1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 NetWinder Floating Point Emulator
4 (c) Rebel.COM, 1998,1999
5 (c) Philip Blundell, 2001
6
7 Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
8
9 */
10
11 #include "fpa11.h"
12 #include "fpopcode.h"
13
14 #include "fpmodule.h"
15 #include "fpmodule.inl"
16
17 #include <linux/compiler.h>
18 #include <linux/string.h>
19
20 /* Reset the FPA11 chip. Called to initialize and reset the emulator. */
21 static void resetFPA11(void)
22 {
23 int i;
24 FPA11 *fpa11 = GET_FPA11();
25
26 /* initialize the register type array */
27 for (i = 0; i <= 7; i++) {
28 fpa11->fType[i] = typeNone;
29 }
30
31 /* FPSR: set system id to FP_EMULATOR, set AC, clear all other bits */
32 fpa11->fpsr = FP_EMULATOR | BIT_AC;
33 }
34
35 int8 SetRoundingMode(const unsigned int opcode)
36 {
37 switch (opcode & MASK_ROUNDING_MODE) {
38 default:
39 case ROUND_TO_NEAREST:
40 return float_round_nearest_even;
41
42 case ROUND_TO_PLUS_INFINITY:
43 return float_round_up;
44
45 case ROUND_TO_MINUS_INFINITY:
46 return float_round_down;
47
48 case ROUND_TO_ZERO:
49 return float_round_to_zero;
50 }
51 }
52
53 int8 SetRoundingPrecision(const unsigned int opcode)
54 {
55 #ifdef CONFIG_FPE_NWFPE_XP
56 switch (opcode & MASK_ROUNDING_PRECISION) {
57 case ROUND_SINGLE:
58 return 32;
59
60 case ROUND_DOUBLE:
61 return 64;
62
63 case ROUND_EXTENDED:
64 return 80;
65
66 default:
67 return 80;
68 }
69 #endif
70 return 80;
71 }
72
73 void nwfpe_init_fpa(union fp_state *fp)
74 {
75 FPA11 *fpa11 = (FPA11 *)fp;
76 #ifdef NWFPE_DEBUG
77 printk("NWFPE: setting up state.\n");
78 #endif
79 memset(fpa11, 0, sizeof(FPA11));
80 resetFPA11();
81 fpa11->initflag = 1;
82 }
83
84 /* Emulate the instruction in the opcode. */
85 unsigned int EmulateAll(unsigned int opcode)
86 {
87 unsigned int code;
88
89 #ifdef NWFPE_DEBUG
90 printk("NWFPE: emulating opcode %08x\n", opcode);
91 #endif
92 code = opcode & 0x00000f00;
93 if (code == 0x00000100 || code == 0x00000200) {
94 /* For coprocessor 1 or 2 (FPA11) */
95 code = opcode & 0x0e000000;
96 if (code == 0x0e000000) {
97 if (opcode & 0x00000010) {
98 /* Emulate conversion opcodes. */
99 /* Emulate register transfer opcodes. */
100 /* Emulate comparison opcodes. */
101 return EmulateCPRT(opcode);
102 } else {
103 /* Emulate monadic arithmetic opcodes. */
104 /* Emulate dyadic arithmetic opcodes. */
105 return EmulateCPDO(opcode);
106 }
107 } else if (code == 0x0c000000) {
108 /* Emulate load/store opcodes. */
109 /* Emulate load/store multiple opcodes. */
110 return EmulateCPDT(opcode);
111 }
112 }
113
114 /* Invalid instruction detected. Return FALSE. */
115 return 0;
116 }
117
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