add mutex.Mutex
R=r
DELTA=349 (348 added, 0 deleted, 1 changed)
OCL=20380
CL=20472
diff --git a/src/lib/Makefile b/src/lib/Makefile
index 7b68551..a50bdf0 100644
--- a/src/lib/Makefile
+++ b/src/lib/Makefile
@@ -18,6 +18,7 @@
reflect\
regexp\
strconv\
+ sync\
tabwriter\
time\
@@ -95,4 +96,5 @@
strconv.dirinstall: os.dirinstall utf8.install
tabwriter.dirinstall: os.dirinstall io.dirinstall container/array.dirinstall
time.dirinstall: once.install os.dirinstall
+sync.dirinstall:
diff --git a/src/lib/sync/Makefile b/src/lib/sync/Makefile
new file mode 100644
index 0000000..86aeeef
--- /dev/null
+++ b/src/lib/sync/Makefile
@@ -0,0 +1,56 @@
+# Copyright 2009 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.
+
+# DO NOT EDIT. Automatically generated by gobuild.
+# gobuild -m >Makefile
+O=6
+GC=$(O)g
+CC=$(O)c -w
+AS=$(O)a
+AR=$(O)ar
+
+default: packages
+
+clean:
+ rm -f *.$O *.a $O.out
+
+test: packages
+ gotest
+
+coverage: packages
+ gotest
+ 6cov -g `pwd` | grep -v '_test\.go:'
+
+%.$O: %.go
+ $(GC) $*.go
+
+%.$O: %.c
+ $(CC) $*.c
+
+%.$O: %.s
+ $(AS) $*.s
+
+O1=\
+ asm_$(GOARCH).$O\
+ mutex.$O\
+
+sync.a: a1
+
+a1: $(O1)
+ $(AR) grc sync.a asm_$(GOARCH).$O mutex.$O
+ rm -f $(O1)
+
+newpkg: clean
+ $(AR) grc sync.a
+
+$(O1): newpkg
+
+nuke: clean
+ rm -f $(GOROOT)/pkg/sync.a
+
+packages: sync.a
+
+install: packages
+ cp sync.a $(GOROOT)/pkg/sync.a
+
diff --git a/src/lib/sync/asm_amd64.s b/src/lib/sync/asm_amd64.s
new file mode 100644
index 0000000..07389dd
--- /dev/null
+++ b/src/lib/sync/asm_amd64.s
@@ -0,0 +1,23 @@
+// Copyright 2009 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.
+
+// func cas(val *int32, old, new int32) bool
+// Atomically:
+// if *val == old {
+// *val = new;
+// return true;
+// }else
+// return false;
+TEXT sync·cas(SB), 7, $0
+ MOVQ 8(SP), BX
+ MOVL 16(SP), AX
+ MOVL 20(SP), CX
+ LOCK
+ CMPXCHGL CX, 0(BX)
+ JZ ok
+ MOVL $0, 24(SP)
+ RET
+ok:
+ MOVL $1, 24(SP)
+ RET
diff --git a/src/lib/sync/mutex.go b/src/lib/sync/mutex.go
new file mode 100644
index 0000000..accf55a
--- /dev/null
+++ b/src/lib/sync/mutex.go
@@ -0,0 +1,39 @@
+// Copyright 2009 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.
+
+package sync
+
+package func cas(val *int32, old, new int32) bool
+
+export type Mutex struct {
+ key int32;
+ sema int32;
+}
+
+func xadd(val *int32, delta int32) (new int32) {
+ for {
+ v := *val;
+ if cas(val, v, v+delta) {
+ return v+delta;
+ }
+ }
+ panic("unreached")
+}
+
+func (m *Mutex) Lock() {
+ if xadd(&m.key, 1) == 1 {
+ // changed from 0 to 1; we hold lock
+ return;
+ }
+ sys.semacquire(&m.sema);
+}
+
+func (m *Mutex) Unlock() {
+ if xadd(&m.key, -1) == 0 {
+ // changed from 1 to 0; no contention
+ return;
+ }
+ sys.semrelease(&m.sema);
+}
+
diff --git a/src/lib/sync/mutex_test.go b/src/lib/sync/mutex_test.go
new file mode 100644
index 0000000..7a6dd18
--- /dev/null
+++ b/src/lib/sync/mutex_test.go
@@ -0,0 +1,53 @@
+// Copyright 2009 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.
+
+// GOMAXPROCS=10 gotest
+
+package sync
+
+import (
+ "sync";
+ "testing"
+)
+
+func HammerSemaphore(s *int32, cdone *chan bool) {
+ for i := 0; i < 1000; i++ {
+ sys.semacquire(s);
+ sys.semrelease(s);
+ }
+ cdone <- true;
+}
+
+export func TestSemaphore(t *testing.T) {
+ s := new(int32);
+ *s = 1;
+ c := new(chan bool);
+ for i := 0; i < 10; i++ {
+ go HammerSemaphore(s, c);
+ }
+ for i := 0; i < 10; i++ {
+ <-c;
+ }
+}
+
+
+func HammerMutex(m *Mutex, cdone *chan bool) {
+ for i := 0; i < 1000; i++ {
+ m.Lock();
+ m.Unlock();
+ }
+ cdone <- true;
+}
+
+export func TestMutex(t *testing.T) {
+ m := new(Mutex);
+ c := new(chan bool);
+ for i := 0; i < 10; i++ {
+ go HammerMutex(m, c);
+ }
+ for i := 0; i < 10; i++ {
+ <-c;
+ }
+}
+
