1 files changed, 71 insertions, 0 deletions
diff --git a/src/runtime/internal/atomic/asm_arm.s b/src/runtime/internal/atomic/asm_arm.s
new file mode 100644
index 0000000000..235e8bfd20
--- /dev/null
+++ b/src/runtime/internal/atomic/asm_arm.s
@@ -0,0 +1,71 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "textflag.h"
+
+// bool armcas(int32 *val, int32 old, int32 new)
+// Atomically:
+//	if(*val == old){
+//		*val = new;
+//		return 1;
+//	}else
+//		return 0;
+//
+// To implement runtime∕internal∕atomic·cas in sys_$GOOS_arm.s
+// using the native instructions, use:
+//
+//	TEXT runtime∕internal∕atomic·cas(SB),NOSPLIT,$0
+//		B	runtime∕internal∕atomic·armcas(SB)
+//
+TEXT runtime∕internal∕atomic·armcas(SB),NOSPLIT,$0-13
+	MOVW	valptr+0(FP), R1
+	MOVW	old+4(FP), R2
+	MOVW	new+8(FP), R3
+casl:
+	LDREX	(R1), R0
+	CMP	R0, R2
+	BNE	casfail
+
+	MOVB	runtime·goarm(SB), R11
+	CMP	$7, R11
+	BLT	2(PC)
+	WORD	$0xf57ff05a	// dmb ishst
+
+	STREX	R3, (R1), R0
+	CMP	$0, R0
+	BNE	casl
+	MOVW	$1, R0
+
+	MOVB	runtime·goarm(SB), R11
+	CMP	$7, R11
+	BLT	2(PC)
+	WORD	$0xf57ff05b	// dmb ish
+
+	MOVB	R0, ret+12(FP)
+	RET
+casfail:
+	MOVW	$0, R0
+	MOVB	R0, ret+12(FP)
+	RET
+
+TEXT runtime∕internal∕atomic·Casuintptr(SB),NOSPLIT,$0-13
+	B	runtime∕internal∕atomic·Cas(SB)
+
+TEXT runtime∕internal∕atomic·Loaduintptr(SB),NOSPLIT,$0-8
+	B	runtime∕internal∕atomic·Load(SB)
+
+TEXT runtime∕internal∕atomic·Loaduint(SB),NOSPLIT,$0-8
+	B	runtime∕internal∕atomic·Load(SB)
+
+TEXT runtime∕internal∕atomic·Storeuintptr(SB),NOSPLIT,$0-8
+	B	runtime∕internal∕atomic·Store(SB)
+
+TEXT runtime∕internal∕atomic·Xadduintptr(SB),NOSPLIT,$0-8
+	B	runtime∕internal∕atomic·Xadd(SB)
+
+TEXT runtime∕internal∕atomic·Loadint64(SB),NOSPLIT,$0-16
+	B	runtime∕internal∕atomic·Load64(SB)
+
+TEXT runtime∕internal∕atomic·Xaddint64(SB),NOSPLIT,$0-16
+	B	runtime∕internal∕atomic·Xadd64(SB)