Perl shift bit problem -

i have problem when try shift bit negative number perl. example:

printf("%d", (-10) >> 2); 

this method print: 1073741821

with same condition, when try javascript:

document.write('test: ' + (-10 >> 2) + '<br>'); 

the output -3

i understand different between perl , javascripts. perl have problem shifting bit negative number?

thank much.

perl uses unsigned binary right shift. if perl runs on 32-bit architecture, following:

-10 == -0xa == 0xfffffff6 0xfffffff6 >> 2 == 0x3ffffffd == 1073741821 

unsigned binary right shift means highest (rigtmost) bits of result become 0.

javascript uses sign-extending binary right shift. javascript shifts treat both input , output 32 bit integers. get:

-10 == -0xa == 0xfffffff6 -3 == -0x3 == 0xfffffffd 0xfffffff6 >> 2 == 0xfffffffd == -3 

sign-extending binary right shift means highest (rigtmost) bits of result copied highest bit of original value.

as tim henigan said in answer, it's possible sign-extending binary right shift perl, specifying use integer;. example:

{ use integer;   printf "%d 0x%x\n", (-10) >> 2, (-10) >> 2;  #: -3 0xfffffffd } printf "%d 0x%x\n", (-10) >> 2, (-10) >> 2;  #: 1073741821 0x3ffffffd