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 #include <asm/system.h>
32
33 /* Reset the FPA11 chip. Called to initialize and reset the emulator. */
resetFPA11(void)34 static void resetFPA11(void)
35 {
36 int i;
37 FPA11 *fpa11 = GET_FPA11();
38
39 /* initialize the register type array */
40 for (i = 0; i <= 7; i++) {
41 fpa11->fType[i] = typeNone;
42 }
43
44 /* FPSR: set system id to FP_EMULATOR, set AC, clear all other bits */
45 fpa11->fpsr = FP_EMULATOR | BIT_AC;
46 }
47
SetRoundingMode(const unsigned int opcode)48 int8 SetRoundingMode(const unsigned int opcode)
49 {
50 switch (opcode & MASK_ROUNDING_MODE) {
51 default:
52 case ROUND_TO_NEAREST:
53 return float_round_nearest_even;
54
55 case ROUND_TO_PLUS_INFINITY:
56 return float_round_up;
57
58 case ROUND_TO_MINUS_INFINITY:
59 return float_round_down;
60
61 case ROUND_TO_ZERO:
62 return float_round_to_zero;
63 }
64 }
65
SetRoundingPrecision(const unsigned int opcode)66 int8 SetRoundingPrecision(const unsigned int opcode)
67 {
68 #ifdef CONFIG_FPE_NWFPE_XP
69 switch (opcode & MASK_ROUNDING_PRECISION) {
70 case ROUND_SINGLE:
71 return 32;
72
73 case ROUND_DOUBLE:
74 return 64;
75
76 case ROUND_EXTENDED:
77 return 80;
78
79 default:
80 return 80;
81 }
82 #endif
83 return 80;
84 }
85
nwfpe_init_fpa(union fp_state * fp)86 void nwfpe_init_fpa(union fp_state *fp)
87 {
88 FPA11 *fpa11 = (FPA11 *)fp;
89 #ifdef NWFPE_DEBUG
90 printk("NWFPE: setting up state.\n");
91 #endif
92 memset(fpa11, 0, sizeof(FPA11));
93 resetFPA11();
94 fpa11->initflag = 1;
95 }
96
97 /* Emulate the instruction in the opcode. */
EmulateAll(unsigned int opcode)98 unsigned int EmulateAll(unsigned int opcode)
99 {
100 unsigned int code;
101
102 #ifdef NWFPE_DEBUG
103 printk("NWFPE: emulating opcode %08x\n", opcode);
104 #endif
105 code = opcode & 0x00000f00;
106 if (code == 0x00000100 || code == 0x00000200) {
107 /* For coprocessor 1 or 2 (FPA11) */
108 code = opcode & 0x0e000000;
109 if (code == 0x0e000000) {
110 if (opcode & 0x00000010) {
111 /* Emulate conversion opcodes. */
112 /* Emulate register transfer opcodes. */
113 /* Emulate comparison opcodes. */
114 return EmulateCPRT(opcode);
115 } else {
116 /* Emulate monadic arithmetic opcodes. */
117 /* Emulate dyadic arithmetic opcodes. */
118 return EmulateCPDO(opcode);
119 }
120 } else if (code == 0x0c000000) {
121 /* Emulate load/store opcodes. */
122 /* Emulate load/store multiple opcodes. */
123 return EmulateCPDT(opcode);
124 }
125 }
126
127 /* Invalid instruction detected. Return FALSE. */
128 return 0;
129 }
130