diff options
Diffstat (limited to 'sysdeps/rs6000/sub_n.s')
| -rw-r--r-- | sysdeps/rs6000/sub_n.s | 47 |
1 files changed, 37 insertions, 10 deletions
diff --git a/sysdeps/rs6000/sub_n.s b/sysdeps/rs6000/sub_n.s index c57675b106..30d4fee861 100644 --- a/sysdeps/rs6000/sub_n.s +++ b/sysdeps/rs6000/sub_n.s @@ -1,7 +1,6 @@ -# IBM POWER __mpn_sub_n -- Subtract two limb vectors of the same length > 0 and -# store difference in a third limb vector. +# IBM POWER __mpn_sub_n -- Subtract two limb vectors of equal, non-zero length. -# Copyright (C) 1992, 1994, 1995 Free Software Foundation, Inc. +# Copyright (C) 1992, 1994, 1995, 1996 Free Software Foundation, Inc. # This file is part of the GNU MP Library. @@ -17,7 +16,8 @@ # You should have received a copy of the GNU Library General Public License # along with the GNU MP Library; see the file COPYING.LIB. If not, write to -# the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +# the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, +# MA 02111-1307, USA. # INPUT PARAMETERS @@ -38,18 +38,45 @@ __mpn_sub_n: .long .__mpn_sub_n, TOC[tc0], 0 .csect [PR] .__mpn_sub_n: - mtctr 6 # copy size into CTR + 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 used - sf 7,0,8 # add least significant limbs, set cy + 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 - stu 7,4(3) # store previous limb in load latency slot - sfe 7,0,8 # add new limbs with cy, set cy + 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: st 7,4(3) # store ultimate result limb + +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 |