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1da177e4 LT |
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 | ||
20 | static void fnop(void) | |
21 | { | |
22 | } | |
23 | ||
24 | static void fclex(void) | |
25 | { | |
26 | partial_status &= ~(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 | ||
67 | static void fstsw_ax(void) | |
68 | { | |
69 | *(short *) &FPU_EAX = status_word(); | |
70 | no_ip_update = 1; | |
71 | } | |
72 | ||
73 | static FUNC const fstsw_table[] = { | |
74 | fstsw_ax, FPU_illegal, FPU_illegal, FPU_illegal, | |
75 | FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal | |
76 | }; | |
77 | ||
78 | void fstsw_(void) | |
79 | { | |
80 | (fstsw_table[FPU_rm])(); | |
81 | } | |
82 | ||
83 | ||
84 | static FUNC const fp_nop_table[] = { | |
85 | fnop, FPU_illegal, FPU_illegal, FPU_illegal, | |
86 | FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal | |
87 | }; | |
88 | ||
89 | void fp_nop(void) | |
90 | { | |
91 | (fp_nop_table[FPU_rm])(); | |
92 | } | |
93 | ||
94 | ||
95 | void fld_i_(void) | |
96 | { | |
97 | FPU_REG *st_new_ptr; | |
98 | int i; | |
99 | u_char tag; | |
100 | ||
101 | if ( STACK_OVERFLOW ) | |
102 | { FPU_stack_overflow(); return; } | |
103 | ||
104 | /* fld st(i) */ | |
105 | i = FPU_rm; | |
106 | if ( NOT_EMPTY(i) ) | |
107 | { | |
108 | reg_copy(&st(i), st_new_ptr); | |
109 | tag = FPU_gettagi(i); | |
110 | push(); | |
111 | FPU_settag0(tag); | |
112 | } | |
113 | else | |
114 | { | |
115 | if ( control_word & CW_Invalid ) | |
116 | { | |
117 | /* The masked response */ | |
118 | FPU_stack_underflow(); | |
119 | } | |
120 | else | |
121 | EXCEPTION(EX_StackUnder); | |
122 | } | |
123 | ||
124 | } | |
125 | ||
126 | ||
127 | void fxch_i(void) | |
128 | { | |
129 | /* fxch st(i) */ | |
130 | FPU_REG t; | |
131 | int i = FPU_rm; | |
132 | FPU_REG *st0_ptr = &st(0), *sti_ptr = &st(i); | |
133 | long tag_word = fpu_tag_word; | |
134 | int regnr = top & 7, regnri = ((regnr + i) & 7); | |
135 | u_char st0_tag = (tag_word >> (regnr*2)) & 3; | |
136 | u_char sti_tag = (tag_word >> (regnri*2)) & 3; | |
137 | ||
138 | if ( st0_tag == TAG_Empty ) | |
139 | { | |
140 | if ( sti_tag == TAG_Empty ) | |
141 | { | |
142 | FPU_stack_underflow(); | |
143 | FPU_stack_underflow_i(i); | |
144 | return; | |
145 | } | |
146 | if ( control_word & CW_Invalid ) | |
147 | { | |
148 | /* Masked response */ | |
149 | FPU_copy_to_reg0(sti_ptr, sti_tag); | |
150 | } | |
151 | FPU_stack_underflow_i(i); | |
152 | return; | |
153 | } | |
154 | if ( sti_tag == TAG_Empty ) | |
155 | { | |
156 | if ( control_word & CW_Invalid ) | |
157 | { | |
158 | /* Masked response */ | |
159 | FPU_copy_to_regi(st0_ptr, st0_tag, i); | |
160 | } | |
161 | FPU_stack_underflow(); | |
162 | return; | |
163 | } | |
164 | clear_C1(); | |
165 | ||
166 | reg_copy(st0_ptr, &t); | |
167 | reg_copy(sti_ptr, st0_ptr); | |
168 | reg_copy(&t, sti_ptr); | |
169 | ||
170 | tag_word &= ~(3 << (regnr*2)) & ~(3 << (regnri*2)); | |
171 | tag_word |= (sti_tag << (regnr*2)) | (st0_tag << (regnri*2)); | |
172 | fpu_tag_word = tag_word; | |
173 | } | |
174 | ||
175 | ||
176 | void ffree_(void) | |
177 | { | |
178 | /* ffree st(i) */ | |
179 | FPU_settagi(FPU_rm, TAG_Empty); | |
180 | } | |
181 | ||
182 | ||
183 | void ffreep(void) | |
184 | { | |
185 | /* ffree st(i) + pop - unofficial code */ | |
186 | FPU_settagi(FPU_rm, TAG_Empty); | |
187 | FPU_pop(); | |
188 | } | |
189 | ||
190 | ||
191 | void fst_i_(void) | |
192 | { | |
193 | /* fst st(i) */ | |
194 | FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm); | |
195 | } | |
196 | ||
197 | ||
198 | void fstp_i(void) | |
199 | { | |
200 | /* fstp st(i) */ | |
201 | FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm); | |
202 | FPU_pop(); | |
203 | } | |
204 |