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/*
Function Name: getTanh
Description: This function takes one input array and generates getTanh result for each elements.
*/
void getTanh(int A[1000], int atanh[12], int sinh[5], int cosh[5]){
int i;
// the result is positive or negative
int is_neg;
// Input angle
int beta;
// Output of the hyperbolic CORDIC block
int outputcosh, outputsinh;
// Result of tanh, sinh and cosh
int result;
// Token for the repetition of the 4th iteration
//char token4 = 0;
// Approximation of cosh(beta) and sinh(beta)
int x = 0x1351;
int y = 0;
int x_new;
int j, k;
int index_trigo;
int result_cosh, result_sinh;
for (i = 0; i < 1000; i++){
beta = A[i];
// Implement approximate range of the hyperbolic CORDIC block
if (beta >= 20480) {
result = 4096; // Saturation effect
} else {
if (beta >= 16384) {
index_trigo = 4;
} else if (beta >= 12288) {
index_trigo = 3;
} else if (beta >= 8192) {
index_trigo = 2;
} else if (beta >= 4096) {
index_trigo = 1;
} else {
index_trigo = 0;
}
beta = beta - index_trigo * 4096;
// Call to the hyperbolic CORDIC block
x = 0x1351;
y = 0;
fp_hyp_cordic:
for (k = 1; k <= 12; k++) {
// force the 3k+1 th iteration to be repeated
if (((k%3)==1) &&( k!=1 )){
for (j=1;j<=2;j++){
// beta<0 anti-clockwise rotation
if (beta < 0) {
x_new = x - (y >> k);
y -= x >> k;
beta += atanh[k - 1];
}
// beta>0 clockwise rotation
else {
x_new = x + (y >> k);
y += (x >> k);
beta -= atanh[k - 1];
}
x = x_new;
}
}
else {
if (beta < 0) {
x_new = x - (y >> k);
y -= x >> k;
beta += atanh[k - 1];
}
// beta>0 clockwise rotation
else {
x_new = x + (y >> k);
y += (x >> k);
beta -= atanh[k - 1];
}
x = x_new;
}
}
outputcosh = x;
outputsinh = y;
// Trigonometric rules application
result_cosh = (sinh[index_trigo] * outputcosh + cosh[index_trigo] * outputsinh);
result_sinh = (cosh[index_trigo] * outputcosh + sinh[index_trigo] * outputsinh) >> 12;
result = result_cosh / result_sinh;
}
A[i] = result;
}
}
int main(){
int atanh[12] = { 0x08C9, 0x0416, 0x0202, 0x0100, 0x0080, 0x0064, 0x0032, 0x0010, 0x0008, 0x0004, 0x0002, 0x0001 };
int cosh[5] = { 0x1000, 0x18B0, 0x3C31, 0xA115, 0x1B4EE};
int sinh[5] = { 0x0, 0x12CD, 0x3A07, 0xA049, 0x1B4A3};
int A[1000];
for (int i = 0; i < 1000; i++)
A[i] = i; // here you can change your input data as you wish.
getTanh(A, atanh, sinh, cosh);
}
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