Visible to Intel only — GUID: yqd1716969303556
Ixiasoft
Visible to Intel only — GUID: yqd1716969303556
Ixiasoft
6.2.3.4.1. Viewing Data
Nodes | Pipeline Stage | Description | Representation |
---|---|---|---|
*D_instr_pc[31..0] | Instruction Decode (D) | Program Counter | Memory address of the instruction being fetched. |
*D_instr_word[31..0] | Instruction Word | Fetched 32-bits instruction word. | |
*D_instr_valid | Instruction Valid | Valid instruction to continue E stage. | |
*E_instr_pc[31..0] | Instruction Execute (E) | Program Counter | Memory address of the instruction being decoded. |
*E_instr_word[6..0] | Instruction Word | 7-bits opcode from 32-bits instruction word. | |
*E_instr_valid | Instruction Valid | Valid instruction to continue M stage. | |
*M0_instr_pc[31..0] | Memory (M) | Program Counter | Memory address of the instruction being executed. |
*M0_instr_valid | Instruction Valid | Valid instruction to continue Write Back stage. |
Using the Signal Tap tab controls, you can scroll through the program execution of the Nios® V processor. If the specified acquisition clock corresponds to the Nios® V processor clock, every rising clock edge corresponds to a new instruction cycle.
You may notice one or more empty instruction entries in the trace data gathered by the Signal Tap logic analyzer. These entries indicate that no instruction was executed by the Nios® V processor during that clock cycle. This behavior is typical, and can occur for the following reasons:
- Cache Miss — The requested instruction address location generates a miss in the instruction cache, and additional clock cycles are required to fill the cache line and return the instruction.
- Memory Contention or Speed — The instruction address location is in memory that requires multiple clock cycles to access, or in memory that is currently controlled by another peripheral or processor.
You can also view the trace data in the Signal Tap list file format. In this tabular format, the trace samples are displayed chronologically in rows. The list file format is useful because it is like the objdump file, simplifying the analysis process. Click File > Create/Update > Create Signal Tap List File to create the Signal Tap list file.