This is a patch of my GSoC project that the goal is to make the existing Universal Intrinsic compatible with scalable (variable-length) backends.

In #22179 and #22353, we have already introduce a new framework of universal intrinsic and some of intrinsic functions are added.

In this patch, we are going to add the remaining universal intrinsic implementations for RVV. When this patch is integrated, the new RVV backend will be done.

Tested with QEMU for RVV backend in various VLEN:

qemu-riscv64 -cpu rv64,x-v=true,vlen=128 ./bin/opencv_test_core --gtest_filter="hal*"
qemu-riscv64 -cpu rv64,x-v=true,vlen=512 ./bin/opencv_test_core --gtest_filter="hal*"

Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake