You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
120 lines
9.0 KiB
120 lines
9.0 KiB
;* ======================================================================== *;
|
|
;* TEXAS INSTRUMENTS, INC. *;
|
|
;* *;
|
|
;* DSPLIB DSP Signal Processing Library *;
|
|
;* *;
|
|
;* Release: Revision 1.04b *;
|
|
;* CVS Revision: 1.12 Fri Nov 1 19:10:29 2002 (UTC) *;
|
|
;* Snapshot date: 23-Oct-2003 *;
|
|
;* *;
|
|
;* This library contains proprietary intellectual property of Texas *;
|
|
;* Instruments, Inc. The library and its source code are protected by *;
|
|
;* various copyrights, and portions may also be protected by patents or *;
|
|
;* other legal protections. *;
|
|
;* *;
|
|
;* This software is licensed for use with Texas Instruments TMS320 *;
|
|
;* family DSPs. This license was provided to you prior to installing *;
|
|
;* the software. You may review this license by consulting the file *;
|
|
;* TI_license.PDF which accompanies the files in this library. *;
|
|
;* ------------------------------------------------------------------------ *;
|
|
;* Copyright (C) 2003 Texas Instruments, Incorporated. *;
|
|
;* All Rights Reserved. *;
|
|
;* ======================================================================== *;
|
|
;* ======================================================================== *;
|
|
;* Assembler compatibility shim for assembling 4.30 and later code on *;
|
|
;* tools prior to 4.30. *;
|
|
;* ======================================================================== *;
|
|
;* ======================================================================== *;
|
|
;* End of assembler compatibility shim. *;
|
|
;* ======================================================================== *;
|
|
* ========================================================================= *
|
|
* NAME *
|
|
* DSP_autocor -- Autocorrelation *
|
|
* *
|
|
* REVISION DATE *
|
|
* 21-Jan-2002 *
|
|
* *
|
|
* USAGE *
|
|
* This routine has the following C prototype: *
|
|
* *
|
|
* void DSP_autocor *
|
|
* ( *
|
|
* short *restrict r, *
|
|
* const short *restrict x, *
|
|
* int nx, *
|
|
* int nr *
|
|
* ); *
|
|
* *
|
|
* r[nr] : Output array *
|
|
* x[nr+nx]: Input array. The first nr elements are assumed to be 0. *
|
|
* Must be double-word aligned. *
|
|
* nx : Length of autocorrelation *
|
|
* Must be a multiple of 8. *
|
|
* nr : Number of lags *
|
|
* Must be a multiple of 4. *
|
|
* *
|
|
* DESCRIPTION *
|
|
* This routine performs an autocorrelation of an input vector *
|
|
* x. The length of the autocorrelation is nx samples. Since nr *
|
|
* such autocorrelations are performed, input vector x needs to be *
|
|
* of length nx + nr. This produces nr output results which are *
|
|
* stored in an output array r. *
|
|
* *
|
|
* The following diagram illustrates how the correlations are *
|
|
* obtained. *
|
|
* *
|
|
* Example for nr=8, nx=24: *
|
|
* 0 nr nx+nr-1 *
|
|
* |-------|----------------------| <- x[] *
|
|
* | |----------------------| -> r[0] *
|
|
* | |----------------------| -> r[1] *
|
|
* | |----------------------| -> r[2] *
|
|
* | |----------------------| -> r[3] *
|
|
* | |----------------------| -> r[4] *
|
|
* | |----------------------| -> r[5] *
|
|
* | |----------------------| -> r[6] *
|
|
* *
|
|
* Note that x[0] is never used, but is required for padding to make *
|
|
* x[nr] double-word aligned. *
|
|
* *
|
|
* TECHNIQUES *
|
|
* Loop coalescing is implemented and both loops are colesced *
|
|
* together. Separate copies of inner loop counter are made to *
|
|
* de-couple input loads and output stores. Double word wide loads *
|
|
* are used on the input data array. *
|
|
* *
|
|
* ASSUMPTIONS *
|
|
* The first nr elements are assumed to be 0. *
|
|
* nx is a multiple of 8 *
|
|
* nr is a multiple of 4 *
|
|
* x[] is double-word aligned *
|
|
* No alignment restrictions on r[] *
|
|
* *
|
|
* MEMORY NOTE *
|
|
* No memory bank hits under any conditions. *
|
|
* This code is a LITTLE ENDIAN implementation. *
|
|
* *
|
|
* NOTES *
|
|
* This code is interrupt tolerant but not interuptible *
|
|
* *
|
|
* CYCLES *
|
|
* nx*nr/4 + 19 *
|
|
* *
|
|
* e.g. nx=160, nr=32, cycles=1299 *
|
|
* *
|
|
* CODESIZE *
|
|
* 508 bytes *
|
|
* *
|
|
* ------------------------------------------------------------------------- *
|
|
* Copyright (c) 2003 Texas Instruments, Incorporated. *
|
|
* All Rights Reserved. *
|
|
* ========================================================================= *
|
|
|
|
.global _DSP_autocor
|
|
|
|
* ========================================================================= *
|
|
* End of file: dsp_autocor.h64 *
|
|
* ------------------------------------------------------------------------- *
|
|
* Copyright (c) 2003 Texas Instruments, Incorporated. *
|
|
* All Rights Reserved. *
|
|
* ========================================================================= *
|
|
|