[APP] add example vector code

apps/vector_addition/main.c

@@ -0,0 +1,46 @@
+#include <stdint.h>
+#include <string.h>
+
+#ifndef SPIKE
+#include "printf.h"
+#else
+#include "util.h"
+#include <stdio.h>
+#endif
+
+uint64_t x[10] = {1,2,3,4,5,6,7,8,9,10};
+uint64_t y[10] = {10,9,8,7,6,5,4,3,2,1};
+uint64_t z[10];
+
+int main() {
+  printf("Ariane says Hello!\n");
+
+  /*
+  * Example of Using Vector Instruction -- Vector Addition Z = Y + X
+  */
+
+  //step1 -- configure the vector length
+  uint64_t VL = 10; 
+  asm volatile("vsetvli zero, %0, e64, m4, ta, ma" ::"r"(VL));
+
+  //step2 -- load x to vector register 0 (v0)
+  asm volatile("vle64.v v0, (%0);" ::"r"(x));
+
+  //step3 -- load y to vector register 4 (v4)
+  asm volatile("vle64.v v4, (%0);" ::"r"(y));
+
+  //step4 -- v0 + v4 -> v8
+  asm volatile("vadd.vv v8, v4, v0;");
+
+  //step5 -- store v8 to z array
+  asm volatile("vse64.v v8, (%0);" ::"r"(z));
+
+
+  // Check the results (CVA6)
+  for (int i = 0; i < 10; ++i)
+  {
+    printf("%d\n", z[i]);
+  }
+
+  return 0;
+}