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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 <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