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mmx.h

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/*!     \file include/arch/mmx.h
 *      \brief Generic MMX extensions.
 *      \author Andrea Righi <drizzt@inwind.it>
 *      \date Last update: 2004-02-07
 *      \note Copyright (&copy;) 2003 Andrea Righi
 */

#ifndef MMX_H
#define MMX_H

#include <arch/paging.h>

//! \brief Clear a page using MMX extensions.
static __inline__ void fast_clear_page( void *page )
{
        int i;

        // Clear the task switch flag.
        __asm__ __volatile__ ("clts");

        // Clear the 64-bit mm0 register.
        __asm__ __volatile__ ("pxor %mm0, %mm0");

        // Fast clear the page.
        for( i=0; i<PAGE_SIZE/128; i++ )
        {
                __asm__ __volatile__ (
                        "movq %%mm0, (%0)\n"
                        "movq %%mm0, 8(%0)\n"
                        "movq %%mm0, 16(%0)\n"
                        "movq %%mm0, 24(%0)\n"
                        "movq %%mm0, 32(%0)\n"
                        "movq %%mm0, 40(%0)\n"
                        "movq %%mm0, 48(%0)\n"
                        "movq %%mm0, 56(%0)\n"
                        "movq %%mm0, 64(%0)\n"
                        "movq %%mm0, 72(%0)\n"
                        "movq %%mm0, 80(%0)\n"
                        "movq %%mm0, 88(%0)\n"
                        "movq %%mm0, 96(%0)\n"
                        "movq %%mm0, 104(%0)\n"
                        "movq %%mm0, 112(%0)\n"
                        "movq %%mm0, 120(%0)\n"
                : : "r"(page) : "memory");
                page += 128;
        }

        // Restore task switch flag.
        do
        {
                unsigned int __cr0;
                __asm__ __volatile__ (
                        "movl %%cr0, %0\n"
                        "or $8, %0\n"
                        "movl %0, %%cr0" : "=r"(__cr0));
        } while( 0 );
}

#endif

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