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# Pyramid __gmpn_sub_n -- Subtract two limb vectors of the same length > 0 and
# store difference in a third limb vector.
# Copyright 1995, 2000 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 3 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. If not, see http://www.gnu.org/licenses/.
.text
.align 2
.globl ___gmpn_sub_n
___gmpn_sub_n:
movw $-1,tr0 # representation for carry clear
movw pr3,tr2
andw $3,tr2
beq Lend0
subw tr2,pr3
Loop0: rsubw $0,tr0 # restore carry bit from carry-save register
movw (pr1),tr1
subwb (pr2),tr1
movw tr1,(pr0)
subwb tr0,tr0
addw $4,pr0
addw $4,pr1
addw $4,pr2
addw $-1,tr2
bne Loop0
mtstw pr3,pr3
beq Lend
Lend0:
Loop: rsubw $0,tr0 # restore carry bit from carry-save register
movw (pr1),tr1
subwb (pr2),tr1
movw tr1,(pr0)
movw 4(pr1),tr1
subwb 4(pr2),tr1
movw tr1,4(pr0)
movw 8(pr1),tr1
subwb 8(pr2),tr1
movw tr1,8(pr0)
movw 12(pr1),tr1
subwb 12(pr2),tr1
movw tr1,12(pr0)
subwb tr0,tr0
addw $16,pr0
addw $16,pr1
addw $16,pr2
addw $-4,pr3
bne Loop
Lend:
mnegw tr0,pr0
ret
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