diff --git a/src/Makefile b/src/Makefile
index c599e38..f6797f4 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,7 +1,7 @@
 #CLI=rk65c02cli
 #CLI_OBJS=rk65c02cli.o
 
-LIB_OBJS=rk65c02.o bus.o instruction.o emulation.o debug.o device_ram.o device_fb.o device_serial.o log.o
+LIB_OBJS=rk65c02.o bus.o instruction.o emulation.o debug.o device_ram.o device_fb.o device_serial.o log.o assembler.o
 LIB_SO=librk65c02.so
 LIB_STATIC=librk65c02.a
 
diff --git a/src/assembler.c b/src/assembler.c
new file mode 100644
index 0000000..d3e4e81
--- /dev/null
+++ b/src/assembler.c
@@ -0,0 +1,104 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <errno.h>
+
+#include <assert.h>
+#include <string.h>
+
+#include <gc/gc.h>
+
+#include "bus.h"
+#include "rk65c02.h"
+#include "log.h"
+#include "assembler.h"
+#include "instruction.h"
+
+assembler_t
+assemble_init(bus_t *b, uint16_t pc)
+{
+	assembler_t asmblr;
+
+	asmblr.bus = b;
+	asmblr.pc = pc;
+
+	return asmblr;
+}
+
+bool
+assemble_single_implied(assembler_t *a, const char *mnemonic)
+{
+	return assemble_single(a, mnemonic, IMPLIED, 0, 0);
+}
+
+bool
+assemble_single(assembler_t *a, const char *mnemonic, addressing_t mode, uint8_t op1, uint8_t op2)
+{
+	uint8_t *asmbuf;
+	uint8_t bsize;
+	bool rv;
+
+	rv = assemble_single_buf(&asmbuf, &bsize, mnemonic, mode, op1, op2);
+	if (rv == false)
+		return rv;
+
+	rv = bus_load_buf(a->bus, a->pc, asmbuf, bsize);
+	a->pc += bsize;
+
+	return rv;
+}
+
+bool
+assemble_single_buf_implied(uint8_t **buf, uint8_t *bsize, const char *mnemonic)
+{
+	return assemble_single_buf(buf, bsize, mnemonic, IMPLIED, 0, 0);
+}
+
+
+bool
+assemble_single_buf(uint8_t **buf, uint8_t *bsize, const char *mnemonic, addressing_t mode, uint8_t op1, uint8_t op2)
+{
+	instrdef_t id;
+	uint8_t opcode;
+	bool found;
+
+	found = false;
+	opcode = 0;
+
+	/* find the opcode for given mnemonic and addressing mode */
+	while (opcode <= 0xFF)  { /* this is stupid */
+		id = instruction_decode(opcode);
+		if ((strcmp(mnemonic, id.mnemonic) == 0) && (id.mode == mode)) {
+			found = true;
+			break;
+		}
+		opcode++;
+	}
+
+	if (!found) {
+		rk65c02_log(LOG_ERROR,
+		    "Couldn't find opcode for mnemonic %s mode %x.",
+		    mnemonic, mode);
+		return false;
+	}
+
+	*bsize = id.size;
+	*buf = GC_MALLOC(id.size);
+	if(*buf == NULL) {
+		rk65c02_log(LOG_ERROR, "Error allocating assembly buffer.");
+		return false;
+	}
+
+	/* fill the buffer */
+	memset(*buf, 0, id.size);
+	(*buf)[0] = opcode;
+	/* XXX */
+	if (id.size > 1) 
+		(*buf)[1] = op1;
+	if (id.size > 2)
+		(*buf)[2] = op2;
+
+	return found;
+}
+
diff --git a/src/assembler.h b/src/assembler.h
new file mode 100644
index 0000000..e12d426
--- /dev/null
+++ b/src/assembler.h
@@ -0,0 +1,22 @@
+#ifndef _ASSEMBLER_H_
+#define _ASSEMBLER_H_
+
+#include "instruction.h"
+#include "rk65c02.h"
+
+struct assembler {
+	bus_t *bus;
+	uint16_t pc;
+};
+
+typedef struct assembler assembler_t;
+
+bool assemble_single_buf_implied(uint8_t **, uint8_t *, const char *);
+bool assemble_single_buf(uint8_t **, uint8_t *, const char *, addressing_t, uint8_t, uint8_t);
+
+assembler_t assemble_init(bus_t *, uint16_t);
+bool assemble_single(assembler_t *, const char *, addressing_t, uint8_t, uint8_t);
+bool assemble_single_implied(assembler_t *, const char *);
+
+#endif /* _ASSEMBLER_H_ */
+
diff --git a/src/instruction.c b/src/instruction.c
index ba9ba6b..d52f7d7 100644
--- a/src/instruction.c
+++ b/src/instruction.c
@@ -135,93 +135,6 @@ instruction_string_get(instruction_t *i)
 	return str;
 }
 
-assembler_t
-assemble_init(bus_t *b, uint16_t pc)
-{
-	assembler_t asmblr;
-
-	asmblr.bus = b;
-	asmblr.pc = pc;
-
-	return asmblr;
-}
-
-bool
-assemble_single_implied(assembler_t *a, const char *mnemonic)
-{
-	return assemble_single(a, mnemonic, IMPLIED, 0, 0);
-}
-
-bool
-assemble_single(assembler_t *a, const char *mnemonic, addressing_t mode, uint8_t op1, uint8_t op2)
-{
-	uint8_t *asmbuf;
-	uint8_t bsize;
-	bool rv;
-
-	rv = assemble_single_buf(&asmbuf, &bsize, mnemonic, mode, op1, op2);
-	if (rv == false)
-		return rv;
-
-	rv = bus_load_buf(a->bus, a->pc, asmbuf, bsize);
-	a->pc += bsize;
-
-	return rv;
-}
-
-bool
-assemble_single_buf_implied(uint8_t **buf, uint8_t *bsize, const char *mnemonic)
-{
-	return assemble_single_buf(buf, bsize, mnemonic, IMPLIED, 0, 0);
-}
-
-
-bool
-assemble_single_buf(uint8_t **buf, uint8_t *bsize, const char *mnemonic, addressing_t mode, uint8_t op1, uint8_t op2)
-{
-	instrdef_t id;
-	uint8_t opcode;
-	bool found;
-
-	found = false;
-	opcode = 0;
-
-	/* find the opcode for given mnemonic and addressing mode */
-	while (opcode <= 0xFF)  { /* this is stupid */
-		id = instruction_decode(opcode);
-		if ((strcmp(mnemonic, id.mnemonic) == 0) && (id.mode == mode)) {
-			found = true;
-			break;
-		}
-		opcode++;
-	}
-
-	if (!found) {
-		rk65c02_log(LOG_ERROR,
-		    "Couldn't find opcode for mnemonic %s mode %x.",
-		    mnemonic, mode);
-		return false;
-	}
-
-	*bsize = id.size;
-	*buf = GC_MALLOC(id.size);
-	if(*buf == NULL) {
-		rk65c02_log(LOG_ERROR, "Error allocating assembly buffer.");
-		return false;
-	}
-
-	/* fill the buffer */
-	memset(*buf, 0, id.size);
-	(*buf)[0] = opcode;
-	/* XXX */
-	if (id.size > 1) 
-		(*buf)[1] = op1;
-	if (id.size > 2)
-		(*buf)[2] = op2;
-
-	return found;
-}
-
 void
 disassemble(bus_t *b, uint16_t addr) 
 {
diff --git a/src/instruction.h b/src/instruction.h
index 6504116..8b358ba 100644
--- a/src/instruction.h
+++ b/src/instruction.h
@@ -41,13 +41,6 @@ struct instrdef {
 
 typedef struct instrdef instrdef_t;
 
-struct assembler {
-	bus_t *bus;
-	uint16_t pc;
-};
-
-typedef struct assembler assembler_t;
-
 instruction_t instruction_fetch(bus_t *, uint16_t);
 instrdef_t instruction_decode(uint8_t);
 void instruction_print(instruction_t *);
@@ -64,11 +57,4 @@ void program_counter_increment(rk65c02emu_t *, instrdef_t *);
 bool instruction_modify_pc(instrdef_t *);
 void program_counter_branch(rk65c02emu_t *, int8_t);
 
-bool assemble_single_buf_implied(uint8_t **, uint8_t *, const char *);
-bool assemble_single_buf(uint8_t **, uint8_t *, const char *, addressing_t, uint8_t, uint8_t);
-
-assembler_t assemble_init(bus_t *, uint16_t);
-bool assemble_single(assembler_t *, const char *, addressing_t, uint8_t, uint8_t);
-bool assemble_single_implied(assembler_t *, const char *);
-
 #endif /* _INSTRUCTION_H_ */
diff --git a/test/test_assemble.c b/test/test_assemble.c
index 0f18e04..d9315d2 100644
--- a/test/test_assemble.c
+++ b/test/test_assemble.c
@@ -7,6 +7,7 @@
 
 #include "bus.h"
 #include "rk65c02.h"
+#include "assembler.h"
 #include "instruction.h"
 #include "utils.h"
 
diff --git a/test/test_debug.c b/test/test_debug.c
index eb93f58..1ae4199 100644
--- a/test/test_debug.c
+++ b/test/test_debug.c
@@ -9,6 +9,7 @@
 
 #include "bus.h"
 #include "rk65c02.h"
+#include "assembler.h"
 #include "instruction.h"
 #include "debug.h"
 #include "utils.h"
diff --git a/test/test_emulation.c b/test/test_emulation.c
index 07517c1..fed334a 100644
--- a/test/test_emulation.c
+++ b/test/test_emulation.c
@@ -6,6 +6,7 @@
 
 #include "bus.h"
 #include "rk65c02.h"
+#include "assembler.h"
 #include "instruction.h"
 #include "debug.h"
 #include "log.h"