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Annotation of linux/include/asm/io.h, revision 1.1.1.8

1.1.1.4   root        1: #ifndef _ASM_IO_H
                      2: #define _ASM_IO_H
                      3: 
1.1.1.5   root        4: /*
                      5:  * Thanks to James van Artsdalen for a better timing-fix than
                      6:  * the two short jumps: using outb's to a nonexistent port seems
                      7:  * to guarantee better timings even on fast machines.
                      8:  *
1.1.1.8 ! root        9:  * On the other hand, I'd like to be sure of a non-existent port:
        !            10:  * I feel a bit unsafe abou using 0x80.
        !            11:  *
1.1.1.5   root       12:  *             Linus
                     13:  */
                     14: 
1.1.1.8 ! root       15: #ifdef SLOW_IO_BY_JUMPING
        !            16: #define __SLOW_DOWN_IO __asm__ __volatile__("jmp 1f\n1:\tjmp 1f\n1:")
        !            17: #else
        !            18: #define __SLOW_DOWN_IO __asm__ __volatile__("inb $0x61,%%al":::"ax")
        !            19: #endif
        !            20: 
        !            21: #ifdef REALLY_SLOW_IO
        !            22: #define SLOW_DOWN_IO { __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; }
        !            23: #else
        !            24: #define SLOW_DOWN_IO __SLOW_DOWN_IO
        !            25: #endif
        !            26: 
1.1.1.4   root       27: extern void inline outb(char value, unsigned short port)
1.1.1.2   root       28: {
1.1.1.8 ! root       29: __asm__ __volatile__ ("outb %%al,%%dx"
1.1.1.3   root       30:                ::"a" ((char) value),"d" ((unsigned short) port));
1.1.1.2   root       31: }
1.1       root       32: 
1.1.1.8 ! root       33: extern unsigned int inline inb(unsigned short port)
1.1.1.2   root       34: {
1.1.1.8 ! root       35:        unsigned int _v;
        !            36: __asm__ __volatile__ ("inb %%dx,%%al"
        !            37:                :"=a" (_v):"d" ((unsigned short) port),"0" (0));
        !            38:        return _v;
1.1.1.2   root       39: }
1.1       root       40: 
1.1.1.8 ! root       41: extern void inline outb_p(char value, unsigned short port)
1.1.1.2   root       42: {
1.1.1.8 ! root       43: __asm__ __volatile__ ("outb %%al,%%dx"
        !            44:                ::"a" ((char) value),"d" ((unsigned short) port));
        !            45:        SLOW_DOWN_IO;
1.1.1.2   root       46: }
1.1       root       47: 
1.1.1.8 ! root       48: extern unsigned int inline inb_p(unsigned short port)
1.1.1.2   root       49: {
1.1.1.8 ! root       50:        unsigned int _v;
        !            51: __asm__ __volatile__ ("inb %%dx,%%al"
        !            52:                :"=a" (_v):"d" ((unsigned short) port),"0" (0));
        !            53:        SLOW_DOWN_IO;
1.1.1.2   root       54:        return _v;
                     55: }
1.1.1.4   root       56: 
                     57: #endif

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