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sync/atomic: add LoadUintptr

Browse Source 
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4985041
This commit is contained in:
Dmitriy Vyukov 2011-09-01 15:17:25 -04:00 committed by Russ Cox
parent 60d47101aa
commit ea23ba3e2d
5 changed files with 113 additions and 6 deletions
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6
src/pkg/sync/atomic/asm_386.s
View File

@ -94,3 +94,9 @@ TEXT ·LoadUint32(SB),7,$0
MOVL 0(AX), AX
MOVL AX, ret+4(FP)
RET
TEXT ·LoadUintptr(SB),7,$0
JMP ·LoadUint32(SB)
TEXT ·LoadPointer(SB),7,$0
JMP ·LoadUint32(SB)

8
src/pkg/sync/atomic/asm_amd64.s
View File

@ -67,3 +67,11 @@ TEXT ·LoadUint32(SB),7,$0
MOVL AX, ret+8(FP)
RET
TEXT ·LoadUintptr(SB),7,$0
JMP ·LoadPointer(SB)
TEXT ·LoadPointer(SB),7,$0
MOVQ addrptr+0(FP), AX
MOVQ 0(AX), AX
MOVQ AX, ret+8(FP)
RET

6
src/pkg/sync/atomic/asm_linux_arm.s
View File

@ -96,3 +96,9 @@ loadloop1:
BCC loadloop1
MOVW R1, val+4(FP)
RET
TEXT ·LoadUintptr(SB),7,$0
B ·LoadUint32(SB)
TEXT ·LoadPointer(SB),7,$0
B ·LoadUint32(SB)

89
src/pkg/sync/atomic/atomic_test.go
View File

@ -348,6 +348,50 @@ func TestLoadUint32(t *testing.T) {
}
}
func TestLoadUintptr(t *testing.T) {
var x struct {
before uintptr
i uintptr
after uintptr
}
var m uint64 = magic64
magicptr := uintptr(m)
x.before = magicptr
x.after = magicptr
for delta := uintptr(1); delta+delta > delta; delta += delta {
k := LoadUintptr(&x.i)
if k != x.i {
t.Fatalf("delta=%d i=%d k=%d", delta, x.i, k)
}
x.i += delta
}
if x.before != magicptr || x.after != magicptr {
t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, magicptr, magicptr)
}
}
func TestLoadPointer(t *testing.T) {
var x struct {
before uintptr
i unsafe.Pointer
after uintptr
}
var m uint64 = magic64
magicptr := uintptr(m)
x.before = magicptr
x.after = magicptr
for delta := uintptr(1); delta+delta > delta; delta += delta {
k := LoadPointer(&x.i)
if k != x.i {
t.Fatalf("delta=%d i=%d k=%d", delta, x.i, k)
}
x.i = unsafe.Pointer(uintptr(x.i) + delta)
}
if x.before != magicptr || x.after != magicptr {
t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, magicptr, magicptr)
}
}
// Tests of correct behavior, with contention.
// (Is the function atomic?)
//
@ -578,8 +622,8 @@ func TestHammer64(t *testing.T) {
}
}
func hammerLoadInt32(t *testing.T, uval *uint32) {
val := (*int32)(unsafe.Pointer(uval))
func hammerLoadInt32(t *testing.T, valp unsafe.Pointer) {
val := (*int32)(valp)
for {
v := LoadInt32(val)
vlo := v & ((1 << 16) - 1)
@ -597,7 +641,8 @@ func hammerLoadInt32(t *testing.T, uval *uint32) {
}
}
func hammerLoadUint32(t *testing.T, val *uint32) {
func hammerLoadUint32(t *testing.T, valp unsafe.Pointer) {
val := (*uint32)(valp)
for {
v := LoadUint32(val)
vlo := v & ((1 << 16) - 1)
@ -615,8 +660,40 @@ func hammerLoadUint32(t *testing.T, val *uint32) {
}
}
func hammerLoadUintptr(t *testing.T, valp unsafe.Pointer) {
val := (*uintptr)(valp)
var test64 uint64 = 1 << 50
arch32 := uintptr(test64) == 0
for {
v := LoadUintptr(val)
new := v
if arch32 {
vlo := v & ((1 << 16) - 1)
vhi := v >> 16
if vlo != vhi {
t.Fatalf("LoadUintptr: %#x != %#x", vlo, vhi)
}
new = v + 1 + 1<<16
if vlo == 1e4 {
new = 0
}
} else {
vlo := v & ((1 << 32) - 1)
vhi := v >> 32
if vlo != vhi {
t.Fatalf("LoadUintptr: %#x != %#x", vlo, vhi)
}
inc := uint64(1 + 1<<32)
new = v + uintptr(inc)
}
if CompareAndSwapUintptr(val, v, new) {
break
}
}
}
func TestHammerLoad(t *testing.T) {
tests := [...]func(*testing.T, *uint32){hammerLoadInt32, hammerLoadUint32}
tests := [...]func(*testing.T, unsafe.Pointer){hammerLoadInt32, hammerLoadUint32, hammerLoadUintptr}
n := 100000
if testing.Short() {
n = 10000
@ -625,11 +702,11 @@ func TestHammerLoad(t *testing.T) {
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(procs))
for _, tt := range tests {
c := make(chan int)
var val uint32
var val uint64
for p := 0; p < procs; p++ {
go func() {
for i := 0; i < n; i++ {
tt(t, &val)
tt(t, unsafe.Pointer(&val))
}
c <- 1
}()

10
src/pkg/sync/atomic/doc.go
View File

@ -22,6 +22,10 @@
//
package atomic
import (
"unsafe"
)
// BUG(rsc): On ARM, the 64-bit functions use instructions unavailable before ARM 11.
//
// On x86-32, the 64-bit functions use instructions unavailable before the Pentium.
@ -62,6 +66,12 @@ func LoadInt32(addr *int32) (val int32)
// LoadUint32 atomically loads *addr.
func LoadUint32(addr *uint32) (val uint32)
// LoadUintptr atomically loads *addr.
func LoadUintptr(addr *uintptr) (val uintptr)
// LoadPointer atomically loads *addr.
func LoadPointer(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)")