src->vm, Makefile is now a bit more abstracted and pretty colours

Changed folder names for sake of clarity (will be introducing a new
build target soon), and Makefile can now easily support more targets.

1 files changed, 777 insertions, 0 deletions

diff --git a/vm/runtime.c b/vm/runtime.c
new file mode 100644
index 0000000..ccda9d0
--- /dev/null
+++ b/vm/runtime.c
@@ -0,0 +1,777 @@
+/* Copyright (C) 2023 Aryadev Chavali
+
+ * You may distribute and modify this code under the terms of the
+ * GPLv2 license.  You should have received a copy of the GPLv2
+ * license with this file.  If not, please write to:
+ * aryadev@aryadevchavali.com.
+
+ * Created: 2023-10-15
+ * Author: Aryadev Chavali
+ * Description: Virtual machine implementation
+ */
+
+#include <assert.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "./runtime.h"
+
+const char *err_as_cstr(err_t err)
+{
+  switch (err)
+  {
+  case ERR_OK:
+    return "OK";
+    break;
+  case ERR_STACK_UNDERFLOW:
+    return "STACK_UNDERFLOW";
+    break;
+  case ERR_STACK_OVERFLOW:
+    return "STACK_OVERFLOW";
+    break;
+  case ERR_INVALID_OPCODE:
+    return "INVALID_OPCODE";
+    break;
+  case ERR_INVALID_REGISTER_BYTE:
+    return "INVALID_REGISTER_BYTE";
+    break;
+  case ERR_INVALID_REGISTER_HWORD:
+    return "INVALID_REGISTER_HWORD";
+    break;
+  case ERR_INVALID_REGISTER_WORD:
+    return "INVALID_REGISTER_WORD";
+    break;
+  case ERR_INVALID_PROGRAM_ADDRESS:
+    return "INVALID_PROGRAM_ADDRESS";
+  case ERR_END_OF_PROGRAM:
+    return "END_OF_PROGRAM";
+    break;
+  default:
+    return "";
+  }
+}
+
+err_t vm_execute(vm_t *vm)
+{
+  static_assert(NUMBER_OF_OPCODES == 46, "vm_execute: Out of date");
+  struct Program *prog = &vm->program;
+  if (prog->ptr >= prog->max)
+    return ERR_END_OF_PROGRAM;
+  inst_t instruction = prog->instructions[prog->ptr];
+
+  if (OPCODE_IS_TYPE(instruction.opcode, OP_PUSH))
+  {
+    prog->ptr++;
+    return PUSH_ROUTINES[instruction.opcode](vm, instruction.operand);
+  }
+  else if (OPCODE_IS_TYPE(instruction.opcode, OP_MOV) ||
+           OPCODE_IS_TYPE(instruction.opcode, OP_PUSH_REGISTER))
+  {
+    prog->ptr++;
+    return REG_ROUTINES[instruction.opcode](vm, instruction.operand.as_byte);
+  }
+  else if (OPCODE_IS_TYPE(instruction.opcode, OP_POP))
+  {
+    // NOTE: We use the first register to hold the result of this pop
+    data_type_t type = OPCODE_DATA_TYPE(instruction.opcode, OP_POP);
+    prog->ptr++;
+    switch (type)
+    {
+    case DATA_TYPE_NIL:
+      break;
+    case DATA_TYPE_BYTE:
+      return vm_mov_byte(vm, 0);
+      break;
+    case DATA_TYPE_HWORD:
+      return vm_mov_hword(vm, 0);
+      break;
+    case DATA_TYPE_WORD:
+      return vm_mov_word(vm, 0);
+      break;
+    }
+    return ERR_OK;
+  }
+  else if (OPCODE_IS_TYPE(instruction.opcode, OP_DUP))
+  {
+    prog->ptr++;
+    return DUP_ROUTINES[instruction.opcode](vm, instruction.operand.as_word);
+  }
+  else if (OPCODE_IS_TYPE(instruction.opcode, OP_NOT) ||
+           OPCODE_IS_TYPE(instruction.opcode, OP_OR) ||
+           OPCODE_IS_TYPE(instruction.opcode, OP_AND) ||
+           OPCODE_IS_TYPE(instruction.opcode, OP_XOR) ||
+           OPCODE_IS_TYPE(instruction.opcode, OP_EQ) ||
+           OPCODE_IS_TYPE(instruction.opcode, OP_PLUS))
+  {
+    prog->ptr++;
+    return STACK_ROUTINES[instruction.opcode](vm);
+  }
+  else if (instruction.opcode == OP_JUMP_ABS)
+    return vm_jump(vm, instruction.operand.as_word);
+  else if (instruction.opcode == OP_JUMP_STACK)
+  {
+    // Set prog->ptr to the word on top of the stack
+    data_t ret = {0};
+    err_t err  = vm_pop_word(vm, &ret);
+    if (err)
+      return err;
+    return vm_jump(vm, ret.as_word);
+  }
+  else if (instruction.opcode == OP_JUMP_REGISTER)
+  {
+    if (instruction.operand.as_byte >= 8)
+      return ERR_INVALID_REGISTER_WORD;
+    word addr = vm->registers.reg[instruction.operand.as_byte];
+    return vm_jump(vm, addr);
+  }
+  else if (OPCODE_IS_TYPE(instruction.opcode, OP_JUMP_IF))
+  {
+    data_t datum = {0};
+    err_t err    = ERR_OK;
+    if (instruction.opcode == OP_JUMP_IF_BYTE)
+      err = vm_pop_byte(vm, &datum);
+    else if (instruction.opcode == OP_JUMP_IF_HWORD)
+      err = vm_pop_hword(vm, &datum);
+    else if (instruction.opcode == OP_JUMP_IF_WORD)
+      err = vm_pop_word(vm, &datum);
+
+    if (err)
+      return err;
+
+    // If datum != 0 then jump, else go to the next instruction
+    if (datum.as_word != 0)
+      return vm_jump(vm, instruction.operand.as_word);
+    else
+      ++prog->ptr;
+  }
+  else if (instruction.opcode >= OP_PRINT_CHAR &&
+           instruction.opcode <= OP_PRINT_WORD)
+  {
+    data_t datum = {0};
+    enum
+    {
+      TYPE_CHAR,
+      TYPE_BYTE,
+      TYPE_INT,
+      TYPE_HWORD,
+      TYPE_LONG,
+      TYPE_WORD
+    } print_type;
+    err_t err = ERR_OK;
+    if (instruction.opcode == OP_PRINT_BYTE ||
+        instruction.opcode == OP_PRINT_CHAR)
+    {
+      print_type = instruction.opcode == OP_PRINT_BYTE ? TYPE_BYTE : TYPE_CHAR;
+      err        = vm_pop_byte(vm, &datum);
+    }
+    else if (instruction.opcode == OP_PRINT_HWORD ||
+             instruction.opcode == OP_PRINT_INT)
+    {
+      print_type = instruction.opcode == OP_PRINT_HWORD ? TYPE_HWORD : TYPE_INT;
+      err        = vm_pop_hword(vm, &datum);
+    }
+    else if (instruction.opcode == OP_PRINT_WORD ||
+             instruction.opcode == OP_PRINT_LONG)
+    {
+      print_type = instruction.opcode == OP_PRINT_WORD ? TYPE_WORD : TYPE_LONG;
+      err        = vm_pop_word(vm, &datum);
+    }
+
+    if (err)
+      return err;
+
+    switch (print_type)
+    {
+    case TYPE_CHAR: {
+      char c = 0;
+      memcpy(&c, &datum.as_byte, 1);
+      printf("%c", c);
+      break;
+    }
+    case TYPE_BYTE:
+      printf("0x%x", datum.as_byte);
+      break;
+    case TYPE_INT: {
+      int32_t i = 0;
+      memcpy(&i, &datum.as_hword, HWORD_SIZE);
+      printf("%" PRId32, i);
+      break;
+    }
+    case TYPE_HWORD:
+      printf("%" PRIu32, datum.as_hword);
+      break;
+    case TYPE_LONG: {
+      int64_t i = 0;
+      memcpy(&i, &datum.as_word, WORD_SIZE);
+      printf("%" PRId64, i);
+      break;
+    }
+    case TYPE_WORD:
+      printf("%" PRIu64, datum.as_word);
+      break;
+    }
+
+    prog->ptr++;
+  }
+  else if (instruction.opcode == OP_HALT)
+  {
+    // Do nothing here.  Should be caught by callers of vm_execute
+  }
+  else
+    return ERR_INVALID_OPCODE;
+  return ERR_OK;
+}
+
+err_t vm_execute_all(vm_t *vm)
+{
+  struct Program *program = &vm->program;
+  err_t err               = ERR_OK;
+#if VERBOSE == 1
+  struct Registers prev_registers = vm->registers;
+  size_t cycles                   = 0;
+  size_t prev_sptr                = 0;
+#endif
+  while (program->instructions[program->ptr].opcode != OP_HALT &&
+         program->ptr < program->max)
+  {
+#if VERBOSE >= 1
+    fprintf(stdout, "[vm_execute_all]: Trace(Cycle %lu)\n", cycles);
+    fputs(
+        "----------------------------------------------------------------------"
+        "----------\n",
+        stdout);
+    vm_print_program(vm, stdout);
+    fputs(
+        "----------------------------------------------------------------------"
+        "----------\n",
+        stdout);
+    if (memcmp(prev_registers.reg, vm->registers.reg,
+               ARR_SIZE(vm->registers.reg)) != 0)
+    {
+      vm_print_registers(vm, stdout);
+      prev_registers = vm->registers;
+      fputs("------------------------------------------------------------------"
+            "----"
+            "----------\n",
+            stdout);
+    }
+    if (prev_sptr != vm->stack.ptr)
+    {
+      vm_print_stack(vm, stdout);
+      prev_sptr = vm->stack.ptr;
+      fputs("------------------------------------------------------------------"
+            "----"
+            "----------\n",
+            stdout);
+    }
+    ++cycles;
+#endif
+    err = vm_execute(vm);
+    if (err)
+      return err;
+  }
+
+#if VERBOSE >= 1
+  fprintf(stdout, "[vm_execute_all]: Final VM state(Cycle %lu)\n", cycles);
+  vm_print_all(vm, stdout);
+#endif
+  return err;
+}
+
+void vm_load_stack(vm_t *vm, byte *bytes, size_t size)
+{
+  vm->stack.data = bytes;
+  vm->stack.max  = size;
+  vm->stack.ptr  = 0;
+}
+
+void vm_load_program(vm_t *vm, inst_t *instructions, size_t size)
+{
+  vm->program.instructions = instructions;
+  vm->program.max          = size;
+  vm->program.ptr          = 0;
+}
+
+void vm_print_registers(vm_t *vm, FILE *fp)
+{
+  struct Registers reg = vm->registers;
+  fprintf(fp, "Registers.reg = [");
+  for (size_t i = 0; i < VM_REGISTERS; ++i)
+  {
+    fprintf(fp, "{%lu:%lX}", i, reg.reg[i]);
+    if (i != VM_REGISTERS - 1)
+      fprintf(fp, ", ");
+  }
+  fprintf(fp, "]\n");
+}
+
+void vm_print_stack(vm_t *vm, FILE *fp)
+{
+  struct Stack stack = vm->stack;
+  fprintf(fp, "Stack.max  = %lu\nStack.ptr  = %lu\nStack.data = [", stack.max,
+          stack.ptr);
+  if (stack.ptr == 0)
+  {
+    fprintf(fp, "]\n");
+    return;
+  }
+  printf("\n");
+  for (size_t i = stack.ptr; i > 0; --i)
+  {
+    byte b = stack.data[i - 1];
+    fprintf(fp, "\t%lu: %X", stack.ptr - i, b);
+    if (i != 1)
+      fprintf(fp, ", ");
+    fprintf(fp, "\n");
+  }
+  fprintf(fp, "]\n");
+}
+
+void vm_print_program(vm_t *vm, FILE *fp)
+{
+  struct Program program = vm->program;
+  fprintf(fp,
+          "Program.max          = %lu\nProgram.ptr          = "
+          "%lu\nProgram.instructions = [\n",
+          program.max, program.ptr);
+  size_t beg = 0;
+  if (program.ptr >= VM_PRINT_PROGRAM_EXCERPT)
+  {
+    fprintf(fp, "\t...\n");
+    beg = program.ptr - VM_PRINT_PROGRAM_EXCERPT;
+  }
+  else
+    beg = 0;
+  size_t end = MIN(program.ptr + VM_PRINT_PROGRAM_EXCERPT, program.max);
+  for (size_t i = beg; i < end; ++i)
+  {
+    fprintf(fp, "\t%lu: ", i);
+    inst_print(program.instructions[i], fp);
+    if (i == program.ptr)
+      fprintf(fp, " <---");
+    fprintf(fp, "\n");
+  }
+  if (end != program.max)
+    fprintf(fp, "\t...\n");
+  fprintf(fp, "]\n");
+}
+
+void vm_print_all(vm_t *vm, FILE *fp)
+{
+  fputs("----------------------------------------------------------------------"
+        "----------\n",
+        fp);
+  vm_print_program(vm, fp);
+  fputs("----------------------------------------------------------------------"
+        "----------\n",
+        fp);
+  vm_print_registers(vm, fp);
+  fputs("----------------------------------------------------------------------"
+        "----------\n",
+        fp);
+  vm_print_stack(vm, fp);
+  fputs("----------------------------------------------------------------------"
+        "----------\n",
+        fp);
+}
+
+err_t vm_jump(vm_t *vm, word w)
+{
+  if (w >= vm->program.max)
+    return ERR_INVALID_PROGRAM_ADDRESS;
+  vm->program.ptr = w;
+  return ERR_OK;
+}
+
+err_t vm_push_byte(vm_t *vm, data_t b)
+{
+  if (vm->stack.ptr >= vm->stack.max)
+    return ERR_STACK_OVERFLOW;
+  vm->stack.data[vm->stack.ptr++] = b.as_byte;
+  return ERR_OK;
+}
+
+err_t vm_push_hword(vm_t *vm, data_t f)
+{
+  if (vm->stack.ptr + HWORD_SIZE >= vm->stack.max)
+    return ERR_STACK_OVERFLOW;
+  byte bytes[HWORD_SIZE] = {0};
+  convert_hword_to_bytes(f.as_hword, bytes);
+  for (size_t i = 0; i < HWORD_SIZE; ++i)
+  {
+    byte b = bytes[HWORD_SIZE - i - 1];
+    vm_push_byte(vm, DBYTE(b));
+  }
+  return ERR_OK;
+}
+
+err_t vm_push_word(vm_t *vm, data_t w)
+{
+  if (vm->stack.ptr + WORD_SIZE >= vm->stack.max)
+    return ERR_STACK_OVERFLOW;
+  byte bytes[WORD_SIZE] = {0};
+  convert_word_to_bytes(w.as_word, bytes);
+  for (size_t i = 0; i < WORD_SIZE; ++i)
+  {
+    byte b = bytes[WORD_SIZE - i - 1];
+    vm_push_byte(vm, DBYTE(b));
+  }
+  return ERR_OK;
+}
+
+err_t vm_push_byte_register(vm_t *vm, byte reg)
+{
+  if (reg >= VM_REGISTERS * 8)
+    return ERR_INVALID_REGISTER_BYTE;
+
+  // Interpret each word based register as 8 byte registers
+  byte b = WORD_NTH_BYTE(vm->registers.reg[reg / 8], reg % 8);
+
+  return vm_push_byte(vm, DBYTE(b));
+}
+
+err_t vm_push_hword_register(vm_t *vm, byte reg)
+{
+  if (reg >= VM_REGISTERS * 2)
+    return ERR_INVALID_REGISTER_HWORD;
+  else if (vm->stack.ptr >= vm->stack.max)
+    return ERR_STACK_OVERFLOW;
+  // Interpret each word based register as 2 hword registers
+  hword hw = WORD_NTH_HWORD(vm->registers.reg[reg / 2], reg % 2);
+  return vm_push_hword(vm, DHWORD(hw));
+}
+
+err_t vm_push_word_register(vm_t *vm, byte reg)
+{
+  if (reg >= VM_REGISTERS)
+    return ERR_INVALID_REGISTER_WORD;
+  else if (vm->stack.ptr >= vm->stack.max)
+    return ERR_STACK_OVERFLOW;
+  return vm_push_word(vm, DWORD(vm->registers.reg[reg]));
+}
+
+err_t vm_mov_byte(vm_t *vm, byte reg)
+{
+  if (reg >= (VM_REGISTERS * 8))
+    return ERR_INVALID_REGISTER_BYTE;
+  data_t ret = {0};
+  err_t err  = vm_pop_byte(vm, &ret);
+  if (err)
+    return err;
+  word *reg_ptr = &vm->registers.reg[reg / 8];
+  size_t shift  = (reg % 8) * 8;
+  // This resets the bits in the specific byte register
+  *reg_ptr = *reg_ptr & ~(0xFF << shift);
+  // This sets the bits
+  *reg_ptr = (*reg_ptr) | (ret.as_word << shift);
+  return ERR_OK;
+}
+
+err_t vm_mov_hword(vm_t *vm, byte reg)
+{
+  if (reg >= (VM_REGISTERS * 2))
+    return ERR_INVALID_REGISTER_HWORD;
+  else if (vm->stack.ptr < sizeof(f64))
+    return ERR_STACK_UNDERFLOW;
+  data_t ret = {0};
+  err_t err  = vm_pop_hword(vm, &ret);
+  if (err)
+    return err;
+  word *reg_ptr = &vm->registers.reg[reg / 2];
+  size_t shift  = (reg % 2) * 2;
+  // This resets the bits in the specific hword register
+  *reg_ptr = *reg_ptr & ~(0xFFFFFFFF << shift);
+  // This sets the bits
+  *reg_ptr = (*reg_ptr) | (ret.as_word << shift);
+  return ERR_OK;
+}
+
+err_t vm_mov_word(vm_t *vm, byte reg)
+{
+  if (reg >= VM_REGISTERS)
+    return ERR_INVALID_REGISTER_WORD;
+  else if (vm->stack.ptr < sizeof(word))
+    return ERR_STACK_UNDERFLOW;
+  data_t ret = {0};
+  err_t err  = vm_pop_word(vm, &ret);
+  if (err)
+    return err;
+  vm->registers.reg[reg] = ret.as_word;
+  return ERR_OK;
+}
+
+err_t vm_dup_byte(vm_t *vm, word w)
+{
+  if (vm->stack.ptr < w + 1)
+    return ERR_STACK_UNDERFLOW;
+  return vm_push_byte(vm, DBYTE(vm->stack.data[vm->stack.ptr - 1 - w]));
+}
+
+err_t vm_dup_hword(vm_t *vm, word w)
+{
+  if (vm->stack.ptr < HWORD_SIZE * (w + 1))
+    return ERR_STACK_UNDERFLOW;
+  byte bytes[HWORD_SIZE] = {0};
+  for (size_t i = 0; i < HWORD_SIZE; ++i)
+    bytes[HWORD_SIZE - i - 1] =
+        vm->stack.data[vm->stack.ptr - (HWORD_SIZE * (w + 1)) + i];
+  return vm_push_hword(vm, DHWORD(convert_bytes_to_hword(bytes)));
+}
+
+err_t vm_dup_word(vm_t *vm, word w)
+{
+  if (vm->stack.ptr < WORD_SIZE * (w + 1))
+    return ERR_STACK_UNDERFLOW;
+  byte bytes[WORD_SIZE] = {0};
+  for (size_t i = 0; i < WORD_SIZE; ++i)
+    bytes[WORD_SIZE - i - 1] =
+        vm->stack.data[vm->stack.ptr - (WORD_SIZE * (w + 1)) + i];
+  return vm_push_word(vm, DWORD(convert_bytes_to_word(bytes)));
+}
+
+err_t vm_pop_byte(vm_t *vm, data_t *ret)
+{
+  if (vm->stack.ptr == 0)
+    return ERR_STACK_UNDERFLOW;
+  *ret = DBYTE(vm->stack.data[--vm->stack.ptr]);
+  return ERR_OK;
+}
+
+err_t vm_pop_hword(vm_t *vm, data_t *ret)
+{
+  if (vm->stack.ptr < HWORD_SIZE)
+    return ERR_STACK_UNDERFLOW;
+  byte bytes[HWORD_SIZE] = {0};
+  for (size_t i = 0; i < HWORD_SIZE; ++i)
+  {
+    data_t b = {0};
+    vm_pop_byte(vm, &b);
+    bytes[i] = b.as_byte;
+  }
+  *ret = DWORD(convert_bytes_to_hword(bytes));
+  return ERR_OK;
+}
+
+err_t vm_pop_word(vm_t *vm, data_t *ret)
+{
+  if (vm->stack.ptr < WORD_SIZE)
+    return ERR_STACK_UNDERFLOW;
+  byte bytes[WORD_SIZE] = {0};
+  for (size_t i = 0; i < WORD_SIZE; ++i)
+  {
+    data_t b = {0};
+    vm_pop_byte(vm, &b);
+    bytes[i] = b.as_byte;
+  }
+  *ret = DWORD(convert_bytes_to_word(bytes));
+  return ERR_OK;
+}
+
+err_t vm_not_byte(vm_t *vm)
+{
+  data_t a  = {0};
+  err_t err = vm_pop_byte(vm, &a);
+  if (err)
+    return err;
+  return vm_push_byte(vm, DBYTE(!a.as_byte));
+}
+
+err_t vm_not_hword(vm_t *vm)
+{
+  data_t a  = {0};
+  err_t err = vm_pop_hword(vm, &a);
+  if (err)
+    return err;
+  return vm_push_hword(vm, DHWORD(!a.as_hword));
+}
+
+err_t vm_not_word(vm_t *vm)
+{
+  data_t a  = {0};
+  err_t err = vm_pop_word(vm, &a);
+  if (err)
+    return err;
+  return vm_push_word(vm, DWORD(!a.as_word));
+}
+
+err_t vm_or_byte(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_byte(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_byte(vm, &b);
+  if (err)
+    return err;
+  return vm_push_byte(vm, DBYTE(a.as_byte | b.as_byte));
+}
+
+err_t vm_or_hword(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_hword(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_hword(vm, &b);
+  if (err)
+    return err;
+  return vm_push_hword(vm, DHWORD(a.as_hword | b.as_hword));
+}
+
+err_t vm_or_word(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_word(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_word(vm, &b);
+  if (err)
+    return err;
+  return vm_push_word(vm, DWORD(a.as_word | b.as_word));
+}
+
+err_t vm_and_byte(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_byte(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_byte(vm, &b);
+  if (err)
+    return err;
+  return vm_push_byte(vm, DBYTE(a.as_byte & b.as_byte));
+}
+
+err_t vm_and_hword(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_hword(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_hword(vm, &b);
+  if (err)
+    return err;
+  return vm_push_hword(vm, DHWORD(a.as_hword & b.as_hword));
+}
+
+err_t vm_and_word(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_word(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_word(vm, &b);
+  if (err)
+    return err;
+  return vm_push_word(vm, DWORD(a.as_word & b.as_word));
+}
+
+err_t vm_xor_byte(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_byte(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_byte(vm, &b);
+  if (err)
+    return err;
+  return vm_push_byte(vm, DBYTE(a.as_byte ^ b.as_byte));
+}
+
+err_t vm_xor_hword(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_hword(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_hword(vm, &b);
+  if (err)
+    return err;
+  return vm_push_hword(vm, DHWORD(a.as_hword ^ b.as_hword));
+}
+
+err_t vm_xor_word(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_word(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_word(vm, &b);
+  if (err)
+    return err;
+  return vm_push_word(vm, DWORD(a.as_word ^ b.as_word));
+}
+
+err_t vm_eq_byte(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_byte(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_byte(vm, &b);
+  if (err)
+    return err;
+  return vm_push_byte(vm, DBYTE(a.as_byte == b.as_byte));
+}
+
+err_t vm_eq_hword(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_hword(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_hword(vm, &b);
+  if (err)
+    return err;
+  return vm_push_hword(vm, DHWORD(a.as_hword == b.as_hword));
+}
+
+err_t vm_eq_word(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_word(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_word(vm, &b);
+  if (err)
+    return err;
+  return vm_push_word(vm, DWORD(a.as_word == b.as_word));
+}
+
+err_t vm_plus_byte(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_byte(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_byte(vm, &b);
+  if (err)
+    return err;
+  return vm_push_byte(vm, DBYTE(a.as_byte + b.as_byte));
+}
+
+err_t vm_plus_hword(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_hword(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_hword(vm, &b);
+  if (err)
+    return err;
+  return vm_push_hword(vm, DHWORD(a.as_hword + b.as_hword));
+}
+
+err_t vm_plus_word(vm_t *vm)
+{
+  data_t a = {0}, b = {0};
+  err_t err = vm_pop_word(vm, &a);
+  if (err)
+    return err;
+  err = vm_pop_word(vm, &b);
+  if (err)
+    return err;
+  return vm_push_word(vm, DWORD(a.as_word + b.as_word));
+}