1 // SPDX-License-Identifier: GPL-2.0-only
2 /* IEEE754 floating point arithmetic
3 * double precision: common utilities
6 * MIPS floating point support
7 * Copyright (C) 1994-2000 Algorithmics Ltd.
10 #include "ieee754dp.h"
12 int ieee754dp_tint(union ieee754dp x)
27 case IEEE754_CLASS_SNAN:
28 case IEEE754_CLASS_QNAN:
29 ieee754_setcx(IEEE754_INVALID_OPERATION);
30 return ieee754si_indef();
32 case IEEE754_CLASS_INF:
33 ieee754_setcx(IEEE754_INVALID_OPERATION);
34 return ieee754si_overflow(xs);
36 case IEEE754_CLASS_ZERO:
39 case IEEE754_CLASS_DNORM:
40 case IEEE754_CLASS_NORM:
44 /* Set invalid. We will only use overflow for floating
46 ieee754_setcx(IEEE754_INVALID_OPERATION);
47 return ieee754si_overflow(xs);
52 } else if (xe < DP_FBITS) {
56 sticky = residue != 0;
59 residue = xm << (64 - DP_FBITS + xe);
60 round = (residue >> 63) != 0;
61 sticky = (residue << 1) != 0;
64 /* Note: At this point upper 32 bits of xm are guaranteed
66 odd = (xm & 0x1) != 0x0;
67 switch (ieee754_csr.rm) {
69 if (round && (sticky || odd))
74 case FPU_CSR_RU: /* toward +Infinity */
75 if ((round || sticky) && !xs)
78 case FPU_CSR_RD: /* toward -Infinity */
79 if ((round || sticky) && xs)
83 /* look for valid corner case 0x80000000 */
84 if ((xm >> 31) != 0 && (xs == 0 || xm != 0x80000000)) {
85 /* This can happen after rounding */
86 ieee754_setcx(IEEE754_INVALID_OPERATION);
87 return ieee754si_overflow(xs);
90 ieee754_setcx(IEEE754_INEXACT);