diff --git a/src/llvm/func.c b/src/llvm/func.c
new file mode 100644
index 0000000..5ac63d8
--- /dev/null
+++ b/src/llvm/func.c
@@ -0,0 +1,81 @@
+
+#include <alloca.h>
+#include <codegen/backend.h>
+#include <llvm-c/Core.h>
+#include <llvm-c/Types.h>
+#include <llvm/parser.h>
+#include <llvm/types.h>
+#include <set/types.h>
+#include <sys/log.h>
+
+BackendError impl_param_type(LLVMBackendCompileUnit* unit,
+                             LLVMGlobalScope* scope, Paramer* param,
+                             LLVMTypeRef* llvm_type) {
+    BackendError err = SUCCESS;
+
+    Type* gemstone_type = NULL;
+    IO_Qualifier qualifier = In;
+
+    if (param->kind == ParameterDeclarationKind) {
+        gemstone_type = &param->impl.declaration.type;
+        qualifier = param->impl.declaration.qualifier;
+    } else {
+        gemstone_type = &param->impl.definiton.declaration.type;
+        qualifier = param->impl.definiton.declaration.qualifier;
+    }
+
+    // wrap output variables as pointers
+    if (qualifier == Out || qualifier == InOut) {
+        Type* reference_type = alloca(sizeof(Type));
+
+        reference_type->kind = TypeKindReference;
+        reference_type->impl.reference = gemstone_type;
+
+        gemstone_type = reference_type;
+    }
+
+    err = get_type_impl(unit, scope, gemstone_type, llvm_type);
+
+    return err;
+}
+
+BackendError impl_func_decl(LLVMBackendCompileUnit* unit,
+                            LLVMGlobalScope* scope, FunctionDefinition* fundef,
+                            LLVMValueRef* llvm_fun, const char* name) {
+    DEBUG("implementing function declaration: %s()", name);
+    BackendError err = SUCCESS;
+
+    Paramer* params = (Paramer*)fundef->parameter;
+    GArray* llvm_params = g_array_new(FALSE, FALSE, sizeof(LLVMTypeRef));
+
+    for (size_t i = 0; i < fundef->parameter->len; i++) {
+        Paramer* param = &params[i];
+
+        LLVMTypeRef llvm_type = NULL;
+        err = impl_param_type(unit, scope, param, &llvm_type);
+
+        if (err.kind != Success) {
+            break;
+        }
+    }
+
+    DEBUG("implemented %ld parameter", llvm_params->len);
+
+    LLVMTypeRef llvm_fun_type =
+        LLVMFunctionType(LLVMVoidTypeInContext(unit->context),
+                         (LLVMTypeRef*)llvm_params->data, llvm_params->len, 0);
+
+    *llvm_fun = LLVMAddFunction(unit->module, name, llvm_fun_type);
+
+    g_array_free(llvm_params, FALSE);
+
+    return err;
+}
+
+BackendError impl_func(LLVMBackendCompileUnit* unit, LLVMGlobalScope* scope,
+                       FunctionDefinition* fundef, const char* name) {
+    BackendError err = SUCCESS;
+
+
+    return err;
+}