Software and processor tools

Does your design run programs?#

Most hardware does not run programs. The Firmware tab tells you which kind of design you have. Fixed-function logic, accelerators, sensors, neuromorphic arrays, and other non-processor hardware are exercised by simulation in Workflow and Goals, so they get no Assembly or C tab.

From CPU to programs#

1. 1
   Set up this CPU (Firmware tab)

   • The Architect writes tb/firmware_tb.sv for your CPU and finds its RISC-V instruction set (for example RV32I, RV32IM, RV32E) and memory map.
   • A built-in instruction test then runs every base instruction (plus M-extension instructions when present) and enables assembly. Two C self-tests enable C.
   • If the CPU computes something wrong, setup names the instruction, for example sra … expected ffffffff, got 00000001.
2. 2
   Assembly tab

   Build and run a program and read its output. Programs can run even before the instruction test passes, so you can debug the CPU; the tab warns you.
3. 3
   C programs tab

   Available when the status is Assembly + C ready.

Rechecks and limits#

• Changing the RTL or the CPU settings shows Needs recheck. Recheck this CPU repeats the checks. Changing compiler flags does not require a recheck.
• CPUs with a custom instruction set use the custom-ISA assembler with your isa.json; C is not available for them.