1 /*
2 NetWinder Floating Point Emulator
3 (c) Rebel.COM, 1998,1999
4
5 Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, see <http://www.gnu.org/licenses/>.
19 */
20
21 #include "qemu/osdep.h"
22 #include "fpa11.h"
23
24 #include "fpopcode.h"
25
26 //#include "fpmodule.h"
27 //#include "fpmodule.inl"
28
29 //#include <asm/system.h>
30
31
32 FPA11* qemufpa = NULL;
33 CPUARMState* user_registers;
34
35 /* Reset the FPA11 chip. Called to initialize and reset the emulator. */
resetFPA11(void)36 void resetFPA11(void)
37 {
38 int i;
39 FPA11 *fpa11 = GET_FPA11();
40
41 /* initialize the register type array */
42 for (i=0;i<=7;i++)
43 {
44 fpa11->fType[i] = typeNone;
45 }
46
47 /* FPSR: set system id to FP_EMULATOR, set AC, clear all other bits */
48 fpa11->fpsr = FP_EMULATOR | BIT_AC;
49
50 /* FPCR: set SB, AB and DA bits, clear all others */
51 #ifdef MAINTAIN_FPCR
52 fpa11->fpcr = MASK_RESET;
53 #endif
54 }
55
SetRoundingMode(const unsigned int opcode)56 void SetRoundingMode(const unsigned int opcode)
57 {
58 int rounding_mode;
59 FPA11 *fpa11 = GET_FPA11();
60
61 #ifdef MAINTAIN_FPCR
62 fpa11->fpcr &= ~MASK_ROUNDING_MODE;
63 #endif
64 switch (opcode & MASK_ROUNDING_MODE)
65 {
66 default:
67 case ROUND_TO_NEAREST:
68 rounding_mode = float_round_nearest_even;
69 #ifdef MAINTAIN_FPCR
70 fpa11->fpcr |= ROUND_TO_NEAREST;
71 #endif
72 break;
73
74 case ROUND_TO_PLUS_INFINITY:
75 rounding_mode = float_round_up;
76 #ifdef MAINTAIN_FPCR
77 fpa11->fpcr |= ROUND_TO_PLUS_INFINITY;
78 #endif
79 break;
80
81 case ROUND_TO_MINUS_INFINITY:
82 rounding_mode = float_round_down;
83 #ifdef MAINTAIN_FPCR
84 fpa11->fpcr |= ROUND_TO_MINUS_INFINITY;
85 #endif
86 break;
87
88 case ROUND_TO_ZERO:
89 rounding_mode = float_round_to_zero;
90 #ifdef MAINTAIN_FPCR
91 fpa11->fpcr |= ROUND_TO_ZERO;
92 #endif
93 break;
94 }
95 set_float_rounding_mode(rounding_mode, &fpa11->fp_status);
96 }
97
SetRoundingPrecision(const unsigned int opcode)98 void SetRoundingPrecision(const unsigned int opcode)
99 {
100 FloatX80RoundPrec rounding_precision;
101 FPA11 *fpa11 = GET_FPA11();
102 #ifdef MAINTAIN_FPCR
103 fpa11->fpcr &= ~MASK_ROUNDING_PRECISION;
104 #endif
105 switch (opcode & MASK_ROUNDING_PRECISION) {
106 case ROUND_SINGLE:
107 rounding_precision = floatx80_precision_s;
108 #ifdef MAINTAIN_FPCR
109 fpa11->fpcr |= ROUND_SINGLE;
110 #endif
111 break;
112
113 case ROUND_DOUBLE:
114 rounding_precision = floatx80_precision_d;
115 #ifdef MAINTAIN_FPCR
116 fpa11->fpcr |= ROUND_DOUBLE;
117 #endif
118 break;
119
120 case ROUND_EXTENDED:
121 rounding_precision = floatx80_precision_x;
122 #ifdef MAINTAIN_FPCR
123 fpa11->fpcr |= ROUND_EXTENDED;
124 #endif
125 break;
126
127 default:
128 rounding_precision = floatx80_precision_x;
129 break;
130 }
131 set_floatx80_rounding_precision(rounding_precision, &fpa11->fp_status);
132 }
133
134 /* Emulate the instruction in the opcode. */
135 /* ??? This is not thread safe. */
EmulateAll(unsigned int opcode,FPA11 * qfpa,CPUARMState * qregs)136 unsigned int EmulateAll(unsigned int opcode, FPA11* qfpa, CPUARMState* qregs)
137 {
138 unsigned int nRc = 0;
139 // unsigned long flags;
140 FPA11 *fpa11;
141 unsigned int cp;
142 // save_flags(flags); sti();
143
144 /* Check that this is really an FPA11 instruction: the coprocessor
145 * field in bits [11:8] must be 1 or 2.
146 */
147 cp = (opcode >> 8) & 0xf;
148 if (cp != 1 && cp != 2) {
149 return 0;
150 }
151
152 qemufpa=qfpa;
153 user_registers=qregs;
154
155 #if 0
156 fprintf(stderr,"emulating FP insn 0x%08x, PC=0x%08x\n",
157 opcode, qregs[ARM_REG_PC]);
158 #endif
159 fpa11 = GET_FPA11();
160
161 if (fpa11->initflag == 0) /* good place for __builtin_expect */
162 {
163 resetFPA11();
164 SetRoundingMode(ROUND_TO_NEAREST);
165 SetRoundingPrecision(ROUND_EXTENDED);
166 fpa11->initflag = 1;
167 }
168
169 set_float_exception_flags(0, &fpa11->fp_status);
170
171 if (TEST_OPCODE(opcode,MASK_CPRT))
172 {
173 //fprintf(stderr,"emulating CPRT\n");
174 /* Emulate conversion opcodes. */
175 /* Emulate register transfer opcodes. */
176 /* Emulate comparison opcodes. */
177 nRc = EmulateCPRT(opcode);
178 }
179 else if (TEST_OPCODE(opcode,MASK_CPDO))
180 {
181 //fprintf(stderr,"emulating CPDO\n");
182 /* Emulate monadic arithmetic opcodes. */
183 /* Emulate dyadic arithmetic opcodes. */
184 nRc = EmulateCPDO(opcode);
185 }
186 else if (TEST_OPCODE(opcode,MASK_CPDT))
187 {
188 //fprintf(stderr,"emulating CPDT\n");
189 /* Emulate load/store opcodes. */
190 /* Emulate load/store multiple opcodes. */
191 nRc = EmulateCPDT(opcode);
192 }
193 else
194 {
195 /* Invalid instruction detected. Return FALSE. */
196 nRc = 0;
197 }
198
199 // restore_flags(flags);
200 if(nRc == 1 && get_float_exception_flags(&fpa11->fp_status))
201 {
202 //printf("fef 0x%x\n",float_exception_flags);
203 nRc = -get_float_exception_flags(&fpa11->fp_status);
204 }
205
206 //printf("returning %d\n",nRc);
207 return(nRc);
208 }
209
210 #if 0
211 unsigned int EmulateAll1(unsigned int opcode)
212 {
213 switch ((opcode >> 24) & 0xf)
214 {
215 case 0xc:
216 case 0xd:
217 if ((opcode >> 20) & 0x1)
218 {
219 switch ((opcode >> 8) & 0xf)
220 {
221 case 0x1: return PerformLDF(opcode); break;
222 case 0x2: return PerformLFM(opcode); break;
223 default: return 0;
224 }
225 }
226 else
227 {
228 switch ((opcode >> 8) & 0xf)
229 {
230 case 0x1: return PerformSTF(opcode); break;
231 case 0x2: return PerformSFM(opcode); break;
232 default: return 0;
233 }
234 }
235 break;
236
237 case 0xe:
238 if (opcode & 0x10)
239 return EmulateCPDO(opcode);
240 else
241 return EmulateCPRT(opcode);
242 break;
243
244 default: return 0;
245 }
246 }
247 #endif
248