Operation of the CAU is controlled via standard ColdFire coprocessor load (cp0ld) and store (cp0st)
instructions. The CAU has a dedicated register file accessed using these instructions. The load instruction
loads CAU registers and specifies CAU operations. The store instruction stores CAU registers. The
example assembler syntax for the CAU is:
cp0ld.l
<ea>,<CMD>
; coprocessor load
cp0st.l
<ea>,<CMD>
; coprocessor store
The <ea> field specifies the source operand (operand1) for load instructions and destination (result) for
store instructions. The basic ColdFire addressing modes {Rn, (An), -(An), (An)+, (d16,An)} are supported
for this field. The <CMD> field is a 9-bit value that specifies the CAU command for an instruction.
shows how the CAU supports a single command (
STR
) for store instructions and 21 commands
for the load instructions. The CAU only supports longword operations. A CAU command can be issued
every clock cycle.
Register
code:
0x2 (CA0)
0x3 (CA1)
0x4 (CA2)
0x5 (CA3)
0x6 (CA4)
0x7 (CA5)
Access: Read/write
via CAU commands
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
R
CA
n
W
Reset 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 24-4. CAU General Purpose Registers (CA
n
)
Table 24-4. CA
n
Field Descriptions
Field
Description
31–0
CA
n
General purpose registers. Used by the CAU commands. Some cryptographic operations work with specific
registers.
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...