summaryrefslogtreecommitdiffstats
path: root/arch/x86/math-emu/fpu_aux.c
blob: 024f6e971174e88df9d96ffb66641f7835b8729d (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
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
/*---------------------------------------------------------------------------+
 |  fpu_aux.c                                                                |
 |                                                                           |
 | Code to implement some of the FPU auxiliary instructions.                 |
 |                                                                           |
 | Copyright (C) 1992,1993,1994,1997                                         |
 |                  W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
 |                  E-mail   billm@suburbia.net                              |
 |                                                                           |
 |                                                                           |
 +---------------------------------------------------------------------------*/

#include "fpu_system.h"
#include "exception.h"
#include "fpu_emu.h"
#include "status_w.h"
#include "control_w.h"

static void fnop(void)
{
}

static void fclex(void)
{
	partial_status &=
	    ~(SW_Backward | SW_Summary | SW_Stack_Fault | SW_Precision |
	      SW_Underflow | SW_Overflow | SW_Zero_Div | SW_Denorm_Op |
	      SW_Invalid);
	no_ip_update = 1;
}

/* Needs to be externally visible */
void fpstate_init_soft(struct swregs_state *soft)
{
	struct address *oaddr, *iaddr;
	memset(soft, 0, sizeof(*soft));
	soft->cwd = 0x037f;
	soft->swd = 0;
	soft->ftop = 0;	/* We don't keep top in the status word internally. */
	soft->twd = 0xffff;
	/* The behaviour is different from that detailed in
	   Section 15.1.6 of the Intel manual */
	oaddr = (struct address *)&soft->foo;
	oaddr->offset = 0;
	oaddr->selector = 0;
	iaddr = (struct address *)&soft->fip;
	iaddr->offset = 0;
	iaddr->selector = 0;
	iaddr->opcode = 0;
	soft->no_update = 1;
}

void finit(void)
{
	fpstate_init_soft(&current->thread.fpu.state.soft);
}

/*
 * These are nops on the i387..
 */
#define feni fnop
#define fdisi fnop
#define fsetpm fnop

static FUNC const finit_table[] = {
	feni, fdisi, fclex, finit,
	fsetpm, FPU_illegal, FPU_illegal, FPU_illegal
};

void finit_(void)
{
	(finit_table[FPU_rm]) ();
}

static void fstsw_ax(void)
{
	*(short *)&FPU_EAX = status_word();
	no_ip_update = 1;
}

static FUNC const fstsw_table[] = {
	fstsw_ax, FPU_illegal, FPU_illegal, FPU_illegal,
	FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal
};

void fstsw_(void)
{
	(fstsw_table[FPU_rm]) ();
}

static FUNC const fp_nop_table[] = {
	fnop, FPU_illegal, FPU_illegal, FPU_illegal,
	FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal
};

void fp_nop(void)
{
	(fp_nop_table[FPU_rm]) ();
}

void fld_i_(void)
{
	FPU_REG *st_new_ptr;
	int i;
	u_char tag;

	if (STACK_OVERFLOW) {
		FPU_stack_overflow();
		return;
	}

	/* fld st(i) */
	i = FPU_rm;
	if (NOT_EMPTY(i)) {
		reg_copy(&st(i), st_new_ptr);
		tag = FPU_gettagi(i);
		push();
		FPU_settag0(tag);
	} else {
		if (control_word & CW_Invalid) {
			/* The masked response */
			FPU_stack_underflow();
		} else
			EXCEPTION(EX_StackUnder);
	}

}

void fxch_i(void)
{
	/* fxch st(i) */
	FPU_REG t;
	int i = FPU_rm;
	FPU_REG *st0_ptr = &st(0), *sti_ptr = &st(i);
	long tag_word = fpu_tag_word;
	int regnr = top & 7, regnri = ((regnr + i) & 7);
	u_char st0_tag = (tag_word >> (regnr * 2)) & 3;
	u_char sti_tag = (tag_word >> (regnri * 2)) & 3;

	if (st0_tag == TAG_Empty) {
		if (sti_tag == TAG_Empty) {
			FPU_stack_underflow();
			FPU_stack_underflow_i(i);
			return;
		}
		if (control_word & CW_Invalid) {
			/* Masked response */
			FPU_copy_to_reg0(sti_ptr, sti_tag);
		}
		FPU_stack_underflow_i(i);
		return;
	}
	if (sti_tag == TAG_Empty) {
		if (control_word & CW_Invalid) {
			/* Masked response */
			FPU_copy_to_regi(st0_ptr, st0_tag, i);
		}
		FPU_stack_underflow();
		return;
	}
	clear_C1();

	reg_copy(st0_ptr, &t);
	reg_copy(sti_ptr, st0_ptr);
	reg_copy(&t, sti_ptr);

	tag_word &= ~(3 << (regnr * 2)) & ~(3 << (regnri * 2));
	tag_word |= (sti_tag << (regnr * 2)) | (st0_tag << (regnri * 2));
	fpu_tag_word = tag_word;
}

static void fcmovCC(void)
{
	/* fcmovCC st(i) */
	int i = FPU_rm;
	FPU_REG *st0_ptr = &st(0);
	FPU_REG *sti_ptr = &st(i);
	long tag_word = fpu_tag_word;
	int regnr = top & 7;
	int regnri = (top + i) & 7;
	u_char sti_tag = (tag_word >> (regnri * 2)) & 3;

	if (sti_tag == TAG_Empty) {
		FPU_stack_underflow();
		clear_C1();
		return;
	}
	reg_copy(sti_ptr, st0_ptr);
	tag_word &= ~(3 << (regnr * 2));
	tag_word |= (sti_tag << (regnr * 2));
	fpu_tag_word = tag_word;
}

void fcmovb(void)
{
	if (FPU_EFLAGS & X86_EFLAGS_CF)
		fcmovCC();
}

void fcmove(void)
{
	if (FPU_EFLAGS & X86_EFLAGS_ZF)
		fcmovCC();
}

void fcmovbe(void)
{
	if (FPU_EFLAGS & (X86_EFLAGS_CF|X86_EFLAGS_ZF))
		fcmovCC();
}

void fcmovu(void)
{
	if (FPU_EFLAGS & X86_EFLAGS_PF)
		fcmovCC();
}

void fcmovnb(void)
{
	if (!(FPU_EFLAGS & X86_EFLAGS_CF))
		fcmovCC();
}

void fcmovne(void)
{
	if (!(FPU_EFLAGS & X86_EFLAGS_ZF))
		fcmovCC();
}

void fcmovnbe(void)
{
	if (!(FPU_EFLAGS & (X86_EFLAGS_CF|X86_EFLAGS_ZF)))
		fcmovCC();
}

void fcmovnu(void)
{
	if (!(FPU_EFLAGS & X86_EFLAGS_PF))
		fcmovCC();
}

void ffree_(void)
{
	/* ffree st(i) */
	FPU_settagi(FPU_rm, TAG_Empty);
}

void ffreep(void)
{
	/* ffree st(i) + pop - unofficial code */
	FPU_settagi(FPU_rm, TAG_Empty);
	FPU_pop();
}

void fst_i_(void)
{
	/* fst st(i) */
	FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm);
}

void fstp_i(void)
{
	/* fstp st(i) */
	FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm);
	FPU_pop();
}
OpenPOWER on IntegriCloud