1// Copyright 2009 The Go Authors. All rights reserved.2// Use of this source code is governed by a BSD-style3// license that can be found in the LICENSE file.45//go:build ignore67package main89import (10	big "."11	"fmt"12	"runtime"13)1415var (16	tmp1  = big.NewInt(0)17	tmp2  = big.NewInt(0)18	numer = big.NewInt(1)19	accum = big.NewInt(0)20	denom = big.NewInt(1)21	ten   = big.NewInt(10)22)2324func extractDigit() int64 {25	if big.CmpInt(numer, accum) > 0 {26		return -127	}28	tmp1.Lsh(numer, 1).Add(tmp1, numer).Add(tmp1, accum)29	big.DivModInt(tmp1, tmp2, tmp1, denom)30	tmp2.Add(tmp2, numer)31	if big.CmpInt(tmp2, denom) >= 0 {32		return -133	}34	return tmp1.Int64()35}3637func nextTerm(k int64) {38	y2 := k*2 + 139	accum.Add(accum, tmp1.Lsh(numer, 1))40	accum.Mul(accum, tmp1.SetInt64(y2))41	numer.Mul(numer, tmp1.SetInt64(k))42	denom.Mul(denom, tmp1.SetInt64(y2))43}4445func eliminateDigit(d int64) {46	accum.Sub(accum, tmp1.Mul(denom, tmp1.SetInt64(d)))47	accum.Mul(accum, ten)48	numer.Mul(numer, ten)49}5051func main() {52	i := 053	k := int64(0)54	for {55		d := int64(-1)56		for d < 0 {57			k++58			nextTerm(k)59			d = extractDigit()60		}61		eliminateDigit(d)62		fmt.Printf("%c", d+'0')6364		if i++; i%50 == 0 {65			fmt.Printf("\n")66			if i >= 1000 {67				break68			}69		}70	}7172	fmt.Printf("\n%d calls; bit sizes: %d %d %d\n", runtime.NumCgoCall(), numer.Len(), accum.Len(), denom.Len())73}