Execution Units
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
26-53
not need to know about the MDEU Context Register initialization values; they are documented
for completeness in the event that the user reads these registers using core processor-controlled
access. MDEU resets via the MDEU Reset Control Register (Section 26.4.4.4, MDEU Reset
Control Register, on page 26-51) or SEC global software reset (Section 26.5.4.1, Master Control
Register (MCR), on page 26-77) does not clear these registers.
26.4.4.11 MDEU Key Registers
The MDEU maintains eight 64-bit registers for writing an HMAC key. The IPAD and OPAD
operations are performed automatically on the key data when required.
Note:
SHA-1 and SHA-256 are big endian. MD5 is little endian. The MDEU module
internally reverses the endianness of the key upon writing to or reading from the
MDEU key registers if the MDEU Mode Register indicates MD5 is the hash of choice.
26.4.4.12 MDEU FIFOs
MDEU uses an input FIFO to hold data to be hashed. Normally, the channels control all access to
this FIFO. For core processor-controlled operation, a write to anywhere in the MDEU FIFO
address space enqueues data to the MDEU input FIFO, and a read from anywhere in this address
space returns all zeros.
When the core processor writes to the MDEU FIFO (using core processor-controlled access), it
can write to any FIFO address by byte, 4-byte, or 8-byte accesses. The MDEU assembles these
bytes from left to right, that is, the first bytes written are placed in the most significant
bit-positions. Whenever the MDEU accumulates 8 bytes, these 8 bytes are automatically
enqueued into the FIFO, and any remaining bytes are left-justified in preparation for assembling
the next 8 bytes. It is not necessary to fill all bytes of the final 8-byte set. Any last bytes
remaining in the staging register are automatically padded with zeros and forced into the input
FIFO when the MDEU End_of_Message Register is written.
Overflows caused by writing the MDEU FIFO are reflected in the MDEU Interrupt Status
Register.
26.4.5 ARC Four Execution Unit (AFEU)
In typical operation, the AFEU is used through channel-controlled access, which means that most
reads and writes of AFEU registers are directed by the SEC channels. Driver software would
perform core processor-controlled register accesses only on a few registers for initial
configuration and error handling.
The following subsections include general descriptions of the AFEU registers and structures.
Section 26.5, Programming Model, on page 26-66 provides a detailed description of each
register and associated register fields.
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 ...