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Diffstat (limited to 'sysdeps/rs6000/sub_n.s')
| -rw-r--r-- | sysdeps/rs6000/sub_n.s | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/sysdeps/rs6000/sub_n.s b/sysdeps/rs6000/sub_n.s new file mode 100644 index 0000000000..d931870935 --- /dev/null +++ b/sysdeps/rs6000/sub_n.s @@ -0,0 +1,82 @@ +# IBM POWER __mpn_sub_n -- Subtract two limb vectors of equal, non-zero length. + +# Copyright (C) 1992, 1994, 1995, 1996 Free Software Foundation, Inc. + +# This file is part of the GNU MP Library. + +# The GNU MP 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 MP 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 MP Library; see the file COPYING.LIB. If not, write to +# the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, +# MA 02111-1307, USA. + + +# INPUT PARAMETERS +# res_ptr r3 +# s1_ptr r4 +# s2_ptr r5 +# size r6 + + .toc + .extern __mpn_sub_n[DS] + .extern .__mpn_sub_n +.csect [PR] + .align 2 + .globl __mpn_sub_n + .globl .__mpn_sub_n + .csect __mpn_sub_n[DS] +__mpn_sub_n: + .long .__mpn_sub_n, TOC[tc0], 0 + .csect [PR] +.__mpn_sub_n: + andil. 10,6,1 # odd or even number of limbs? + l 8,0(4) # load least significant s1 limb + l 0,0(5) # load least significant s2 limb + cal 3,-4(3) # offset res_ptr, it's updated before it's used + sri 10,6,1 # count for unrolled loop + sf 7,0,8 # subtract least significant limbs, set cy + mtctr 10 # copy count into CTR + beq 0,Leven # branch if even # of limbs (# of limbs >= 2) + +# We have an odd # of limbs. Add the first limbs separately. + cmpi 1,10,0 # is count for unrolled loop zero? + bne 1,L1 # branch if not + st 7,4(3) + sfe 3,0,0 # load !cy into ... + sfi 3,3,0 # ... return value register + br # return + +# We added least significant limbs. Now reload the next limbs to enter loop. +L1: lu 8,4(4) # load s1 limb and update s1_ptr + lu 0,4(5) # load s2 limb and update s2_ptr + stu 7,4(3) + sfe 7,0,8 # subtract limbs, set cy +Leven: lu 9,4(4) # load s1 limb and update s1_ptr + lu 10,4(5) # load s2 limb and update s2_ptr + bdz Lend # If done, skip loop + +Loop: lu 8,4(4) # load s1 limb and update s1_ptr + lu 0,4(5) # load s2 limb and update s2_ptr + sfe 11,10,9 # subtract previous limbs with cy, set cy + stu 7,4(3) # + lu 9,4(4) # load s1 limb and update s1_ptr + lu 10,4(5) # load s2 limb and update s2_ptr + sfe 7,0,8 # subtract previous limbs with cy, set cy + stu 11,4(3) # + bdn Loop # decrement CTR and loop back + +Lend: sfe 11,10,9 # subtract limbs with cy, set cy + st 7,4(3) # + st 11,8(3) # + sfe 3,0,0 # load !cy into ... + sfi 3,3,0 # ... return value register + br |