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lib/raid6/altivec.uc
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/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright 2002-2004 H. Peter Anvin - All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, Inc., 53 Temple Place Ste 330,
* Boston MA 02111-1307, USA; either version 2 of the License, or
* (at your option) any later version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* raid6altivec$#.c
*
* $#-way unrolled portable integer math RAID-6 instruction set
*
* This file is postprocessed using unroll.awk
*
* <benh> hpa: in process,
* you can just "steal" the vec unit with enable_kernel_altivec() (but
* bracked this with preempt_disable/enable or in a lock)
*/
#include <linux/raid/pq.h>
#include <altivec.h>
#ifdef __KERNEL__
# include <asm/cputable.h>
# include <asm/switch_to.h>
/*
* This is the C data type to use. We use a vector of
* signed char so vec_cmpgt() will generate the right
* instruction.
*/
typedef vector signed char unative_t;
#define NBYTES(x) ((vector signed char) {x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x})
#define NSIZE sizeof(unative_t)
/*
* The SHLBYTE() operation shifts each byte left by 1, *not*
* rolling over into the next byte
*/
static inline __attribute_const__ unative_t SHLBYTE(unative_t v)
{
return vec_add(v,v);
}
/*
* The MASK() operation returns 0xFF in any byte for which the high
* bit is 1, 0x00 for any byte for which the high bit is 0.
*/
static inline __attribute_const__ unative_t MASK(unative_t v)
{
unative_t zv = NBYTES(0);
/* vec_cmpgt returns a vector bool char; thus the need for the cast */
return (unative_t)vec_cmpgt(zv, v);
}
/* This is noinline to make damned sure that gcc doesn't move any of the
Altivec code around the enable/disable code */
static void noinline
raid6_altivec$#_gen_syndrome_real(int disks, size_t bytes, void **ptrs)
{
u8 **dptr = (u8 **)ptrs;
u8 *p, *q;
int d, z, z0;
unative_t wd$$, wq$$, wp$$, w1$$, w2$$;
unative_t x1d = NBYTES(0x1d);
z0 = disks - 3; /* Highest data disk */
p = dptr[z0+1]; /* XOR parity */
q = dptr[z0+2]; /* RS syndrome */
for ( d = 0 ; d < bytes ; d += NSIZE*$# ) {
wq$$ = wp$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE];
for ( z = z0-1 ; z >= 0 ; z-- ) {
wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE];
wp$$ = vec_xor(wp$$, wd$$);
w2$$ = MASK(wq$$);
w1$$ = SHLBYTE(wq$$);
w2$$ = vec_and(w2$$, x1d);
w1$$ = vec_xor(w1$$, w2$$);
wq$$ = vec_xor(w1$$, wd$$);
}
*(unative_t *)&p[d+NSIZE*$$] = wp$$;
*(unative_t *)&q[d+NSIZE*$$] = wq$$;
}
}
static void raid6_altivec$#_gen_syndrome(int disks, size_t bytes, void **ptrs)
{
preempt_disable();
enable_kernel_altivec();
raid6_altivec$#_gen_syndrome_real(disks, bytes, ptrs);
disable_kernel_altivec();
preempt_enable();
}
int raid6_have_altivec(void);
#if $# == 1
int raid6_have_altivec(void)
{
/* This assumes either all CPUs have Altivec or none does */
# ifdef __KERNEL__
return cpu_has_feature(CPU_FTR_ALTIVEC);
# else
return 1;
# endif
}
#endif
const struct raid6_calls raid6_altivec$# = {
raid6_altivec$#_gen_syndrome,
NULL, /* XOR not yet implemented */
raid6_have_altivec,
"altivecx$#",
0
};
#endif /* CONFIG_ALTIVEC */
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