Linux Kernel  3.7.1
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fpa11.c
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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 <[email protected]>
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. */
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 
47 int8 SetRoundingMode(const unsigned int opcode)
48 {
49  switch (opcode & MASK_ROUNDING_MODE) {
50  default:
51  case ROUND_TO_NEAREST:
53 
55  return float_round_up;
56 
58  return float_round_down;
59 
60  case ROUND_TO_ZERO:
61  return float_round_to_zero;
62  }
63 }
64 
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 
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. */
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 }