ibex_tracer can be used to create a log of the executed instructions.
It is used by
ibex_top_tracing which forwards the RVFI signals to the tracer (see also RISC-V Formal Interface).
All traced instructions are written to a log file.
By default, the log file is named
<HARTID> being the 8 digit hart ID of the core being traced.
The file name base, defaulting to
trace_core can be set using the
ibex_tracer_file_base plusarg passed to the simulation.
+ibex_tracer_file_base=ibex_my_trace will produce log files named
The exact syntax of passing plusargs to a simulation depends on the simulator.
Disabling the tracer¶
If the instruction log is not needed for a specific simulation run, the tracer can be disabled.
ibex_tracer_enable controls the tracer.
The tracer is enabled by default.
To disable the tracer use
ibex_tracer_enable=0 with the correct plusarg syntax of the simulator.
Trace output format¶
The trace output is in tab-separated columns.
Time: The current simulation time.
Cycle: The number of cycles since the last reset.
PC: The program counter
Instr: The executed instruction (base 16). 32 bit wide instructions (8 hex digits) are uncompressed instructions, 16 bit wide instructions (4 hex digits) are compressed instructions.
Decoded instruction: The decoded (disassembled) instruction in a format equal to what objdump produces when calling it like
objdump -Mnumeric -Mno-aliases -D.
Unsigned numbers are given in hex (prefixed with
0x), signed numbers are given as decimal numbers.
Numeric register names are used (e.g.
Symbolic CSR names are used.
Jump/branch targets are given as absolute address if possible (PC + immediate).
Register and memory contents: For all accessed registers, the value before and after the instruction execution is given. Writes to registers are indicated as
registername=value, reads as
registername:value. For memory accesses, the address and the loaded and stored data are given.
Time Cycle PC Instr Decoded instruction Register and memory contents 130 61 00000150 4481 c.li x9,0 x9=0x00000000 132 62 00000152 00008437 lui x8,0x8 x8=0x00008000 134 63 00000156 fff40413 addi x8,x8,-1 x8:0x00008000 x8=0x00007fff 136 64 0000015a 8c65 c.and x8,x9 x8:0x00007fff x9:0x00000000 x8=0x00000000 142 67 0000015c c622 c.swsp x8,12(x2) x2:0x00002000 x8:0x00000000 PA:0x0000200c store:0x00000000 load:0xffffffff