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Annotation of OpenXM_contrib/gmp/mpn/power/sub_n.asm, Revision 1.1

1.1     ! ohara       1: dnl  IBM POWER mpn_sub_n -- Subtract two limb vectors of equal, non-zero
        !             2: dnl  length.
        !             3:
        !             4: dnl  Copyright 1992, 1994, 1995, 1996, 1999, 2000, 2001 Free Software
        !             5: dnl  Foundation, Inc.
        !             6:
        !             7: dnl  This file is part of the GNU MP Library.
        !             8:
        !             9: dnl  The GNU MP Library is free software; you can redistribute it and/or modify
        !            10: dnl  it under the terms of the GNU Lesser General Public License as published
        !            11: dnl  by the Free Software Foundation; either version 2.1 of the License, or (at
        !            12: dnl  your option) any later version.
        !            13:
        !            14: dnl  The GNU MP Library is distributed in the hope that it will be useful, but
        !            15: dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
        !            16: dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
        !            17: dnl  License for more details.
        !            18:
        !            19: dnl  You should have received a copy of the GNU Lesser General Public License
        !            20: dnl  along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
        !            21: dnl  the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
        !            22: dnl  MA 02111-1307, USA.
        !            23:
        !            24:
        !            25: dnl  INPUT PARAMETERS
        !            26: dnl  res_ptr   r3
        !            27: dnl  s1_ptr    r4
        !            28: dnl  s2_ptr    r5
        !            29: dnl  size      r6
        !            30:
        !            31: include(`../config.m4')
        !            32:
        !            33: ASM_START()
        !            34: PROLOGUE(mpn_sub_n)
        !            35:        andil.  10,6,1          C odd or even number of limbs?
        !            36:        l       8,0(4)          C load least significant s1 limb
        !            37:        l       0,0(5)          C load least significant s2 limb
        !            38:        cal     3,-4(3)         C offset res_ptr, it's updated before it's used
        !            39:        sri     10,6,1          C count for unrolled loop
        !            40:        sf      7,0,8           C subtract least significant limbs, set cy
        !            41:        mtctr   10              C copy count into CTR
        !            42:        beq     0,Leven         C branch if even C of limbs (C of limbs >= 2)
        !            43:
        !            44: C We have an odd C of limbs.  Add the first limbs separately.
        !            45:        cmpi    1,10,0          C is count for unrolled loop zero?
        !            46:        bc      4,6,L1          C bne cr1,L1 (misassembled by gas)
        !            47:        st      7,4(3)
        !            48:        sfe     3,0,0           C load !cy into ...
        !            49:        sfi     3,3,0           C ... return value register
        !            50:        br                      C return
        !            51:
        !            52: C We added least significant limbs.  Now reload the next limbs to enter loop.
        !            53: L1:    lu      8,4(4)          C load s1 limb and update s1_ptr
        !            54:        lu      0,4(5)          C load s2 limb and update s2_ptr
        !            55:        stu     7,4(3)
        !            56:        sfe     7,0,8           C subtract limbs, set cy
        !            57: Leven: lu      9,4(4)          C load s1 limb and update s1_ptr
        !            58:        lu      10,4(5)         C load s2 limb and update s2_ptr
        !            59:        bdz     Lend            C If done, skip loop
        !            60:
        !            61: Loop:  lu      8,4(4)          C load s1 limb and update s1_ptr
        !            62:        lu      0,4(5)          C load s2 limb and update s2_ptr
        !            63:        sfe     11,10,9         C subtract previous limbs with cy, set cy
        !            64:        stu     7,4(3)          C
        !            65:        lu      9,4(4)          C load s1 limb and update s1_ptr
        !            66:        lu      10,4(5)         C load s2 limb and update s2_ptr
        !            67:        sfe     7,0,8           C subtract previous limbs with cy, set cy
        !            68:        stu     11,4(3)         C
        !            69:        bdn     Loop            C decrement CTR and loop back
        !            70:
        !            71: Lend:  sfe     11,10,9         C subtract limbs with cy, set cy
        !            72:        st      7,4(3)          C
        !            73:        st      11,8(3)         C
        !            74:        sfe     3,0,0           C load !cy into ...
        !            75:        sfi     3,3,0           C ... return value register
        !            76:        br
        !            77: EPILOGUE(mpn_sub_n)