Introduced new instructions for comparison

Comparing signed and unsigned versions of numbers.  Same for EQ as
well.

Notice the irregular pattern of BYTE, CHAR, INT, HWORD,LONG,WORD as
OPCODE_IS_TYPE requires the subcodes to be surrounded by BYTE and
WORD.

vm/inst.h

@@ -62,17 +62,44 @@ typedef enum
   OP_XOR_WORD,
 
   OP_EQ_BYTE,
+  OP_EQ_CHAR,
   OP_EQ_HWORD,
+  OP_EQ_INT,
+  OP_EQ_LONG,
   OP_EQ_WORD,
 
   // Mathematical operations
+  OP_LT_BYTE,
+  OP_LT_CHAR,
+  OP_LT_HWORD,
+  OP_LT_INT,
+  OP_LT_LONG,
+  OP_LT_WORD,
+  OP_LTE_BYTE,
+  OP_LTE_CHAR,
+  OP_LTE_HWORD,
+  OP_LTE_INT,
+  OP_LTE_LONG,
+  OP_LTE_WORD,
+  OP_GT_BYTE,
+  OP_GT_CHAR,
+  OP_GT_HWORD,
+  OP_GT_INT,
+  OP_GT_LONG,
+  OP_GT_WORD,
+  OP_GTE_BYTE,
+  OP_GTE_CHAR,
+  OP_GTE_HWORD,
+  OP_GTE_INT,
+  OP_GTE_LONG,
+  OP_GTE_WORD,
   OP_PLUS_BYTE,
   OP_PLUS_HWORD,
   OP_PLUS_WORD,
 
   // Simple I/O
-  OP_PRINT_CHAR,
   OP_PRINT_BYTE,
+  OP_PRINT_CHAR,
   OP_PRINT_INT,
   OP_PRINT_HWORD,
   OP_PRINT_LONG,
@@ -143,6 +170,10 @@ inst_t *insts_read_bytecode_file(FILE *, size_t *);
 #define INST_AND(TYPE)  ((inst_t){.opcode = OP_AND_##TYPE})
 #define INST_XOR(TYPE)  ((inst_t){.opcode = OP_XOR_##TYPE})
 #define INST_EQ(TYPE)   ((inst_t){.opcode = OP_EQ_##TYPE})
+#define INST_LT(TYPE)   ((inst_t){.opcode = OP_LT_##TYPE})
+#define INST_LTE(TYPE)  ((inst_t){.opcode = OP_LTE_##TYPE})
+#define INST_GT(TYPE)   ((inst_t){.opcode = OP_GT_##TYPE})
+#define INST_GTE(TYPE)  ((inst_t){.opcode = OP_GTE_##TYPE})
 #define INST_PLUS(TYPE) ((inst_t){.opcode = OP_PLUS_##TYPE})
 
 #define INST_JUMP_ABS(OP) \