It is if a byte is 16 bits.
> it was not designed for efficient execution by a software interpreter.
It's not bad at all for that. On my i9-13900HX laptop, if I take http://hoult.org/primes.txt and compile it for x86 and for RISC-V:
- 5.6 seconds for riscv64-linux-gnu-gcc -O primes.c -o prime run in QEMU [1]
- 3.8 seconds for gcc primes.c -o primes run natively
- 2.0 seconds for gcc -O primes.c -o primes run natively
Emulating RISC-V is worse than forgetting to compile with `-O`, but not much. It's far faster than Python or Ruby and comparable to Java, C#, JavaScript, or WebASM.
Also, QEMU is not the fastest emulator around, just the most flexible and complete. The experimental RV8 and the nearly-ready-for-prime-time RVVM [2] are much closer to native speeds.
Note that if I do exactly the same thing for arm64 (i.e. docker/QEMU) the primes program takes 14.4 seconds and the whole Ubuntu in docker experience just feels a lot more laggy. Running the x86_864 binary in qemu-x86_64 instead of natively takes 10.5 seconds.
RISC-V is a lot easier to emulate quickly than Aarch64 or x86.
[1] or if you have Docker Desktop (on Mac, Windows, or Linux) then you can just work like a native:
bruce@i9:~$ docker run --platform linux/riscv64 -it riscv64/ubuntu
Unable to find image 'riscv64/ubuntu:latest' locally
latest: Pulling from riscv64/ubuntu
53300d777b1a: Pull complete
Digest: sha256:6a392b2c64f4e0021bfcff62e58975ddce0f1eccc5a72708b114aeb50999ff22
Status: Downloaded newer image for riscv64/ubuntu:latest
root@5f2edc942403:/# apt update
:
root@5f2edc942403:/# apt install wget gcc
:
root@5f2edc942403:/# wget -q http://hoult.org/primes.txt
root@5f2edc942403:/# mv primes.txt primes.c
root@5f2edc942403:/# gcc -O primes.c -o primes
root@5f2edc942403:/# ./primes
Starting run
3713160 primes found in 5609 ms
216 bytes of code in countPrimes()
root@5f2edc942403:/#