1// SPDX-License-Identifier: GPL-2.0-only
 2/* IEEE754 floating point arithmetic
 3 * double precision: common utilities
 4 */
 5/*
 6 * MIPS floating point support
 7 * Copyright (C) 1994-2000 Algorithmics Ltd.
 8 * Copyright (C) 2017 Imagination Technologies, Ltd.
 9 * Author: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
10 */
11
12#include "ieee754dp.h"
13
14union ieee754dp ieee754dp_rint(union ieee754dp x)
15{
16	union ieee754dp ret;
17	u64 residue;
18	int sticky;
19	int round;
20	int odd;
21
22	COMPXDP;
23
24	ieee754_clearcx();
25
26	EXPLODEXDP;
27	FLUSHXDP;
28
29	if (xc == IEEE754_CLASS_SNAN)
30		return ieee754dp_nanxcpt(x);
31
32	if ((xc == IEEE754_CLASS_QNAN) ||
33	    (xc == IEEE754_CLASS_INF) ||
34	    (xc == IEEE754_CLASS_ZERO))
35		return x;
36
37	if (xe >= DP_FBITS)
38		return x;
39
40	if (xe < -1) {
41		residue = xm;
42		round = 0;
43		sticky = residue != 0;
44		xm = 0;
45	} else {
46		residue = xm << (64 - DP_FBITS + xe);
47		round = (residue >> 63) != 0;
48		sticky = (residue << 1) != 0;
49		xm >>= DP_FBITS - xe;
50	}
51
52	odd = (xm & 0x1) != 0x0;
53
54	switch (ieee754_csr.rm) {
55	case FPU_CSR_RN:	/* toward nearest */
56		if (round && (sticky || odd))
57			xm++;
58		break;
59	case FPU_CSR_RZ:	/* toward zero */
60		break;
61	case FPU_CSR_RU:	/* toward +infinity */
62		if ((round || sticky) && !xs)
63			xm++;
64		break;
65	case FPU_CSR_RD:	/* toward -infinity */
66		if ((round || sticky) && xs)
67			xm++;
68		break;
69	}
70
71	if (round || sticky)
72		ieee754_setcx(IEEE754_INEXACT);
73
74	ret = ieee754dp_flong(xm);
75	DPSIGN(ret) = xs;
76
77	return ret;
78}

 1// SPDX-License-Identifier: GPL-2.0-only
 2/* IEEE754 floating point arithmetic
 3 * double precision: common utilities
 4 */
 5/*
 6 * MIPS floating point support
 7 * Copyright (C) 1994-2000 Algorithmics Ltd.
 8 * Copyright (C) 2017 Imagination Technologies, Ltd.
 9 * Author: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
10 */
11
12#include "ieee754dp.h"
13
14union ieee754dp ieee754dp_rint(union ieee754dp x)
15{
16	union ieee754dp ret;
17	u64 residue;
18	int sticky;
19	int round;
20	int odd;
21
22	COMPXDP;
23
24	ieee754_clearcx();
25
26	EXPLODEXDP;
27	FLUSHXDP;
28
29	if (xc == IEEE754_CLASS_SNAN)
30		return ieee754dp_nanxcpt(x);
31
32	if ((xc == IEEE754_CLASS_QNAN) ||
33	    (xc == IEEE754_CLASS_INF) ||
34	    (xc == IEEE754_CLASS_ZERO))
35		return x;
36
37	if (xe >= DP_FBITS)
38		return x;
39
40	if (xe < -1) {
41		residue = xm;
42		round = 0;
43		sticky = residue != 0;
44		xm = 0;
45	} else {
46		residue = xm << (64 - DP_FBITS + xe);
47		round = (residue >> 63) != 0;
48		sticky = (residue << 1) != 0;
49		xm >>= DP_FBITS - xe;
50	}
51
52	odd = (xm & 0x1) != 0x0;
53
54	switch (ieee754_csr.rm) {
55	case FPU_CSR_RN:	/* toward nearest */
56		if (round && (sticky || odd))
57			xm++;
58		break;
59	case FPU_CSR_RZ:	/* toward zero */
60		break;
61	case FPU_CSR_RU:	/* toward +infinity */
62		if ((round || sticky) && !xs)
63			xm++;
64		break;
65	case FPU_CSR_RD:	/* toward -infinity */
66		if ((round || sticky) && xs)
67			xm++;
68		break;
69	}
70
71	if (round || sticky)
72		ieee754_setcx(IEEE754_INEXACT);
73
74	ret = ieee754dp_flong(xm);
75	DPSIGN(ret) = xs;
76
77	return ret;
78}