# (1 \<\< 0x40000000)\[0x40000000\]

**URL:** <https://www.ruby-forum.com/t/1-0x40000000-0x40000000/110074>\
**Category:** Development\
**Created:** [July 22, 2007, 5:36pm UTC](https://www.ruby-forum.com/t/1-0x40000000-0x40000000/110074 "2007-07-22T17:36:22Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [July 22, 2007, 5:36pm UTC](https://www.ruby-forum.com/t/1-0x40000000-0x40000000/110074/1 "2007-07-22T17:36:22Z")

</div>

e$B\<!$N$h$&$K!"e(B(1 \<\< 0x40000000)[0x40000000] e$B$,e(B 0  
e$B$K$J$j$^$9!#e(B

% ./ruby -ve ‘p((1 \<\< 0x40000000)[0x40000000])’  
ruby 1.9.0 (2007-07-22 patchlevel 0) [i686-linux]  
0

e$B$^$?!"e(B(-1 \<\< 0x40000001)[0x40000000] e$B$,e(B 1 e$B$K$J$j$^$9!#e(B

% ./ruby -e ‘p((-1 \<\< 0x40000001)[0x40000000])’  
1

e$B$"$H!"e(B(-0x40000002)[big\_zero] e$B$,e(B 1 e$B$K!"e(B  
0x400000001[big\_zero] e$B$,e(B 0 e$B$K$J$j$^$9!#e(B

% ./ruby -e ‘big\_zero = 0x40000000.coerce(0)[0];  
p((-0x40000002)[big\_zero])’  
1  
% ./ruby -e ‘big\_zero = 0x40000000.coerce(0)[0];  
p(0x400000001[big\_zero])’  
0

---

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [July 22, 2007, 8:16pm UTC](https://www.ruby-forum.com/t/1-0x40000000-0x40000000/110074/2 "2007-07-22T20:16:33Z")

</div>

e$B$J$+$@$G$9!#e(B

At Mon, 23 Jul 2007 00:35:30 +0900,  
Tanaka A. wrote in [ruby-dev:31271]:

> e$B\<!$N$h$&$K!"e(B(1 \<\< 0x40000000)[0x40000000] e$B$,e(B 0 e$B$K$J$j$^$9!#e(B  
> (e$B0J2\<N,e(B)

# Index: trunk/bignum.c

— trunk/bignum.c (revision 12828)  
+++ trunk/bignum.c (working copy)  
@@ -2062,27 +2062,37 @@ rb\_big\_aref(VALUE x, VALUE y)  
{  
BDIGIT \*xds;

- int shift;
- long s1, s2;

- BDIGIT\_DBL num;

- VALUE shift;

- long i, s1, s2;

- if (!RBIGNUM(y)-\>sign || RBIGNUM(x)-\>sign)

- if (!RBIGNUM(y)-\>sign)  
return INT2FIX(0);

- return INT2FIX(1);

- if (RBIGNUM(bigtrunc(y))-\>len \> SIZEOF\_VALUE/SIZEOF\_BDIGITS) {
- out\_of\_range:
- 

```
 return RBIGNUM(x)->sign ? INT2FIX(0) : INT2FIX(1);

```

- }
- shift = big2ulong(y, “long”, Qfalse);
- }
- else {
- i = NUM2LONG(y);
- if (i \< 0) return INT2FIX(0);
- shift = (VALUE)i;  
}

- shift = NUM2INT(y);
- if (shift \< 0) return INT2FIX(0);  
s1 = shift/BITSPERDIG;  
s2 = shift%BITSPERDIG;

- if (s1 \>= RBIGNUM(x)-\>len) goto out\_of\_range;  
if (!RBIGNUM(x)-\>sign) {

- if (s1 \>= RBIGNUM(x)-\>len) return INT2FIX(1);
- x = rb\_big\_clone(x);
- get2comp(x);

- xds = BDIGITS(x);
- i = 0; num = 1;
- while (num += ~xds[i], ++i \<= s1) {
- 

```
 num = BIGDN(num);

```

- }  
}  
else {

- if (s1 \>= RBIGNUM(x)-\>len) return INT2FIX(0);

- num = BDIGITS(x)[s1];  
}

- xds = BDIGITS(x);
- if (xds[s1] & (1\<\<s2))

- if (num & ((BDIGIT\_DBL)1\<\<s2))  
return INT2FIX(1);  
return INT2FIX(0);  
Index: stable/bignum.c  
===================================================================  
— stable/bignum.c (revision 12828)  
+++ stable/bignum.c (working copy)  
@@ -2152,27 +2152,37 @@ rb\_big\_aref(x, y)  
{  
BDIGIT \*xds;

- int shift;
- long s1, s2;

- BDIGIT\_DBL num;

- unsigned long shift;

- long i, s1, s2;

- if (!RBIGNUM(y)-\>sign || RBIGNUM(x)-\>sign)

- if (!RBIGNUM(y)-\>sign)  
return INT2FIX(0);

- return INT2FIX(1);

- if (RBIGNUM(bigtrunc(y))-\>len \> SIZEOF\_LONG/SIZEOF\_BDIGITS) {
- out\_of\_range:
- 

```
 return RBIGNUM(x)->sign ? INT2FIX(0) : INT2FIX(1);

```

- }
- shift = big2ulong(y, “long”, Qfalse);
- }
- else {
- i = NUM2LONG(y);
- if (i \< 0) return INT2FIX(0);
- shift = (VALUE)i;  
}

- shift = NUM2INT(y);
- if (shift \< 0) return INT2FIX(0);  
s1 = shift/BITSPERDIG;  
s2 = shift%BITSPERDIG;

- if (s1 \>= RBIGNUM(x)-\>len) goto out\_of\_range;  
if (!RBIGNUM(x)-\>sign) {

- if (s1 \>= RBIGNUM(x)-\>len) return INT2FIX(1);
- x = rb\_big\_clone(x);
- get2comp(x);

- xds = BDIGITS(x);
- i = 0; num = 1;
- while (num += ~xds[i], ++i \<= s1) {
- 

```
 num = BIGDN(num);

```

- }  
}  
else {

- if (s1 \>= RBIGNUM(x)-\>len) return INT2FIX(0);

- num = BDIGITS(x)[s1];  
}

- xds = BDIGITS(x);
- if (xds[s1] & (1\<\<s2))

- if (num & ((BDIGIT\_DBL)1\<\<s2))  
return INT2FIX(1);  
return INT2FIX(0);