runtime/internal/atomic: add Store8

We already have Load8, And8, and Or8.

For #10958, #24543, but makes sense on its own.

Change-Id: I478529fc643edc57efdeccaae413c99edd19b2eb
Reviewed-on: https://go-review.googlesource.com/c/go/+/203283
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

src/runtime/internal/atomic/asm_386.s

@@ -229,3 +229,9 @@ TEXT runtime∕internal∕atomic·And8(SB), NOSPLIT, $0-5
 	LOCK
 	ANDB	BX, (AX)
 	RET
+
+TEXT runtime∕internal∕atomic·Store8(SB), NOSPLIT, $0-5
+	MOVL	ptr+0(FP), BX
+	MOVB	val+4(FP), AX
+	XCHGB	AX, 0(BX)
+	RET

src/runtime/internal/atomic/asm_amd64.s

@@ -136,6 +136,12 @@ TEXT runtime∕internal∕atomic·Store(SB), NOSPLIT, $0-12
 TEXT runtime∕internal∕atomic·StoreRel(SB), NOSPLIT, $0-12
 	JMP	runtime∕internal∕atomic·Store(SB)
 
+TEXT runtime∕internal∕atomic·Store8(SB), NOSPLIT, $0-9
+	MOVQ	ptr+0(FP), BX
+	MOVB	val+8(FP), AX
+	XCHGB	AX, 0(BX)
+	RET
+
 TEXT runtime∕internal∕atomic·Store64(SB), NOSPLIT, $0-16
 	MOVQ	ptr+0(FP), BX
 	MOVQ	val+8(FP), AX

src/runtime/internal/atomic/asm_mips64x.s

@@ -166,6 +166,14 @@ TEXT ·Store(SB), NOSPLIT, $0-12
 	SYNC
 	RET
 
+TEXT ·Store8(SB), NOSPLIT, $0-9
+	MOVV	ptr+0(FP), R1
+	MOVB	val+8(FP), R2
+	SYNC
+	MOVB	R2, 0(R1)
+	SYNC
+	RET
+
 TEXT ·Store64(SB), NOSPLIT, $0-16
 	MOVV	ptr+0(FP), R1
 	MOVV	val+8(FP), R2

src/runtime/internal/atomic/asm_mipsx.s

@@ -32,6 +32,14 @@ TEXT ·Store(SB),NOSPLIT,$0-8
 	SYNC
 	RET
 
+TEXT ·Store8(SB),NOSPLIT,$0-5
+	MOVW	ptr+0(FP), R1
+	MOVB	val+4(FP), R2
+	SYNC
+	MOVB	R2, 0(R1)
+	SYNC
+	RET
+
 TEXT ·Load(SB),NOSPLIT,$0-8
 	MOVW	ptr+0(FP), R1
 	SYNC

src/runtime/internal/atomic/asm_ppc64x.s

@@ -170,6 +170,13 @@ TEXT runtime∕internal∕atomic·Store(SB), NOSPLIT, $0-12
 	MOVW	R4, 0(R3)
 	RET
 
+TEXT runtime∕internal∕atomic·Store8(SB), NOSPLIT, $0-9
+	MOVD	ptr+0(FP), R3
+	MOVB	val+8(FP), R4
+	SYNC
+	MOVB	R4, 0(R3)
+	RET
+
 TEXT runtime∕internal∕atomic·Store64(SB), NOSPLIT, $0-16
 	MOVD	ptr+0(FP), R3
 	MOVD	val+8(FP), R4

src/runtime/internal/atomic/asm_s390x.s

@@ -12,6 +12,14 @@ TEXT ·Store(SB), NOSPLIT, $0
 	SYNC
 	RET
 
+// func Store8(ptr *uint8, val uint8)
+TEXT ·Store8(SB), NOSPLIT, $0
+	MOVD	ptr+0(FP), R2
+	MOVB	val+8(FP), R3
+	MOVB	R3, 0(R2)
+	SYNC
+	RET
+
 // func Store64(ptr *uint64, val uint64)
 TEXT ·Store64(SB), NOSPLIT, $0
 	MOVD	ptr+0(FP), R2

src/runtime/internal/atomic/atomic_386.go

@@ -74,6 +74,9 @@ func CasRel(ptr *uint32, old, new uint32) bool
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 

src/runtime/internal/atomic/atomic_amd64.go

@@ -76,6 +76,9 @@ func CasRel(ptr *uint32, old, new uint32) bool
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 

src/runtime/internal/atomic/atomic_arm.go

@@ -209,5 +209,8 @@ func Xchg64(addr *uint64, v uint64) uint64
 //go:noescape
 func Load64(addr *uint64) uint64
 
+//go:noescape
+func Store8(addr *uint8, v uint8)
+
 //go:noescape
 func Store64(addr *uint64, v uint64)

src/runtime/internal/atomic/atomic_arm64.go

@@ -56,6 +56,9 @@ func CasRel(ptr *uint32, old, new uint32) bool
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 

src/runtime/internal/atomic/atomic_arm64.s

@@ -48,6 +48,12 @@ TEXT runtime∕internal∕atomic·Store(SB), NOSPLIT, $0-12
 	STLRW	R1, (R0)
 	RET
 
+TEXT runtime∕internal∕atomic·Store8(SB), NOSPLIT, $0-9
+	MOVD	ptr+0(FP), R0
+	MOVB	val+8(FP), R1
+	STLRB	R1, (R0)
+	RET
+
 TEXT runtime∕internal∕atomic·Store64(SB), NOSPLIT, $0-16
 	MOVD	ptr+0(FP), R0
 	MOVD	val+8(FP), R1

src/runtime/internal/atomic/atomic_mips64x.go

@@ -58,6 +58,9 @@ func CasRel(ptr *uint32, old, new uint32) bool
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 

src/runtime/internal/atomic/atomic_mipsx.go

@@ -141,6 +141,9 @@ func Or8(ptr *uint8, val uint8)
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 // NO go:noescape annotation; see atomic_pointer.go.
 func StorepNoWB(ptr unsafe.Pointer, val unsafe.Pointer)
 

src/runtime/internal/atomic/atomic_ppc64x.go

@@ -58,6 +58,9 @@ func CasRel(ptr *uint32, old, new uint32) bool
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 

src/runtime/internal/atomic/atomic_s390x.go

@@ -44,6 +44,9 @@ func LoadAcq(ptr *uint32) uint32 {
 //go:noescape
 func Store(ptr *uint32, val uint32)
 
+//go:noescape
+func Store8(ptr *uint8, val uint8)
+
 //go:noescape
 func Store64(ptr *uint64, val uint64)
 

src/runtime/internal/atomic/atomic_wasm.go

@@ -141,6 +141,12 @@ func StoreRel(ptr *uint32, val uint32) {
 	*ptr = val
 }
 
+//go:nosplit
+//go:noinline
+func Store8(ptr *uint8, val uint8) {
+	*ptr = val
+}
+
 //go:nosplit
 //go:noinline
 func Store64(ptr *uint64, val uint64) {

src/runtime/internal/atomic/sys_linux_arm.s

@@ -120,3 +120,25 @@ end:
 	MOVB	R1, ret+4(FP)
 	RET
 
+TEXT	·Store8(SB),NOSPLIT,$0-5
+	MOVW	addr+0(FP), R1
+	MOVB	v+4(FP), R2
+
+	MOVB	runtime·goarm(SB), R8
+	CMP	$7, R8
+	BGE	native_barrier
+	BL	memory_barrier<>(SB)
+	B	store
+native_barrier:
+	DMB	MB_ISH
+
+store:
+	MOVB	R2, (R1)
+
+	CMP	$7, R8
+	BGE	native_barrier2
+	BL	memory_barrier<>(SB)
+	RET
+native_barrier2:
+	DMB	MB_ISH
+	RET

src/runtime/internal/atomic/sys_nonlinux_arm.s

@@ -60,3 +60,20 @@ TEXT	·Load8(SB),NOSPLIT|NOFRAME,$0-5
 
 	MOVB	R1, ret+4(FP)
 	RET
+
+TEXT	·Store8(SB),NOSPLIT,$0-5
+	MOVW	addr+0(FP), R1
+	MOVB	v+4(FP), R2
+
+	MOVB	runtime·goarm(SB), R8
+	CMP	$7, R8
+	BLT	2(PC)
+	DMB	MB_ISH
+
+	MOVB	R2, (R1)
+
+	CMP	$7, R8
+	BLT	2(PC)
+	DMB	MB_ISH
+	RET
+