• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 
fnop(void)19 static void fnop(void)
20 {
21 }
22 
fclex(void)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 */
fpstate_init_soft(struct swregs_state * soft)33 void fpstate_init_soft(struct swregs_state *soft)
34 {
35 	struct address *oaddr, *iaddr;
36 	memset(soft, 0, sizeof(*soft));
37 	soft->cwd = 0x037f;
38 	soft->swd = 0;
39 	soft->ftop = 0;	/* We don't keep top in the status word internally. */
40 	soft->twd = 0xffff;
41 	/* The behaviour is different from that detailed in
42 	   Section 15.1.6 of the Intel manual */
43 	oaddr = (struct address *)&soft->foo;
44 	oaddr->offset = 0;
45 	oaddr->selector = 0;
46 	iaddr = (struct address *)&soft->fip;
47 	iaddr->offset = 0;
48 	iaddr->selector = 0;
49 	iaddr->opcode = 0;
50 	soft->no_update = 1;
51 }
52 
finit(void)53 void finit(void)
54 {
55 	fpstate_init_soft(&current->thread.fpu.state.soft);
56 }
57 
58 /*
59  * These are nops on the i387..
60  */
61 #define feni fnop
62 #define fdisi fnop
63 #define fsetpm fnop
64 
65 static FUNC const finit_table[] = {
66 	feni, fdisi, fclex, finit,
67 	fsetpm, FPU_illegal, FPU_illegal, FPU_illegal
68 };
69 
finit_(void)70 void finit_(void)
71 {
72 	(finit_table[FPU_rm]) ();
73 }
74 
fstsw_ax(void)75 static void fstsw_ax(void)
76 {
77 	*(short *)&FPU_EAX = status_word();
78 	no_ip_update = 1;
79 }
80 
81 static FUNC const fstsw_table[] = {
82 	fstsw_ax, FPU_illegal, FPU_illegal, FPU_illegal,
83 	FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal
84 };
85 
fstsw_(void)86 void fstsw_(void)
87 {
88 	(fstsw_table[FPU_rm]) ();
89 }
90 
91 static FUNC const fp_nop_table[] = {
92 	fnop, FPU_illegal, FPU_illegal, FPU_illegal,
93 	FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal
94 };
95 
fp_nop(void)96 void fp_nop(void)
97 {
98 	(fp_nop_table[FPU_rm]) ();
99 }
100 
fld_i_(void)101 void fld_i_(void)
102 {
103 	FPU_REG *st_new_ptr;
104 	int i;
105 	u_char tag;
106 
107 	if (STACK_OVERFLOW) {
108 		FPU_stack_overflow();
109 		return;
110 	}
111 
112 	/* fld st(i) */
113 	i = FPU_rm;
114 	if (NOT_EMPTY(i)) {
115 		reg_copy(&st(i), st_new_ptr);
116 		tag = FPU_gettagi(i);
117 		push();
118 		FPU_settag0(tag);
119 	} else {
120 		if (control_word & CW_Invalid) {
121 			/* The masked response */
122 			FPU_stack_underflow();
123 		} else
124 			EXCEPTION(EX_StackUnder);
125 	}
126 
127 }
128 
fxch_i(void)129 void fxch_i(void)
130 {
131 	/* fxch st(i) */
132 	FPU_REG t;
133 	int i = FPU_rm;
134 	FPU_REG *st0_ptr = &st(0), *sti_ptr = &st(i);
135 	long tag_word = fpu_tag_word;
136 	int regnr = top & 7, regnri = ((regnr + i) & 7);
137 	u_char st0_tag = (tag_word >> (regnr * 2)) & 3;
138 	u_char sti_tag = (tag_word >> (regnri * 2)) & 3;
139 
140 	if (st0_tag == TAG_Empty) {
141 		if (sti_tag == TAG_Empty) {
142 			FPU_stack_underflow();
143 			FPU_stack_underflow_i(i);
144 			return;
145 		}
146 		if (control_word & CW_Invalid) {
147 			/* Masked response */
148 			FPU_copy_to_reg0(sti_ptr, sti_tag);
149 		}
150 		FPU_stack_underflow_i(i);
151 		return;
152 	}
153 	if (sti_tag == TAG_Empty) {
154 		if (control_word & CW_Invalid) {
155 			/* Masked response */
156 			FPU_copy_to_regi(st0_ptr, st0_tag, i);
157 		}
158 		FPU_stack_underflow();
159 		return;
160 	}
161 	clear_C1();
162 
163 	reg_copy(st0_ptr, &t);
164 	reg_copy(sti_ptr, st0_ptr);
165 	reg_copy(&t, sti_ptr);
166 
167 	tag_word &= ~(3 << (regnr * 2)) & ~(3 << (regnri * 2));
168 	tag_word |= (sti_tag << (regnr * 2)) | (st0_tag << (regnri * 2));
169 	fpu_tag_word = tag_word;
170 }
171 
fcmovCC(void)172 static void fcmovCC(void)
173 {
174 	/* fcmovCC st(i) */
175 	int i = FPU_rm;
176 	FPU_REG *st0_ptr = &st(0);
177 	FPU_REG *sti_ptr = &st(i);
178 	long tag_word = fpu_tag_word;
179 	int regnr = top & 7;
180 	int regnri = (top + i) & 7;
181 	u_char sti_tag = (tag_word >> (regnri * 2)) & 3;
182 
183 	if (sti_tag == TAG_Empty) {
184 		FPU_stack_underflow();
185 		clear_C1();
186 		return;
187 	}
188 	reg_copy(sti_ptr, st0_ptr);
189 	tag_word &= ~(3 << (regnr * 2));
190 	tag_word |= (sti_tag << (regnr * 2));
191 	fpu_tag_word = tag_word;
192 }
193 
fcmovb(void)194 void fcmovb(void)
195 {
196 	if (FPU_EFLAGS & X86_EFLAGS_CF)
197 		fcmovCC();
198 }
199 
fcmove(void)200 void fcmove(void)
201 {
202 	if (FPU_EFLAGS & X86_EFLAGS_ZF)
203 		fcmovCC();
204 }
205 
fcmovbe(void)206 void fcmovbe(void)
207 {
208 	if (FPU_EFLAGS & (X86_EFLAGS_CF|X86_EFLAGS_ZF))
209 		fcmovCC();
210 }
211 
fcmovu(void)212 void fcmovu(void)
213 {
214 	if (FPU_EFLAGS & X86_EFLAGS_PF)
215 		fcmovCC();
216 }
217 
fcmovnb(void)218 void fcmovnb(void)
219 {
220 	if (!(FPU_EFLAGS & X86_EFLAGS_CF))
221 		fcmovCC();
222 }
223 
fcmovne(void)224 void fcmovne(void)
225 {
226 	if (!(FPU_EFLAGS & X86_EFLAGS_ZF))
227 		fcmovCC();
228 }
229 
fcmovnbe(void)230 void fcmovnbe(void)
231 {
232 	if (!(FPU_EFLAGS & (X86_EFLAGS_CF|X86_EFLAGS_ZF)))
233 		fcmovCC();
234 }
235 
fcmovnu(void)236 void fcmovnu(void)
237 {
238 	if (!(FPU_EFLAGS & X86_EFLAGS_PF))
239 		fcmovCC();
240 }
241 
ffree_(void)242 void ffree_(void)
243 {
244 	/* ffree st(i) */
245 	FPU_settagi(FPU_rm, TAG_Empty);
246 }
247 
ffreep(void)248 void ffreep(void)
249 {
250 	/* ffree st(i) + pop - unofficial code */
251 	FPU_settagi(FPU_rm, TAG_Empty);
252 	FPU_pop();
253 }
254 
fst_i_(void)255 void fst_i_(void)
256 {
257 	/* fst st(i) */
258 	FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm);
259 }
260 
fstp_i(void)261 void fstp_i(void)
262 {
263 	/* fstp st(i) */
264 	FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm);
265 	FPU_pop();
266 }
267