Masking a bit in C returning unexpected result

Posted by Eamorr on Stack Overflow See other posts from Stack Overflow or by Eamorr
Published on 2011-01-14T19:43:03Z Indexed on 2011/01/14 19:53 UTC
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c

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bit-manipulation

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mask

0x7F000000 is 0111 1111 0000 0000 0000 0000 0000 0000 in 32 bit binary.
0x01000058 is 0000 0001 0000 0000 0000 0000 0101 1000.

When I AND the two numbers together I expect 0000 0001 0000 0000 0000 0000 0000 0000, but for some reason I get 0.

Here is my code:

#define MASK_binop     0x80000000
#define MASK_operation 0x7F000000

int instruction=atoi(line);
if((MASK_binop & instruction)>0)
    printf("binop\n");
else if((MASK_operation & instruction)>0)
    printf("operation\n");

Each of the above comparisons keeps returning zero. Is it something to do with 32/64 bits? I'm using 64-bit compiler.

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Masking a bit in C returning unexpected result - Developer IT

Masking a bit in C returning unexpected result

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bit-manipulation

mask

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