diff --git a/Makefile b/Makefile
index 6c52f71..dd22cf8 100644
--- a/Makefile
+++ b/Makefile
@@ -71,6 +71,7 @@ dist:
 		$(PACKAGE)-$(VERSION)/src/arch/sparc.c \
 		$(PACKAGE)-$(VERSION)/src/arch/sparc64.c \
 		$(PACKAGE)-$(VERSION)/src/arch/yasep.c \
+		$(PACKAGE)-$(VERSION)/src/arch/yasep16.c \
 		$(PACKAGE)-$(VERSION)/src/arch/Makefile \
 		$(PACKAGE)-$(VERSION)/src/arch/amd64.ins \
 		$(PACKAGE)-$(VERSION)/src/arch/amd64.reg \
@@ -121,6 +122,7 @@ dist:
 		$(PACKAGE)-$(VERSION)/test/sparc.S \
 		$(PACKAGE)-$(VERSION)/test/sparc64.S \
 		$(PACKAGE)-$(VERSION)/test/yasep.S \
+		$(PACKAGE)-$(VERSION)/test/yasep16.S \
 		$(PACKAGE)-$(VERSION)/test/Makefile \
 		$(PACKAGE)-$(VERSION)/test/project.conf \
 		$(PACKAGE)-$(VERSION)/Makefile \
diff --git a/src/arch/Makefile b/src/arch/Makefile
index de2e65c..e660014 100644
--- a/src/arch/Makefile
+++ b/src/arch/Makefile
@@ -1,4 +1,4 @@
-TARGETS	= amd64.so arm.so armeb.so armel.so dalvik.so i386.so i386_real.so i486.so i586.so i686.so java.so mips.so mipseb.so mipsel.so sparc.so sparc64.so yasep.so
+TARGETS	= amd64.so arm.so armeb.so armel.so dalvik.so i386.so i386_real.so i486.so i586.so i686.so java.so mips.so mipseb.so mipsel.so sparc.so sparc64.so yasep.so yasep16.so
 PREFIX	= /usr/local
 DESTDIR	=
 LIBDIR	= $(PREFIX)/lib
@@ -137,6 +137,13 @@ yasep_LDFLAGS = $(LDFLAGSF) $(LDFLAGS)
 yasep.so: $(yasep_OBJS)
 	$(CCSHARED) -o yasep.so $(yasep_OBJS) $(yasep_LDFLAGS)
 
+yasep16_OBJS = yasep16.o
+yasep16_CFLAGS = $(CPPFLAGSF) $(CPPFLAGS) $(CFLAGSF) $(CFLAGS)
+yasep16_LDFLAGS = $(LDFLAGSF) $(LDFLAGS)
+
+yasep16.so: $(yasep16_OBJS)
+	$(CCSHARED) -o yasep16.so $(yasep16_OBJS) $(yasep16_LDFLAGS)
+
 amd64.o: amd64.c amd64.ins amd64.reg common.ins null.ins i386.h i386.ins i386.reg i486.ins i686.ins i686.reg
 	$(CC) $(amd64_CFLAGS) -c amd64.c
 
@@ -188,8 +195,11 @@ sparc64.o: sparc64.c common.ins null.ins sparc.h sparc.ins sparc.reg
 yasep.o: yasep.c common.ins null.ins yasep.ins yasep.reg
 	$(CC) $(yasep_CFLAGS) -c yasep.c
 
+yasep16.o: yasep16.c common.ins null.ins yasep.ins yasep.reg
+	$(CC) $(yasep16_CFLAGS) -c yasep16.c
+
 clean:
-	$(RM) -- $(amd64_OBJS) $(arm_OBJS) $(armeb_OBJS) $(armel_OBJS) $(dalvik_OBJS) $(i386_OBJS) $(i386_real_OBJS) $(i486_OBJS) $(i586_OBJS) $(i686_OBJS) $(java_OBJS) $(mips_OBJS) $(mipseb_OBJS) $(mipsel_OBJS) $(sparc_OBJS) $(sparc64_OBJS) $(yasep_OBJS)
+	$(RM) -- $(amd64_OBJS) $(arm_OBJS) $(armeb_OBJS) $(armel_OBJS) $(dalvik_OBJS) $(i386_OBJS) $(i386_real_OBJS) $(i486_OBJS) $(i586_OBJS) $(i686_OBJS) $(java_OBJS) $(mips_OBJS) $(mipseb_OBJS) $(mipsel_OBJS) $(sparc_OBJS) $(sparc64_OBJS) $(yasep_OBJS) $(yasep16_OBJS)
 
 distclean: clean
 	$(RM) -- $(TARGETS)
@@ -229,6 +239,8 @@ install: $(TARGETS)
 	$(INSTALL) -m 0644 -- sparc64.so $(DESTDIR)$(LIBDIR)/asm/arch/sparc64.so
 	$(MKDIR) $(DESTDIR)$(LIBDIR)/asm/arch
 	$(INSTALL) -m 0644 -- yasep.so $(DESTDIR)$(LIBDIR)/asm/arch/yasep.so
+	$(MKDIR) $(DESTDIR)$(LIBDIR)/asm/arch
+	$(INSTALL) -m 0644 -- yasep16.so $(DESTDIR)$(LIBDIR)/asm/arch/yasep16.so
 
 uninstall:
 	$(RM) -- $(DESTDIR)$(LIBDIR)/asm/arch/amd64.so
@@ -248,5 +260,6 @@ uninstall:
 	$(RM) -- $(DESTDIR)$(LIBDIR)/asm/arch/sparc.so
 	$(RM) -- $(DESTDIR)$(LIBDIR)/asm/arch/sparc64.so
 	$(RM) -- $(DESTDIR)$(LIBDIR)/asm/arch/yasep.so
+	$(RM) -- $(DESTDIR)$(LIBDIR)/asm/arch/yasep16.so
 
 .PHONY: all clean distclean install uninstall
diff --git a/src/arch/project.conf b/src/arch/project.conf
index 6a13f47..c02b7b1 100644
--- a/src/arch/project.conf
+++ b/src/arch/project.conf
@@ -1,4 +1,4 @@
-targets=amd64,arm,armeb,armel,dalvik,i386,i386_real,i486,i586,i686,java,mips,mipseb,mipsel,sparc,sparc64,yasep
+targets=amd64,arm,armeb,armel,dalvik,i386,i386_real,i486,i586,i686,java,mips,mipseb,mipsel,sparc,sparc64,yasep,yasep16
 cppflags_force=-I ../../include
 cflags_force=-W `pkg-config --cflags libSystem`
 cflags=-Wall -g -O2 -fPIC -pedantic
@@ -139,3 +139,11 @@ install=$(LIBDIR)/asm/arch
 
 [yasep.c]
 depends=common.ins,null.ins,yasep.ins,yasep.reg
+
+[yasep16]
+type=plugin
+sources=yasep16.c
+install=$(LIBDIR)/asm/arch
+
+[yasep16.c]
+depends=common.ins,null.ins,yasep.ins,yasep.reg
diff --git a/src/arch/yasep.c b/src/arch/yasep.c
index 6eac656..37622b2 100644
--- a/src/arch/yasep.c
+++ b/src/arch/yasep.c
@@ -17,13 +17,22 @@
 
 #include <stddef.h>
 #include "Asm.h"
-#define ARCH_yasep32
+#ifndef ARCH_yasep
+# define ARCH_yasep	32
+# define ARCH_yasep32
+# define _yasep_name	"yasep"
+#endif
 
 
 /* yasep */
 /* private */
 /* variables */
 /* plug-in */
+static ArchDescription _yasep_description =
+{
+	"flat", ARCH_ENDIAN_LITTLE, 32, 16, 0
+};
+
 #define REG(name, size, id) { "" # name, size, id },
 static ArchRegister _yasep_registers[] =
 {
@@ -47,13 +56,13 @@ static int _yasep_encode(ArchPlugin * plugin, ArchInstruction * instruction,
 static int _yasep_decode(ArchPlugin * plugin, ArchInstructionCall * call);
 
 
-/* protected */
+/* public */
 /* variables */
 ArchPlugin arch_plugin =
 {
 	NULL,
-	"yasep",
-	NULL,
+	_yasep_name,
+	&_yasep_description,
 	_yasep_registers,
 	_yasep_instructions,
 	NULL,
diff --git a/src/arch/yasep.ins b/src/arch/yasep.ins
index b71bfe0..9dd1eac 100644
--- a/src/arch/yasep.ins
+++ b/src/arch/yasep.ins
@@ -1,5 +1,6 @@
 /* $Id$ */
 /* Copyright (c) 2011 Pierre Pronchery <khorben@defora.org> */
+/* Copyright (c) 2011 Yann Guidon <yg@ygdes.org> */
 /* This file is part of DeforaOS Devel asm */
 /* This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
diff --git a/src/arch/yasep16.c b/src/arch/yasep16.c
new file mode 100644
index 0000000..3f1330d
--- /dev/null
+++ b/src/arch/yasep16.c
@@ -0,0 +1,21 @@
+/* $Id$ */
+/* Copyright (c) 2011 Pierre Pronchery <khorben@defora.org> */
+/* This file is part of DeforaOS Devel asm */
+/* This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+
+
+#define ARCH_yasep	16
+#define ARCH_yasep16
+#define _yasep_name	"yasep16"
+#include "yasep.c"
diff --git a/src/parser.c b/src/parser.c
index 72dd6ac..48d7d65 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -40,12 +40,12 @@ typedef struct _State
 
 
 /* prototypes */
-static int _parser_scan(State * state);
 static int _parser_check(State * state, TokenCode code);
+static int _parser_defines(State * state, AsmPrefs * ap);
+static int _parser_error(State * state, char const * format, ...);
 static int _parser_is_code(State * state, TokenCode code);
 static int _parser_in_set(State * state, TokenSet set);
-
-static int _parser_error(State * state, char const * format, ...);
+static int _parser_scan(State * state);
 static int _parser_warning(State * state, char const * format, ...);
 
 /* grammar */
@@ -132,6 +132,31 @@ static int _parser_check(State * state, TokenCode code)
 }
 
 
+/* parser_defines */
+static int _parser_defines(State * state, AsmPrefs * ap)
+{
+	int ret = 0;
+	char const * p;
+	char * q;
+	size_t len;
+	size_t i;
+
+	if((p = asmcode_get_arch(state->code)) != NULL
+			&& (len = strlen(p)) > 0)
+	{
+		if((q = malloc(len + 5)) == NULL)
+			return -error_set_code(1, "%s", strerror(errno));
+		snprintf(q, len + 5, "__%s__", p);
+		ret |= cpp_define_add(state->cpp, q, NULL);
+		free(q);
+	}
+	if(ret == 0 && ap != NULL)
+		for(i = 0; i < ap->defines_cnt; i++)
+			ret |= cpp_define_add(state->cpp, ap->defines[i], NULL);
+	return ret;
+}
+
+
 /* parser_is_code */
 static int _parser_is_code(State * state, TokenCode code)
 {
@@ -193,7 +218,6 @@ int parser(AsmPrefs * ap, AsmCode * code, char const * infile)
 {
 	CppPrefs prefs;
 	State state;
-	size_t i;
 
 	memset(&prefs, 0, sizeof(prefs));
 	prefs.filename = infile;
@@ -202,12 +226,16 @@ int parser(AsmPrefs * ap, AsmCode * code, char const * infile)
 	state.code = code;
 	if((state.cpp = cpp_new(&prefs)) == NULL)
 		return -1;
-	if(ap != NULL)
-		for(i = 0; i < ap->defines_cnt; i++)
-			/* FIXME check errors */
-			cpp_define_add(state.cpp, ap->defines[i], NULL);
+	if(_parser_defines(&state, ap) != 0)
+	{
+		cpp_delete(state.cpp);
+		return -1;
+	}
 	if(_parser_scan(&state) != 0)
+	{
+		cpp_delete(state.cpp);
 		return _parser_error(&state, "%s", error_get());
+	}
 	if(_program(&state) != 0)
 		error_set_code(1, "%s%s%u%s%u%s", infile,
 				": Compilation failed with ", state.error_cnt,
diff --git a/test/Makefile b/test/Makefile
index 9d9a31b..f48b778 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -1,4 +1,4 @@
-TARGETS	= amd64.o arm.o armeb.o armel.o dalvik.o i386.o i386_real.o i486.o i586.o i686.o mips.o mipseb.o mipsel.o java.o sparc.o sparc64.o yasep.o
+TARGETS	= amd64.o arm.o armeb.o armel.o dalvik.o i386.o i386_real.o i486.o i586.o i686.o mips.o mipseb.o mipsel.o java.o sparc.o sparc64.o yasep.o yasep16.o
 PREFIX	= /usr/local
 DESTDIR	=
 BINDIR	= $(PREFIX)/bin
@@ -63,6 +63,9 @@ sparc64.o_ASFLAGS = $(CPPFLAGSF) $(CPPFLAGS) $(ASFLAGS) -a sparc64
 yasep.o_OBJS = yasep.o
 yasep.o_ASFLAGS = $(CPPFLAGSF) $(CPPFLAGS) $(ASFLAGS) -a yasep -f flat
 
+yasep16.o_OBJS = yasep16.o
+yasep16.o_ASFLAGS = $(CPPFLAGSF) $(CPPFLAGS) $(ASFLAGS) -a yasep16 -f flat
+
 amd64.o: amd64.S ../src/asm
 	$(AS) $(amd64.o_ASFLAGS) -o amd64.o amd64.S
 
@@ -114,8 +117,11 @@ sparc64.o: sparc64.S ../src/asm
 yasep.o: yasep.S ../src/asm
 	$(AS) $(yasep.o_ASFLAGS) -o yasep.o yasep.S
 
+yasep16.o: yasep16.S ../src/asm yasep.S
+	$(AS) $(yasep16.o_ASFLAGS) -o yasep16.o yasep16.S
+
 clean:
-	$(RM) -- $(amd64.o_OBJS) $(arm.o_OBJS) $(armeb.o_OBJS) $(armel.o_OBJS) $(dalvik.o_OBJS) $(i386.o_OBJS) $(i386_real.o_OBJS) $(i486.o_OBJS) $(i586.o_OBJS) $(i686.o_OBJS) $(mips.o_OBJS) $(mipseb.o_OBJS) $(mipsel.o_OBJS) $(java.o_OBJS) $(sparc.o_OBJS) $(sparc64.o_OBJS) $(yasep.o_OBJS)
+	$(RM) -- $(amd64.o_OBJS) $(arm.o_OBJS) $(armeb.o_OBJS) $(armel.o_OBJS) $(dalvik.o_OBJS) $(i386.o_OBJS) $(i386_real.o_OBJS) $(i486.o_OBJS) $(i586.o_OBJS) $(i686.o_OBJS) $(mips.o_OBJS) $(mipseb.o_OBJS) $(mipsel.o_OBJS) $(java.o_OBJS) $(sparc.o_OBJS) $(sparc64.o_OBJS) $(yasep.o_OBJS) $(yasep16.o_OBJS)
 
 distclean: clean
 	$(RM) -- $(TARGETS)
diff --git a/test/project.conf b/test/project.conf
index 9facf7a..a099ea2 100644
--- a/test/project.conf
+++ b/test/project.conf
@@ -1,4 +1,4 @@
-targets=amd64.o,arm.o,armeb.o,armel.o,dalvik.o,i386.o,i386_real.o,i486.o,i586.o,i686.o,mips.o,mipseb.o,mipsel.o,java.o,sparc.o,sparc64.o,yasep.o
+targets=amd64.o,arm.o,armeb.o,armel.o,dalvik.o,i386.o,i386_real.o,i486.o,i586.o,i686.o,mips.o,mipseb.o,mipsel.o,java.o,sparc.o,sparc64.o,yasep.o,yasep16.o
 as=../src/asm-static
 dist=Makefile
 
@@ -137,3 +137,11 @@ sources=yasep.S
 [yasep.S]
 asflags=-a yasep -f flat
 depends=../src/asm
+
+[yasep16.o]
+type=object
+sources=yasep16.S
+
+[yasep16.S]
+asflags=-a yasep16 -f flat
+depends=../src/asm,yasep.S
diff --git a/test/yasep.S b/test/yasep.S
index 3b04af7..bba791a 100644
--- a/test/yasep.S
+++ b/test/yasep.S
@@ -13,9 +13,13 @@
 	get	$0x09, %r1
 	get	%r10, %r11
 	lsb	%r12, %r13
+#ifdef __yasep__
 	lsh	%r14, %r15
+#endif
 	lzb	%npc, %d5
+#ifdef __yasep__
 	lzh	%a5, %d4
+#endif
 	mov	$0x04, %a4
 	mov	%d3, %a3
 	mul8h	$0x03, %d2
@@ -41,10 +45,12 @@
 	sar	%r0, %r1
 	sb	$0x08, %r1
 	sb	%r0, %r1
+#ifdef __yasep__
 	sh	$0x09, %r1
 	sh	%r0, %r1
 	shh	$0x0a, %r1
 	shh	%r0, %r1
+#endif
 	shl	$0x0b, %r1
 	shl	%r0, %r1
 	shr	$0x0c, %r1
diff --git a/test/yasep16.S b/test/yasep16.S
new file mode 100644
index 0000000..985453f
--- /dev/null
+++ b/test/yasep16.S
@@ -0,0 +1,2 @@
+/* $Id$ */
+#include "yasep.S"