/* Shift a limb left, low level routine.
   Copyright (C) 1996, 1997, 1999, 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 <bp-sym.h>
#include <bp-asm.h>

/* mp_limb_t mpn_lshift (mp_ptr wp, mp_srcptr up, mp_size_t usize,
                         unsigned int cnt)  */

EALIGN (BP_SYM (__mpn_lshift), 3, 0)

#if __BOUNDED_POINTERS__
        slwi r10,r5,2           /* convert limbs to bytes */
        CHECK_BOUNDS_BOTH_WIDE (r3, r8, r9, r10)
        CHECK_BOUNDS_BOTH_WIDE (r4, r8, r9, r10)
#endif
        mtctr   r5              # copy size into CTR
        cmplwi  cr0,r5,16       # is size < 16
        slwi    r0,r5,2
        add     r7,r3,r0        # make r7 point at end of res
        add     r4,r4,r0        # make r4 point at end of s1
        lwzu    r11,-4(r4)      # load first s1 limb
        subfic  r8,r6,32
        srw     r3,r11,r8       # compute function return value
        bge     cr0,L(big)      # branch if size >= 16

        bdz     L(end1)

L(0):   lwzu    r10,-4(r4)
        slw     r9,r11,r6
        srw     r12,r10,r8
        or      r9,r9,r12
        stwu    r9,-4(r7)
        bdz     L(end2)
        lwzu    r11,-4(r4)
        slw     r9,r10,r6
        srw     r12,r11,r8
        or      r9,r9,r12
        stwu    r9,-4(r7)
        bdnz    L(0)

L(end1):slw     r0,r11,r6
        stw     r0,-4(r7)
        blr


/* Guaranteed not to succeed.  */
L(boom): tweq    r0,r0

/* We imitate a case statement, by using (yuk!) fixed-length code chunks,
   of size 4*12 bytes.  We have to do this (or something) to make this PIC.  */
L(big): mflr    r9
        bltl-   cr0,L(boom)     # Never taken, only used to set LR.
        slwi    r10,r6,4
        mflr    r12
        add     r10,r12,r10
        slwi    r8,r6,5
        add     r10,r8,r10
        mtctr   r10
        addi    r5,r5,-1
        mtlr    r9
        bctr

L(end2):slw     r0,r10,r6
        stw     r0,-4(r7)
        blr

#define DO_LSHIFT(n) \
        mtctr   r5;                                                     \
L(n):   lwzu    r10,-4(r4);                                             \
        slwi    r9,r11,n;                                               \
        inslwi  r9,r10,n,32-n;                                  \
        stwu    r9,-4(r7);                                              \
        bdz-    L(end2);                                                \
        lwzu    r11,-4(r4);                                             \
        slwi    r9,r10,n;                                               \
        inslwi  r9,r11,n,32-n;                                  \
        stwu    r9,-4(r7);                                              \
        bdnz    L(n);                                                   \
        b       L(end1)

        DO_LSHIFT(1)
        DO_LSHIFT(2)
        DO_LSHIFT(3)
        DO_LSHIFT(4)
        DO_LSHIFT(5)
        DO_LSHIFT(6)
        DO_LSHIFT(7)
        DO_LSHIFT(8)
        DO_LSHIFT(9)
        DO_LSHIFT(10)
        DO_LSHIFT(11)
        DO_LSHIFT(12)
        DO_LSHIFT(13)
        DO_LSHIFT(14)
        DO_LSHIFT(15)
        DO_LSHIFT(16)
        DO_LSHIFT(17)
        DO_LSHIFT(18)
        DO_LSHIFT(19)
        DO_LSHIFT(20)
        DO_LSHIFT(21)
        DO_LSHIFT(22)
        DO_LSHIFT(23)
        DO_LSHIFT(24)
        DO_LSHIFT(25)
        DO_LSHIFT(26)
        DO_LSHIFT(27)
        DO_LSHIFT(28)
        DO_LSHIFT(29)
        DO_LSHIFT(30)
        DO_LSHIFT(31)

END (BP_SYM (__mpn_lshift))