FreeBSD/Linux Kernel Cross Reference
sys/i386/include/cpufunc.h

     /*-
      * Copyright (c) 1993 The Regents of the University of California.
      * 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 the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
     *
     * $FreeBSD: src/sys/i386/include/cpufunc.h,v 1.59.2.3 1999/09/05 08:11:44 peter Exp $
     */
    
    /*
     * Functions to provide access to special i386 instructions.
     */
    
    #ifndef _MACHINE_CPUFUNC_H_
    #define _MACHINE_CPUFUNC_H_
    
    #include <sys/cdefs.h>
    #include <sys/types.h>
    
    #ifdef  __GNUC__
    
    static __inline void
    breakpoint(void)
    {
            __asm __volatile("int $3");
    }
    
    static __inline void
    disable_intr(void)
    {
            __asm __volatile("cli" : : : "memory");
    }
    
    static __inline void
    enable_intr(void)
    {
            __asm __volatile("sti");
    }
    
    #define HAVE_INLINE_FFS
    
    static __inline int
    ffs(int mask)
    {
            int     result;
            /*
             * bsfl turns out to be not all that slow on 486's.  It can beaten
             * using a binary search to reduce to 4 bits and then a table lookup,
             * but only if the code is inlined and in the cache, and the code
             * is quite large so inlining it probably busts the cache.
             *
             * Note that gcc-2's builtin ffs would be used if we didn't declare
             * this inline or turn off the builtin.  The builtin is faster but
             * broken in gcc-2.4.5 and slower but working in gcc-2.5 and 2.6.
             */
            __asm __volatile("testl %0,%0; je 1f; bsfl %0,%0; incl %0; 1:"
                             : "=r" (result) : "" (mask));
            return (result);
    }
    
    #define HAVE_INLINE_FLS
    
    static __inline int
    fls(int mask)
    {
            int     result;
            __asm __volatile("testl %0,%0; je 1f; bsrl %0,%0; incl %0; 1:"
                             : "=r" (result) : "" (mask));
            return (result);
    }
    
    #if __GNUC__ < 2
    
   #define inb(port)               inbv(port)
   #define outb(port, data)        outbv(port, data)
   
   #else /* __GNUC >= 2 */
   
   /*
    * The following complications are to get around gcc not having a
    * constraint letter for the range 0..255.  We still put "d" in the
    * constraint because "i" isn't a valid constraint when the port
    * isn't constant.  This only matters for -O0 because otherwise
    * the non-working version gets optimized away.
    * 
    * Use an expression-statement instead of a conditional expression
    * because gcc-2.6.0 would promote the operands of the conditional
    * and produce poor code for "if ((inb(var) & const1) == const2)".
    *
    * The unnecessary test `(port) < 0x10000' is to generate a warning if
    * the `port' has type u_short or smaller.  Such types are pessimal.
    * This actually only works for signed types.  The range check is
    * careful to avoid generating warnings.
    */
   #define inb(port) __extension__ ({                                      \
           u_char  _data;                                                  \
           if (__builtin_constant_p(port) && ((port) & 0xffff) < 0x100     \
               && (port) < 0x10000)                                        \
                   _data = inbc(port);                                     \
           else                                                            \
                   _data = inbv(port);                                     \
           _data; })
   
   #define outb(port, data) (                                              \
           __builtin_constant_p(port) && ((port) & 0xffff) < 0x100         \
           && (port) < 0x10000                                             \
           ? outbc(port, data) : outbv(port, data))
   
   static __inline u_char
   inbc(u_int port)
   {
           u_char  data;
   
           __asm __volatile("inb %1,%0" : "=a" (data) : "id" ((u_short)(port)));
           return (data);
   }
   
   static __inline void
   outbc(u_int port, u_char data)
   {
           __asm __volatile("outb %0,%1" : : "a" (data), "id" ((u_short)(port)));
   }
   
   #endif /* __GNUC <= 2 */
   
   static __inline u_char
   inbv(u_int port)
   {
           u_char  data;
           /*
            * We use %%dx and not %1 here because i/o is done at %dx and not at
            * %edx, while gcc generates inferior code (movw instead of movl)
            * if we tell it to load (u_short) port.
            */
           __asm __volatile("inb %%dx,%0" : "=a" (data) : "d" (port));
           return (data);
   }
   
   static __inline u_long
   inl(u_int port)
   {
           u_long  data;
   
           __asm __volatile("inl %%dx,%0" : "=a" (data) : "d" (port));
           return (data);
   }
   
   static __inline void
   insb(u_int port, void *addr, size_t cnt)
   {
           __asm __volatile("cld; rep; insb"
                            : : "d" (port), "D" (addr), "c" (cnt)
                            : "di", "cx", "memory");
   }
   
   static __inline void
   insw(u_int port, void *addr, size_t cnt)
   {
           __asm __volatile("cld; rep; insw"
                            : : "d" (port), "D" (addr), "c" (cnt)
                            : "di", "cx", "memory");
   }
   
   static __inline void
   insl(u_int port, void *addr, size_t cnt)
   {
           __asm __volatile("cld; rep; insl"
                            : : "d" (port), "D" (addr), "c" (cnt)
                            : "di", "cx", "memory");
   }
   
   static __inline void
   invd(void)
   {
           __asm __volatile("invd");
   }
   
   static __inline void
   invlpg(u_int addr)
   {
           __asm __volatile("invlpg (%0)" : : "r" (addr) : "memory");
   }
   
   static __inline void
   invltlb(void)
   {
           u_long  temp;
           /*
            * This should be implemented as load_cr3(rcr3()) when load_cr3()
            * is inlined.
            */
           __asm __volatile("movl %%cr3, %0; movl %0, %%cr3" : "=r" (temp)
                            : : "memory");
   }
   
   static __inline u_short
   inw(u_int port)
   {
           u_short data;
   
           __asm __volatile("inw %%dx,%0" : "=a" (data) : "d" (port));
           return (data);
   }
   
   static __inline u_int
   loadandclear(u_int *addr)
   {
           u_int   result;
   
           __asm __volatile("xorl %0,%0; xchgl %1,%0"
                            : "=&r" (result) : "m" (*addr));
           return (result);
   }
   
   static __inline void
   outbv(u_int port, u_char data)
   {
           u_char  al;
           /*
            * Use an unnecessary assignment to help gcc's register allocator.
            * This make a large difference for gcc-1.40 and a tiny difference
            * for gcc-2.6.0.  For gcc-1.40, al had to be ``asm("ax")'' for
            * best results.  gcc-2.6.0 can't handle this.
            */
           al = data;
           __asm __volatile("outb %0,%%dx" : : "a" (al), "d" (port));
   }
   
   static __inline void
   outl(u_int port, u_long data)
   {
           /*
            * outl() and outw() aren't used much so we haven't looked at
            * possible micro-optimizations such as the unnecessary
            * assignment for them.
            */
           __asm __volatile("outl %0,%%dx" : : "a" (data), "d" (port));
   }
   
   static __inline void
   outsb(u_int port, const void *addr, size_t cnt)
   {
           __asm __volatile("cld; rep; outsb"
                            : : "d" (port), "S" (addr), "c" (cnt)
                            : "si", "cx");
   }
   
   static __inline void
   outsw(u_int port, const void *addr, size_t cnt)
   {
           __asm __volatile("cld; rep; outsw"
                            : : "d" (port), "S" (addr), "c" (cnt)
                            : "si", "cx");
   }
   
   static __inline void
   outsl(u_int port, const void *addr, size_t cnt)
   {
           __asm __volatile("cld; rep; outsl"
                            : : "d" (port), "S" (addr), "c" (cnt)
                            : "si", "cx");
   }
   
   static __inline void
   outw(u_int port, u_short data)
   {
           __asm __volatile("outw %0,%%dx" : : "a" (data), "d" (port));
   }
   
   static __inline u_long
   rcr2(void)
   {
           u_long  data;
   
           __asm __volatile("movl %%cr2,%0" : "=r" (data));
           return (data);
   }
   
   static __inline u_long
   read_eflags(void)
   {
           u_long  ef;
   
           __asm __volatile("pushfl; popl %0" : "=r" (ef));
           return (ef);
   }
   
   static __inline quad_t
   rdmsr(u_int msr)
   {
           quad_t rv;
   
           __asm __volatile(".byte 0x0f, 0x32" : "=A" (rv) : "c" (msr));
           return (rv);
   }
   
   static __inline quad_t
   rdpmc(u_int pmc)
   {
           quad_t rv;
   
           __asm __volatile(".byte 0x0f, 0x33" : "=A" (rv) : "c" (pmc));
           return (rv);
   }
   
   static __inline quad_t
   rdtsc(void)
   {
           quad_t rv;
   
           __asm __volatile(".byte 0x0f, 0x31" : "=A" (rv));
           return (rv);
   }
   
   static __inline void
   setbits(volatile unsigned *addr, u_int bits)
   {
           __asm __volatile("orl %1,%0" : "=m" (*addr) : "ir" (bits));
   }
   
   static __inline void
   wbinvd(void)
   {
           __asm __volatile("wbinvd");
   }
   
   static __inline void
   write_eflags(u_long ef)
   {
           __asm __volatile("pushl %0; popfl" : : "r" (ef));
   }
   
   static __inline void
   wrmsr(u_int msr, quad_t newval)
   {
           __asm __volatile(".byte 0x0f, 0x30" : : "A" (newval), "c" (msr));
   }
   
   #else /* !__GNUC__ */
   
   int     breakpoint      __P((void));
   void    disable_intr    __P((void));
   void    enable_intr     __P((void));
   u_char  inb             __P((u_int port));
   u_long  inl             __P((u_int port));
   void    insb            __P((u_int port, void *addr, size_t cnt));
   void    insl            __P((u_int port, void *addr, size_t cnt));
   void    insw            __P((u_int port, void *addr, size_t cnt));
   void    invd            __P((void));
   void    invlpg          __P((u_int addr));
   void    invltlb         __P((void));
   u_short inw             __P((u_int port));
   u_int   loadandclear    __P((u_int *addr));
   void    outb            __P((u_int port, u_char data));
   void    outl            __P((u_int port, u_long data));
   void    outsb           __P((u_int port, void *addr, size_t cnt));
   void    outsl           __P((u_int port, void *addr, size_t cnt));
   void    outsw           __P((u_int port, void *addr, size_t cnt));
   void    outw            __P((u_int port, u_short data));
   u_long  rcr2            __P((void));
   quad_t  rdmsr           __P((u_int msr));
   quad_t  rdpmc           __P((u_int pmc));
   quad_t  rdtsc           __P((void));
   u_long  read_eflags     __P((void));
   void    setbits         __P((volatile unsigned *addr, u_int bits));
   void    wbinvd          __P((void));
   void    write_eflags    __P((u_long ef));
   void    wrmsr           __P((u_int msr, quad_t newval));
   
   #endif  /* __GNUC__ */
   
   void    load_cr0        __P((u_long cr0));
   void    load_cr3        __P((u_long cr3));
   void    ltr             __P((u_short sel));
   u_int   rcr0            __P((void));
   u_long  rcr3            __P((void));
   
   #include <machine/spl.h>        /* XXX belongs elsewhere */
   
   #endif /* !_MACHINE_CPUFUNC_H_ */

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