FreeBSD/Linux Kernel Cross Reference
sys/powerpc/powerpc/altivec.c

     /*-
      * Copyright (C) 1996 Wolfgang Solfrank.
      * Copyright (C) 1996 TooLs GmbH.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by TooLs GmbH.
     * 4. The name of TooLs GmbH may not be used to endorse or promote products
     *    derived from this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     *
     *      $NetBSD: fpu.c,v 1.5 2001/07/22 11:29:46 wiz Exp $
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/8.0/sys/powerpc/powerpc/altivec.c 188860 2009-02-20 17:48:40Z nwhitehorn $");
    
    #include <sys/param.h>
    #include <sys/proc.h>
    #include <sys/systm.h>
    #include <sys/limits.h>
    
    #include <machine/altivec.h>
    #include <machine/pcb.h>
    #include <machine/psl.h>
    
    void
    enable_vec(struct thread *td)
    {
            int     msr;
            struct  pcb *pcb;
            struct  trapframe *tf;
    
            pcb = td->td_pcb;
            tf = trapframe(td);
    
            /*
             * Save the thread's Altivec CPU number, and set the CPU's current
             * vector thread
             */
            td->td_pcb->pcb_veccpu = PCPU_GET(cpuid);
            PCPU_SET(vecthread, td);
    
            /*
             * Enable the vector unit for when the thread returns from the
             * exception. If this is the first time the unit has been used by
             * the thread, initialise the vector registers and VSCR to 0, and
             * set the flag to indicate that the vector unit is in use.
             */
            tf->srr1 |= PSL_VEC;
            if (!(pcb->pcb_flags & PCB_VEC)) {
                    memset(&pcb->pcb_vec, 0, sizeof pcb->pcb_vec);
                    pcb->pcb_flags |= PCB_VEC;
            }
    
            /*
             * Temporarily enable the vector unit so the registers
             * can be restored.
             */
            msr = mfmsr();
            mtmsr(msr | PSL_VEC);
            isync();
    
            /*
             * Restore VSCR by first loading it into a vector and then into VSCR.
             * (this needs to done before loading the user's vector registers
             * since we need to use a scratch vector register)
             */
            __asm __volatile("vxor 0,0,0; lvewx 0,0,%0; mtvscr 0" \
                              :: "b"(&pcb->pcb_vec.vscr));
    
    #define LVX(n)   __asm ("lvx " #n ",0,%0" \
                    :: "b"(&pcb->pcb_vec.vr[n]));
            LVX(0);         LVX(1);         LVX(2);         LVX(3);
            LVX(4);         LVX(5);         LVX(6);         LVX(7);
            LVX(8);         LVX(9);         LVX(10);        LVX(11);
            LVX(12);        LVX(13);        LVX(14);        LVX(15);
            LVX(16);        LVX(17);        LVX(18);        LVX(19);
            LVX(20);        LVX(21);        LVX(22);        LVX(23);
            LVX(24);        LVX(25);        LVX(26);        LVX(27);
           LVX(28);        LVX(29);        LVX(30);        LVX(31);
   #undef LVX
   
           isync();
           mtmsr(msr);
   }
   
   void
   save_vec(struct thread *td)
   {
           int     msr;
           struct  pcb *pcb;
   
           pcb = td->td_pcb;
   
           /*
            * Temporarily re-enable the vector unit during the save
            */
           msr = mfmsr();
           mtmsr(msr | PSL_VEC);
           isync();
   
           /*
            * Save the vector registers and VSCR to the PCB
            */
   #define STVX(n)   __asm ("stvx %1,0,%0" \
                   :: "b"(pcb->pcb_vec.vr[n]), "n"(n));
           STVX(0);        STVX(1);        STVX(2);        STVX(3);
           STVX(4);        STVX(5);        STVX(6);        STVX(7);
           STVX(8);        STVX(9);        STVX(10);       STVX(11);
           STVX(12);       STVX(13);       STVX(14);       STVX(15);
           STVX(16);       STVX(17);       STVX(18);       STVX(19);
           STVX(20);       STVX(21);       STVX(22);       STVX(23);
           STVX(24);       STVX(25);       STVX(26);       STVX(27);
           STVX(28);       STVX(29);       STVX(30);       STVX(31);
   #undef STVX
   
           __asm __volatile("mfvscr 0; stvewx 0,0,%0" :: "b"(&pcb->pcb_vec.vscr));
   
           /*
            * Disable vector unit again
            */
           isync();
           mtmsr(msr);
   
           /*
            * Clear the current vec thread and pcb's CPU id
            * XXX should this be left clear to allow lazy save/restore ?
            */
           pcb->pcb_veccpu = INT_MAX;
           PCPU_SET(vecthread, NULL);
   }
   

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