2 NetWinder Floating Point Emulator
3 (c) Rebel.COM, 1998,1999
5 Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
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.
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.
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.
26 //#include "fpmodule.h"
27 //#include "fpmodule.inl"
29 //#include <asm/system.h>
33 /* forward declarations */
34 unsigned int EmulateCPDO(const unsigned int);
35 unsigned int EmulateCPDT(const unsigned int);
36 unsigned int EmulateCPRT(const unsigned int);
39 unsigned int* user_registers=0;
41 /* Reset the FPA11 chip. Called to initialize and reset the emulator. */
45 FPA11 *fpa11 = GET_FPA11();
47 /* initialize the register type array */
50 fpa11->fType[i] = typeNone;
53 /* FPSR: set system id to FP_EMULATOR, set AC, clear all other bits */
54 fpa11->fpsr = FP_EMULATOR | BIT_AC;
56 /* FPCR: set SB, AB and DA bits, clear all others */
58 fpa11->fpcr = MASK_RESET;
62 void SetRoundingMode(const unsigned int opcode)
65 FPA11 *fpa11 = GET_FPA11();
66 fpa11->fpcr &= ~MASK_ROUNDING_MODE;
68 switch (opcode & MASK_ROUNDING_MODE)
71 case ROUND_TO_NEAREST:
72 float_rounding_mode = float_round_nearest_even;
74 fpa11->fpcr |= ROUND_TO_NEAREST;
78 case ROUND_TO_PLUS_INFINITY:
79 float_rounding_mode = float_round_up;
81 fpa11->fpcr |= ROUND_TO_PLUS_INFINITY;
85 case ROUND_TO_MINUS_INFINITY:
86 float_rounding_mode = float_round_down;
88 fpa11->fpcr |= ROUND_TO_MINUS_INFINITY;
93 float_rounding_mode = float_round_to_zero;
95 fpa11->fpcr |= ROUND_TO_ZERO;
101 void SetRoundingPrecision(const unsigned int opcode)
104 FPA11 *fpa11 = GET_FPA11();
105 fpa11->fpcr &= ~MASK_ROUNDING_PRECISION;
107 switch (opcode & MASK_ROUNDING_PRECISION)
110 floatx80_rounding_precision = 32;
112 fpa11->fpcr |= ROUND_SINGLE;
117 floatx80_rounding_precision = 64;
119 fpa11->fpcr |= ROUND_DOUBLE;
124 floatx80_rounding_precision = 80;
126 fpa11->fpcr |= ROUND_EXTENDED;
130 default: floatx80_rounding_precision = 80;
134 /* Emulate the instruction in the opcode. */
135 unsigned int EmulateAll(unsigned int opcode, FPA11* qfpa, unsigned int* qregs)
137 unsigned int nRc = 0;
138 // unsigned long flags;
140 // save_flags(flags); sti();
143 user_registers=qregs;
146 fprintf(stderr,"emulating FP insn 0x%08x, PC=0x%08x\n",
147 opcode, qregs[REG_PC]);
151 if (fpa11->initflag == 0) /* good place for __builtin_expect */
154 SetRoundingMode(ROUND_TO_NEAREST);
155 SetRoundingPrecision(ROUND_EXTENDED);
159 if (TEST_OPCODE(opcode,MASK_CPRT))
161 //fprintf(stderr,"emulating CPRT\n");
162 /* Emulate conversion opcodes. */
163 /* Emulate register transfer opcodes. */
164 /* Emulate comparison opcodes. */
165 nRc = EmulateCPRT(opcode);
167 else if (TEST_OPCODE(opcode,MASK_CPDO))
169 //fprintf(stderr,"emulating CPDO\n");
170 /* Emulate monadic arithmetic opcodes. */
171 /* Emulate dyadic arithmetic opcodes. */
172 nRc = EmulateCPDO(opcode);
174 else if (TEST_OPCODE(opcode,MASK_CPDT))
176 //fprintf(stderr,"emulating CPDT\n");
177 /* Emulate load/store opcodes. */
178 /* Emulate load/store multiple opcodes. */
179 nRc = EmulateCPDT(opcode);
183 /* Invalid instruction detected. Return FALSE. */
187 // restore_flags(flags);
189 //printf("returning %d\n",nRc);
194 unsigned int EmulateAll1(unsigned int opcode)
196 switch ((opcode >> 24) & 0xf)
200 if ((opcode >> 20) & 0x1)
202 switch ((opcode >> 8) & 0xf)
204 case 0x1: return PerformLDF(opcode); break;
205 case 0x2: return PerformLFM(opcode); break;
211 switch ((opcode >> 8) & 0xf)
213 case 0x1: return PerformSTF(opcode); break;
214 case 0x2: return PerformSFM(opcode); break;
222 return EmulateCPDO(opcode);
224 return EmulateCPRT(opcode);