diff --git a/asm/include/ivy/asm/instr.h b/asm/include/ivy/asm/instr.h
index af9ac31..8541ab2 100644
--- a/asm/include/ivy/asm/instr.h
+++ b/asm/include/ivy/asm/instr.h
@@ -3,6 +3,26 @@
 
 #include <ivy/opcode.h>
 
+enum ivy_instr_operand_type {
+	IVY_OPERAND_NONE = 0,
+	IVY_INSTR_OPERAND_CONST,
+	IVY_INSTR_OPERAND_REGISTER,
+	IVY_INSTR_OPERAND_SELF_INDEX_REG,
+	IVY_INSTR_OPERAND_SELF_INDEX_CONST,
+	IVY_INSTR_OPERAND_POOL_INDEX_REG,
+	IVY_INSTR_OPERAND_POOL_INDEX_CONST,
+	IVY_INSTR_OPERAND_SP_INDEX_REG,
+	IVY_INSTR_OPERAND_SP_INDEX_CONST,
+	IVY_INSTR_OPERAND_BP_INDEX_REG,
+	IVY_INSTR_OPERAND_BP_INDEX_CONST,
+};
+
+struct ivy_instr_definition {
+	enum ivy_instr_id i_id;
+	enum ivy_opcopde i_opcode;
+	enum ivy_instr_operand_type i_operand[3];
+};
+
 struct ivy_instr {
 	enum ivy_opcode i_op;
 	long i_a0;
diff --git a/asm/instr.c b/asm/instr.c
new file mode 100644
index 0000000..3b2f511
--- /dev/null
+++ b/asm/instr.c
@@ -0,0 +1,37 @@
+#include <ivy/asm/instr.h>
+
+#define INSTR(id, op, ...) \
+	[op] = { .i_id = (id), .i_opcode = (op), .i_operand = { __VA_ARGS__ }}
+
+/* clang-format off */
+static const struct ivy_instr_definition instructions[] = {
+	INSTR(IVY_INSTR_LDR,	IVY_OP_LDR_SP_REG,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_SP_INDEX_REG),
+	INSTR(IVY_INSTR_LDR,	IVY_OP_LDR_SP_CONST,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_SP_INDEX_CONST),
+	INSTR(IVY_INSTR_LDR,	IVY_OP_LDR_BP_REG,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_BP_INDEX_REG),
+	INSTR(IVY_INSTR_LDR,	IVY_OP_LDR_BP_CONST,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_BP_INDEX_CONST),
+	INSTR(IVY_INSTR_LDR,	IVY_OP_LDR_SELF_REG,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_SELF_INDEX_REG),
+	INSTR(IVY_INSTR_LDR,	IVY_OP_LDR_SELF_CONST,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_SELF_INDEX_CONST),
+	INSTR(IVY_INSTR_LDR,	IVY_OP_LDR_POOL_REG,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_POOL_INDEX_REG),
+	INSTR(IVY_INSTR_LDR,	IVY_OP_LDR_POOL_CONST,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_POOL_INDEX_CONST),
+	
+	INSTR(IVY_INSTR_STR,	IVY_OP_LDR_SP_REG,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_SP_INDEX_REG),
+	INSTR(IVY_INSTR_STR,	IVY_OP_LDR_SP_CONST,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_SP_INDEX_CONST),
+	INSTR(IVY_INSTR_STR,	IVY_OP_LDR_BP_REG,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_BP_INDEX_REG),
+	INSTR(IVY_INSTR_STR,	IVY_OP_LDR_BP_CONST,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_BP_INDEX_CONST),
+	INSTR(IVY_INSTR_STR,	IVY_OP_LDR_SELF_REG,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_SELF_INDEX_REG),
+	INSTR(IVY_INSTR_STR,	IVY_OP_LDR_SELF_CONST,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_SELF_INDEX_CONST),
+	
+	INSTR(IVY_INSTR_PUSH,	IVY_OP_PUSH_REG,	IVY_INSTR_OPERAND_REGISTER),
+	INSTR(IVY_INSTR_PUSH,	IVY_OP_PUSH_CONST,	IVY_INSTR_OPERAND_CONST),
+	INSTR(IVY_INSTR_POP,	IVY_OP_POP,		IVY_INSTR_OPERAND_REGISTER),
+	
+	INSTR(IVY_INSTR_MSG,	IVY_OP_MSG_REG,		IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_REGISTER),
+	INSTR(IVY_INSTR_MSG,	IVY_OP_MSG_CONST,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_CONST),
+
+	INSTR(IVY_INSTR_ADD,	IVY_OP_ADD,		IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_REGISTER),
+	INSTR(IVY_INSTR_SUB,	IVY_OP_SUB,		IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_REGISTER),
+	INSTR(IVY_INSTR_MUL,	IVY_OP_MUL,		IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_REGISTER),
+	INSTR(IVY_INSTR_DIV,	IVY_OP_DIV,		IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_REGISTER,	IVY_INSTR_OPERAND_REGISTER),
+
+};
+/* clang-format on */
\ No newline at end of file
diff --git a/common/include/ivy/opcode.h b/common/include/ivy/opcode.h
index fec7415..db7d94b 100644
--- a/common/include/ivy/opcode.h
+++ b/common/include/ivy/opcode.h
@@ -41,21 +41,29 @@ enum ivy_instr_id {
 enum ivy_opcode {
 	IVY_OP_NONE = 0,
 
-	IVY_OP_LDR_SP,
-	IVY_OP_LDR_BP,
-	IVY_OP_LDR_SELF,
+	IVY_OP_LDR_SP_REG,
+	IVY_OP_LDR_SP_CONST,
+	IVY_OP_LDR_BP_REG,
+	IVY_OP_LDR_BP_CONST,
+	IVY_OP_LDR_SELF_REG,
+	IVY_OP_LDR_SELF_CONST,
+	IVY_OP_LDR_POOL_REG,
+	IVY_OP_LDR_POOL_CONST,
 	IVY_OP_LDR_IMM,
-	IVY_OP_LDR_POOL,
 
-	IVY_OP_STR_SP,
-	IVY_OP_STR_BP,
-	IVY_OP_STR_SELF,
+	IVY_OP_STR_SP_REG,
+	IVY_OP_STR_SP_CONST,
+	IVY_OP_STR_BP_REG,
+	IVY_OP_STR_BP_CONST,
+	IVY_OP_STR_SELF_REG,
+	IVY_OP_STR_SELF_CONST,
 
-	IVY_OP_PUSH,
+	IVY_OP_PUSH_REG,
+	IVY_OP_PUSH_CONST,
 	IVY_OP_POP,
 
-	IVY_OP_MSG_R,
-	IVY_OP_MSG_I,
+	IVY_OP_MSG_REG,
+	IVY_OP_MSG_CONST,
 
 	IVY_OP_ADD,
 	IVY_OP_SUB,