diff --git a/lib/base.h b/lib/base.h
index e0cabc0..1eaf9ba 100644
--- a/lib/base.h
+++ b/lib/base.h
@@ -77,7 +77,7 @@ typedef enum
 #define SWORD_SIZE  sizeof(s_word)
 
 // Macros to extract the nth byte or nth hword from a word
-#define WORD_NTH_BYTE(WORD, N)  (((WORD) >> ((N)*8)) & 0xff)
+#define WORD_NTH_BYTE(WORD, N)  (((WORD) >> ((N)*8)) & 0xFF)
 #define WORD_NTH_HWORD(WORD, N) (((WORD) >> ((N)*2)) & 0xFFFFFFFF)
 
 // Assume array contains 4 bytes.
diff --git a/lib/inst.h b/lib/inst.h
index 10f8dc7..63b1669 100644
--- a/lib/inst.h
+++ b/lib/inst.h
@@ -229,8 +229,9 @@ inst_t *insts_read_bytecode_file(FILE *, size_t *);
 
 #define INST_JUMP_ABS(OP) \
   ((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_STACK ((inst_t){.opcode = OP_JUMP_STACK})
+#define INST_JUMP_REGISTER(OP) \
+  ((inst_t){.opcode = OP_JUMP_REGISTER, .operand = DWORD(OP)})
 #define INST_JUMP_IF(TYPE, OP) \
   ((inst_t){.opcode = OP_JUMP_IF_##TYPE, .operand = DWORD(OP)})