diff --git a/src/lib/ultra/os/probetlb.c b/src/lib/ultra/os/probetlb.c
deleted file mode 100644
index fed4530cb..000000000
--- a/src/lib/ultra/os/probetlb.c
+++ /dev/null
@@ -1,56 +0,0 @@
-#include <libultra_internal.h>
-#include "data.h"
-
-GLOBAL_ASM(
-glabel __osProbeTLB
-/*    51c90:	40085000 */ 	mfc0	$t0,$10
-/*    51c94:	310900ff */ 	andi	$t1,$t0,0xff
-/*    51c98:	2401e000 */ 	addiu	$at,$zero,-8192
-/*    51c9c:	00815024 */ 	and	$t2,$a0,$at
-/*    51ca0:	012a4825 */ 	or	$t1,$t1,$t2
-/*    51ca4:	40895000 */ 	mtc0	$t1,$10
-/*    51ca8:	00000000 */ 	nop
-/*    51cac:	00000000 */ 	nop
-/*    51cb0:	00000000 */ 	nop
-/*    51cb4:	42000008 */ 	tlbp
-/*    51cb8:	00000000 */ 	nop
-/*    51cbc:	00000000 */ 	nop
-/*    51cc0:	400b0000 */ 	mfc0	$t3,$0
-/*    51cc4:	3c018000 */ 	lui	$at,0x8000
-/*    51cc8:	01615824 */ 	and	$t3,$t3,$at
-/*    51ccc:	1560001a */ 	bnez	$t3,.L00051d38
-/*    51cd0:	00000000 */ 	nop
-/*    51cd4:	42000001 */ 	tlbr
-/*    51cd8:	00000000 */ 	nop
-/*    51cdc:	00000000 */ 	nop
-/*    51ce0:	00000000 */ 	nop
-/*    51ce4:	400b2800 */ 	mfc0	$t3,$5
-/*    51ce8:	216b2000 */ 	addi	$t3,$t3,0x2000
-/*    51cec:	000b5842 */ 	srl	$t3,$t3,0x1
-/*    51cf0:	01646024 */ 	and	$t4,$t3,$a0
-/*    51cf4:	15800004 */ 	bnez	$t4,.L00051d08
-/*    51cf8:	216bffff */ 	addi	$t3,$t3,-1
-/*    51cfc:	40021000 */ 	mfc0	$v0,$2
-/*    51d00:	10000002 */ 	b	.L00051d0c
-/*    51d04:	00000000 */ 	nop
-.L00051d08:
-/*    51d08:	40021800 */ 	mfc0	$v0,$3
-.L00051d0c:
-/*    51d0c:	304d0002 */ 	andi	$t5,$v0,0x2
-/*    51d10:	11a00009 */ 	beqz	$t5,.L00051d38
-/*    51d14:	00000000 */ 	nop
-/*    51d18:	3c013fff */ 	lui	$at,0x3fff
-/*    51d1c:	3421ffc0 */ 	ori	$at,$at,0xffc0
-/*    51d20:	00411024 */ 	and	$v0,$v0,$at
-/*    51d24:	00021180 */ 	sll	$v0,$v0,0x6
-/*    51d28:	008b6824 */ 	and	$t5,$a0,$t3
-/*    51d2c:	004d1020 */ 	add	$v0,$v0,$t5
-/*    51d30:	10000002 */ 	b	.L00051d3c
-/*    51d34:	00000000 */ 	nop
-.L00051d38:
-/*    51d38:	2402ffff */ 	addiu	$v0,$zero,-1
-.L00051d3c:
-/*    51d3c:	40885000 */ 	mtc0	$t0,$10
-/*    51d40:	03e00008 */ 	jr	$ra
-/*    51d44:	00000000 */ 	nop
-);
diff --git a/src/lib/ultra/os/probetlb.s b/src/lib/ultra/os/probetlb.s
new file mode 100644
index 000000000..595f2243a
--- /dev/null
+++ b/src/lib/ultra/os/probetlb.s
@@ -0,0 +1,57 @@
+#include "macros.inc"
+.set noat
+.set noreorder
+
+.section .text
+
+glabel __osProbeTLB
+	mfc0  $t0, $10
+	andi  $t1, $t0, 0xff
+	addiu $at, $zero, -8192
+	and   $t2, $a0, $at
+	or    $t1, $t1, $t2
+	mtc0  $t1, $10
+ 	nop
+ 	nop
+ 	nop
+ 	tlbp
+ 	nop
+ 	nop
+	mfc0  $t3, $0
+	lui   $at, 0x8000
+	and   $t3, $t3, $at
+	bnez  $t3, .L00051d38
+ 	nop
+ 	tlbr
+ 	nop
+ 	nop
+ 	nop
+	mfc0  $t3, $5
+	addi  $t3, $t3, 0x2000
+	srl   $t3, $t3, 0x1
+	and   $t4, $t3, $a0
+	bnez  $t4, .L00051d08
+	addi  $t3, $t3, -1
+	mfc0  $v0, $2
+	b     .L00051d0c
+ 	nop
+.L00051d08:
+	mfc0  $v0, $3
+.L00051d0c:
+	andi  $t5, $v0, 0x2
+	beqz  $t5, .L00051d38
+ 	nop
+	lui   $at, 0x3fff
+	ori   $at, $at, 0xffc0
+	and   $v0, $v0, $at
+	sll   $v0, $v0, 0x6
+	and   $t5, $a0, $t3
+	add   $v0, $v0, $t5
+	b     .L00051d3c
+ 	nop
+.L00051d38:
+	addiu $v0, $zero, -1
+.L00051d3c:
+	mtc0  $t0, $10
+	jr    $ra
+ 	nop