xref: /kernel/linux/linux-6.6/arch/arm/nwfpe/fpa11.c (revision 62306a36) 
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. */
21static 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
35int8 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
53int8 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
73void 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. */
85unsigned 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