IQmath Library

atoIQN
String to IQN
Description
Declaration
This function converts a string to IQ number.
Global IQ function (IQ format = GLOBAL_Q)
float _atoIQ( char *S)
Q format specific IQ function (IQ format = IQ1 to IQ30)
float _atoIQN( char *S)
Input
This function recognizes (in order) an optional sign, a string of digits
optionally containing a radix character.
Valid Input strings:
“12.23456”, “-12.23456”, “0.2345”, “0.0” , “0” , “127” , “-89”
Output
The first unrecognized character ends the string and returns zero. If the
input string converts to a number greater then the max/min values for the
given Q value, then the returned value will be limited to the min/max
values
Global IQ function (IQ format = GLOBAL_Q)
Fixed point equivalent of input string in GLOBAL_Q format
Q format specific IQ function (IQ format = IQ1 to IQ29)
Fixed point equivalent of input string in IQN format
Usage
This is useful for programs that need to process user input or ASCII
strings.
Example:
The following code prompts the user to enter the value X:
char buffer[N];
_iq X;
printf("Enter value X = ");
gets(buffer);
X = _atoIQ(buffer);
// IQ value (GLOBAL_Q)
©Texas Instruments Inc., June 2002 16