1 /*
2 NetWinder Floating Point Emulator
3 (c) Rebel.COM, 1998,1999
4 (c) Philip Blundell, 2001
5
6 Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23 #include "fpa11.h"
24 #include "fpopcode.h"
25
26 #include "fpmodule.h"
27 #include "fpmodule.inl"
28
29 #include <linux/compiler.h>
30 #include <linux/string.h>
31
32 /* Reset the FPA11 chip. Called to initialize and reset the emulator. */
resetFPA11(void)33 static void resetFPA11(void)
34 {
35 int i;
36 FPA11 *fpa11 = GET_FPA11();
37
38 /* initialize the register type array */
39 for (i = 0; i <= 7; i++) {
40 fpa11->fType[i] = typeNone;
41 }
42
43 /* FPSR: set system id to FP_EMULATOR, set AC, clear all other bits */
44 fpa11->fpsr = FP_EMULATOR | BIT_AC;
45 }
46
SetRoundingMode(const unsigned int opcode)47 int8 SetRoundingMode(const unsigned int opcode)
48 {
49 switch (opcode & MASK_ROUNDING_MODE) {
50 default:
51 case ROUND_TO_NEAREST:
52 return float_round_nearest_even;
53
54 case ROUND_TO_PLUS_INFINITY:
55 return float_round_up;
56
57 case ROUND_TO_MINUS_INFINITY:
58 return float_round_down;
59
60 case ROUND_TO_ZERO:
61 return float_round_to_zero;
62 }
63 }
64
SetRoundingPrecision(const unsigned int opcode)65 int8 SetRoundingPrecision(const unsigned int opcode)
66 {
67 #ifdef CONFIG_FPE_NWFPE_XP
68 switch (opcode & MASK_ROUNDING_PRECISION) {
69 case ROUND_SINGLE:
70 return 32;
71
72 case ROUND_DOUBLE:
73 return 64;
74
75 case ROUND_EXTENDED:
76 return 80;
77
78 default:
79 return 80;
80 }
81 #endif
82 return 80;
83 }
84
nwfpe_init_fpa(union fp_state * fp)85 void nwfpe_init_fpa(union fp_state *fp)
86 {
87 FPA11 *fpa11 = (FPA11 *)fp;
88 #ifdef NWFPE_DEBUG
89 printk("NWFPE: setting up state.\n");
90 #endif
91 memset(fpa11, 0, sizeof(FPA11));
92 resetFPA11();
93 fpa11->initflag = 1;
94 }
95
96 /* Emulate the instruction in the opcode. */
EmulateAll(unsigned int opcode)97 unsigned int EmulateAll(unsigned int opcode)
98 {
99 unsigned int code;
100
101 #ifdef NWFPE_DEBUG
102 printk("NWFPE: emulating opcode %08x\n", opcode);
103 #endif
104 code = opcode & 0x00000f00;
105 if (code == 0x00000100 || code == 0x00000200) {
106 /* For coprocessor 1 or 2 (FPA11) */
107 code = opcode & 0x0e000000;
108 if (code == 0x0e000000) {
109 if (opcode & 0x00000010) {
110 /* Emulate conversion opcodes. */
111 /* Emulate register transfer opcodes. */
112 /* Emulate comparison opcodes. */
113 return EmulateCPRT(opcode);
114 } else {
115 /* Emulate monadic arithmetic opcodes. */
116 /* Emulate dyadic arithmetic opcodes. */
117 return EmulateCPDO(opcode);
118 }
119 } else if (code == 0x0c000000) {
120 /* Emulate load/store opcodes. */
121 /* Emulate load/store multiple opcodes. */
122 return EmulateCPDT(opcode);
123 }
124 }
125
126 /* Invalid instruction detected. Return FALSE. */
127 return 0;
128 }
129