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/*

 * arch/alpha/lib/strchr.S

 * Contributed by Richard Henderson (rth@tamu.edu)

 *

 * Return the address of a given character within a null-terminated

 * string, or null if it is not found.

 */

#include 

        .set noreorder

        .set noat

        .align 3

        .globl strchr

        .ent strchr

strchr:

        .frame sp, 0, ra

        .prologue 0

        zapnot  a1, 1, a1       # e0    : zero extend the search character

        ldq_u   t0, 0(a0)       # .. e1 : load first quadword

        sll     a1, 8, t5       # e0    : replicate the search character

        andnot  a0, 7, v0       # .. e1 : align our loop pointer

        or      t5, a1, a1      # e0    :

        lda     t4, -1          # .. e1 : build garbage mask

        sll     a1, 16, t5      # e0    :

        cmpbge  zero, t0, t2    # .. e1 : bits set iff byte == zero

        mskqh   t4, a0, t4      # e0    :

        or      t5, a1, a1      # .. e1 :

        sll     a1, 32, t5      # e0    :

        cmpbge  zero, t4, t4    # .. e1 : bits set iff byte is garbage

        or      t5, a1, a1      # e0    :

        xor     t0, a1, t1      # .. e1 : make bytes == c zero

        cmpbge  zero, t1, t3    # e0    : bits set iff byte == c

        or      t2, t3, t0      # e1    : bits set iff char match or zero match

        andnot  t0, t4, t0      # e0    : clear garbage bits

        bne     t0, $found      # .. e1 (zdb)

$loop:  ldq     t0, 8(v0)       # e0    :

        addq    v0, 8, v0       # .. e1 :

        nop                     # e0    :

        xor     t0, a1, t1      # .. e1 (ev5 data stall)

        cmpbge  zero, t0, t2    # e0    : bits set iff byte == 0

        cmpbge  zero, t1, t3    # .. e1 : bits set iff byte == c

        or      t2, t3, t0      # e0    :

        beq     t0, $loop       # .. e1 (zdb)

$found: negq    t0, t1          # e0    : clear all but least set bit

        and     t0, t1, t0      # e1 (stall)

        and     t0, t3, t1      # e0    : bit set iff byte was the char

        beq     t1, $retnull    # .. e1 (zdb)

        and     t0, 0xf0, t2    # e0    : binary search for that set bit

        and     t0, 0xcc, t3    # .. e1 :

        and     t0, 0xaa, t4    # e0    :

        cmovne  t2, 4, t2       # .. e1 :

        cmovne  t3, 2, t3       # e0    :

        cmovne  t4, 1, t4       # .. e1 :

        addq    t2, t3, t2      # e0    :

        addq    v0, t4, v0      # .. e1 :

        addq    v0, t2, v0      # e0    :

        ret                     # .. e1 :

$retnull:

        mov     zero, v0        # e0    :

        ret                     # .. e1 :

        .end strchr