Question 1

Is Litessera Lux a RISC-V assembler or a simulator?

Accepted Answer

Both. Litessera Lux assembles RISC-V assembly source into machine code, then simulates a RISC-V CPU to execute that code, so you can write, assemble, and run RV32IM programs in one place without a separate toolchain.

Question 2

Is Litessera Lux free to use?

Accepted Answer

Yes. Litessera Lux is a completely free online RISC-V assembler and simulator. It runs entirely in your browser with no installation, no toolchain setup, and no account required.

Question 3

Which RISC-V instructions does it support?

Accepted Answer

It supports the full RV32I base integer instruction set plus the RV32M multiply and divide extension, along with common pseudo-instructions such as li, la, mv, j, call, and ret.

Question 4

Does it follow the standard a7 ecall convention?

Accepted Answer

Yes. System calls place their service number in register a7 and pass arguments in a0–a1, matching the standard RISC-V / RARS convention used on real hardware.

Question 5

Can I use it to learn computer architecture?

Accepted Answer

Yes. The lessons start from the first instruction and build up to functions and memory, and the instruction reference documents every RV32IM instruction.