Instruction Pipeline
4-8
ADSP-BF535 Blackfin Processor Hardware Reference
The Sequencer decodes and distributes operations to the Instruction
Memory Unit and Instruction Alignment Unit. It also controls stalling
and invalidating the instructions in the pipeline. The Sequencer ensures
that the pipeline is fully interlocked and that the programmer does not
need to manage the pipeline.
The instruction fetch and branch logic generates 32-bit fetch addresses for
the Instruction Memory Unit. The Instruction Alignment Unit returns
instructions and their width information at the end of the IF2 stage.
For each instruction type (16-, 32-, or 64-bit), the Alignment Unit
ensures that the alignment buffers have enough valid data to be able to
provide an instruction every cycle. Since the instructions can be 16, 32, or
64 bits wide, the Alignment Unit may not need to fetch data from the
cache every cycle. For example, for a series of 16-bit instructions, the
Alignment Unit gets data from the Instruction Memory Unit once in 4
cycles. The alignment logic requests the next instruction address based on
the status of the alignment buffers. The Sequencer responds by generating
the next fetch address in the next cycle, provided there is no change of
flow.
The Sequencer holds the fetch address until it receives a request from the
alignment logic or until a change of flow occurs. It always increments the
previous fetch address by 8 (the next 8 bytes). If a change of flow occurs,
such as a branch or an interrupt, the Sequencer communicates it to the
Instruction Memory Unit, which invalidates the data in the Alignment
Unit. In addition to the change-of-flow indication, the Sequencer can also
kill instructions in IF1 and IF2 stages or stall the Instruction Memory
Unit.
The Execution Unit contains two 16-bit multipliers, two 40-bit ALUs,
two 40-bit accumulators, one 40-bit shifter, a video unit (which adds 8-bit
ALU support), and an 8-entry 32-bit Data Register File.
Summary of Contents for ADSP-BF535 Blackfin
Page 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Page 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Page 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Page 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Page 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Page 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Page 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Page 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Page 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...