1 /*-
2 * Copyright (C) 1996 Wolfgang Solfrank.
3 * Copyright (C) 1996 TooLs GmbH.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by TooLs GmbH.
17 * 4. The name of TooLs GmbH may not be used to endorse or promote products
18 * derived from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
26 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
28 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
29 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 *
31 * $NetBSD: fpu.c,v 1.5 2001/07/22 11:29:46 wiz Exp $
32 */
33
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36
37 #include <sys/param.h>
38 #include <sys/proc.h>
39 #include <sys/systm.h>
40 #include <sys/limits.h>
41
42 #include <machine/fpu.h>
43 #include <machine/pcb.h>
44 #include <machine/psl.h>
45
46 void
enable_fpu(struct thread * td)47 enable_fpu(struct thread *td)
48 {
49 int msr;
50 struct pcb *pcb;
51 struct trapframe *tf;
52
53 pcb = td->td_pcb;
54 tf = trapframe(td);
55
56 /*
57 * Save the thread's FPU CPU number, and set the CPU's current
58 * FPU thread
59 */
60 td->td_pcb->pcb_fpcpu = PCPU_GET(cpuid);
61 PCPU_SET(fputhread, td);
62
63 /*
64 * Enable the FPU for when the thread returns from the exception.
65 * If this is the first time the FPU has been used by the thread,
66 * initialise the FPU registers and FPSCR to 0, and set the flag
67 * to indicate that the FPU is in use.
68 */
69 pcb->pcb_flags |= PCB_FPU;
70 tf->srr1 |= PSL_FP;
71 if (!(pcb->pcb_flags & PCB_FPREGS)) {
72 memset(&pcb->pcb_fpu, 0, sizeof pcb->pcb_fpu);
73 pcb->pcb_flags |= PCB_FPREGS;
74 }
75
76 /*
77 * Temporarily enable floating-point so the registers
78 * can be restored.
79 */
80 msr = mfmsr();
81 mtmsr(msr | PSL_FP);
82 isync();
83
84 /*
85 * Load the floating point registers and FPSCR from the PCB.
86 * (A value of 0xff for mtfsf specifies that all 8 4-bit fields
87 * of the saved FPSCR are to be loaded from the FPU reg).
88 */
89 __asm __volatile ("lfd 0,0(%0); mtfsf 0xff,0"
90 :: "b"(&pcb->pcb_fpu.fpscr));
91
92 #define LFP(n) __asm ("lfd " #n ", 0(%0)" \
93 :: "b"(&pcb->pcb_fpu.fpr[n]));
94 LFP(0); LFP(1); LFP(2); LFP(3);
95 LFP(4); LFP(5); LFP(6); LFP(7);
96 LFP(8); LFP(9); LFP(10); LFP(11);
97 LFP(12); LFP(13); LFP(14); LFP(15);
98 LFP(16); LFP(17); LFP(18); LFP(19);
99 LFP(20); LFP(21); LFP(22); LFP(23);
100 LFP(24); LFP(25); LFP(26); LFP(27);
101 LFP(28); LFP(29); LFP(30); LFP(31);
102 #undef LFP
103
104 isync();
105 mtmsr(msr);
106 }
107
108 void
save_fpu(struct thread * td)109 save_fpu(struct thread *td)
110 {
111 int msr;
112 struct pcb *pcb;
113
114 pcb = td->td_pcb;
115
116 /*
117 * Temporarily re-enable floating-point during the save
118 */
119 msr = mfmsr();
120 mtmsr(msr | PSL_FP);
121 isync();
122
123 /*
124 * Save the floating-point registers and FPSCR to the PCB
125 */
126 #define SFP(n) __asm ("stfd " #n ", 0(%0)" \
127 :: "b"(&pcb->pcb_fpu.fpr[n]));
128 SFP(0); SFP(1); SFP(2); SFP(3);
129 SFP(4); SFP(5); SFP(6); SFP(7);
130 SFP(8); SFP(9); SFP(10); SFP(11);
131 SFP(12); SFP(13); SFP(14); SFP(15);
132 SFP(16); SFP(17); SFP(18); SFP(19);
133 SFP(20); SFP(21); SFP(22); SFP(23);
134 SFP(24); SFP(25); SFP(26); SFP(27);
135 SFP(28); SFP(29); SFP(30); SFP(31);
136 #undef SFP
137 __asm __volatile ("mffs 0; stfd 0,0(%0)" :: "b"(&pcb->pcb_fpu.fpscr));
138
139 /*
140 * Disable floating-point again
141 */
142 isync();
143 mtmsr(msr);
144
145 /*
146 * Clear the current fp thread and pcb's CPU id
147 * XXX should this be left clear to allow lazy save/restore ?
148 */
149 pcb->pcb_fpcpu = INT_MAX;
150 PCPU_SET(fputhread, NULL);
151 }
152
153