Made a sample program, loaded into VM and executed

Seems pretty nice to use, and it works according to GDB.

src/main.c

@@ -13,6 +13,7 @@
 #include <stdio.h>
 #include <string.h>
 
+#include "./inst.h"
 #include "./runtime.h"
 
 int main(void)
@@ -20,5 +21,14 @@ int main(void)
   byte stack_data[256];
   vm_t vm = {0};
   vm_load_stack(&vm, stack_data, ARR_SIZE(stack_data));
+  inst_t instructions[] = {
+      INST_BPUSH(0xfa),  INST_BMOV(0),      INST_BPUSH(0xfb),
+      INST_BMOV(1),      INST_BPUSH(0xfc),  INST_BMOV(2),
+      INST_BPUSH(0xfd),  INST_BMOV(3),      INST_BPUSH_REG(3),
+      INST_BPUSH_REG(2), INST_BPUSH_REG(1), INST_BPUSH_REG(0),
+  };
+  vm_load_program(&vm, instructions, ARR_SIZE(instructions));
+  for (size_t i = 0; i < ARR_SIZE(instructions); ++i)
+    vm_execute(&vm);
   return 0;
 }