diff --git a/arch/avr32/lib/io-readsb.S b/arch/avr32/lib/io-readsb.S
new file mode 100644
index 0000000..b319d5e
--- /dev/null
+++ b/arch/avr32/lib/io-readsb.S
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2004-2006 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+	.text
+.Lnot_word_aligned:
+1:	ld.ub	r8, r12[0]
+	sub	r10, 1
+	st.b	r11++, r8
+	reteq	r12
+	tst	r11, r9
+	brne	1b
+
+	/* fall through */
+
+	.global	__raw_readsb
+	.type	__raw_readsb,@function
+__raw_readsb:
+	cp.w	r10, 0
+	mov	r9, 3
+	reteq	r12
+
+	tst	r11, r9
+	brne	.Lnot_word_aligned
+
+	sub	r10, 4
+	brlt	2f
+
+1:	ldins.b	r8:t, r12[0]
+	ldins.b	r8:u, r12[0]
+	ldins.b	r8:l, r12[0]
+	ldins.b r8:b, r12[0]
+	st.w	r11++, r8
+	sub	r10, 4
+	brge	1b
+
+2:	sub	r10, -4
+	reteq	r12
+
+3:	ld.uh	r8, r12[0]
+	sub	r10, 1
+	st.b	r11++, r8
+	brne	3b