diff --git a/meson.build b/meson.build
index 01681df..fa4334e 100644
--- a/meson.build
+++ b/meson.build
@@ -12,6 +12,7 @@ executable(meson.project_name(),
   'src/wren/configuration.cpp',
   'src/wren/def_configuration.cpp',
   'src/wren/dynafunc_maker.cpp',
+  'src/dynafunc_amd64_gnu.S',
   dependencies: [wren_dep],
   install: true,
 )
diff --git a/src/dynafunc_amd64_gnu.asm b/src/dynafunc_amd64_gnu.S
similarity index 76%
rename from src/dynafunc_amd64_gnu.asm
rename to src/dynafunc_amd64_gnu.S
index 59ef322..8615028 100644
--- a/src/dynafunc_amd64_gnu.asm
+++ b/src/dynafunc_amd64_gnu.S
@@ -2,8 +2,12 @@
 #objcopy -j .text -O binary dynafunc.o dynafunc.bin
 #xxd -i dynafunc.bin
 
-dynafunc:
+.global g_dynafunc
+.global g_dynafunc_end
+
+g_dynafunc:
 	movq $0xdeadbeefdeadbeef, %rdi
 	movq $0xbadc0ffee0ddf00d, %rdx
 	jmp *%rdx
 	ret
+g_dynafunc_end:
diff --git a/src/wren/dynafunc_maker.cpp b/src/wren/dynafunc_maker.cpp
index 9c7f0b0..5e8177a 100644
--- a/src/wren/dynafunc_maker.cpp
+++ b/src/wren/dynafunc_maker.cpp
@@ -14,13 +14,12 @@
 
 namespace wren {
 	namespace {
-#if defined(__amd64__) and defined(__gnu_linux__)
 		//see src/dynafunc_amd64_gnu.asm
-		const constexpr unsigned char g_dynafunc[] = {
-			0x48, 0xbf, 0xef, 0xbe, 0xad, 0xde, 0xef, 0xbe, 0xad, 0xde, 0x48, 0xba,
-			0x0d, 0xf0, 0xdd, 0xe0, 0xfe, 0x0f, 0xdc, 0xba, 0xff, 0xe2, 0xc3
-		};
-		const constexpr unsigned int g_dynafunc_len = 23;
+		extern "C" const char g_dynafunc[];
+		extern "C" const char g_dynafunc_end[];
+		const unsigned int g_dynafunc_len = g_dynafunc_end - g_dynafunc;
+
+#if defined(__amd64__) and defined(__gnu_linux__)
 		const constexpr unsigned int g_dynafunc_ptr1_size = 8;
 		const constexpr unsigned int g_dynafunc_ptr2_size = 8;
 		const constexpr unsigned char g_dynafunc_ptr1[g_dynafunc_ptr1_size] = {0xef, 0xbe, 0xad, 0xde, 0xef, 0xbe, 0xad, 0xde};
@@ -43,9 +42,8 @@ namespace wren {
 			std::copy(ptr, ptr + sizeof(T), subseq);
 		}
 
-		void make_dynafunc_asm(unsigned char* out, unsigned int len, VM* ptr1, foreign_method_t ptr2) {
-			assert(g_dynafunc_len == len);
-			std::copy(g_dynafunc, g_dynafunc + g_dynafunc_len, out);
+		void make_dynafunc_asm(unsigned char* out, VM* ptr1, foreign_method_t ptr2) {
+			std::copy(g_dynafunc, g_dynafunc_end, out);
 
 			replace_ptr(out, out + g_dynafunc_len, g_dynafunc_ptr1, ptr1);
 			replace_ptr(out, out + g_dynafunc_len, g_dynafunc_ptr2, ptr2);
@@ -69,7 +67,7 @@ namespace wren {
 
 	void* DynafuncMaker::make (VM* vm, foreign_method_t cb) {
 		unsigned char* const mem = allocate_chunk();
-		make_dynafunc_asm(mem, g_dynafunc_len, vm, cb);
+		make_dynafunc_asm(mem, vm, cb);
 		return mem;
 	}