/* ======================================================================== */
/* TEXAS INSTRUMENTS, INC. */
/* */
/* DSPLIB DSP Signal Processing Library */
/* */
/* Release: Version 1.02 */
/* CVS Revision: 1.8 Fri Mar 29 20:22:54 2002 (UTC) */
/* Snapshot date: 18-Apr-2002 */
/* */
/* 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) 2002 Texas Instruments, Incorporated. */
/* All Rights Reserved. */
/* ======================================================================== */
/* ======================================================================== */
/* NAME */
/* DSP_bexp -- Block exponent of a vector */
/* */
/* REVISION DATE */
/* 28-Jan-2002 */
/* */
/* USAGE */
/* This routine has the following C prototype: */
/* */
/* int DSP_bexp */
/* ( */
/* const int *x, // Input Data // */
/* unsigned nx // Number of elements // */
/* ); */
/* */
/* The DSP_bexp routine accepts a list of 'num' input points and */
/* performs the determination of the block exponent. It returns */
/* the minimum number of "redundant sign bits" observed on the */
/* block of data. */
/* */
/* DESCRIPTION */
/* The DSP_bexp function, performs a determination of the block */
/* exponent of the vector of elements and returns the maximum */
/* exponent. This information can then be used to re-normalize */
/* the vector. This operation is useful when auto-scaling is */
/* required as in a FFT. The DSP_bexp operation returns the */
/* minimum norm of the vector. The minimum norm corresponds to */
/* the maximum exponent. */
/* */
/* C CODE */
/* The following is a general C code description of the algorithm */
/* without restrictions. This implementation may have restrictions */
/* as noted under 'ASSUMPTIONS' below. */
/* */
/* int DSP_bexp(const int *x, short nx) */
/* { */
/* int i; */
/* int mask, mag; */
/* */
/* mask = 0; */
/* */
/* // ---------------------------------------------------- // */
/* // Merge the absolute values of all the elements // */
/* // together. The leftmost bit-change on this mask // */
/* // gives us the magnitude we desire. // */
/* // ---------------------------------------------------- // */
/* for (i = 0; i < nx; i++) */
/* mask |= x[i] ^ (x[i] >> 31); */
/* */
/* // ---------------------------------------------------- // */
/* // Find the magnitude of the mask. // */
/* // ---------------------------------------------------- // */
/* for (mag = 0; (1 << mag) < mask; mag++) */
/* ; */
/* */
/* return 31 - mag; */
/* } */
/* */
/* ASSUMPTIONS */
/* nx >= 6. */
/* nx % 2 == 0. */
/* */
/* NOTES */
/* This code is interrupt tolerant, but not interruptible. It masks */
/* interrupts for its entire duration with branch delay slots. */
/* */
/* This code is ENDIAN NEUTRAL. */
/* */
/* SOURCE */
/* DSPLIB. */
/* */
/* CYCLES */
/* cycles = nx + 17, including 6 cycle function call overhead. */
/* For nx = 32, cycles = 49. */
/* */
/* CODESIZE */
/* 128 bytes. */
/* ------------------------------------------------------------------------ */
/* Copyright (c) 2002 Texas Instruments, Incorporated. */
/* All Rights Reserved. */
/* ======================================================================== */
#ifndef DSP_BEXP_H_
#define DSP_BEXP_H_ 1
int DSP_bexp
(
const int *x, /* Input Data */
unsigned nx /* Number of elements */
);
#endif
/* ======================================================================== */
/* End of file: dsp_bexp.h */
/* ------------------------------------------------------------------------ */
/* Copyright (c) 2002 Texas Instruments, Incorporated. */
/* All Rights Reserved. */
/* ======================================================================== */