Bit Functions
GPC allows you to manipulate the bits of a given variable. Bit operations are quite complicated, however, there is not really much call for them in the GPC environment and most users will never need them. Therefore, this section will assume you have an understanding of bits, bit masks, and how they correlate with bytes and the binary system.
Function
Description
set_bit
Sets one bit.
clear_bit
Clears one bit.
test_bit
Tests a bit.
set_bits
Stores a value into a bit index.
get_bits
Gets a value from the bit index.
set_bit
set_bit sets one bit of a variable based on its bit index
Code-Snippet
set_bit(a,5);Syntax
set_bit( <variable>, <bit_index> );
Parameters
<variable> : the variable to modify
<bit_index> : index of the bit to be set with a range of 0 to 15 (16-bit firmware) or 0 to 31 (32-bit firmware).
Returns
None
clear_bit
clear_bit clears one bit of a variable based on its bit index
Code-Snippet
Syntax
clear_bit( <variable> , <bit_index> );
Parameters
<variable> : the variable to modify
<bit_index> : index of the bit to be set with a range of 0 to 15 (16-bit firmware) or 0 to 31 (32-bit firmware).
Returns
Nothing
test_bit
test_bit tests a bit index point in a value to check if it is set or not (TRUE or FALSE.
Code-Snippet
Syntax
test_bit( <value> , <bit_index> );
Parameters
<value> : the value to check
<bit_index> : index of the bit to be set with a range of 0 to 15 (16-bit firmware) or 0 to 31 (32-bit firmware).
Returns
TRUE if the bit is set, FALSE if it is not.
set_bits
set_bits stores a value into a variable based on its bit index and bit mask.
Code-Snippet
Syntax
set_bits( <variable> , <value>, <bit_index>, <bit_mask> );
Parameters
<variable> : the variable to modify
<value> : the value to insert into the variable
<bit_index> : the starting index of the bits to be set with a range of 0 to 15 (16-bit firmware) or 0 to 31 (32-bit firmware).
<bit_mask> : bit mask to use when inserting the value
Returns
Nothing
get_bits
get_bits extracts a value from another value based on a bit index and bit mask
Code-Snippet
Syntax
get_bits( <value> , <bit_index>, <bit_mask> );
Parameters
<value> : the value to extract the value from
<bit_index> : the starting index of the bits to read with a range of 0 to 15 (16-bit firmware) or 0 to 31 (32-bit firmware).
<bit_mask> : bit mask to use with the final value
Returns
The value shifted into the low bits from the variable used
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