MSC8144E Reference Manual, Rev. 3
1-12
Freescale
Semiconductor
Overview
can perform one address calculation and drive one data memory access per cycle. Data access
widths are flexible from 8 to 64 bits. The AGU can support a throughput of up to 102.4/128 Gbps
between the core and the memory.
Arithmetic operations use both fractional and integer data types, enabling the user to choose an
individual style of code development or to use coding techniques derived from an
application-specific standard. Parts of many algorithms use data with reduced width such as 8 or
16 bits. For better efficiency, the SC3400 core also supports single-instruction multiple-data
(SIMD) instructions working on 2-word or 4-byte operands packed in a register. This packing
allows the core to perform 2 to 4 operations per instruction (a maximum of 10 to 18 operation per
VLES including AGU operations). In addition, the SC3400 supports special instructions to
support special operations, such as Viterbi and video applications.
Although the SC3400 is a DSP, the rich instruction set also gives special attention to control
code, making the SC3400 core ideal for applications that embed DSP and communications
operations as general control code. Among the features that support control code are the
interlocked pipeline that solves dependency hazards. The powerful SC3400 compiler translates
code written in C/C++ into parallel fetch sets and maintains high code density and/or high
performance by taking advantage of these features and the compiler-friendly instruction set. Even
compiled pure control code yields results with high code density.
The SC3400 core supports general micro-controller capabilities, making it a suitable target for
advanced operating systems. These capabilities include support for user and supervisor privilege
levels that enable (with the off-core MMU) a protected software model implementation. Precise
exceptions for memory accesses allow implementation of advanced memory management
schemes and soft error correction.
The SC3400 core includes a dynamic branch prediction mechanism that contains a 32-entry
branch target buffer (BTB) to improve performance by reducing the change of flow latency.
1.4.2 L1 Instruction Cache
The ICache with real-time support is highly optimized for real-time DSP applications and
minimizes miss ratios, latencies, bus bandwidth requirements, and silicon area. The 16 KB
ICache is 8-way set associative. Each of the 8 ways contains eight 256 bytes long lines and is
divided into 16 fetch sets (VBRs), each with an associated valid bit. The 3-bit index field of the
address serves as an index to the line within the way. The tag field in the address selects the line
with the matching tag.
When a cache miss occurs, new data is fetched in bursts from the target memory. Descriptors
inside the MMU indicate the burst size. For example, accesses to the M2 may occur in bursts of
four beats, and accesses to the DDR may occur in bursts of two beats. There is also an option to
have an interruptible pre-fetch to the end of the line. This option, referred to as prefetch, takes
advantage of the spatial locality of the code. When a new fetch is required and all the ways of the
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 ...