回复:[RISC-V] [tech-vector-ext] Configuring qemu for Vector Extension


"刘志伟
 

Hi Mick,

The vector 0.7.1 version has been implemented in T-Head Xuantie c910v CPU and AllWinner D1 Soc.  If that's what you want or If you want to use the QEMU upstream currently, I can give you some advice.

The toolchian binary you can download from the link:

You can compile your program with -march rv64gcv -mabi=lp64dv.

The programming intrinsic is very similiar to the upstrem gcc and please see the attachment.

Thanks,
Zhiwei

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发件人:Mick Thomas Lim <mickthomaslim@...>
发送时间:2021年9月13日(星期一) 08:24
收件人:tech-vector-ext <tech-vector-ext@...>
主 题:[RISC-V] [tech-vector-ext] Configuring qemu for Vector Extension

Does a known-good guide exist for building riscv64 qemu to be able to run Vector instructions?

From the main qemu repo, we are to build the riscv64-softmmu target and run the 64-bit Buildroot Image, as described here:

A "Hello World" program compiled with riscv64-unknown-linux-gnu-gcc does work.
But we aren't seeing expected behavior when running the simple rvv_vadd.c program described here:

For example: vl = vsetvl_e32m2 (n) seems to return 0.

This is the qemu run command we're using for buildroot:
qemu-system-riscv64 -cpu rv64,x-v=true,vlen=256,elen=64,vext_spec=v0.7.1    -M virt -nographic    -bios output/images/fw_jump.elf    -kernel output/images/Image    -append "root=/dev/vda ro"    -drive file=output/images/rootfs.ext2,format=raw,id=hd0    -device virtio-blk-device,drive=hd0    -netdev user,id=net0 -device virtio-net-device,netdev=net0

Assistance would much appreciated!

Sincerely,
Mick