Execution Units
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
26-59
To signal the ICV checking result by status writeback, turn on either the IWSE bit or AWSE bit
in the Channel Configuration Register (see Section 26.5.5.1, Channel Configuration Registers
for Channels 1–4 (CCR[1–4]), on page 26-89), and mask the ICE bit in the Interrupt Mask
Register (Section 26.5.11.7, KEU Interrupt Mask Register (KEUIMR), on page 26-169). In this
case the normal done signalling (by interrupt or writeback) is undisturbed.
To signal the ICV checking result by interrupt, unmask the ICE bit in the Interrupt Mask Register
and turn off the IWSE and AWSE bits in the Channel Configuration Register. If there is no ICV
mismatch, then the normal done signalling (by interrupt or writeback) occurs. When there is an
ICV mismatch, e an error interrupt is generated to the core processor, but no done interrupt or
writeback is issued.
The following subsections include general descriptions of the KEU registers and structures.
Section 26.5, Programming Model, on page 26-66 provides a detailed description of each
register and associated register fields.
26.4.6.1 KEU Mode Register
The KEU Mode Register contains several bits used to program the KEU. The Mode Register is
cleared when the KEU is reset or reinitialized. Setting a reserved mode bit generates a data error.
Setting both the GSM and EDGE bits to one generates a data error. If the KEU Mode Register is
modified during processing, a context error is generated.
26.4.6.2 KEU Key Size Register
The KEU Key Size Register stores the number of bytes in the key. It should be set to 16 bytes.
This register is cleared when the KEU is reset or reinitialized. If a specified key size does not
match the selected algorithm(s), an illegal key size error is generated.
26.4.6.3 KEU Data Size Register
The KEU Data Size Register stores the number of bits to process in the final message set.
Because Kasumi allows for bit level granularity for encryption/decryption, there are no illegal
data sizes. The user must write the proper bit length of the message to notify the KEU of any
padding performed by the core processor. This register is cleared when the KEU is reset or
reinitialized. Writing to this register signals the KEU to start processing data from the input FIFO
as soon as it is available. If the value of data size is modified during processing, a context error is
generated.
Example 26-1. F8 Function Example
If the 64-bit F8 keystream is ‘0x1234567890abcdef’and the Data Size Register contains
0x0a (10 = 1 byte + 2 bits), the final ten message bits is XORed with ten bits of keystream
‘0x120’. The PE (Process End of Message) mode bit must be set (see Section 26.5.11.1,
KEU Mode Register (KEUMR), on page 26-161).
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...