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/*
* $Id$
*
* Copyright © 2004 Keith Packard
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name of Keith Packard not be used in
* advertising or publicity pertaining to distribution of the software without
* specific, written prior permission. Keith Packard makes no
* representations about the suitability of this software for any purpose. It
* is provided "as is" without express or implied warranty.
*
* KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
#include "twinint.h"
#if 0
#include <stdio.h>
#define F(f) twin_fixed_to_double(f)
#define DBGMSG(x) printf x
#else
#define DBGMSG(x)
#endif
#define uint32_lo(i) ((i) & 0xffff)
#define uint32_hi(i) ((i) >> 16)
#define uint32_carry16 ((1) << 16)
#if 0
twin_fixed_t
twin_fixed_mul (twin_fixed_t af, twin_fixed_t bf)
{
uint32_t a;
uint32_t b;
uint16_t ah, al, bh, bl;
uint32_t r0, r1, r2, r3;
uint32_t hi, lo;
twin_fixed_t r;
twin_bool_t negative = TWIN_FALSE;
a = (uint32_t) af;
b = (uint32_t) bf;
if (af < 0)
{
negative = !negative;
a = -a;
}
if (bf < 0)
{
negative = !negative;
b = -b;
}
al = uint32_lo (a);
ah = uint32_hi (a);
bl = uint32_lo (b);
bh = uint32_hi (b);
r0 = (uint32_t) al * bl;
r1 = (uint32_t) al * bh;
r2 = (uint32_t) ah * bl;
r3 = (uint32_t) ah * bh;
r1 += uint32_hi(r0); /* no carry possible */
r1 += r2; /* but this can carry */
if (r1 < r2) /* check */
r3 += uint32_carry16;
hi = r3 + uint32_hi(r1);
lo = (uint32_lo (r1) << 16) + uint32_lo (r0);
DBGMSG (("0x%x * 0x%x = 0x%x%08x\n", a, b, hi, lo));
r = (twin_fixed_t) ((hi << 16) | (lo >> 16));
if (negative)
r = -r;
DBGMSG (("%9.4f * %9.4f = %9.4f\n",
twin_fixed_to_double(af), twin_fixed_to_double(bf),
twin_fixed_to_double (r)));
return r;
}
#endif
#if 0
twin_fixed_t
twin_fixed_div (twin_fixed_t a, twin_fixed_t b)
{
twin_fixed_t q;
q = (twin_fixed_t) ((((int64_t) a) << 16) / b);
return q;
}
#endif
twin_fixed_t
twin_fixed_sqrt (twin_fixed_t a)
{
twin_fixed_t max, min, mid;
twin_fixed_t sqr;
max = a;
min = 0;
while (max > min)
{
mid = (max + min) >> 1;
sqr = twin_fixed_mul (mid, mid);
if (sqr == a)
return mid;
if (sqr < a)
min = mid + 1;
else
max = mid - 1;
}
return (max + min) >> 1;
}
twin_sfixed_t
_twin_sfixed_sqrt (twin_sfixed_t as)
{
twin_dfixed_t max = as, min = 0, mid;
twin_dfixed_t a = twin_sfixed_to_dfixed (as);
twin_dfixed_t sqr;
while (max > min)
{
mid = (max + min) >> 1;
sqr = mid * mid;
if (sqr == a)
return (twin_sfixed_t) mid;
if (sqr < a)
min = mid + 1;
else
max = mid - 1;
}
return (twin_sfixed_t) ((max + min) >> 1);
}
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