/usr/include/sipxtapi/mp/MpDspUtilsIntSqrt.h is in libsipxtapi-dev 3.3.0~test17-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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// Copyright (C) 2008 SIPfoundry Inc.
// Licensed by SIPfoundry under the LGPL license.
//
// Copyright (C) 2008 SIPez LLC.
// Licensed to SIPfoundry under a Contributor Agreement.
//
// $$
//////////////////////////////////////////////////////////////////////////////
// Author: Alexander Chemeris <Alexander DOT Chemeris AT SIPez DOT com>
#ifndef _MpDspUtilsIntSqrt_h_
#define _MpDspUtilsIntSqrt_h_
/**
* @file
*
* DO NOT INCLUDE THIS FILE DIRECTLY! This files is designed to be included
* to <mp/MpDspUtils.h> and should not be used outside of it.
*
* This code is taken from http://www.azillionmonkeys.com/qed/sqroot.html
* (c) Copyright 1996-2006 by Paul Hsieh
*
* Everything you ever wanted to know about square roots, but were afraid to ask.
*/
/* ============================ INLINE METHODS ============================ */
#if !defined(_WIN32) || !defined(_MSC_VER)
// Use plain C implementation.
uint32_t MpDspUtils::sqrt(uint32_t val)
{
uint32_t temp;
uint32_t g = 0;
if (val >= 0x40000000)
{
g = 0x8000;
val -= 0x40000000;
}
#define INNER_ISQRT(s) \
temp = (g << (s)) + (1 << ((s) * 2 - 2)); \
if (val >= temp) \
{ \
g += 1 << ((s)-1); \
val -= temp; \
}
INNER_ISQRT (15);
INNER_ISQRT (14);
INNER_ISQRT (13);
INNER_ISQRT (12);
INNER_ISQRT (11);
INNER_ISQRT (10);
INNER_ISQRT ( 9);
INNER_ISQRT ( 8);
INNER_ISQRT ( 7);
INNER_ISQRT ( 6);
INNER_ISQRT ( 5);
INNER_ISQRT ( 4);
INNER_ISQRT ( 3);
INNER_ISQRT ( 2);
#undef INNER_ISQRT
temp = g+g+1;
if (val >= temp)
{
g++;
}
return g;
}
#else
// Use asm-optimized version
/* by Norbert Juffa */
static inline
__declspec (naked) uint32_t __stdcall MpDspUtils_sqrt(uint32_t x) {
/* based on posting by Wilco Dijkstra in comp.sys.arm in 1996 */
/*
* For processors that provide single cycle latency
* LEA, the first four instructions of the following
* macro could be replaced as follows
* __asm lea edx, [eax+(1<<(N))]
* __asm lea ebx, [eax+(2<<(N))]
*/
#if CPU == ATHLON || CPU == ATHLON64
#define iterasm(N) \
__asm mov edx, (1 << (N)) \
__asm mov ebx, (2 << (N)) \
__asm or edx, eax \
__asm or ebx, eax \
__asm shl edx, (N) \
__asm mov esi, ecx \
__asm sub ecx, edx \
__asm cmovnc eax, ebx \
__asm cmovc ecx, esi
#else /* generic 386+ */
#define iterasm(N) \
__asm mov edx, (1 << (N)) \
__asm mov ebx, (2 << (N)) \
__asm or edx, eax \
__asm or ebx, eax \
__asm shl edx, (N) \
__asm sub ecx, edx \
__asm sbb esi, esi \
__asm sub eax, ebx \
__asm and eax, esi \
__asm add eax, ebx \
__asm and edx, esi \
__asm add ecx, edx
#endif
__asm {
mov ecx, [esp+4] ; x
push ebx ; save as per calling convention
push esi ; save as per calling convention
xor eax, eax ; 2*root
/* iteration 15 */
mov ebx, (2 << (15))
mov esi, ecx
sub ecx, (1 << (30))
cmovnc eax, ebx
cmovc ecx, esi
iterasm (14);
iterasm (13);
iterasm (12);
iterasm (11);
iterasm (10);
iterasm (9);
iterasm (8);
iterasm (7);
iterasm (6);
iterasm (5);
iterasm (4);
iterasm (3);
iterasm (2);
iterasm (1);
/* iteration 0 */
mov edx, 1
mov ebx, 2
add edx, eax
add ebx, eax
sub ecx, edx
cmovnc eax, ebx
shr eax, 1
mov esi, [esp] ; restore as per calling convention
mov ebx, [esp+4] ; restore as per calling convention
add esp, 8 ; remove temp variables
ret 4 ; pop one DWORD arg and return
}
#undef iterasm
}
uint32_t MpDspUtils::sqrt(uint32_t x)
{
return MpDspUtils_sqrt(x);
}
#endif
#endif // _MpDspUtilsIntSqrt_h_
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