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-rw-r--r--arch/arm/lib/io-writesb.S91
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diff --git a/arch/arm/lib/io-writesb.S b/arch/arm/lib/io-writesb.S
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+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * linux/arch/arm/lib/io-writesb.S
+ *
+ * Copyright (C) 1995-2000 Russell King
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+ .macro outword, rd
+#ifndef __ARMEB__
+ strb \rd, [r0]
+ mov \rd, \rd, lsr #8
+ strb \rd, [r0]
+ mov \rd, \rd, lsr #8
+ strb \rd, [r0]
+ mov \rd, \rd, lsr #8
+ strb \rd, [r0]
+#else
+ mov lr, \rd, lsr #24
+ strb lr, [r0]
+ mov lr, \rd, lsr #16
+ strb lr, [r0]
+ mov lr, \rd, lsr #8
+ strb lr, [r0]
+ strb \rd, [r0]
+#endif
+ .endm
+
+.Loutsb_align: rsb ip, ip, #4
+ cmp ip, r2
+ movgt ip, r2
+ cmp ip, #2
+ ldrb r3, [r1], #1
+ strb r3, [r0]
+ ldrbge r3, [r1], #1
+ strbge r3, [r0]
+ ldrbgt r3, [r1], #1
+ strbgt r3, [r0]
+ subs r2, r2, ip
+ bne .Loutsb_aligned
+
+ENTRY(__raw_writesb)
+ teq r2, #0 @ do we have to check for the zero len?
+ reteq lr
+ ands ip, r1, #3
+ bne .Loutsb_align
+
+.Loutsb_aligned:
+ stmfd sp!, {r4, r5, lr}
+
+ subs r2, r2, #16
+ bmi .Loutsb_no_16
+
+.Loutsb_16_lp: ldmia r1!, {r3, r4, r5, ip}
+ outword r3
+ outword r4
+ outword r5
+ outword ip
+ subs r2, r2, #16
+ bpl .Loutsb_16_lp
+
+ tst r2, #15
+ ldmfdeq sp!, {r4, r5, pc}
+
+.Loutsb_no_16: tst r2, #8
+ beq .Loutsb_no_8
+
+ ldmia r1!, {r3, r4}
+ outword r3
+ outword r4
+
+.Loutsb_no_8: tst r2, #4
+ beq .Loutsb_no_4
+
+ ldr r3, [r1], #4
+ outword r3
+
+.Loutsb_no_4: ands r2, r2, #3
+ ldmfdeq sp!, {r4, r5, pc}
+
+ cmp r2, #2
+ ldrb r3, [r1], #1
+ strb r3, [r0]
+ ldrbge r3, [r1], #1
+ strbge r3, [r0]
+ ldrbgt r3, [r1]
+ strbgt r3, [r0]
+
+ ldmfd sp!, {r4, r5, pc}
+ENDPROC(__raw_writesb)