swab.h

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#ifndef _ALPHA_SWAB_H
#define _ALPHA_SWAB_H

#include <linux/types.h>
#include <linux/compiler.h>
#include <asm/compiler.h>

#ifdef __GNUC__

static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
{
    /*
     * Unfortunately, we can't use the 6 instruction sequence
     * on ev6 since the latency of the UNPKBW is 3, which is
     * pretty hard to hide.  Just in case a future implementation
     * has a lower latency, here's the sequence (also by Mike Burrows)
     *
     * UNPKBW a0, v0       v0: 00AA00BB00CC00DD
     * SLL v0, 24, a0      a0: BB00CC00DD000000
     * BIS v0, a0, a0      a0: BBAACCBBDDCC00DD
     * EXTWL a0, 6, v0     v0: 000000000000BBAA
     * ZAP a0, 0xf3, a0    a0: 00000000DDCC0000
     * ADDL a0, v0, v0     v0: ssssssssDDCCBBAA
     */

    __u64 t0, t1, t2, t3;

    t0 = __kernel_inslh(x, 7);  /* t0 : 0000000000AABBCC */
    t1 = __kernel_inswl(x, 3);  /* t1 : 000000CCDD000000 */
    t1 |= t0;           /* t1 : 000000CCDDAABBCC */
    t2 = t1 >> 16;          /* t2 : 0000000000CCDDAA */
    t0 = t1 & 0xFF00FF00;       /* t0 : 00000000DD00BB00 */
    t3 = t2 & 0x00FF00FF;       /* t3 : 0000000000CC00AA */
    t1 = t0 + t3;           /* t1 : ssssssssDDCCBBAA */

    return t1;
}
#define __arch_swab32 __arch_swab32

#endif /* __GNUC__ */

#endif /* _ALPHA_SWAB_H */