initrfft.asm

基于320VC5416的512点实数FFT源程序.内含数据.

*********************************************************************************
*       (C) COPYRIGHT TEXAS INSTRUMENTS, INC. 1996                              *
*********************************************************************************
*                                                                               *
* MODULE NAME:  initrfft.asm                                                    *
*                                                                               *
* AUTHORS:      Simon Lau and Nathan Baltz                                      *
*                                                                               *
* DESCRIPTION:  This module initilizes all of the variable, buffers, and tables *
*               used by the 'C54x Real FFT code.                                *
*                                                                               *
* DATE:         7-16-1996                                                       *
*                                                                               *
*********************************************************************************

        .include    "fft_size.inc"
        .def        fft_data, _real_fft_input,_real_fft_in, real_fft_output, sine, cosine
        .def        FFT_DP, d_grps_cnt, d_twid_idx, d_data_idx, BOS, TOS


; Set start addresses of buffers

                .data
fft_data        .space  2*K_FFT_SIZE*16       ; fft data processing buffer
_real_fft_input  .space  2*K_FFT_SIZE*16    ; real fft input buffer   
_real_fft_in  .space  2*K_FFT_SIZE*16    ; real fft input buffer   
                
                .sect   "power"
real_fft_output .space  2*K_FFT_SIZE*16     ; real fft output buffer (power)


; Copy twiddle tables

        .sect  "sin_tbl"
sine    .copy   twiddle1                        ; sine table

        .sect  "cos_tbl"
cosine  .copy   twiddle2                        ; cosine table


; Define variables for indexing input data and twiddle tables

FFT_DP      .usect  "fft_vars",0
d_grps_cnt  .usect  "fft_vars",1                ; (# groups in current stage)-1
d_twid_idx  .usect  "fft_vars",1                ; index of twiddle tables
d_data_idx  .usect  "fft_vars",1                ; index of input data table


; Set up stack

BOS     .usect  "stack",0Fh
TOS     .usect  "stack",1

        .end