106 lines
4.1 KiB
C++
Executable File
106 lines
4.1 KiB
C++
Executable File
/*============================================================================
|
|
This source file is an extension to the SoftFloat IEC/IEEE Floating-point
|
|
Arithmetic Package, Release 2b, written for Bochs (x86 achitecture simulator)
|
|
floating point emulation.
|
|
|
|
THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort has
|
|
been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT TIMES
|
|
RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO PERSONS
|
|
AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ALL LOSSES,
|
|
COSTS, OR OTHER PROBLEMS THEY INCUR DUE TO THE SOFTWARE, AND WHO FURTHERMORE
|
|
EFFECTIVELY INDEMNIFY JOHN HAUSER AND THE INTERNATIONAL COMPUTER SCIENCE
|
|
INSTITUTE (possibly via similar legal warning) AGAINST ALL LOSSES, COSTS, OR
|
|
OTHER PROBLEMS INCURRED BY THEIR CUSTOMERS AND CLIENTS DUE TO THE SOFTWARE.
|
|
|
|
Derivative works are acceptable, even for commercial purposes, so long as
|
|
(1) the source code for the derivative work includes prominent notice that
|
|
the work is derivative, and (2) the source code includes prominent notice with
|
|
these four paragraphs for those parts of this code that are retained.
|
|
=============================================================================*/
|
|
|
|
/*============================================================================
|
|
* Written for Bochs (x86 achitecture simulator) by
|
|
* Stanislav Shwartsman (gate at fidonet.org.il)
|
|
* ==========================================================================*/
|
|
|
|
#define FLOAT128
|
|
|
|
#include <assert.h>
|
|
#include "softfloat.h"
|
|
|
|
// 2 3 4 n
|
|
// f(x) ~ C + (C * x) + (C * x) + (C * x) + (C * x) + ... + (C * x)
|
|
// 0 1 2 3 4 n
|
|
//
|
|
// -- 2k -- 2k+1
|
|
// p(x) = > C * x q(x) = > C * x
|
|
// -- 2k -- 2k+1
|
|
//
|
|
// f(x) ~ [ p(x) + x * q(x) ]
|
|
//
|
|
|
|
float128 EvalPoly(float128 x, float128 *arr, unsigned n, float_status_t &status)
|
|
{
|
|
float128 x2 = float128_mul(x, x, status);
|
|
unsigned i;
|
|
|
|
assert(n > 1);
|
|
|
|
float128 r1 = arr[--n];
|
|
i = n;
|
|
while(i >= 2) {
|
|
r1 = float128_mul(r1, x2, status);
|
|
i -= 2;
|
|
r1 = float128_add(r1, arr[i], status);
|
|
}
|
|
if (i) r1 = float128_mul(r1, x, status);
|
|
|
|
float128 r2 = arr[--n];
|
|
i = n;
|
|
while(i >= 2) {
|
|
r2 = float128_mul(r2, x2, status);
|
|
i -= 2;
|
|
r2 = float128_add(r2, arr[i], status);
|
|
}
|
|
if (i) r2 = float128_mul(r2, x, status);
|
|
|
|
return float128_add(r1, r2, status);
|
|
}
|
|
|
|
// 2 4 6 8 2n
|
|
// f(x) ~ C + (C * x) + (C * x) + (C * x) + (C * x) + ... + (C * x)
|
|
// 0 1 2 3 4 n
|
|
//
|
|
// -- 4k -- 4k+2
|
|
// p(x) = > C * x q(x) = > C * x
|
|
// -- 2k -- 2k+1
|
|
//
|
|
// 2
|
|
// f(x) ~ [ p(x) + x * q(x) ]
|
|
//
|
|
|
|
float128 EvenPoly(float128 x, float128 *arr, unsigned n, float_status_t &status)
|
|
{
|
|
return EvalPoly(float128_mul(x, x, status), arr, n, status);
|
|
}
|
|
|
|
// 3 5 7 9 2n+1
|
|
// f(x) ~ (C * x) + (C * x) + (C * x) + (C * x) + (C * x) + ... + (C * x)
|
|
// 0 1 2 3 4 n
|
|
// 2 4 6 8 2n
|
|
// = x * [ C + (C * x) + (C * x) + (C * x) + (C * x) + ... + (C * x)
|
|
// 0 1 2 3 4 n
|
|
//
|
|
// -- 4k -- 4k+2
|
|
// p(x) = > C * x q(x) = > C * x
|
|
// -- 2k -- 2k+1
|
|
//
|
|
// 2
|
|
// f(x) ~ x * [ p(x) + x * q(x) ]
|
|
//
|
|
|
|
float128 OddPoly(float128 x, float128 *arr, unsigned n, float_status_t &status)
|
|
{
|
|
return float128_mul(x, EvenPoly(x, arr, n, status), status);
|
|
}
|