# Integer#to\_s(2) works on x86, fails on x86\_64

**URL:** <https://www.ruby-forum.com/t/integer-to-s-2-works-on-x86-fails-on-x86-64/78354>\
**Category:** Ruby\
**Created:** [December 5, 2006, 8:56am UTC](https://www.ruby-forum.com/t/integer-to-s-2-works-on-x86-fails-on-x86-64/78354 "2006-12-05T08:56:18Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![snk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/d9b06d/32.png) [@snk](https://www.ruby-forum.com/u/snk)\
**Post date:** [December 5, 2006, 8:56am UTC](https://www.ruby-forum.com/t/integer-to-s-2-works-on-x86-fails-on-x86-64/78354/1 "2006-12-05T08:56:18Z")

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Hello,

Can anyone explain why this is happening?

---- on x86\_64 ----

$ ruby -v  
ruby 1.8.4 (2005-12-24) [x86\_64-linux]

$ irb

> > 2956350890592680056.to\_s(2)  
> > RangeError: integer 2956350890592680056 too big to convert to `int' from (irb):1:in`to\_s’  
> > from (irb):1  
> > from :0

---- on x86 ----

$ ruby -v  
ruby 1.8.4 (2005-12-24) [i486-linux]

$ irb

> > 2956350890592680056.to\_s(2)  
> > =\> “10100100000111000100010111100010111001001011111011100001111000”

Thanks for your consideration.

---

<div class="post-metadata">

**Author:** ![snk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/d9b06d/32.png) [@snk](https://www.ruby-forum.com/u/snk)\
**Post date:** [December 5, 2006, 9:40am UTC](https://www.ruby-forum.com/t/integer-to-s-2-works-on-x86-fails-on-x86-64/78354/2 "2006-12-05T09:40:32Z")

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Suraj K. wrote:

> $ irb  
> ruby 1.8.4 (2005-12-24) [i486-linux]
> 
> $ irb
> 
> > > 2956350890592680056.to\_s(2)  
> > > =\> “10100100000111000100010111100010111001001011111011100001111000”
> 
> Thanks for your consideration.

It’s way too large to fit into an old-style integer of 32 bits, but it  
fits  
with two bits to spare in a 64-bit integer. Also, in Ruby, normally an  
integer too large for the Fixnum class is automatically converted to a  
Bignum, so this error should not have happened.

Try this test:

32.upto(128) do |p|  
puts 2 \*\* p  
end

See what happens on both platforms. BTW I am thinking this is an error  
in  
the x86\_64 Ruby code.

---

<div class="post-metadata">

**Author:** ![snk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/d9b06d/32.png) [@snk](https://www.ruby-forum.com/u/snk)\
**Post date:** [December 5, 2006, 9:44am UTC](https://www.ruby-forum.com/t/integer-to-s-2-works-on-x86-fails-on-x86-64/78354/3 "2006-12-05T09:44:33Z")

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Suraj K. schrieb:

> Hello,
> 
> Can anyone explain why this is happening?

no, but it works here:

patrick@Dragon:~$ irb  
irb(main):001:0\> 2956350890592680056.to\_s(2)  
=\> “10100100000111000100010111100010111001001011111011100001111000”  
irb(main):002:0\> quit  
patrick@Dragon:~$ ruby -v  
ruby 1.8.5 (2006-08-25) [x86\_64-linux]

maybe it helps to track the problem.

thanks,  
patrick

---

<div class="post-metadata">

**Author:** ![snk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/d9b06d/32.png) [@snk](https://www.ruby-forum.com/u/snk)\
**Post date:** [December 5, 2006, 10:46am UTC](https://www.ruby-forum.com/t/integer-to-s-2-works-on-x86-fails-on-x86-64/78354/4 "2006-12-05T10:46:45Z")

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Paul L. wrote:

> See what happens on both platforms. BTW I am thinking this is an error in  
> the x86\_64 Ruby code.

The same Exception is thrown on my machine.

From cpuinfo:  
processor : 0  
vendor\_id : AuthenticAMD  
cpu family : 15  
model : 47  
model name : AMD Athlon™ 64 Processor 3000+  
stepping : 2

Operating System is Ubuntu 6.06 LTS.

Ruby version (installed via OS package manager): ruby 1.8.4 (2005-12-24)  
[x86\_64-linux].

16.upto(128) do |p|  
n = 2 \*\* p  
puts("#{p}: #{n}: #{n.class}")  
end

shows a conversion at

61: 2305843009213693952: Fixnum  
62: 4611686018427387904: Bignum

where to\_s(2) fails at p == 31

16.upto(128) do |p|  
n = 2 \*\* p  
puts("#{p}: #{n}: #{n.class}")  
puts(n.to\_s(2))  
end

31: 2147483648: Fixnum  
RangeError: integer 2147483648 too big to convert to `int’

Stefan

---

<div class="post-metadata">

**Author:** ![snk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/d9b06d/32.png) [@snk](https://www.ruby-forum.com/u/snk)\
**Post date:** [December 5, 2006, 2:07pm UTC](https://www.ruby-forum.com/t/integer-to-s-2-works-on-x86-fails-on-x86-64/78354/5 "2006-12-05T14:07:07Z")

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Suraj K.:

> $ ruby -v  
> ruby 1.8.4 (2005-12-24) [x86\_64-linux]
> 
> $ irb
> 
> > > 2956350890592680056.to\_s(2)  
> > > RangeError: integer 2956350890592680056 too big to convert to `int’

irb\> “#{RUBY\_VERSION} #{RUBY\_PLATFORM} #{RUBY\_RELEASE\_DATE}”  
=\> “1.9.0 x86\_64-linux 2006-10-16”  
irb\> 2956350890592680056.to\_s(2)  
=\> “10100100000111000100010111100010111001001011111011100001111000”

irb\> “#{RUBY\_VERSION} #{RUBY\_PLATFORM} #{RUBY\_RELEASE\_DATE}”  
=\> “1.8.4 x86\_64-linux 2005-12-24”  
irb\> 2956350890592680056.to\_s(2)  
RangeError: integer 2956350890592680056 too big to convert to `int' from (irb):2:in`to\_s’  
from (irb):2

Kalman

---

<div class="post-metadata">

**Author:** ![snk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/d9b06d/32.png) [@snk](https://www.ruby-forum.com/u/snk)\
**Post date:** [December 5, 2006, 3:25pm UTC](https://www.ruby-forum.com/t/integer-to-s-2-works-on-x86-fails-on-x86-64/78354/6 "2006-12-05T15:25:16Z")

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Kalman N. wrote:

> > 
> 
> ```
> from (irb):2:in `to_s'
> from (irb):2
> 
> ```
> 
> Kalman

Seems on 1.8.5 is ok aswell, so the problem is \< 1.8.4

irb(main):001:0\> “#{RUBY\_VERSION} #{RUBY\_PLATFORM} #{RUBY\_RELEASE\_DATE}”  
=\> “1.8.5 x86\_64-linux 2006-12-04”  
irb(main):002:0\> 2956350890592680056.to\_s(2)  
=\> “10100100000111000100010111100010111001001011111011100001111000”

---

<div class="post-metadata">

**Author:** ![snk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/d9b06d/32.png) [@snk](https://www.ruby-forum.com/u/snk)\
**Post date:** [December 5, 2006, 3:41pm UTC](https://www.ruby-forum.com/t/integer-to-s-2-works-on-x86-fails-on-x86-64/78354/7 "2006-12-05T15:41:19Z")

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On Tue, 05 Dec 2006 23:24:57 +0900, Mihai Vlad wrote:

> > > RangeError: integer 2956350890592680056 too big to convert to `int' RangeError: integer 2956350890592680056 too big to convert to `int’  
> > > =\> “1.8.5 x86\_64-linux 2006-12-04”  
> > > irb(main):002:0\> 2956350890592680056.to\_s(2)  
> > > =\> “10100100000111000100010111100010111001001011111011100001111000”

Yep. Here are the relevant changelog entries.

Fri Aug 25 17:15:17 2006 Yukihiro M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

```
    * stable version 1.8.5 released.

```

Sun Feb 5 21:05:34 2006 Hirokazu Yamamoto [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

```
    * numeric.c (fix_to_s): removed workaround for radix 2. 

```

Historically,  
rb\_fix2str could only handle radix 8, 10, 16. (Rev1.37) But  
for now,  
it can handle radix 2…36. [ruby-Bugs#3438] [ruby-core:7300]  
Sat Feb 4 15:56:37 2006 Hirokazu Yamamoto [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

```
    * numeric.c (fix_to_s): (2**32).to_s(2) fails with exception 

```

where  
sizeof(int) == 4 \< sizeof(long). [ruby-core:7300]

Sat Dec 24 18:58:14 2005 Yukihiro M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

```
    * stable version 1.8.4 released.

```