/*******************************************************************************
Vendor: Xilinx 
Associated Filename: hamming_window.c
Purpose: Vivado HLS tutorial example 
Revision History: March 1, 2013 - initial release
                                                
*******************************************************************************
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#include "hamming_window.h" // Provides default WINDOW_LEN if not user defined

// Translation module function prototypes:
static void hamming_rom_init(in_data_t rom_array[]);

// Function definitions:
void hamming_window(out_data_t outdata[WINDOW_LEN], in_data_t indata[WINDOW_LEN])
{
   static in_data_t window_coeff[WINDOW_LEN];
   unsigned i;

   // In order to ensure that 'window_coeff' is inferred and properly
   // initialized as a ROM, it is recommended that the arrya initialization
   // be done in a sub-function with global (wrt this source file) scope.
   hamming_rom_init(window_coeff);

   for (i = 0; i < WINDOW_LEN; i++) {
#pragma AP pipeline
      outdata[i] = (out_data_t)window_coeff[i] * (out_data_t)indata[i];
   }
}

// This initialization function will be optimized away during high level
// sythesis (HLS), resulting in the underlying memory being inferred as a ROM
// by RTL synthesis.
static void hamming_rom_init(in_data_t rom_array[WINDOW_LEN])
{
   int i;
   for (i = 0; i < WINDOW_LEN; i++) {
      float real_val = 0.54f -
         0.46f * cos(2.0f * M_PI * i / (float)(WINDOW_LEN - 1));
      rom_array[i] = (in_data_t)(WIN_COEFF_SCALE * real_val);
   }
}

