Q Format

This module regroups the options used to configure the signed fixed point Q format.
This module regroups the options used to configure the signed fixed point Q format.
Here is a description of the Q-Format:
Q-format: Qa.b

• a is the number of bits used to defined the integer value.
• b is to define the number of bits used after the radix point (the fractional value).

Here is the formula linking a Q-format number (x) to a decimal number (d):

• Xn: The value of the bit number n of the Q-formatted number x.
• N: The number of bits of the Q-formatted number x.

The resolution of a Q-formatted number is calculated as follow:

The range of a Q-formatted number x defines the maximum and minimum numbers which frame x. Here is a formula to calculate those values:

• N: The number of bits of the Q-formatted number x.

Example:
For the Q1.15 type:

• Resolution: 0.00003
• Range: -1. <= range <= 0.99997

For the Q1.31 type:

• Resolution: 0.00000000047
• Range: -1. <= range <= 0.99999999953

Here is a link where you can find more information http://en.wikipedia.org/wiki/Fixed-point_arithmetic on fixed-point formats.

Q Format definition for the 16-bit type
Note The 16-bit functions are optimized to work with a Q1.15 format: Resolution: 0.00003 Range: [-1.; 0.99997]
#define	DSP16_QA   1
	number of integer bits More...
#define	DSP16_QB   15
	number of fractional bits More...

Q Format definition for the 32-bit type
Note The 32-bit functions are optimized to work with a Q1.31 format: Resolution: 0.00000000047 Range: [-1.; 0.99999999953]
#define	DSP32_QA   1
	number of integer bits More...
#define	DSP32_QB   31
	number of fractional bits More...

#define DSP16_QA   1

number of integer bits

Referenced by dsp16_debug_print(), dsp16_debug_print_complex(), dsp16_op_exp(), dsp16_op_ln(), dsp16_op_ln_raw(), dsp16_op_log10(), dsp16_op_log2(), dsp16_op_pow(), dsp16_op_rand(), dsp16_op_sqrt(), dsp16_vect_max(), dsp16_vect_min(), dsp32_op_rand(), and print().

#define DSP16_QB   15

number of fractional bits

Referenced by dsp16_op_asin(), dsp16_op_div(), dsp16_op_exp(), dsp16_op_kernel_cosfix(), dsp16_op_kernel_sinfix(), dsp16_op_ln(), dsp16_op_ln_raw(), dsp16_op_log10(), dsp16_op_log2(), dsp16_op_mul(), dsp16_op_pow(), dsp16_op_sin(), dsp16_op_sqrt(), dsp16_vect_dotdiv_kernel_ext(), dsp16_vect_dotmul_kernel_ext(), dsp16_vect_max(), dsp16_vect_min(), dsp16_vect_realdiv_kernel_ext(), and dsp16_vect_realmul_kernel_ext().

#define DSP32_QA   1

number of integer bits

Referenced by dsp32_debug_print(), dsp32_debug_print_complex(), dsp32_op_exp(), dsp32_op_ln(), dsp32_op_ln_raw(), dsp32_op_log10(), dsp32_op_log2(), dsp32_op_pow(), dsp32_op_rand(), dsp32_vect_max(), dsp32_vect_min(), and print().

#define DSP32_QB   31

number of fractional bits

Referenced by dsp32_op_asin(), dsp32_op_div(), dsp32_op_exp(), dsp32_op_kernel_cosfix(), dsp32_op_kernel_sinfix(), dsp32_op_ln(), dsp32_op_ln_raw(), dsp32_op_log10(), dsp32_op_log2(), dsp32_op_mul(), dsp32_op_pow(), dsp32_op_sin(), dsp32_op_sqrt(), dsp32_trans_realcomplexfft(), dsp32_vect_dotdiv(), dsp32_vect_dotmul(), dsp32_vect_max(), dsp32_vect_min(), dsp32_vect_realdiv(), and dsp32_vect_realmul_kernel_ext().