diff --git a/disas/main.c b/disas/main.c
index 2c21a9a..c52e83c 100644
--- a/disas/main.c
+++ b/disas/main.c
@@ -11,9 +11,25 @@
 #define OP_ADDR_MODE (OP_ADDR_IMPL | OP_ADDR_REL | OP_ADDR_IND	\
 					  | OP_ADDR_IMM | OP_ADDR_ABS)
 
+#define COLOR_RED    31
+#define COLOR_GREEN  32
+#define COLOR_YELLOW 33
+#define COLOR_BLUE   34
+#define COLOR_RESET  0
+
 char *prg_name;
 FILE *input;
 FILE *output;
+int colorize = 1;
+
+void
+term_color(FILE *stream, int color)
+{
+	if (!colorize) return;
+
+	fprintf(stream, "\033[%dm", color);
+}
+
 
 uint8_t
 readu8(void)
@@ -85,16 +101,40 @@ fatal(const char *str, ...)
 {
 	va_list ap;
 
+	term_color(stderr, COLOR_RED);
 	fprintf(stderr, "%s: ", prg_name);
 	va_start(ap, str);
 	vfprintf(stderr, str, ap);
 	va_end(ap);
 	fprintf(stderr, "\n");
+	term_color(stderr, COLOR_RESET);
 
 	exit(EXIT_FAILURE);
 }
 
-void
+static void
+decode_value(int size, int is_addr)
+{
+	term_color(output, COLOR_GREEN);
+	if (!is_addr) fprintf(output, "#");
+	switch (size)
+	{
+	case SIZE_BYTE:
+		fprintf(output, "$%X", readu8());
+		break;
+	case SIZE_WORD:
+		fprintf(output, "$%hX", readu16());
+		break;
+	case SIZE_LONG:
+		fprintf(output, "$%X", readu32());
+		break;
+	default:
+		break;
+	}
+	term_color(output, COLOR_RESET);
+}
+
+static void
 decode_target_suffix(uint8_t attr)
 {
 	fprintf(output, ".");
@@ -117,23 +157,41 @@ decode_target_suffix(uint8_t attr)
 	}
 }
 
-void
-decode_address(uint8_t attr)
+static void
+decode_opcode(uint8_t opcode, uint8_t attr)
 {
-	switch (GET_ADDRESS_SIZE(attr))
+	uint8_t addressing;
+
+	addressing = opcode_addr[opcode];
+	term_color(output, COLOR_BLUE);
+	fprintf(output, "%s", opcode_str[opcode]);
+	if ((addressing & OP_ADDR_IMPL) == 0
+		&& (addressing & OP_ADDR_REL) == 0
+		&& opcode != OP_JMP_abs
+		&& opcode != OP_JMP_ind
+		&& opcode != OP_JSR_abs)
 	{
-	case SIZE_BYTE:
-		fprintf(output, " %%%X", readu8());
-		break;
-	case SIZE_WORD:
-		fprintf(output, " %%%hX", readu16());
-		break;
-	case SIZE_LONG:
-		fprintf(output, " %%%X", readu32());
-		break;
-	default:
-		break;
+		decode_target_suffix(attr);
 	}
+	term_color(output, COLOR_RESET);
+}
+
+static void
+decode_register(uint8_t opcode)
+{
+	uint8_t addr;
+
+	addr = opcode_addr[opcode];
+	term_color(output, COLOR_YELLOW);
+	if (addr & OP_ADDR_X)
+	{
+		fprintf(output, "X");
+	}
+	else if (addr & OP_ADDR_Y)
+	{
+		fprintf(output, "Y");
+	}
+	term_color(output, COLOR_RESET);
 }
 
 void
@@ -143,22 +201,10 @@ decode_imm(uint8_t opcode)
 
 	attr = readu8();
 
-	fprintf(output, "%s", opcode_str[opcode]);
-	decode_target_suffix(attr);
-	switch (GET_TARGET_SIZE(attr))
-	{
-	case SIZE_BYTE:
-		fprintf(output, " #$%X\n", readu8());
-		break;
-	case SIZE_WORD:
-		fprintf(output, " #$%hX\n", readu16());
-		break;
-	case SIZE_LONG:
-		fprintf(output, " #$%X\n", readu32());
-		break;
-	default:
-		break;
-	}
+	decode_opcode(opcode, attr);
+	fprintf(output, " ");
+	decode_value(GET_TARGET_SIZE(attr), 0);
+	fprintf(output, "\n");
 }
 
 void
@@ -166,30 +212,26 @@ decode_ind(uint8_t opcode)
 {
 	uint8_t attr;
 
-	fprintf(output, "%s", opcode_str[opcode]);
 	attr = readu8();
-	if (opcode != OP_JMP_ind)
-	{
-		decode_target_suffix(attr);
-	}
+	decode_opcode(opcode, attr);
+	fprintf(output, " ");
 	if (opcode_addr[opcode] & (OP_ADDR_X | OP_ADDR_Y))
 	{
-		fprintf(output, " (");
-	}
-	else
-	{
-		fprintf(output, " ");
+		fprintf(output, "(");
 	}
 
-	decode_address(attr);
+	decode_value(GET_ADDRESS_SIZE(attr), 1);
 
 	if (opcode_addr[opcode] & OP_ADDR_X)
 	{
-		fprintf(output, ", X)");
+		fprintf(output, ", ");
+		decode_register(opcode);
+		fprintf(output, ")");
 	}
 	else if (opcode_addr[opcode] & OP_ADDR_Y)
 	{
-		fprintf(output, "), Y");
+		fprintf(output, "), ");
+		decode_register(opcode);
 	}
 	fprintf(output, "\n");
 }
@@ -199,22 +241,14 @@ decode_abs(uint8_t opcode)
 {
 	uint8_t attr;
 
-	fprintf(output, "%s", opcode_str[opcode]);
 	attr = readu8();
-	if (opcode != OP_JSR_abs
-		|| opcode != OP_JMP_abs)
+	decode_opcode(opcode, attr);
+	fprintf(output, " ");
+	decode_value(GET_ADDRESS_SIZE(attr), 1);
+	if (opcode_addr[opcode] & (OP_ADDR_X | OP_ADDR_Y))
 	{
-		decode_target_suffix(attr);
-	}
-	decode_address(attr);
-
-	if (opcode_addr[opcode] & OP_ADDR_X)
-	{
-		fprintf(output, ", X");
-	}
-	else if (opcode_addr[opcode] & OP_ADDR_Y)
-	{
-		fprintf(output, ", Y");
+		fprintf(output, ", ");
+		decode_register(opcode);
 	}
 	fprintf(output, "\n");
 }
@@ -231,18 +265,20 @@ decode(void)
 		switch (opcode_addr[opcode] & OP_ADDR_MODE)
 		{
 		case OP_ADDR_IMPL:
+			decode_opcode(opcode, 0);
 			if (opcode_addr[opcode] & OP_ADDR_A)
 			{
-				fprintf(output, "%s A\n", opcode_str[opcode]);
-			}
-			else
-			{
-				fprintf(output, "%s\n", opcode_str[opcode]);
+				term_color(output, COLOR_YELLOW);
+				fprintf(output, " A");
+				term_color(output, COLOR_RESET);
 			}
+			fprintf(output, "\n");
 			break;
 		case OP_ADDR_REL:
-			relative = read16();
-			fprintf(output, "%s $%hX\n", opcode_str[opcode], relative);
+			decode_opcode(opcode, 0);
+			fprintf(output, " ");
+			decode_value(SIZE_WORD, 1);
+			fprintf(output, "\n");
 			break;
 		case OP_ADDR_IMM:
 			decode_imm(opcode);
@@ -292,6 +328,8 @@ version(void)
 int
 main(int argc, char **argv)
 {
+	char *no_color;
+
 #ifdef HAVE_LIBGEN_H
 	prg_name = basename(argv[0]);
 #else
@@ -300,6 +338,12 @@ main(int argc, char **argv)
 	input = stdin;
 	output = stdout;
 
+	no_color = getenv("NO_COLOR");
+	if (no_color != NULL && no_color[0] != '\0')
+	{
+		colorize = 0;
+	}
+
 	while ((argc > 1) && (argv[1][0] == '-'))
 	{
 		switch (argv[1][1])
@@ -321,6 +365,7 @@ main(int argc, char **argv)
 
 	if (argc > 2)
 	{
+		colorize = 0;
 		output = fopen(argv[2], "w");
 		if (output == NULL) fatal("can't open %s.", argv[2]);
 	}
diff --git a/lib/op.h b/lib/op.h
index d93c83c..76c392e 100644
--- a/lib/op.h
+++ b/lib/op.h
@@ -5,14 +5,14 @@
 
 # define OP_MAX 256
 
-# define OP_ADDR_IMPL 0
-# define OP_ADDR_REL  1 << 0
-# define OP_ADDR_IMM  1 << 1
-# define OP_ADDR_IND  1 << 2
-# define OP_ADDR_ABS  1 << 3
-# define OP_ADDR_X    1 << 4
-# define OP_ADDR_Y    1 << 5
-# define OP_ADDR_A    1 << 6
+# define OP_ADDR_IMPL 1 << 0
+# define OP_ADDR_REL  1 << 1
+# define OP_ADDR_IMM  1 << 2
+# define OP_ADDR_IND  1 << 3
+# define OP_ADDR_ABS  1 << 4
+# define OP_ADDR_X    1 << 5
+# define OP_ADDR_Y    1 << 6
+# define OP_ADDR_A    1 << 7
 
 # define OP_BRK_impl  0x00
 # define OP_ORA_x_ind 0x01