sync/atomic: add Store functions

R=rsc
CC=golang-dev
https://golang.org/cl/4950060

src/pkg/sync/atomic/asm_386.s

@@ -18,6 +18,9 @@ TEXT ·CompareAndSwapUint32(SB),7,$0
 TEXT ·CompareAndSwapUintptr(SB),7,$0
 	JMP	·CompareAndSwapUint32(SB)
 
+TEXT ·CompareAndSwapPointer(SB),7,$0
+	JMP	·CompareAndSwapUint32(SB)
+
 TEXT ·CompareAndSwapInt64(SB),7,$0
 	JMP	·CompareAndSwapUint64(SB)
 
@@ -100,3 +103,18 @@ TEXT ·LoadUintptr(SB),7,$0
 
 TEXT ·LoadPointer(SB),7,$0
 	JMP	·LoadUint32(SB)
+
+TEXT ·StoreInt32(SB),7,$0
+	JMP	·StoreUint32(SB)
+
+TEXT ·StoreUint32(SB),7,$0
+	MOVL	addrptr+0(FP), BP
+	MOVL	val+4(FP), AX
+	XCHGL	AX, 0(BP)
+	RET
+
+TEXT ·StoreUintptr(SB),7,$0
+	JMP	·StoreUint32(SB)
+
+TEXT ·StorePointer(SB),7,$0
+	JMP	·StoreUint32(SB)

src/pkg/sync/atomic/asm_amd64.s

@@ -17,6 +17,9 @@ TEXT ·CompareAndSwapUint32(SB),7,$0
 TEXT ·CompareAndSwapUintptr(SB),7,$0
 	JMP	·CompareAndSwapUint64(SB)
 
+TEXT ·CompareAndSwapPointer(SB),7,$0
+	JMP	·CompareAndSwapUint64(SB)
+
 TEXT ·CompareAndSwapInt64(SB),7,$0
 	JMP	·CompareAndSwapUint64(SB)
 
@@ -75,3 +78,21 @@ TEXT ·LoadPointer(SB),7,$0
 	MOVQ	0(AX), AX
 	MOVQ	AX, ret+8(FP)
 	RET
+
+TEXT ·StoreInt32(SB),7,$0
+	JMP	·StoreUint32(SB)
+
+TEXT ·StoreUint32(SB),7,$0
+	MOVQ	addrptr+0(FP), BP
+	MOVL	val+8(FP), AX
+	XCHGL	AX, 0(BP)
+	RET
+
+TEXT ·StoreUintptr(SB),7,$0
+	JMP	·StorePointer(SB)
+
+TEXT ·StorePointer(SB),7,$0
+	MOVQ	addrptr+0(FP), BP
+	MOVQ	val+8(FP), AX
+	XCHGQ	AX, 0(BP)
+	RET

src/pkg/sync/atomic/asm_linux_arm.s

@@ -50,6 +50,9 @@ cascheck:
 TEXT ·CompareAndSwapUintptr(SB),7,$0
 	B	·CompareAndSwapUint32(SB)
 
+TEXT ·CompareAndSwapPointer(SB),7,$0
+	B	·CompareAndSwapUint32(SB)
+
 TEXT ·AddInt32(SB),7,$0
 	B	·AddUint32(SB)
 
@@ -102,3 +105,21 @@ TEXT ·LoadUintptr(SB),7,$0
 
 TEXT ·LoadPointer(SB),7,$0
 	B	·LoadUint32(SB)
+
+TEXT ·StoreInt32(SB),7,$0
+	B	·StoreUint32(SB)
+
+TEXT ·StoreUint32(SB),7,$0
+	MOVW	addrptr+0(FP), R2
+	MOVW	val+4(FP), R1
+storeloop1:
+	MOVW	0(R2), R0
+	BL	cas<>(SB)
+	BCC	storeloop1
+	RET
+
+TEXT ·StoreUintptr(SB),7,$0
+	B	·StoreUint32(SB)
+
+TEXT ·StorePointer(SB),7,$0
+	B	·StoreUint32(SB)

src/pkg/sync/atomic/doc.go

@@ -45,6 +45,9 @@ func CompareAndSwapUint64(val *uint64, old, new uint64) (swapped bool)
 // CompareAndSwapUintptr executes the compare-and-swap operation for a uintptr value.
 func CompareAndSwapUintptr(val *uintptr, old, new uintptr) (swapped bool)
 
+// CompareAndSwapPointer executes the compare-and-swap operation for a unsafe.Pointer value.
+func CompareAndSwapPointer(val *unsafe.Pointer, old, new unsafe.Pointer) (swapped bool)
+
 // AddInt32 atomically adds delta to *val and returns the new value.
 func AddInt32(val *int32, delta int32) (new int32)
 
@@ -72,6 +75,18 @@ func LoadUintptr(addr *uintptr) (val uintptr)
 // LoadPointer atomically loads *addr.
 func LoadPointer(addr *unsafe.Pointer) (val unsafe.Pointer)
 
+// StoreInt32 atomically stores val into *addr.
+func StoreInt32(addr *int32, val int32)
+
+// StoreUint32 atomically stores val into *addr.
+func StoreUint32(addr *uint32, val uint32)
+
+// StoreUintptr atomically stores val into *addr.
+func StoreUintptr(addr *uintptr, val uintptr)
+
+// StorePointer atomically stores val into *addr.
+func StorePointer(addr *unsafe.Pointer, val unsafe.Pointer)
+
 // Helper for ARM.  Linker will discard on other systems
 func panic64() {
 	panic("sync/atomic: broken 64-bit atomic operations (buggy QEMU)")