Added NUMBER_OF_OPCODES which aids in compilation errors

If I add a new operand I want the build system to be more helpful in
finding the places I need to change to make it work.

src/inst.c

@@ -10,6 +10,7 @@
  * Description: Implementation of bytecode for instructions
  */
 
+#include <assert.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <string.h>
@@ -116,6 +117,9 @@ const char *opcode_as_cstr(opcode_t code)
   case OP_HALT:
     return "HALT";
     break;
+  case NUMBER_OF_OPCODES:
+    return "";
+    break;
   }
   return "";
 }
@@ -201,6 +205,7 @@ void inst_print(inst_t instruction, FILE *fp)
 
 size_t inst_bytecode_size(inst_t inst)
 {
+  static_assert(NUMBER_OF_OPCODES == 31, "inst_bytecode_size: Out of date");
   size_t size = 1; // for opcode
   if (OPCODE_IS_TYPE(inst.opcode, OP_PUSH))
   {
@@ -223,6 +228,7 @@ size_t inst_bytecode_size(inst_t inst)
 
 void inst_write_bytecode(inst_t inst, darr_t *darr)
 {
+  static_assert(NUMBER_OF_OPCODES == 31, "inst_write_bytecode: Out of date");
   // Append opcode
   darr_append_byte(darr, inst.opcode);
   // Then append 0 or more operands
@@ -294,11 +300,12 @@ data_t read_type_from_darr(darr_t *darr, data_type_t type)
 
 inst_t inst_read_bytecode(darr_t *darr)
 {
+  static_assert(NUMBER_OF_OPCODES == 31, "inst_read_bytecode: Out of date");
   if (darr->used >= darr->available)
     return (inst_t){0};
   inst_t inst     = {0};
   opcode_t opcode = darr->data[darr->used++];
-  if (opcode > OP_HALT)
+  if (opcode > OP_HALT || opcode == NUMBER_OF_OPCODES)
     // Translate to NOOP
     return inst;
   // Read operands

src/inst.h

@@ -65,6 +65,8 @@ typedef enum
   OP_EQ_HWORD,
   OP_EQ_WORD,
 
+  // Should not be an opcode
+  NUMBER_OF_OPCODES,
   OP_HALT = 0b11111111, // top of the byte is a HALT
 } opcode_t;
 

src/runtime.c

@@ -10,6 +10,7 @@
  * Description: Virtual machine implementation
  */
 
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -18,6 +19,7 @@
 
 void vm_execute(vm_t *vm)
 {
+  static_assert(NUMBER_OF_OPCODES == 31, "vm_execute: Out of date");
   struct Program *prog = &vm->program;
   if (prog->ptr >= prog->max)
     // TODO: Error (Went past end of program)