diff --git a/src/lib/ultra/os/writebackdcacheall.c b/src/lib/ultra/os/writebackdcacheall.c
deleted file mode 100644
index 0920b7fef..000000000
--- a/src/lib/ultra/os/writebackdcacheall.c
+++ /dev/null
@@ -1,16 +0,0 @@
-#include <ultra64.h>
-
-GLOBAL_ASM(
-glabel osWritebackDCacheAll
-/*    48120:	3c088000 */ 	lui	$t0,0x8000
-/*    48124:	240a2000 */ 	addiu	$t2,$zero,0x2000
-/*    48128:	010a4821 */ 	addu	$t1,$t0,$t2
-/*    4812c:	2529fff0 */ 	addiu	$t1,$t1,-16
-.L00048130:
-/*    48130:	bd010000 */ 	cache	0x1,0x0($t0)
-/*    48134:	0109082b */ 	sltu	$at,$t0,$t1
-/*    48138:	1420fffd */ 	bnez	$at,.L00048130
-/*    4813c:	25080010 */ 	addiu	$t0,$t0,0x10
-/*    48140:	03e00008 */ 	jr	$ra
-/*    48144:	00000000 */ 	nop
-);
diff --git a/src/lib/ultra/os/writebackdcacheall.s b/src/lib/ultra/os/writebackdcacheall.s
new file mode 100644
index 000000000..2335cb891
--- /dev/null
+++ b/src/lib/ultra/os/writebackdcacheall.s
@@ -0,0 +1,18 @@
+#include "macros.inc"
+.set noat
+.set noreorder
+
+.section .text
+
+glabel osWritebackDCacheAll
+	lui   $t0, 0x8000
+	addiu $t2, $zero, 0x2000
+	addu  $t1, $t0, $t2
+	addiu $t1, $t1, -16
+.L00048130:
+	cache 0x1, 0x0($t0)
+	sltu  $at, $t0, $t1
+	bnez  $at, .L00048130
+	addiu $t0, $t0, 0x10
+	jr    $ra
+ 	nop