58 lines
1.3 KiB
C
58 lines
1.3 KiB
C
#ifndef _ASM_IO_H
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#define _ASM_IO_H
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/*
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* Thanks to James van Artsdalen for a better timing-fix than
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* the two short jumps: using outb's to a nonexistent port seems
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* to guarantee better timings even on fast machines.
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*
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* On the other hand, I'd like to be sure of a non-existent port:
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* I feel a bit unsafe abou using 0x80.
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*
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* Linus
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*/
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#ifdef SLOW_IO_BY_JUMPING
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#define __SLOW_DOWN_IO __asm__ __volatile__("jmp 1f\n1:\tjmp 1f\n1:")
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#else
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#define __SLOW_DOWN_IO __asm__ __volatile__("outb %al,$0x80")
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#endif
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#ifdef REALLY_SLOW_IO
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#define SLOW_DOWN_IO { __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; }
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#else
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#define SLOW_DOWN_IO __SLOW_DOWN_IO
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#endif
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extern void inline outb(char value, unsigned short port)
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{
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__asm__ __volatile__ ("outb %%al,%%dx"
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::"a" ((char) value),"d" ((unsigned short) port));
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}
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extern unsigned int inline inb(unsigned short port)
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{
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unsigned int _v;
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__asm__ __volatile__ ("inb %%dx,%%al"
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:"=a" (_v):"d" ((unsigned short) port),"0" (0));
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return _v;
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}
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extern void inline outb_p(char value, unsigned short port)
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{
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__asm__ __volatile__ ("outb %%al,%%dx"
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::"a" ((char) value),"d" ((unsigned short) port));
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SLOW_DOWN_IO;
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}
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extern unsigned int inline inb_p(unsigned short port)
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{
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unsigned int _v;
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__asm__ __volatile__ ("inb %%dx,%%al"
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:"=a" (_v):"d" ((unsigned short) port),"0" (0));
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SLOW_DOWN_IO;
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return _v;
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}
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#endif
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