summaryrefslogtreecommitdiffstats
path: root/kernel/arch/parisc/math-emu/denormal.c
blob: 60687e13c34f8c042418f508ec5ed021310952b5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
/*
 * Linux/PA-RISC Project (http://www.parisc-linux.org/)
 *
 * Floating-point emulation code
 *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2, or (at your option)
 *    any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
/*
 * BEGIN_DESC
 *
 *  File:
 *	@(#)	pa/fp/denormal.c		$ Revision: $
 *
 *  Purpose:
 *	<<please update with a synopsis of the functionality provided by this file>>
 *
 *  External Interfaces:
 *	<<the following list was autogenerated, please review>>
 *	dbl_denormalize(dbl_opndp1,dbl_opndp2,inexactflag,rmode)
 *	sgl_denormalize(sgl_opnd,inexactflag,rmode)
 *
 *  Internal Interfaces:
 *	<<please update>>
 *
 *  Theory:
 *	<<please update with a overview of the operation of this file>>
 *
 * END_DESC
*/



#include "float.h"
#include "sgl_float.h"
#include "dbl_float.h"
#include "hppa.h"
#include <linux/kernel.h>
/* #include <machine/sys/mdep_private.h> */

#undef Fpustatus_register
#define Fpustatus_register Fpu_register[0]

void
sgl_denormalize(unsigned int *sgl_opnd, boolean *inexactflag, int rmode)
{
	unsigned int opnd;
	int sign, exponent;
	boolean guardbit = FALSE, stickybit, inexact;

	opnd = *sgl_opnd;
	stickybit = *inexactflag;
        exponent = Sgl_exponent(opnd) - SGL_WRAP;
        sign = Sgl_sign(opnd);
	Sgl_denormalize(opnd,exponent,guardbit,stickybit,inexact);
	if (inexact) {
	    switch (rmode) {
	      case ROUNDPLUS:
		if (sign == 0) {
			Sgl_increment(opnd);
		}
		break;
	      case ROUNDMINUS:
		if (sign != 0) {
			Sgl_increment(opnd);
		}
		break;
	      case ROUNDNEAREST:
		if (guardbit && (stickybit || 
		       Sgl_isone_lowmantissa(opnd))) {
			   Sgl_increment(opnd);
		}
		break;
	    }
	}
	Sgl_set_sign(opnd,sign);
	*sgl_opnd = opnd;
	*inexactflag = inexact;
	return;
}

void
dbl_denormalize(unsigned int *dbl_opndp1,
	unsigned int * dbl_opndp2,
	boolean *inexactflag,
	int rmode)
{
	unsigned int opndp1, opndp2;
	int sign, exponent;
	boolean guardbit = FALSE, stickybit, inexact;

	opndp1 = *dbl_opndp1;
	opndp2 = *dbl_opndp2;
	stickybit = *inexactflag;
	exponent = Dbl_exponent(opndp1) - DBL_WRAP;
	sign = Dbl_sign(opndp1);
	Dbl_denormalize(opndp1,opndp2,exponent,guardbit,stickybit,inexact);
	if (inexact) {
	    switch (rmode) {
	      case ROUNDPLUS:
		if (sign == 0) {
			Dbl_increment(opndp1,opndp2);
		}
		break;
	      case ROUNDMINUS:
		if (sign != 0) {
			Dbl_increment(opndp1,opndp2);
		}
		break;
	      case ROUNDNEAREST:
		if (guardbit && (stickybit || 
		       Dbl_isone_lowmantissap2(opndp2))) {
			   Dbl_increment(opndp1,opndp2);
		}
		break;
	    }
	}
	Dbl_set_sign(opndp1,sign);
	*dbl_opndp1 = opndp1;
	*dbl_opndp2 = opndp2;
	*inexactflag = inexact;
	return;
}