diff --git a/include/Asm/arch.h b/include/Asm/arch.h
index 14da11e..fcbf617 100644
--- a/include/Asm/arch.h
+++ b/include/Asm/arch.h
@@ -24,6 +24,8 @@
 
 /* AsmArch */
 /* types */
+typedef struct _Arch Arch;
+
 typedef enum _ArchEndian
 {
 	ARCH_ENDIAN_BIG = 0,
@@ -142,7 +144,7 @@ typedef uint32_t ArchOperandDefinition;
 
 typedef struct _ArchInstruction
 {
-	char * name;
+	char const * name;
 	uint32_t opcode;
 	ArchOperandDefinition flags;
 	ArchOperandDefinition op1;
@@ -152,29 +154,29 @@ typedef struct _ArchInstruction
 
 typedef struct _ArchInstructionCall
 {
-	char * name;
+	char const * name;
 	ArchOperand operands[3];
 	size_t operands_cnt;
 } ArchInstructionCall;
 
 typedef struct _ArchRegister
 {
-	char * name;
+	char const * name;
 	uint32_t size;
 	uint32_t id;
 } ArchRegister;
 
 typedef struct _ArchPluginHelper
 {
-	void * priv;
+	Arch * arch;
 
 	/* variables */
 	char const * filename;
 	FILE * fp;
 
 	/* callbacks */
-	int32_t (*get_register_by_name_size)(void * priv, char const * name,
-			uint32_t size);
+	ArchRegister * (*get_register_by_name_size)(Arch * arch,
+			char const * name, uint32_t size);
 } ArchPluginHelper;
 
 typedef struct _ArchPlugin ArchPlugin;
diff --git a/src/arch.c b/src/arch.c
index 1dc581d..d1ead4a 100644
--- a/src/arch.c
+++ b/src/arch.c
@@ -171,7 +171,7 @@ ArchInstruction * arch_get_instruction_by_opcode(Arch * arch, uint8_t size,
 
 
 /* arch_get_instruction_by_call */
-static int _call_operands(Arch * arch, ArchInstruction * ai,
+static int _call_operands(Arch * arch, ArchInstruction * instruction,
 		ArchInstructionCall * call);
 static int _call_operands_dregister(Arch * arch,
 		ArchOperandDefinition definition, ArchOperand * operand);
@@ -188,7 +188,7 @@ ArchInstruction * arch_get_instruction_by_call(Arch * arch,
 	int found = 0;
 
 #ifdef DEBUG
-	fprintf(stderr, "DEBUG: %s(\"%s\")\n", __func__, name);
+	fprintf(stderr, "DEBUG: %s(\"%s\")\n", __func__, call->name);
 #endif
 	for(i = 0; i < arch->instructions_cnt; i++)
 	{
@@ -205,7 +205,7 @@ ArchInstruction * arch_get_instruction_by_call(Arch * arch,
 	return NULL;
 }
 
-static int _call_operands(Arch * arch, ArchInstruction * ai,
+static int _call_operands(Arch * arch, ArchInstruction * instruction,
 		ArchInstructionCall * call)
 {
 	size_t i;
@@ -214,13 +214,13 @@ static int _call_operands(Arch * arch, ArchInstruction * ai,
 
 	for(i = 0; i < call->operands_cnt; i++)
 	{
-		definition = (i == 0) ? ai->op1 : ((i == 1) ? ai->op2
-				: ai->op3);
+		definition = (i == 0) ? instruction->op1 : ((i == 1)
+				? instruction->op2 : instruction->op3);
 		operand = &call->operands[i];
 #ifdef DEBUG
 		fprintf(stderr, "DEBUG: %s() operand %lu, type %u, type %u\n",
 				__func__, i, AO_GET_TYPE(definition),
-				AO_GET_TYPE(operand->definition));
+				AO_GET_TYPE(operand->type));
 #endif
 		if(AO_GET_TYPE(definition) != operand->type)
 			return -1;
@@ -252,7 +252,8 @@ static int _call_operands_dregister(Arch * arch,
 	uint64_t offset;
 
 #ifdef DEBUG
-	fprintf(stderr, "DEBUG: %s() %ld\n", __func__, ao->dereference);
+	fprintf(stderr, "DEBUG: %s() %ld\n", __func__,
+			operand->value.dregister.offset);
 #endif
 	if(_call_operands_register(arch, definition, operand) != 0)
 		return -1;
@@ -386,7 +387,7 @@ int arch_init(Arch * arch, char const * filename, FILE * fp)
 	fprintf(stderr, "DEBUG: %s(\"%s\", %p)\n", __func__, filename,
 			(void *)fp);
 #endif
-	arch->helper.priv = arch;
+	arch->helper.arch = arch;
 	arch->helper.filename = filename;
 	arch->helper.fp = fp;
 	arch->helper.get_register_by_name_size = arch_get_register_by_name_size;
diff --git a/src/arch.h b/src/arch.h
index c1359bd..ceefe69 100644
--- a/src/arch.h
+++ b/src/arch.h
@@ -20,15 +20,11 @@
 
 # include <stdint.h>
 # include <stdio.h>
-# include "Asm.h"
+# include "Asm/arch.h"
 
 
 /* Arch */
 /* public */
-/* types */
-typedef struct _Arch Arch;
-
-
 /* functions */
 Arch * arch_new(char const * name);
 void arch_delete(Arch * arch);
diff --git a/src/arch/i386.c b/src/arch/i386.c
index 7cf1d0a..49ac098 100644
--- a/src/arch/i386.c
+++ b/src/arch/i386.c
@@ -187,17 +187,20 @@ static int _write_register(ArchPlugin * plugin,
 		ArchOperandDefinition definition, ArchOperand * operand)
 {
 	ArchPluginHelper * helper = plugin->helper;
-	ArchOperandDefinition idefinition;
-	ArchOperand ioperand;
 	char const * name = operand->value._register.name;
 	size_t size = AO_GET_SIZE(definition);
+	ArchRegister * ar;
+	ArchOperandDefinition idefinition;
+	ArchOperand ioperand;
 
 	if(AO_GET_FLAGS(definition) & AOF_IMPLICIT)
 		return 0;
+	if((ar = helper->get_register_by_name_size(helper->arch, name, size))
+			== NULL)
+		return -1;
 	idefinition = AO_IMMEDIATE(0, 0, 8);
 	memset(&ioperand, 0, sizeof(ioperand));
 	ioperand.type = AOT_IMMEDIATE;
-	ioperand.value.immediate.value = helper->get_register_by_name_size(
-			helper->priv, name, size);
+	ioperand.value.immediate.value = ar->id;
 	return _write_immediate(plugin, idefinition, &ioperand);
 }
diff --git a/src/code.c b/src/code.c
index db61d39..990797d 100644
--- a/src/code.c
+++ b/src/code.c
@@ -178,24 +178,6 @@ int code_function(Code * code, char const * function)
 
 
 /* code_instruction */
-static int _instruction_fixed(Code * code, ArchInstruction * ai,
-		ArchOperand ** operands, size_t operands_cnt);
-static int _instruction_fixed_immediate(ArchOperand operand, ArchOperand * ao,
-		uint32_t * pu);
-static int _instruction_fixed_register(Code * code, ArchOperand operand,
-		ArchOperand * ao, uint32_t * pu);
-static int _instruction_variable(Code * code, ArchInstruction * ai,
-		ArchOperand ** operands, size_t operands_cnt);
-static int _instruction_variable_dregister(Code * code, ArchInstruction * ai,
-		ArchOperand operand, ArchOperand * ao);
-static int _instruction_variable_immediate(Code * code, ArchInstruction * ai,
-		ArchOperand operand, void * value, int swap);
-static int _instruction_variable_opcode(Code * code, ArchInstruction * ai);
-static int _instruction_variable_operand(Code * code, ArchInstruction * ai,
-		ArchOperand operand, ArchOperand * ao);
-static int _instruction_variable_register(Code * code, ArchInstruction * ai,
-		ArchOperand operand, ArchOperand * ao);
-
 int code_instruction(Code * code, ArchInstructionCall * call)
 {
 	ArchInstruction * ai;