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1.1 root 1: /*
2: NetWinder Floating Point Emulator
3: (c) Rebel.COM, 1998,1999
4:
5: Direct questions, comments to Scott Bambrough <[email protected]>
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, write to the Free Software
19: Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20: */
21:
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: #include <stdio.h>
32:
33: /* forward declarations */
34: unsigned int EmulateCPDO(const unsigned int);
35: unsigned int EmulateCPDT(const unsigned int);
36: unsigned int EmulateCPRT(const unsigned int);
37:
38: FPA11* qemufpa=0;
39: unsigned int* user_registers=0;
40:
41: /* Reset the FPA11 chip. Called to initialize and reset the emulator. */
42: void resetFPA11(void)
43: {
44: int i;
45: FPA11 *fpa11 = GET_FPA11();
46:
47: /* initialize the register type array */
48: for (i=0;i<=7;i++)
49: {
50: fpa11->fType[i] = typeNone;
51: }
52:
53: /* FPSR: set system id to FP_EMULATOR, set AC, clear all other bits */
54: fpa11->fpsr = FP_EMULATOR | BIT_AC;
55:
56: /* FPCR: set SB, AB and DA bits, clear all others */
57: #if MAINTAIN_FPCR
58: fpa11->fpcr = MASK_RESET;
59: #endif
60: }
61:
62: void SetRoundingMode(const unsigned int opcode)
63: {
64: int rounding_mode;
65: FPA11 *fpa11 = GET_FPA11();
66:
67: #if MAINTAIN_FPCR
68: fpa11->fpcr &= ~MASK_ROUNDING_MODE;
69: #endif
70: switch (opcode & MASK_ROUNDING_MODE)
71: {
72: default:
73: case ROUND_TO_NEAREST:
74: rounding_mode = float_round_nearest_even;
75: #if MAINTAIN_FPCR
76: fpa11->fpcr |= ROUND_TO_NEAREST;
77: #endif
78: break;
79:
80: case ROUND_TO_PLUS_INFINITY:
81: rounding_mode = float_round_up;
82: #if MAINTAIN_FPCR
83: fpa11->fpcr |= ROUND_TO_PLUS_INFINITY;
84: #endif
85: break;
86:
87: case ROUND_TO_MINUS_INFINITY:
88: rounding_mode = float_round_down;
89: #if MAINTAIN_FPCR
90: fpa11->fpcr |= ROUND_TO_MINUS_INFINITY;
91: #endif
92: break;
93:
94: case ROUND_TO_ZERO:
95: rounding_mode = float_round_to_zero;
96: #if MAINTAIN_FPCR
97: fpa11->fpcr |= ROUND_TO_ZERO;
98: #endif
99: break;
100: }
101: set_float_rounding_mode(rounding_mode, &fpa11->fp_status);
102: }
103:
104: void SetRoundingPrecision(const unsigned int opcode)
105: {
106: int rounding_precision;
107: FPA11 *fpa11 = GET_FPA11();
108: #if MAINTAIN_FPCR
109: fpa11->fpcr &= ~MASK_ROUNDING_PRECISION;
110: #endif
111: switch (opcode & MASK_ROUNDING_PRECISION)
112: {
113: case ROUND_SINGLE:
114: rounding_precision = 32;
115: #if MAINTAIN_FPCR
116: fpa11->fpcr |= ROUND_SINGLE;
117: #endif
118: break;
119:
120: case ROUND_DOUBLE:
121: rounding_precision = 64;
122: #if MAINTAIN_FPCR
123: fpa11->fpcr |= ROUND_DOUBLE;
124: #endif
125: break;
126:
127: case ROUND_EXTENDED:
128: rounding_precision = 80;
129: #if MAINTAIN_FPCR
130: fpa11->fpcr |= ROUND_EXTENDED;
131: #endif
132: break;
133:
134: default: rounding_precision = 80;
135: }
136: set_floatx80_rounding_precision(rounding_precision, &fpa11->fp_status);
137: }
138:
139: /* Emulate the instruction in the opcode. */
140: unsigned int EmulateAll(unsigned int opcode, FPA11* qfpa, unsigned int* qregs)
141: {
142: unsigned int nRc = 0;
143: // unsigned long flags;
144: FPA11 *fpa11;
145: // save_flags(flags); sti();
146:
147: qemufpa=qfpa;
148: user_registers=qregs;
149:
150: #if 0
151: fprintf(stderr,"emulating FP insn 0x%08x, PC=0x%08x\n",
152: opcode, qregs[REG_PC]);
153: #endif
154: fpa11 = GET_FPA11();
155:
156: if (fpa11->initflag == 0) /* good place for __builtin_expect */
157: {
158: resetFPA11();
159: SetRoundingMode(ROUND_TO_NEAREST);
160: SetRoundingPrecision(ROUND_EXTENDED);
161: fpa11->initflag = 1;
162: }
163:
164: if (TEST_OPCODE(opcode,MASK_CPRT))
165: {
166: //fprintf(stderr,"emulating CPRT\n");
167: /* Emulate conversion opcodes. */
168: /* Emulate register transfer opcodes. */
169: /* Emulate comparison opcodes. */
170: nRc = EmulateCPRT(opcode);
171: }
172: else if (TEST_OPCODE(opcode,MASK_CPDO))
173: {
174: //fprintf(stderr,"emulating CPDO\n");
175: /* Emulate monadic arithmetic opcodes. */
176: /* Emulate dyadic arithmetic opcodes. */
177: nRc = EmulateCPDO(opcode);
178: }
179: else if (TEST_OPCODE(opcode,MASK_CPDT))
180: {
181: //fprintf(stderr,"emulating CPDT\n");
182: /* Emulate load/store opcodes. */
183: /* Emulate load/store multiple opcodes. */
184: nRc = EmulateCPDT(opcode);
185: }
186: else
187: {
188: /* Invalid instruction detected. Return FALSE. */
189: nRc = 0;
190: }
191:
192: // restore_flags(flags);
193:
194: //printf("returning %d\n",nRc);
195: return(nRc);
196: }
197:
198: #if 0
199: unsigned int EmulateAll1(unsigned int opcode)
200: {
201: switch ((opcode >> 24) & 0xf)
202: {
203: case 0xc:
204: case 0xd:
205: if ((opcode >> 20) & 0x1)
206: {
207: switch ((opcode >> 8) & 0xf)
208: {
209: case 0x1: return PerformLDF(opcode); break;
210: case 0x2: return PerformLFM(opcode); break;
211: default: return 0;
212: }
213: }
214: else
215: {
216: switch ((opcode >> 8) & 0xf)
217: {
218: case 0x1: return PerformSTF(opcode); break;
219: case 0x2: return PerformSFM(opcode); break;
220: default: return 0;
221: }
222: }
223: break;
224:
225: case 0xe:
226: if (opcode & 0x10)
227: return EmulateCPDO(opcode);
228: else
229: return EmulateCPRT(opcode);
230: break;
231:
232: default: return 0;
233: }
234: }
235: #endif
236:
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