1 files changed, 97 insertions, 0 deletions
diff --git a/arch/arm/lib/io-writesw-armv4.S b/arch/arm/lib/io-writesw-armv4.S
new file mode 100644
index 0000000000..12eec53266
--- /dev/null
+++ b/arch/arm/lib/io-writesw-armv4.S
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *  linux/arch/arm/lib/io-writesw-armv4.S
+ *
+ *  Copyright (C) 1995-2000 Russell King
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+		.macro	outword, rd
+#ifndef __ARMEB__
+		strh	\rd, [r0]
+		mov	\rd, \rd, lsr #16
+		strh	\rd, [r0]
+#else
+		mov	lr, \rd, lsr #16
+		strh	lr, [r0]
+		strh	\rd, [r0]
+#endif
+		.endm
+
+.Loutsw_align:	movs	ip, r1, lsl #31
+		bne	.Loutsw_noalign
+
+		ldrh	r3, [r1], #2
+		sub	r2, r2, #1
+		strh	r3, [r0]
+
+ENTRY(__raw_writesw)
+		teq	r2, #0
+		reteq	lr
+		ands	r3, r1, #3
+		bne	.Loutsw_align
+
+		stmfd	sp!, {r4, r5, lr}
+
+		subs	r2, r2, #8
+		bmi	.Lno_outsw_8
+
+.Loutsw_8_lp:	ldmia	r1!, {r3, r4, r5, ip}
+		subs	r2, r2, #8
+		outword	r3
+		outword	r4
+		outword	r5
+		outword	ip
+		bpl	.Loutsw_8_lp
+
+.Lno_outsw_8:	tst	r2, #4
+		beq	.Lno_outsw_4
+
+		ldmia	r1!, {r3, ip}
+		outword	r3
+		outword	ip
+
+.Lno_outsw_4:	movs	r2, r2, lsl #31
+		bcc	.Lno_outsw_2
+
+		ldr	r3, [r1], #4
+		outword	r3
+
+.Lno_outsw_2:	ldrhne	r3, [r1]
+		strhne	r3, [r0]
+
+		ldmfd	sp!, {r4, r5, pc}
+
+#ifdef __ARMEB__
+#define pull_hbyte0	lsl #8
+#define push_hbyte1	lsr #24
+#else
+#define pull_hbyte0	lsr #24
+#define push_hbyte1	lsl #8
+#endif
+
+.Loutsw_noalign:
+ ARM(		ldr	r3, [r1, -r3]!	)
+ THUMB(		rsb	r3, r3, #0	)
+ THUMB(		ldr	r3, [r1, r3]	)
+ THUMB(		sub	r1, r3		)
+		subcs	r2, r2, #1
+		bcs	2f
+		subs	r2, r2, #2
+		bmi	3f
+
+1:		mov	ip, r3, lsr #8
+		strh	ip, [r0]
+2:		mov	ip, r3, pull_hbyte0
+		ldr	r3, [r1, #4]!
+		subs	r2, r2, #2
+		orr	ip, ip, r3, push_hbyte1
+		strh	ip, [r0]
+		bpl	1b
+
+		tst	r2, #1
+3:		movne	ip, r3, lsr #8
+		strhne	ip, [r0]
+		ret	lr
+ENDPROC(__raw_writesw)