#include "wlc_phy_qmath.h"
/*
-Description: This function saturate input 32 bit number into a 16 bit number.
-If input number is greater than 0x7fff then output is saturated to 0x7fff.
-else if input number is less than 0xffff8000 then output is saturated to 0xffff8000
-else output is same as input.
-*/
-s16 qm_sat32(s32 op)
-{
- s16 result;
- if (op > (s32) 0x7fff) {
- result = 0x7fff;
- } else if (op < (s32) 0xffff8000) {
- result = (s16) (0x8000);
- } else {
- result = (s16) op;
- }
- return result;
-}
-
-/*
-Description: This function multiply two input 16 bit numbers and return the 32 bit result.
-This multiplication is similar to compiler multiplication. This operation is defined if
-16 bit multiplication on the processor platform is cheaper than 32 bit multiplication (as
-the most of qmath functions can be replaced with processor intrinsic instructions).
-*/
-s32 qm_mul321616(s16 op1, s16 op2)
-{
- return (s32) (op1) * (s32) (op2);
-}
-
-/*
-Description: This function make 16 bit multiplication and return the result in 16 bits.
-To fit the result into 16 bits the 32 bit multiplication result is right
-shifted by 16 bits.
-*/
-s16 qm_mul16(s16 op1, s16 op2)
-{
- s32 result;
- result = ((s32) (op1) * (s32) (op2));
- return (s16) (result >> 16);
-}
-
-/*
-Description: This function multiply two 16 bit numbers and return the result in 32 bits.
-This function remove the extra sign bit created by the multiplication by leftshifting the
-32 bit multiplication result by 1 bit before returning the result. So the output is
-twice that of compiler multiplication. (i.e. qm_muls321616(2,3)=12).
-When both input 16 bit numbers are 0x8000, then the result is saturated to 0x7fffffff.
-*/
-s32 qm_muls321616(s16 op1, s16 op2)
-{
- s32 result;
- if (op1 == (s16) (0x8000) && op2 == (s16) (0x8000)) {
- result = 0x7fffffff;
- } else {
- result = ((s32) (op1) * (s32) (op2));
- result = result << 1;
- }
- return result;
-}
-
-/*
Description: This function make 16 bit unsigned multiplication. To fit the output into
16 bits the 32 bit multiplication result is right shifted by 16 bits.
*/
}
/*
-Description: This function make 32 bit subtraction and return the 32bit result.
-If the result overflow 32 bits, the output will be saturated to 32bits.
-*/
-s32 qm_sub32(s32 op1, s32 op2)
-{
- s32 result;
- result = op1 - op2;
- if (op1 >= 0 && op2 < 0 && result < 0) {
- result = 0x7fffffff;
- } else if (op1 < 0 && op2 > 0 && result > 0) {
- result = 0x80000000;
- }
- return result;
-}
-
-/*
-Description: This function multiply input 16 bit numbers and accumulate the result
-into the input 32 bit number and return the 32 bit accumulated result.
-If the accumulation result in overflow, then the output will be saturated.
-*/
-s32 qm_mac321616(s32 acc, s16 op1, s16 op2)
-{
- s32 result;
- result = qm_add32(acc, qm_mul321616(op1, op2));
- return result;
-}
-
-/*
Description: This function make a 32 bit saturated left shift when the specified shift
is +ve. This function will make a 32 bit right shift when the specified shift is -ve.
This function return the result after shifting operation.
}
/*
-Description: This function make a 32 bit right shift when shift is +ve.
-This function make a 32 bit saturated left shift when shift is -ve. This function
-return the result of the shift operation.
-*/
-s32 qm_shr32(s32 op, int shift)
-{
- return qm_shl32(op, -shift);
-}
-
-/*
Description: This function make a 16 bit saturated left shift when the specified shift
is +ve. This function will make a 16 bit right shift when the specified shift is -ve.
This function return the result after shifting operation.
}
/*
-Description: This function return the number of redundant sign bits in a 16 bit number.
-Example: qm_norm16(0x0080) = 7.
-*/
-s16 qm_norm16(s16 op)
-{
- u16 u16extraSignBits;
- if (op == 0) {
- return 15;
- } else {
- u16extraSignBits = 0;
- while ((op >> 15) == (op >> 14)) {
- u16extraSignBits++;
- op = op << 1;
- }
- }
- return u16extraSignBits;
-}
-
-/*
Description: This function return the number of redundant sign bits in a 32 bit number.
Example: qm_norm32(0x00000080) = 23
*/
return u16extraSignBits;
}
-/*
-Description: This function divide two 16 bit unsigned numbers.
-The numerator should be less than denominator. So the quotient is always less than 1.
-This function return the quotient in q.15 format.
-*/
-s16 qm_div_s(s16 num, s16 denom)
-{
- s16 var_out;
- s16 iteration;
- s32 L_num;
- s32 L_denom;
- L_num = (num) << 15;
- L_denom = (denom) << 15;
- for (iteration = 0; iteration < 15; iteration++) {
- L_num <<= 1;
- if (L_num >= L_denom) {
- L_num = qm_sub32(L_num, L_denom);
- L_num = qm_add32(L_num, 1);
- }
- }
- var_out = (s16) (L_num & 0x7fff);
- return var_out;
-}
-
-/*
-Description: This function compute the absolute value of a 16 bit number.
-*/
-s16 qm_abs16(s16 op)
-{
- if (op < 0) {
- if (op == (s16) 0xffff8000) {
- return 0x7fff;
- } else {
- return -op;
- }
- } else {
- return op;
- }
-}
-
-/*
-Description: This function divide two 16 bit numbers.
-The quotient is returned through return value.
-The qformat of the quotient is returned through the pointer (qQuotient) passed
-to this function. The qformat of quotient is adjusted appropriately such that
-the quotient occupies all 16 bits.
-*/
-s16 qm_div16(s16 num, s16 denom, s16 *qQuotient)
-{
- s16 sign;
- s16 nNum, nDenom;
- sign = num ^ denom;
- num = qm_abs16(num);
- denom = qm_abs16(denom);
- nNum = qm_norm16(num);
- nDenom = qm_norm16(denom);
- num = qm_shl16(num, nNum - 1);
- denom = qm_shl16(denom, nDenom);
- *qQuotient = nNum - 1 - nDenom + 15;
- if (sign >= 0) {
- return qm_div_s(num, denom);
- } else {
- return -qm_div_s(num, denom);
- }
-}
-
-/*
-Description: This function compute absolute value of a 32 bit number.
-*/
-s32 qm_abs32(s32 op)
-{
- if (op < 0) {
- if (op == (s32) 0x80000000) {
- return 0x7fffffff;
- } else {
- return -op;
- }
- } else {
- return op;
- }
-}
-
-/*
-Description: This function divide two 32 bit numbers. The division is performed
-by considering only important 16 bits in 32 bit numbers.
-The quotient is returned through return value.
-The qformat of the quotient is returned through the pointer (qquotient) passed
-to this function. The qformat of quotient is adjusted appropriately such that
-the quotient occupies all 16 bits.
-*/
-s16 qm_div163232(s32 num, s32 denom, s16 *qquotient)
-{
- s32 sign;
- s16 nNum, nDenom;
- sign = num ^ denom;
- num = qm_abs32(num);
- denom = qm_abs32(denom);
- nNum = qm_norm32(num);
- nDenom = qm_norm32(denom);
- num = qm_shl32(num, nNum - 1);
- denom = qm_shl32(denom, nDenom);
- *qquotient = nNum - 1 - nDenom + 15;
- if (sign >= 0) {
- return qm_div_s((s16) (num >> 16), (s16) (denom >> 16));
- } else {
- return -qm_div_s((s16) (num >> 16), (s16) (denom >> 16));
- }
-}
-
-/*
-Description: This function multiply a 32 bit number with a 16 bit number.
-The multiplicaton result is right shifted by 16 bits to fit the result
-into 32 bit output.
-*/
-s32 qm_mul323216(s32 op1, s16 op2)
-{
- s16 hi;
- u16 lo;
- s32 result;
- hi = op1 >> 16;
- lo = (s16) (op1 & 0xffff);
- result = qm_mul321616(hi, op2);
- result = result + (qm_mulsu321616(op2, lo) >> 16);
- return result;
-}
-
-/*
-Description: This function multiply signed 16 bit number with unsigned 16 bit number and return
-the result in 32 bits.
-*/
-s32 qm_mulsu321616(s16 op1, u16 op2)
-{
- return (s32) (op1) * op2;
-}
-
-/*
-Description: This function multiply 32 bit number with 16 bit number. The multiplication result is
-right shifted by 15 bits to fit the result into 32 bits. Right shifting by only 15 bits instead of
-16 bits is done to remove the extra sign bit formed by multiplication from the return value.
-When the input numbers are 0x80000000, 0x8000 the return value is saturated to 0x7fffffff.
-*/
-s32 qm_muls323216(s32 op1, s16 op2)
-{
- s16 hi;
- u16 lo;
- s32 result;
- hi = op1 >> 16;
- lo = (s16) (op1 & 0xffff);
- result = qm_muls321616(hi, op2);
- result = qm_add32(result, (qm_mulsu321616(op2, lo) >> 15));
- return result;
-}
-
-/*
-Description: This function multiply two 32 bit numbers. The multiplication result is right
-shifted by 32 bits to fit the multiplication result into 32 bits. The right shifted
-multiplication result is returned as output.
-*/
-s32 qm_mul32(s32 a, s32 b)
-{
- s16 hi1, hi2;
- u16 lo1, lo2;
- s32 result;
- hi1 = a >> 16;
- hi2 = b >> 16;
- lo1 = (u16) (a & 0xffff);
- lo2 = (u16) (b & 0xffff);
- result = qm_mul321616(hi1, hi2);
- result = result + (qm_mulsu321616(hi1, lo2) >> 16);
- result = result + (qm_mulsu321616(hi2, lo1) >> 16);
- return result;
-}
-
-/*
-Description: This function multiply two 32 bit numbers. The multiplication result is
-right shifted by 31 bits to fit the multiplication result into 32 bits. The right
-shifted multiplication result is returned as output. Right shifting by only 31 bits
-instead of 32 bits is done to remove the extra sign bit formed by multiplication.
-When the input numbers are 0x80000000, 0x80000000 the return value is saturated to
-0x7fffffff.
-*/
-s32 qm_muls32(s32 a, s32 b)
-{
- s16 hi1, hi2;
- u16 lo1, lo2;
- s32 result;
- hi1 = a >> 16;
- hi2 = b >> 16;
- lo1 = (u16) (a & 0xffff);
- lo2 = (u16) (b & 0xffff);
- result = qm_muls321616(hi1, hi2);
- result = qm_add32(result, (qm_mulsu321616(hi1, lo2) >> 15));
- result = qm_add32(result, (qm_mulsu321616(hi2, lo1) >> 15));
- result = qm_add32(result, (qm_mulu16(lo1, lo2) >> 15));
- return result;
-}
-
/* This table is log2(1+(i/32)) where i=[0:1:31], in q.15 format */
static const s16 log_table[] = {
0,
return;
}
-
-/*
-Description:
-This routine compute 1/N.
-This routine reformates the given no N as N * 2^qN where N is in between 0.5 and 1.0
-in q.15 format in 16 bits. So the problem now boils down to finding the inverse of a
-q.15 no in 16 bits which is in the range of 0.5 to 1.0. The output is always between
-2.0 to 1. So the output is 2.0 to 1.0 in q.30 format. Once the final output format is found
-by taking the qN into account. Inverse is found with newton rapson method. Initially
-inverse (x) is guessed as 1/0.75 (with appropriate sign). The new guess is calculated
-using the formula x' = 2*x - N*x*x. After 4 or 5 iterations the inverse is very close to
-inverse of N.
-Inputs:
-N - number to which 1/N has to be found.
-qn - q format of N.
-sqrtN - address where 1/N has to be written.
-qsqrtN - address where q format of 1/N has to be written.
-*/
-#define qx 29
-void qm_1byN(s32 N, s16 qN, s32 *result, s16 *qResult)
-{
- s16 normN;
- s32 s32firstTerm, s32secondTerm, x;
- int i;
-
- normN = qm_norm32(N);
-
- /* limit N to least significant 16 bits. 15th bit is the sign bit. */
- N = qm_shl32(N, normN - 16);
- qN = qN + normN - 16 - 15;
- /* -15 is added to treat N as 16 bit q.15 number in the range from 0.5 to 1 */
-
- /* Take the initial guess as 1/0.75 in qx format with appropriate sign. */
- if (N >= 0) {
- x = (s32) ((1 / 0.75) * (1 << qx));
- /* input no is in the range 0.5 to 1. So 1/0.75 is taken as initial guess. */
- } else {
- x = (s32) ((1 / -0.75) * (1 << qx));
- /* input no is in the range -0.5 to -1. So 1/-0.75 is taken as initial guess. */
- }
-
- /* iterate the equation x = 2*x - N*x*x for 4 times. */
- for (i = 0; i < 4; i++) {
- s32firstTerm = qm_shl32(x, 1); /* s32firstTerm = 2*x in q.29 */
- s32secondTerm =
- qm_muls321616((s16) (s32firstTerm >> 16),
- (s16) (s32firstTerm >> 16));
- /* s32secondTerm = x*x in q.(29+1-16)*2+1 */
- s32secondTerm =
- qm_muls321616((s16) (s32secondTerm >> 16), (s16) N);
- /* s32secondTerm = N*x*x in q.((29+1-16)*2+1)-16+15+1 i.e. in q.29 */
- x = qm_sub32(s32firstTerm, s32secondTerm);
- /* can be added directly as both are in q.29 */
- }
-
- /* Bring the x to q.30 format. */
- *result = qm_shl32(x, 1);
- /* giving the output in q.30 format for q.15 input in 16 bits. */
-
- /* compute the final q format of the result. */
- *qResult = -qN + 30; /* adjusting the q format of actual output */
-
- return;
-}
-
-#undef qx