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(r, &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(r, &st(1));
104	FPU_settagi(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(r, &st(0));
113
114	fpu_tag_word &= ~(3 << (regnr * 2));
115	fpu_tag_word |= (tag & 3) << (regnr * 2);
116}
117