1// SPDX-License-Identifier: GPL-2.0
2/*---------------------------------------------------------------------------+
3 | fpu_tags.c |
4 | |
5 | Set FPU register tags. |
6 | |
7 | Copyright (C) 1997 |
8 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
9 | E-mail billm@jacobi.maths.monash.edu.au |
10 | |
11 | |
12 +---------------------------------------------------------------------------*/
13
14#include "fpu_emu.h"
15#include "fpu_system.h"
16#include "exception.h"
17
18void FPU_pop(void)
19{
20 fpu_tag_word |= 3 << ((top & 7) * 2);
21 top++;
22}
23
24int FPU_gettag0(void)
25{
26 return (fpu_tag_word >> ((top & 7) * 2)) & 3;
27}
28
29int FPU_gettagi(int stnr)
30{
31 return (fpu_tag_word >> (((top + stnr) & 7) * 2)) & 3;
32}
33
34int FPU_gettag(int regnr)
35{
36 return (fpu_tag_word >> ((regnr & 7) * 2)) & 3;
37}
38
39void FPU_settag0(int tag)
40{
41 int regnr = top;
42 regnr &= 7;
43 fpu_tag_word &= ~(3 << (regnr * 2));
44 fpu_tag_word |= (tag & 3) << (regnr * 2);
45}
46
47void FPU_settagi(int stnr, int tag)
48{
49 int regnr = stnr + top;
50 regnr &= 7;
51 fpu_tag_word &= ~(3 << (regnr * 2));
52 fpu_tag_word |= (tag & 3) << (regnr * 2);
53}
54
55void FPU_settag(int regnr, int tag)
56{
57 regnr &= 7;
58 fpu_tag_word &= ~(3 << (regnr * 2));
59 fpu_tag_word |= (tag & 3) << (regnr * 2);
60}
61
62int FPU_Special(FPU_REG const *ptr)
63{
64 int exp = exponent(ptr);
65
66 if (exp == EXP_BIAS + EXP_UNDER)
67 return TW_Denormal;
68 else if (exp != EXP_BIAS + EXP_OVER)
69 return TW_NaN;
70 else if ((ptr->sigh == 0x80000000) && (ptr->sigl == 0))
71 return TW_Infinity;
72 return TW_NaN;
73}
74
75int isNaN(FPU_REG const *ptr)
76{
77 return ((exponent(ptr) == EXP_BIAS + EXP_OVER)
78 && !((ptr->sigh == 0x80000000) && (ptr->sigl == 0)));
79}
80
81int FPU_empty_i(int stnr)
82{
83 int regnr = (top + stnr) & 7;
84
85 return ((fpu_tag_word >> (regnr * 2)) & 3) == TAG_Empty;
86}
87
88int FPU_stackoverflow(FPU_REG ** st_new_ptr)
89{
90 *st_new_ptr = &st(-1);
91
92 return ((fpu_tag_word >> (((top - 1) & 7) * 2)) & 3) != TAG_Empty;
93}
94
95void FPU_copy_to_regi(FPU_REG const *r, u_char tag, int stnr)
96{
97 reg_copy(x: r, y: &st(stnr));
98 FPU_settagi(stnr, tag);
99}
100
101void FPU_copy_to_reg1(FPU_REG const *r, u_char tag)
102{
103 reg_copy(x: r, y: &st(1));
104 FPU_settagi(stnr: 1, tag);
105}
106
107void FPU_copy_to_reg0(FPU_REG const *r, u_char tag)
108{
109 int regnr = top;
110 regnr &= 7;
111
112 reg_copy(x: r, y: &st(0));
113
114 fpu_tag_word &= ~(3 << (regnr * 2));
115 fpu_tag_word |= (tag & 3) << (regnr * 2);
116}
117

source code of linux/arch/x86/math-emu/fpu_tags.c