diff --git a/src/lib/ultra/os/invaldcache.c b/src/lib/ultra/os/invaldcache.c
deleted file mode 100644
index 20a7eebe8..000000000
--- a/src/lib/ultra/os/invaldcache.c
+++ /dev/null
@@ -1,54 +0,0 @@
-#include <libultra_internal.h>
-#include "data.h"
-
-GLOBAL_ASM(
-glabel osInvalDCache
-/*    4e480:	18a0001f */ 	blez	$a1,.L0004e500
-/*    4e484:	00000000 */ 	nop
-/*    4e488:	240b2000 */ 	addiu	$t3,$zero,0x2000
-/*    4e48c:	00ab082b */ 	sltu	$at,$a1,$t3
-/*    4e490:	1020001d */ 	beqz	$at,.L0004e508
-/*    4e494:	00000000 */ 	nop
-/*    4e498:	00804025 */ 	or	$t0,$a0,$zero
-/*    4e49c:	00854821 */ 	addu	$t1,$a0,$a1
-/*    4e4a0:	0109082b */ 	sltu	$at,$t0,$t1
-/*    4e4a4:	10200016 */ 	beqz	$at,.L0004e500
-/*    4e4a8:	00000000 */ 	nop
-/*    4e4ac:	310a000f */ 	andi	$t2,$t0,0xf
-/*    4e4b0:	11400007 */ 	beqz	$t2,.L0004e4d0
-/*    4e4b4:	2529fff0 */ 	addiu	$t1,$t1,-16
-/*    4e4b8:	010a4023 */ 	subu	$t0,$t0,$t2
-/*    4e4bc:	bd150000 */ 	cache	0x15,0x0($t0)
-/*    4e4c0:	0109082b */ 	sltu	$at,$t0,$t1
-/*    4e4c4:	1020000e */ 	beqz	$at,.L0004e500
-/*    4e4c8:	00000000 */ 	nop
-/*    4e4cc:	25080010 */ 	addiu	$t0,$t0,0x10
-.L0004e4d0:
-/*    4e4d0:	312a000f */ 	andi	$t2,$t1,0xf
-/*    4e4d4:	11400006 */ 	beqz	$t2,.L0004e4f0
-/*    4e4d8:	00000000 */ 	nop
-/*    4e4dc:	012a4823 */ 	subu	$t1,$t1,$t2
-/*    4e4e0:	bd350010 */ 	cache	0x15,0x10($t1)
-/*    4e4e4:	0128082b */ 	sltu	$at,$t1,$t0
-/*    4e4e8:	14200005 */ 	bnez	$at,.L0004e500
-/*    4e4ec:	00000000 */ 	nop
-.L0004e4f0:
-/*    4e4f0:	bd110000 */ 	cache	0x11,0x0($t0)
-/*    4e4f4:	0109082b */ 	sltu	$at,$t0,$t1
-/*    4e4f8:	1420fffd */ 	bnez	$at,.L0004e4f0
-/*    4e4fc:	25080010 */ 	addiu	$t0,$t0,0x10
-.L0004e500:
-/*    4e500:	03e00008 */ 	jr	$ra
-/*    4e504:	00000000 */ 	nop
-.L0004e508:
-/*    4e508:	3c088000 */ 	lui	$t0,0x8000
-/*    4e50c:	010b4821 */ 	addu	$t1,$t0,$t3
-/*    4e510:	2529fff0 */ 	addiu	$t1,$t1,-16
-.L0004e514:
-/*    4e514:	bd010000 */ 	cache	0x1,0x0($t0)
-/*    4e518:	0109082b */ 	sltu	$at,$t0,$t1
-/*    4e51c:	1420fffd */ 	bnez	$at,.L0004e514
-/*    4e520:	25080010 */ 	addiu	$t0,$t0,0x10
-/*    4e524:	03e00008 */ 	jr	$ra
-/*    4e528:	00000000 */ 	nop
-);
diff --git a/src/lib/ultra/os/invaldcache.s b/src/lib/ultra/os/invaldcache.s
new file mode 100644
index 000000000..5e1ee023f
--- /dev/null
+++ b/src/lib/ultra/os/invaldcache.s
@@ -0,0 +1,55 @@
+#include "macros.inc"
+.set noat
+.set noreorder
+
+.section .text
+
+glabel osInvalDCache
+	blez  $a1, .L0004e500
+ 	nop
+	addiu $t3, $zero, 0x2000
+	sltu  $at, $a1, $t3
+	beqz  $at, .L0004e508
+ 	nop
+	move  $t0, $a0
+	addu  $t1, $a0, $a1
+	sltu  $at, $t0, $t1
+	beqz  $at, .L0004e500
+ 	nop
+	andi  $t2, $t0, 0xf
+	beqz  $t2, .L0004e4d0
+	addiu $t1, $t1, -16
+	subu  $t0, $t0, $t2
+	cache 0x15, 0x0($t0)
+	sltu  $at, $t0, $t1
+	beqz  $at, .L0004e500
+ 	nop
+	addiu $t0, $t0, 0x10
+.L0004e4d0:
+	andi  $t2, $t1, 0xf
+	beqz  $t2, .L0004e4f0
+ 	nop
+	subu  $t1, $t1, $t2
+	cache 0x15, 0x10($t1)
+	sltu  $at, $t1, $t0
+	bnez  $at, .L0004e500
+ 	nop
+.L0004e4f0:
+	cache 0x11, 0x0($t0)
+	sltu  $at, $t0, $t1
+	bnez  $at, .L0004e4f0
+	addiu $t0, $t0, 0x10
+.L0004e500:
+	jr    $ra
+ 	nop
+.L0004e508:
+	lui   $t0, 0x8000
+	addu  $t1, $t0, $t3
+	addiu $t1, $t1, -16
+.L0004e514:
+	cache 0x1, 0x0($t0)
+	sltu  $at, $t0, $t1
+	bnez  $at, .L0004e514
+	addiu $t0, $t0, 0x10
+	jr    $ra
+ 	nop