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go/misc/cgo/gmp/fib.go
Russ Cox 133a158bd8 8c, 8l dynamic loading support.
better mach binaries.
cgo working on darwin+linux amd64+386.
eliminated context switches - pi is 30x faster.
add libcgo to build.

on snow leopard:
  - non-cgo binaries work; all tests pass.
  - cgo binaries work on amd64 but not 386.

R=r
DELTA=2031  (1316 added, 626 deleted, 89 changed)
OCL=35264
CL=35304
2009-10-03 10:37:12 -07:00

44 lines
917 B
Go

// 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.
// Compute Fibonacci numbers with two goroutines
// that pass integers back and forth. No actual
// concurrency, just threads and synchronization
// and foreign code on multiple pthreads.
package main
import (
big "gmp";
"runtime";
)
func fibber(c chan *big.Int, out chan string, n int64) {
// Keep the fibbers in dedicated operating system
// threads, so that this program tests coordination
// between pthreads and not just goroutines.
runtime.LockOSThread();
i := big.NewInt(n);
if n == 0 {
c <- i;
}
for {
j := <-c;
out <- j.String();
i.Add(i, j);
c <- i;
}
}
func main() {
c := make(chan *big.Int);
out := make(chan string);
go fibber(c, out, 0);
go fibber(c, out, 1);
for i := 0; i < 200; i++ {
println(<-out);
}
}