# riscv-p [P spec](https://github.com/riscv/riscv-p-spec/blob/33be869910077afd52653031f18a235b1f9d4442/P-ext-proposal.adoc?fbclid=IwAR2U7sVmOmFrj51NHvBBeXS5Nn4cnFKmnqWohjRE4hEfB8rNA4PUpqMb_r4) Complie cmd ```=bash riscv32-unknown-elf-gcc -mext-dsp ksub64.c -o ksub64 ``` RVP Intrinsic ```=c // ksub64.c #include <nds_intrinsic.h> #include <stdio.h> #include <stdlib.h> #include <sys/types.h> int main() { printf("0x%016llX\n", __nds__ksub64(0x7F7F, 0x80FF)); return 0; } ```