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bit_clear, bit_test

 
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Wirgle
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bit_clear, bit_test
PostPosted: Tue Sep 22, 2009 5:16 am     Reply with quote
Where can i find the function definition of bit_set and bit_clear ?

O.
ckielstra



Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands

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PostPosted: Tue Sep 22, 2009 5:29 am     Reply with quote
There is no real 'function definition' for these functions, they map directly onto the machine assembly instructions 'BSF' and 'BCF'.
Wirgle
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PostPosted: Tue Sep 22, 2009 5:39 am     Reply with quote
So, if i want to make my own... What should i do?
treitmey



Joined: 23 Jan 2004
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Location: Appleton,WI USA

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PostPosted: Tue Sep 22, 2009 8:38 am     Reply with quote
This is like saying ..
I hand you a bucket of water.
And you say but I want to make my own water.
Its done for you. Why would you re-invent the wheel?


that being said..
from the help file for bit test.
Quote:
Tests the specified bit (0-7,0-15 or 0-31) in the given variable. The least significant bit is 0. This function is much more efficient than, but otherwise the same as: ((var & (1<<bit)) != 0)

you can use something similar for bit set
Code:
var |= (1<<bit);

and bit clear
Code:
var &= ~(1<<bit);


But the built in way is what you should use.
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