mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-22 20:23:57 +08:00
e8d591dc71
manually clean up some of the damage that lindent caused. (this is a separate commit so that in the unlikely case of a typo we can bisect it down to the manual edits.) Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
146 lines
4.4 KiB
C
146 lines
4.4 KiB
C
/*---------------------------------------------------------------------------+
|
|
| poly_2xm1.c |
|
|
| |
|
|
| Function to compute 2^x-1 by a polynomial approximation. |
|
|
| |
|
|
| Copyright (C) 1992,1993,1994,1997 |
|
|
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
|
|
| E-mail billm@suburbia.net |
|
|
| |
|
|
| |
|
|
+---------------------------------------------------------------------------*/
|
|
|
|
#include "exception.h"
|
|
#include "reg_constant.h"
|
|
#include "fpu_emu.h"
|
|
#include "fpu_system.h"
|
|
#include "control_w.h"
|
|
#include "poly.h"
|
|
|
|
#define HIPOWER 11
|
|
static const unsigned long long lterms[HIPOWER] = {
|
|
0x0000000000000000LL, /* This term done separately as 12 bytes */
|
|
0xf5fdeffc162c7543LL,
|
|
0x1c6b08d704a0bfa6LL,
|
|
0x0276556df749cc21LL,
|
|
0x002bb0ffcf14f6b8LL,
|
|
0x0002861225ef751cLL,
|
|
0x00001ffcbfcd5422LL,
|
|
0x00000162c005d5f1LL,
|
|
0x0000000da96ccb1bLL,
|
|
0x0000000078d1b897LL,
|
|
0x000000000422b029LL
|
|
};
|
|
|
|
static const Xsig hiterm = MK_XSIG(0xb17217f7, 0xd1cf79ab, 0xc8a39194);
|
|
|
|
/* Four slices: 0.0 : 0.25 : 0.50 : 0.75 : 1.0,
|
|
These numbers are 2^(1/4), 2^(1/2), and 2^(3/4)
|
|
*/
|
|
static const Xsig shiftterm0 = MK_XSIG(0, 0, 0);
|
|
static const Xsig shiftterm1 = MK_XSIG(0x9837f051, 0x8db8a96f, 0x46ad2318);
|
|
static const Xsig shiftterm2 = MK_XSIG(0xb504f333, 0xf9de6484, 0x597d89b3);
|
|
static const Xsig shiftterm3 = MK_XSIG(0xd744fcca, 0xd69d6af4, 0x39a68bb9);
|
|
|
|
static const Xsig *shiftterm[] = { &shiftterm0, &shiftterm1,
|
|
&shiftterm2, &shiftterm3
|
|
};
|
|
|
|
/*--- poly_2xm1() -----------------------------------------------------------+
|
|
| Requires st(0) which is TAG_Valid and < 1. |
|
|
+---------------------------------------------------------------------------*/
|
|
int poly_2xm1(u_char sign, FPU_REG *arg, FPU_REG *result)
|
|
{
|
|
long int exponent, shift;
|
|
unsigned long long Xll;
|
|
Xsig accumulator, Denom, argSignif;
|
|
u_char tag;
|
|
|
|
exponent = exponent16(arg);
|
|
|
|
#ifdef PARANOID
|
|
if (exponent >= 0) { /* Don't want a |number| >= 1.0 */
|
|
/* Number negative, too large, or not Valid. */
|
|
EXCEPTION(EX_INTERNAL | 0x127);
|
|
return 1;
|
|
}
|
|
#endif /* PARANOID */
|
|
|
|
argSignif.lsw = 0;
|
|
XSIG_LL(argSignif) = Xll = significand(arg);
|
|
|
|
if (exponent == -1) {
|
|
shift = (argSignif.msw & 0x40000000) ? 3 : 2;
|
|
/* subtract 0.5 or 0.75 */
|
|
exponent -= 2;
|
|
XSIG_LL(argSignif) <<= 2;
|
|
Xll <<= 2;
|
|
} else if (exponent == -2) {
|
|
shift = 1;
|
|
/* subtract 0.25 */
|
|
exponent--;
|
|
XSIG_LL(argSignif) <<= 1;
|
|
Xll <<= 1;
|
|
} else
|
|
shift = 0;
|
|
|
|
if (exponent < -2) {
|
|
/* Shift the argument right by the required places. */
|
|
if (FPU_shrx(&Xll, -2 - exponent) >= 0x80000000U)
|
|
Xll++; /* round up */
|
|
}
|
|
|
|
accumulator.lsw = accumulator.midw = accumulator.msw = 0;
|
|
polynomial_Xsig(&accumulator, &Xll, lterms, HIPOWER - 1);
|
|
mul_Xsig_Xsig(&accumulator, &argSignif);
|
|
shr_Xsig(&accumulator, 3);
|
|
|
|
mul_Xsig_Xsig(&argSignif, &hiterm); /* The leading term */
|
|
add_two_Xsig(&accumulator, &argSignif, &exponent);
|
|
|
|
if (shift) {
|
|
/* The argument is large, use the identity:
|
|
f(x+a) = f(a) * (f(x) + 1) - 1;
|
|
*/
|
|
shr_Xsig(&accumulator, -exponent);
|
|
accumulator.msw |= 0x80000000; /* add 1.0 */
|
|
mul_Xsig_Xsig(&accumulator, shiftterm[shift]);
|
|
accumulator.msw &= 0x3fffffff; /* subtract 1.0 */
|
|
exponent = 1;
|
|
}
|
|
|
|
if (sign != SIGN_POS) {
|
|
/* The argument is negative, use the identity:
|
|
f(-x) = -f(x) / (1 + f(x))
|
|
*/
|
|
Denom.lsw = accumulator.lsw;
|
|
XSIG_LL(Denom) = XSIG_LL(accumulator);
|
|
if (exponent < 0)
|
|
shr_Xsig(&Denom, -exponent);
|
|
else if (exponent > 0) {
|
|
/* exponent must be 1 here */
|
|
XSIG_LL(Denom) <<= 1;
|
|
if (Denom.lsw & 0x80000000)
|
|
XSIG_LL(Denom) |= 1;
|
|
(Denom.lsw) <<= 1;
|
|
}
|
|
Denom.msw |= 0x80000000; /* add 1.0 */
|
|
div_Xsig(&accumulator, &Denom, &accumulator);
|
|
}
|
|
|
|
/* Convert to 64 bit signed-compatible */
|
|
exponent += round_Xsig(&accumulator);
|
|
|
|
result = &st(0);
|
|
significand(result) = XSIG_LL(accumulator);
|
|
setexponent16(result, exponent);
|
|
|
|
tag = FPU_round(result, 1, 0, FULL_PRECISION, sign);
|
|
|
|
setsign(result, sign);
|
|
FPU_settag0(tag);
|
|
|
|
return 0;
|
|
|
|
}
|