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Annotation of OpenXM/src/kan96xx/gmp-2.0.2-ssh-2/mpn/alpha/mul_1.s, Revision 1.1

1.1     ! takayama    1:  # Alpha 21064 __mpn_mul_1 -- Multiply a limb vector with a limb and store
        !             2:  # the result in a second limb vector.
        !             3:
        !             4:  # Copyright (C) 1992, 1994, 1995 Free Software Foundation, Inc.
        !             5:
        !             6:  # This file is part of the GNU MP Library.
        !             7:
        !             8:  # The GNU MP Library is free software; you can redistribute it and/or modify
        !             9:  # it under the terms of the GNU Library General Public License as published by
        !            10:  # the Free Software Foundation; either version 2 of the License, or (at your
        !            11:  # option) any later version.
        !            12:
        !            13:  # The GNU MP Library is distributed in the hope that it will be useful, but
        !            14:  # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
        !            15:  # or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
        !            16:  # License for more details.
        !            17:
        !            18:  # You should have received a copy of the GNU Library General Public License
        !            19:  # along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
        !            20:  # the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
        !            21:  # MA 02111-1307, USA.
        !            22:
        !            23:
        !            24:  # INPUT PARAMETERS
        !            25:  # res_ptr     r16
        !            26:  # s1_ptr      r17
        !            27:  # size                r18
        !            28:  # s2_limb     r19
        !            29:
        !            30:  # This code runs at 42 cycles/limb on the EV4 and 18 cycles/limb on the EV5.
        !            31:
        !            32:  # To improve performance for long multiplications, we would use
        !            33:  # 'fetch' for S1 and 'fetch_m' for RES.  It's not obvious how to use
        !            34:  # these instructions without slowing down the general code: 1. We can
        !            35:  # only have two prefetches in operation at any time in the Alpha
        !            36:  # architecture.  2. There will seldom be any special alignment
        !            37:  # between RES_PTR and S1_PTR.  Maybe we can simply divide the current
        !            38:  # loop into an inner and outer loop, having the inner loop handle
        !            39:  # exactly one prefetch block?
        !            40:
        !            41:        .set    noreorder
        !            42:        .set    noat
        !            43: .text
        !            44:        .align  3
        !            45:        .globl  __mpn_mul_1
        !            46:        .ent    __mpn_mul_1 2
        !            47: __mpn_mul_1:
        !            48:        .frame  $30,0,$26
        !            49:
        !            50:        ldq     $2,0($17)       # $2 = s1_limb
        !            51:        subq    $18,1,$18       # size--
        !            52:        mulq    $2,$19,$3       # $3 = prod_low
        !            53:        bic     $31,$31,$4      # clear cy_limb
        !            54:        umulh   $2,$19,$0       # $0 = prod_high
        !            55:        beq     $18,Lend1       # jump if size was == 1
        !            56:        ldq     $2,8($17)       # $2 = s1_limb
        !            57:        subq    $18,1,$18       # size--
        !            58:        stq     $3,0($16)
        !            59:        beq     $18,Lend2       # jump if size was == 2
        !            60:
        !            61:        .align  3
        !            62: Loop:  mulq    $2,$19,$3       # $3 = prod_low
        !            63:        addq    $4,$0,$0        # cy_limb = cy_limb + 'cy'
        !            64:        subq    $18,1,$18       # size--
        !            65:        umulh   $2,$19,$4       # $4 = cy_limb
        !            66:        ldq     $2,16($17)      # $2 = s1_limb
        !            67:        addq    $17,8,$17       # s1_ptr++
        !            68:        addq    $3,$0,$3        # $3 = cy_limb + prod_low
        !            69:        stq     $3,8($16)
        !            70:        cmpult  $3,$0,$0        # $0 = carry from (cy_limb + prod_low)
        !            71:        addq    $16,8,$16       # res_ptr++
        !            72:        bne     $18,Loop
        !            73:
        !            74: Lend2: mulq    $2,$19,$3       # $3 = prod_low
        !            75:        addq    $4,$0,$0        # cy_limb = cy_limb + 'cy'
        !            76:        umulh   $2,$19,$4       # $4 = cy_limb
        !            77:        addq    $3,$0,$3        # $3 = cy_limb + prod_low
        !            78:        cmpult  $3,$0,$0        # $0 = carry from (cy_limb + prod_low)
        !            79:        stq     $3,8($16)
        !            80:        addq    $4,$0,$0        # cy_limb = prod_high + cy
        !            81:        ret     $31,($26),1
        !            82: Lend1: stq     $3,0($16)
        !            83:        ret     $31,($26),1
        !            84:
        !            85:        .end    __mpn_mul_1