101 строка
2.0 KiB
C
101 строка
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/* IEEE754 floating point arithmetic
|
|
* double precision: common utilities
|
|
*/
|
|
/*
|
|
* MIPS floating point support
|
|
* Copyright (C) 1994-2000 Algorithmics Ltd.
|
|
*/
|
|
|
|
#include "ieee754dp.h"
|
|
|
|
s64 ieee754dp_tlong(union ieee754dp x)
|
|
{
|
|
u64 residue;
|
|
int round;
|
|
int sticky;
|
|
int odd;
|
|
|
|
COMPXDP;
|
|
|
|
ieee754_clearcx();
|
|
|
|
EXPLODEXDP;
|
|
FLUSHXDP;
|
|
|
|
switch (xc) {
|
|
case IEEE754_CLASS_SNAN:
|
|
case IEEE754_CLASS_QNAN:
|
|
ieee754_setcx(IEEE754_INVALID_OPERATION);
|
|
return ieee754di_indef();
|
|
|
|
case IEEE754_CLASS_INF:
|
|
ieee754_setcx(IEEE754_INVALID_OPERATION);
|
|
return ieee754di_overflow(xs);
|
|
|
|
case IEEE754_CLASS_ZERO:
|
|
return 0;
|
|
|
|
case IEEE754_CLASS_DNORM:
|
|
case IEEE754_CLASS_NORM:
|
|
break;
|
|
}
|
|
if (xe >= 63) {
|
|
/* look for valid corner case */
|
|
if (xe == 63 && xs && xm == DP_HIDDEN_BIT)
|
|
return -0x8000000000000000LL;
|
|
/* Set invalid. We will only use overflow for floating
|
|
point overflow */
|
|
ieee754_setcx(IEEE754_INVALID_OPERATION);
|
|
return ieee754di_overflow(xs);
|
|
}
|
|
/* oh gawd */
|
|
if (xe > DP_FBITS) {
|
|
xm <<= xe - DP_FBITS;
|
|
} else if (xe < DP_FBITS) {
|
|
if (xe < -1) {
|
|
residue = xm;
|
|
round = 0;
|
|
sticky = residue != 0;
|
|
xm = 0;
|
|
} else {
|
|
/* Shifting a u64 64 times does not work,
|
|
* so we do it in two steps. Be aware that xe
|
|
* may be -1 */
|
|
residue = xm << (xe + 1);
|
|
residue <<= 63 - DP_FBITS;
|
|
round = (residue >> 63) != 0;
|
|
sticky = (residue << 1) != 0;
|
|
xm >>= DP_FBITS - xe;
|
|
}
|
|
odd = (xm & 0x1) != 0x0;
|
|
switch (ieee754_csr.rm) {
|
|
case FPU_CSR_RN:
|
|
if (round && (sticky || odd))
|
|
xm++;
|
|
break;
|
|
case FPU_CSR_RZ:
|
|
break;
|
|
case FPU_CSR_RU: /* toward +Infinity */
|
|
if ((round || sticky) && !xs)
|
|
xm++;
|
|
break;
|
|
case FPU_CSR_RD: /* toward -Infinity */
|
|
if ((round || sticky) && xs)
|
|
xm++;
|
|
break;
|
|
}
|
|
if ((xm >> 63) != 0) {
|
|
/* This can happen after rounding */
|
|
ieee754_setcx(IEEE754_INVALID_OPERATION);
|
|
return ieee754di_overflow(xs);
|
|
}
|
|
if (round || sticky)
|
|
ieee754_setcx(IEEE754_INEXACT);
|
|
}
|
|
if (xs)
|
|
return -xm;
|
|
else
|
|
return xm;
|
|
}
|