/* Pentium optimized __mpn_lshift --
   Copyright (C) 1992, 94, 95, 96, 97, 98, 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include "sysdep.h"
#include "asm-syntax.h"
#include "bp-sym.h"
#include "bp-asm.h"

#define PARMS   LINKAGE+16              /* space for 4 saved regs */
#define RES     PARMS
#define S       RES+PTR_SIZE
#define SIZE    S+PTR_SIZE
#define CNT     SIZE+4

        .text
ENTRY (BP_SYM (__mpn_lshift))
        ENTER

        pushl   %edi
        pushl   %esi
        pushl   %ebp
        pushl   %ebx

        movl    RES(%esp),%edi
        movl    S(%esp),%esi
        movl    SIZE(%esp),%ebx
        movl    CNT(%esp),%ecx
#if __BOUNDED_POINTERS__
        shll    $2, %ebx                /* convert limbs to bytes */
        CHECK_BOUNDS_BOTH_WIDE (%edi, RES(%esp), %ebx)
        CHECK_BOUNDS_BOTH_WIDE (%esi, S(%esp), %ebx)
        shrl    $2, %ebx
#endif

/* We can use faster code for shift-by-1 under certain conditions.  */
        cmp     $1,%ecx
        jne     L(normal)
        leal    4(%esi),%eax
        cmpl    %edi,%eax
        jnc     L(special)              /* jump if s_ptr + 1 >= res_ptr */
        leal    (%esi,%ebx,4),%eax
        cmpl    %eax,%edi
        jnc     L(special)              /* jump if res_ptr >= s_ptr + size */

L(normal):
        leal    -4(%edi,%ebx,4),%edi
        leal    -4(%esi,%ebx,4),%esi

        movl    (%esi),%edx
        subl    $4,%esi
        xorl    %eax,%eax
        shldl   %cl,%edx,%eax           /* compute carry limb */
        pushl   %eax                    /* push carry limb onto stack */

        decl    %ebx
        pushl   %ebx
        shrl    $3,%ebx
        jz      L(end)

        movl    (%edi),%eax             /* fetch destination cache line */

        ALIGN   (2)
L(oop): movl    -28(%edi),%eax          /* fetch destination cache line */
        movl    %edx,%ebp

        movl    (%esi),%eax
        movl    -4(%esi),%edx
        shldl   %cl,%eax,%ebp
        shldl   %cl,%edx,%eax
        movl    %ebp,(%edi)
        movl    %eax,-4(%edi)

        movl    -8(%esi),%ebp
        movl    -12(%esi),%eax
        shldl   %cl,%ebp,%edx
        shldl   %cl,%eax,%ebp
        movl    %edx,-8(%edi)
        movl    %ebp,-12(%edi)

        movl    -16(%esi),%edx
        movl    -20(%esi),%ebp
        shldl   %cl,%edx,%eax
        shldl   %cl,%ebp,%edx
        movl    %eax,-16(%edi)
        movl    %edx,-20(%edi)

        movl    -24(%esi),%eax
        movl    -28(%esi),%edx
        shldl   %cl,%eax,%ebp
        shldl   %cl,%edx,%eax
        movl    %ebp,-24(%edi)
        movl    %eax,-28(%edi)

        subl    $32,%esi
        subl    $32,%edi
        decl    %ebx
        jnz     L(oop)

L(end): popl    %ebx
        andl    $7,%ebx
        jz      L(end2)
L(oop2):
        movl    (%esi),%eax
        shldl   %cl,%eax,%edx
        movl    %edx,(%edi)
        movl    %eax,%edx
        subl    $4,%esi
        subl    $4,%edi
        decl    %ebx
        jnz     L(oop2)

L(end2):
        shll    %cl,%edx                /* compute least significant limb */
        movl    %edx,(%edi)             /* store it */

        popl    %eax                    /* pop carry limb */

        popl    %ebx
        popl    %ebp
        popl    %esi
        popl    %edi

        LEAVE
        ret

/* We loop from least significant end of the arrays, which is only
   permissible if the source and destination don't overlap, since the
   function is documented to work for overlapping source and destination.
*/

L(special):
        movl    (%esi),%edx
        addl    $4,%esi

        decl    %ebx
        pushl   %ebx
        shrl    $3,%ebx

        addl    %edx,%edx
        incl    %ebx
        decl    %ebx
        jz      L(Lend)

        movl    (%edi),%eax             /* fetch destination cache line */

        ALIGN   (2)
L(Loop):
        movl    28(%edi),%eax           /* fetch destination cache line */
        movl    %edx,%ebp

        movl    (%esi),%eax
        movl    4(%esi),%edx
        adcl    %eax,%eax
        movl    %ebp,(%edi)
        adcl    %edx,%edx
        movl    %eax,4(%edi)

        movl    8(%esi),%ebp
        movl    12(%esi),%eax
        adcl    %ebp,%ebp
        movl    %edx,8(%edi)
        adcl    %eax,%eax
        movl    %ebp,12(%edi)

        movl    16(%esi),%edx
        movl    20(%esi),%ebp
        adcl    %edx,%edx
        movl    %eax,16(%edi)
        adcl    %ebp,%ebp
        movl    %edx,20(%edi)

        movl    24(%esi),%eax
        movl    28(%esi),%edx
        adcl    %eax,%eax
        movl    %ebp,24(%edi)
        adcl    %edx,%edx
        movl    %eax,28(%edi)

        leal    32(%esi),%esi           /* use leal not to clobber carry */
        leal    32(%edi),%edi
        decl    %ebx
        jnz     L(Loop)

L(Lend):
        popl    %ebx
        sbbl    %eax,%eax               /* save carry in %eax */
        andl    $7,%ebx
        jz      L(Lend2)
        addl    %eax,%eax               /* restore carry from eax */
L(Loop2):
        movl    %edx,%ebp
        movl    (%esi),%edx
        adcl    %edx,%edx
        movl    %ebp,(%edi)

        leal    4(%esi),%esi            /* use leal not to clobber carry */
        leal    4(%edi),%edi
        decl    %ebx
        jnz     L(Loop2)

        jmp     L(L1)
L(Lend2):
        addl    %eax,%eax               /* restore carry from eax */
L(L1):  movl    %edx,(%edi)             /* store last limb */

        sbbl    %eax,%eax
        negl    %eax

        popl    %ebx
        popl    %ebp
        popl    %esi
        popl    %edi

        LEAVE
        ret
END (BP_SYM (__mpn_lshift))