148 lines
4.4 KiB
ArmAsm
148 lines
4.4 KiB
ArmAsm
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# Alpha __mpn_sub_n -- Subtract two limb vectors of the same length > 0 and
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# store difference in a third limb vector.
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# Copyright (C) 1995-2022 Free Software Foundation, Inc.
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# This file is part of the GNU MP Library.
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# The GNU MP Library is free software; you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License as published by
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# the Free Software Foundation; either version 2.1 of the License, or (at your
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# option) any later version.
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# The GNU MP Library is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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# License for more details.
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# You should have received a copy of the GNU Lesser General Public License
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# along with the GNU MP Library. If not, see <https://www.gnu.org/licenses/>.
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# INPUT PARAMETERS
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# res_ptr $16
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# s1_ptr $17
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# s2_ptr $18
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# size $19
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.set noreorder
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.set noat
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.text
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.align 3
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.globl __mpn_sub_n
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.ent __mpn_sub_n
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__mpn_sub_n:
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.frame $30,0,$26,0
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or $31,$31,$25 # clear cy
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subq $19,4,$19 # decr loop cnt
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blt $19,.Lend2 # if less than 4 limbs, goto 2nd loop
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# Start software pipeline for 1st loop
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ldq $0,0($18)
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ldq $1,8($18)
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ldq $4,0($17)
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ldq $5,8($17)
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addq $17,32,$17 # update s1_ptr
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ldq $2,16($18)
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subq $4,$0,$20 # 1st main sub
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ldq $3,24($18)
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subq $19,4,$19 # decr loop cnt
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ldq $6,-16($17)
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cmpult $4,$20,$25 # compute cy from last sub
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ldq $7,-8($17)
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addq $1,$25,$28 # cy add
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addq $18,32,$18 # update s2_ptr
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subq $5,$28,$21 # 2nd main sub
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cmpult $28,$25,$8 # compute cy from last add
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blt $19,.Lend1 # if less than 4 limbs remain, jump
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# 1st loop handles groups of 4 limbs in a software pipeline
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.align 4
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.Loop: cmpult $5,$21,$25 # compute cy from last add
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ldq $0,0($18)
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or $8,$25,$25 # combine cy from the two adds
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ldq $1,8($18)
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addq $2,$25,$28 # cy add
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ldq $4,0($17)
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subq $6,$28,$22 # 3rd main sub
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ldq $5,8($17)
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cmpult $28,$25,$8 # compute cy from last add
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cmpult $6,$22,$25 # compute cy from last add
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stq $20,0($16)
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or $8,$25,$25 # combine cy from the two adds
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stq $21,8($16)
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addq $3,$25,$28 # cy add
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subq $7,$28,$23 # 4th main sub
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cmpult $28,$25,$8 # compute cy from last add
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cmpult $7,$23,$25 # compute cy from last add
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addq $17,32,$17 # update s1_ptr
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or $8,$25,$25 # combine cy from the two adds
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addq $16,32,$16 # update res_ptr
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addq $0,$25,$28 # cy add
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ldq $2,16($18)
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subq $4,$28,$20 # 1st main sub
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ldq $3,24($18)
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cmpult $28,$25,$8 # compute cy from last add
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ldq $6,-16($17)
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cmpult $4,$20,$25 # compute cy from last add
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ldq $7,-8($17)
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or $8,$25,$25 # combine cy from the two adds
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subq $19,4,$19 # decr loop cnt
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stq $22,-16($16)
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addq $1,$25,$28 # cy add
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stq $23,-8($16)
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subq $5,$28,$21 # 2nd main sub
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addq $18,32,$18 # update s2_ptr
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cmpult $28,$25,$8 # compute cy from last add
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bge $19,.Loop
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# Finish software pipeline for 1st loop
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.Lend1: cmpult $5,$21,$25 # compute cy from last add
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or $8,$25,$25 # combine cy from the two adds
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addq $2,$25,$28 # cy add
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subq $6,$28,$22 # 3rd main sub
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cmpult $28,$25,$8 # compute cy from last add
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cmpult $6,$22,$25 # compute cy from last add
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stq $20,0($16)
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or $8,$25,$25 # combine cy from the two adds
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stq $21,8($16)
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addq $3,$25,$28 # cy add
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subq $7,$28,$23 # 4th main sub
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cmpult $28,$25,$8 # compute cy from last add
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cmpult $7,$23,$25 # compute cy from last add
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or $8,$25,$25 # combine cy from the two adds
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addq $16,32,$16 # update res_ptr
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stq $22,-16($16)
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stq $23,-8($16)
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.Lend2: addq $19,4,$19 # restore loop cnt
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beq $19,.Lret
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# Start software pipeline for 2nd loop
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ldq $0,0($18)
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ldq $4,0($17)
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subq $19,1,$19
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beq $19,.Lend0
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# 2nd loop handles remaining 1-3 limbs
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.align 4
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.Loop0: addq $0,$25,$28 # cy add
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ldq $0,8($18)
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subq $4,$28,$20 # main sub
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ldq $1,8($17)
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addq $18,8,$18
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cmpult $28,$25,$8 # compute cy from last add
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addq $17,8,$17
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stq $20,0($16)
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cmpult $4,$20,$25 # compute cy from last add
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subq $19,1,$19 # decr loop cnt
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or $8,$25,$25 # combine cy from the two adds
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addq $16,8,$16
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or $1,$31,$4
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bne $19,.Loop0
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.Lend0: addq $0,$25,$28 # cy add
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subq $4,$28,$20 # main sub
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cmpult $28,$25,$8 # compute cy from last add
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cmpult $4,$20,$25 # compute cy from last add
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stq $20,0($16)
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or $8,$25,$25 # combine cy from the two adds
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.Lret: or $25,$31,$0 # return cy
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ret $31,($26),1
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.end __mpn_sub_n
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