diff --git a/programs/test_slow_decompression.c b/programs/test_slow_decompression.c
index 4890453..7726224 100644
--- a/programs/test_slow_decompression.c
+++ b/programs/test_slow_decompression.c
@@ -7,28 +7,6 @@
 
 #include "test_util.h"
 
-struct output_bitstream {
-	unsigned long bitbuf;
-	int bitcount;
-	u8 *next;
-	u8 *end;
-};
-
-static bool
-put_bits(struct output_bitstream *os, unsigned long bits, int num_bits)
-{
-	os->bitbuf |= bits << os->bitcount;
-	os->bitcount += num_bits;
-	while (os->bitcount >= 8) {
-		if (os->next == os->end)
-			return false;
-		*os->next++ = os->bitbuf;
-		os->bitcount -= 8;
-		os->bitbuf >>= 8;
-	}
-	return true;
-}
-
 /*
  * Generate a DEFLATE stream containing all empty "static Huffman" blocks.
  *
diff --git a/programs/test_util.c b/programs/test_util.c
index cadff14..189035d 100644
--- a/programs/test_util.c
+++ b/programs/test_util.c
@@ -202,3 +202,18 @@ u64 timer_KB_per_s(u64 bytes, u64 ticks)
 {
 	return bytes * timer_frequency() / ticks / 1000;
 }
+
+bool
+put_bits(struct output_bitstream *os, machine_word_t bits, int num_bits)
+{
+	os->bitbuf |= bits << os->bitcount;
+	os->bitcount += num_bits;
+	while (os->bitcount >= 8) {
+		if (os->next == os->end)
+			return false;
+		*os->next++ = os->bitbuf;
+		os->bitcount -= 8;
+		os->bitbuf >>= 8;
+	}
+	return true;
+}
diff --git a/programs/test_util.h b/programs/test_util.h
index c6a12f6..bbdc546 100644
--- a/programs/test_util.h
+++ b/programs/test_util.h
@@ -52,4 +52,14 @@ extern u64 timer_ticks_to_ms(u64 ticks);
 extern u64 timer_MB_per_s(u64 bytes, u64 ticks);
 extern u64 timer_KB_per_s(u64 bytes, u64 ticks);
 
+struct output_bitstream {
+	machine_word_t bitbuf;
+	int bitcount;
+	u8 *next;
+	u8 *end;
+};
+
+extern bool put_bits(struct output_bitstream *os, machine_word_t bits,
+		     int num_bits);
+
 #endif /* PROGRAMS_TEST_UTIL_H */