Merge branch 'for_rmk' of git://git.mnementh.co.uk/linux-2.6-im
[linux-2.6] / arch / x86 / math-emu / fpu_aux.c
1 /*---------------------------------------------------------------------------+
2  |  fpu_aux.c                                                                |
3  |                                                                           |
4  | Code to implement some of the FPU auxiliary instructions.                 |
5  |                                                                           |
6  | Copyright (C) 1992,1993,1994,1997                                         |
7  |                  W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
8  |                  E-mail   billm@suburbia.net                              |
9  |                                                                           |
10  |                                                                           |
11  +---------------------------------------------------------------------------*/
12
13 #include "fpu_system.h"
14 #include "exception.h"
15 #include "fpu_emu.h"
16 #include "status_w.h"
17 #include "control_w.h"
18
19 static void fnop(void)
20 {
21 }
22
23 static void fclex(void)
24 {
25         partial_status &=
26             ~(SW_Backward | SW_Summary | SW_Stack_Fault | SW_Precision |
27               SW_Underflow | SW_Overflow | SW_Zero_Div | SW_Denorm_Op |
28               SW_Invalid);
29         no_ip_update = 1;
30 }
31
32 /* Needs to be externally visible */
33 void finit(void)
34 {
35         control_word = 0x037f;
36         partial_status = 0;
37         top = 0;                /* We don't keep top in the status word internally. */
38         fpu_tag_word = 0xffff;
39         /* The behaviour is different from that detailed in
40            Section 15.1.6 of the Intel manual */
41         operand_address.offset = 0;
42         operand_address.selector = 0;
43         instruction_address.offset = 0;
44         instruction_address.selector = 0;
45         instruction_address.opcode = 0;
46         no_ip_update = 1;
47 }
48
49 /*
50  * These are nops on the i387..
51  */
52 #define feni fnop
53 #define fdisi fnop
54 #define fsetpm fnop
55
56 static FUNC const finit_table[] = {
57         feni, fdisi, fclex, finit,
58         fsetpm, FPU_illegal, FPU_illegal, FPU_illegal
59 };
60
61 void finit_(void)
62 {
63         (finit_table[FPU_rm]) ();
64 }
65
66 static void fstsw_ax(void)
67 {
68         *(short *)&FPU_EAX = status_word();
69         no_ip_update = 1;
70 }
71
72 static FUNC const fstsw_table[] = {
73         fstsw_ax, FPU_illegal, FPU_illegal, FPU_illegal,
74         FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal
75 };
76
77 void fstsw_(void)
78 {
79         (fstsw_table[FPU_rm]) ();
80 }
81
82 static FUNC const fp_nop_table[] = {
83         fnop, FPU_illegal, FPU_illegal, FPU_illegal,
84         FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal
85 };
86
87 void fp_nop(void)
88 {
89         (fp_nop_table[FPU_rm]) ();
90 }
91
92 void fld_i_(void)
93 {
94         FPU_REG *st_new_ptr;
95         int i;
96         u_char tag;
97
98         if (STACK_OVERFLOW) {
99                 FPU_stack_overflow();
100                 return;
101         }
102
103         /* fld st(i) */
104         i = FPU_rm;
105         if (NOT_EMPTY(i)) {
106                 reg_copy(&st(i), st_new_ptr);
107                 tag = FPU_gettagi(i);
108                 push();
109                 FPU_settag0(tag);
110         } else {
111                 if (control_word & CW_Invalid) {
112                         /* The masked response */
113                         FPU_stack_underflow();
114                 } else
115                         EXCEPTION(EX_StackUnder);
116         }
117
118 }
119
120 void fxch_i(void)
121 {
122         /* fxch st(i) */
123         FPU_REG t;
124         int i = FPU_rm;
125         FPU_REG *st0_ptr = &st(0), *sti_ptr = &st(i);
126         long tag_word = fpu_tag_word;
127         int regnr = top & 7, regnri = ((regnr + i) & 7);
128         u_char st0_tag = (tag_word >> (regnr * 2)) & 3;
129         u_char sti_tag = (tag_word >> (regnri * 2)) & 3;
130
131         if (st0_tag == TAG_Empty) {
132                 if (sti_tag == TAG_Empty) {
133                         FPU_stack_underflow();
134                         FPU_stack_underflow_i(i);
135                         return;
136                 }
137                 if (control_word & CW_Invalid) {
138                         /* Masked response */
139                         FPU_copy_to_reg0(sti_ptr, sti_tag);
140                 }
141                 FPU_stack_underflow_i(i);
142                 return;
143         }
144         if (sti_tag == TAG_Empty) {
145                 if (control_word & CW_Invalid) {
146                         /* Masked response */
147                         FPU_copy_to_regi(st0_ptr, st0_tag, i);
148                 }
149                 FPU_stack_underflow();
150                 return;
151         }
152         clear_C1();
153
154         reg_copy(st0_ptr, &t);
155         reg_copy(sti_ptr, st0_ptr);
156         reg_copy(&t, sti_ptr);
157
158         tag_word &= ~(3 << (regnr * 2)) & ~(3 << (regnri * 2));
159         tag_word |= (sti_tag << (regnr * 2)) | (st0_tag << (regnri * 2));
160         fpu_tag_word = tag_word;
161 }
162
163 void ffree_(void)
164 {
165         /* ffree st(i) */
166         FPU_settagi(FPU_rm, TAG_Empty);
167 }
168
169 void ffreep(void)
170 {
171         /* ffree st(i) + pop - unofficial code */
172         FPU_settagi(FPU_rm, TAG_Empty);
173         FPU_pop();
174 }
175
176 void fst_i_(void)
177 {
178         /* fst st(i) */
179         FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm);
180 }
181
182 void fstp_i(void)
183 {
184         /* fstp st(i) */
185         FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm);
186         FPU_pop();
187 }