Added and implemented OP_JUMP_IF_*

Performs a jump when the (BYTE|HWORD|WORD) at the top of the stack is
non zero.

3 files changed, 48 insertions, 18 deletions

diff --git a/src/inst.c b/src/inst.c
index dbfb885..3980173 100644
--- a/src/inst.c
+++ b/src/inst.c
@@ -132,6 +132,15 @@ const char *opcode_as_cstr(opcode_t code)
   case OP_JUMP_REGISTER:
     return "JUMP_REGISTER";
     break;
+  case OP_JUMP_IF_BYTE:
+    return "JUMP_IF_BYTE";
+    break;
+  case OP_JUMP_IF_HWORD:
+    return "JUMP_IF_HWORD";
+    break;
+  case OP_JUMP_IF_WORD:
+    return "JUMP_IF_WORD";
+    break;
   case OP_PRINT_CHAR:
     return "PRINT_CHAR";
     break;
@@ -204,7 +213,7 @@ word convert_bytes_to_word(byte *bytes)
 
 void inst_print(inst_t instruction, FILE *fp)
 {
-  static_assert(NUMBER_OF_OPCODES == 43, "inst_bytecode_size: Out of date");
+  static_assert(NUMBER_OF_OPCODES == 46, "inst_bytecode_size: Out of date");
   fprintf(fp, "%s(", opcode_as_cstr(instruction.opcode));
   if (OPCODE_IS_TYPE(instruction.opcode, OP_PUSH))
   {
@@ -223,7 +232,8 @@ void inst_print(inst_t instruction, FILE *fp)
   {
     fprintf(fp, "n=%lu", instruction.operand.as_word);
   }
-  else if (instruction.opcode == OP_JUMP_ABS)
+  else if (instruction.opcode == OP_JUMP_ABS ||
+           OPCODE_IS_TYPE(instruction.opcode, OP_JUMP_IF))
   {
     fprintf(fp, "address=0x");
     data_print(instruction.operand, DATA_TYPE_WORD, fp);
@@ -233,7 +243,7 @@ void inst_print(inst_t instruction, FILE *fp)
 
 size_t inst_bytecode_size(inst_t inst)
 {
-  static_assert(NUMBER_OF_OPCODES == 43, "inst_bytecode_size: Out of date");
+  static_assert(NUMBER_OF_OPCODES == 46, "inst_bytecode_size: Out of date");
   size_t size = 1; // for opcode
   if (OPCODE_IS_TYPE(inst.opcode, OP_PUSH))
   {
@@ -249,16 +259,15 @@ size_t inst_bytecode_size(inst_t inst)
            inst.opcode == OP_JUMP_REGISTER)
     // Only need a byte for the register
     ++size;
-  else if (OPCODE_IS_TYPE(inst.opcode, OP_DUP))
-    size += WORD_SIZE;
-  else if (inst.opcode == OP_JUMP_ABS)
+  else if (OPCODE_IS_TYPE(inst.opcode, OP_DUP) || inst.opcode == OP_JUMP_ABS ||
+           OPCODE_IS_TYPE(inst.opcode, OP_JUMP_IF))
     size += WORD_SIZE;
   return size;
 }
 
 void inst_write_bytecode(inst_t inst, darr_t *darr)
 {
-  static_assert(NUMBER_OF_OPCODES == 43, "inst_write_bytecode: Out of date");
+  static_assert(NUMBER_OF_OPCODES == 46, "inst_write_bytecode: Out of date");
   // Append opcode
   darr_append_byte(darr, inst.opcode);
   // Then append 0 or more operands
@@ -269,7 +278,8 @@ void inst_write_bytecode(inst_t inst, darr_t *darr)
            OPCODE_IS_TYPE(inst.opcode, OP_MOV) ||
            inst.opcode == OP_JUMP_REGISTER)
     to_append = DATA_TYPE_BYTE;
-  else if (OPCODE_IS_TYPE(inst.opcode, OP_DUP) || inst.opcode == OP_JUMP_ABS)
+  else if (OPCODE_IS_TYPE(inst.opcode, OP_DUP) || inst.opcode == OP_JUMP_ABS ||
+           OPCODE_IS_TYPE(inst.opcode, OP_JUMP_IF))
     to_append = DATA_TYPE_WORD;
 
   switch (to_append)
@@ -331,7 +341,7 @@ 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 == 43, "inst_read_bytecode: Out of date");
+  static_assert(NUMBER_OF_OPCODES == 46, "inst_read_bytecode: Out of date");
   if (darr->used >= darr->available)
     return (inst_t){0};
   inst_t inst     = {0};
@@ -346,7 +356,8 @@ inst_t inst_read_bytecode(darr_t *darr)
   else if (OPCODE_IS_TYPE(opcode, OP_PUSH_REGISTER) ||
            OPCODE_IS_TYPE(opcode, OP_MOV) || inst.opcode == OP_JUMP_STACK)
     inst.operand = read_type_from_darr(darr, DATA_TYPE_BYTE);
-  else if (OPCODE_IS_TYPE(opcode, OP_DUP) || opcode == OP_JUMP_ABS)
+  else if (OPCODE_IS_TYPE(opcode, OP_DUP) || opcode == OP_JUMP_ABS ||
+           OPCODE_IS_TYPE(opcode, OP_JUMP_IF))
     inst.operand = read_type_from_darr(darr, DATA_TYPE_WORD);
   // Otherwise opcode doesn't take operands
 
diff --git a/src/inst.h b/src/inst.h
index b9e0e9b..8902757 100644
--- a/src/inst.h
+++ b/src/inst.h
@@ -82,6 +82,9 @@ typedef enum
   OP_JUMP_ABS,
   OP_JUMP_STACK,
   OP_JUMP_REGISTER,
+  OP_JUMP_IF_BYTE,
+  OP_JUMP_IF_HWORD,
+  OP_JUMP_IF_WORD,
 
   // Should not be an opcode
   NUMBER_OF_OPCODES,
@@ -146,6 +149,8 @@ inst_t *insts_read_bytecode_file(FILE *, size_t *);
   ((inst_t){.opcode = OP_JUMP_ABS, .operand = DWORD(OP)})
 #define INST_JUMP_STACK    ((inst_t){.opcode = OP_JUMP_STACK})
 #define INST_JUMP_REGISTER ((inst_t){.opcode = OP_JUMP_REGISTER})
+#define INST_JUMP_IF(TYPE, OP) \
+  ((inst_t){.opcode = OP_JUMP_IF_##TYPE, .operand = DWORD(OP)})
 
 #define INST_PRINT(TYPE) ((inst_t){.opcode = OP_PRINT_##TYPE})
 #endif
diff --git a/src/runtime.c b/src/runtime.c
index cf66480..acc0062 100644
--- a/src/runtime.c
+++ b/src/runtime.c
@@ -55,7 +55,7 @@ const char *err_as_cstr(err_t err)
 
 err_t vm_execute(vm_t *vm)
 {
-  static_assert(NUMBER_OF_OPCODES == 43, "vm_execute: Out of date");
+  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;
@@ -109,13 +109,7 @@ err_t vm_execute(vm_t *vm)
     return STACK_ROUTINES[instruction.opcode](vm);
   }
   else if (instruction.opcode == OP_JUMP_ABS)
-  {
-    // Set prog->ptr to the jump point requested
-    if (instruction.operand.as_word >= vm->program.max)
-      return ERR_INVALID_PROGRAM_ADDRESS;
-    prog->ptr = instruction.operand.as_word;
-    return ERR_OK;
-  }
+    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
@@ -132,6 +126,26 @@ err_t vm_execute(vm_t *vm)
     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)
   {