91 lines
2.3 KiB
NASM
91 lines
2.3 KiB
NASM
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; core2 mpn_divexact_byff
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; Copyright 2009 Jason Moxham
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; Windows Converdxon Copyright 2008 Brian Gladman
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;
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; This file is part of the MPIR Library.
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; The MPIR 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
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; by the Free Software Foundation; either verdxon 2.1 of the License, or (at
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; your option) any later verdxon.
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; The MPIR 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 MPIR Library; see the file COPYING.LIB. If not, write
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; to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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; Boston, MA 02110-1301, USA.
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;
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; (rcx, r8) = (rdx, r8)/0xFFFFFFFFFFFFFFFF
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; rax = "remainder"
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; where (rdx, r8) = (rcx, r8)*(B - 1) -rax*B^r8 and 0 <= rax < B - 1 B = 0xFFFFFFFFFFFFFFFF
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;
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; this is good but suffers from alignment slowdown
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; we dont seem to have much freedom to re-arrange the instructions to avoid
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; it , I suppose we could detect alignment at the start and have different
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; routines for different alignments
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%include "..\yasm_mac.inc"
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CPU Core2
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BITS 64
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LEAF_PROC mpn_divexact_byff
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movsxd r8, r8d
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xor eax, eax
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mov r9, r8
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and r9, 3
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shr r8, 2
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cmp r8, 0
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; carry flag is clear here
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jnz loop1
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sbb rax, [rdx]
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mov [rcx], rax
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dec r9
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jz end1
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sbb rax, [rdx+8]
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mov [rcx+8], rax
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dec r9
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jz end1
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sbb rax, [rdx+16]
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mov [rcx+16], rax
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dec r9
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end1:
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sbb rax, 0
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ret
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xalign 16
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loop1:
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sbb rax, [rdx]
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mov [rcx], rax
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sbb rax, [rdx+8]
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mov [rcx+8], rax
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sbb rax, [rdx+16]
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mov [rcx+16], rax
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sbb rax, [rdx+24]
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mov [rcx+24], rax
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lea rdx, [rdx+32]
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dec r8
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lea rcx, [rcx+32]
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jnz loop1
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inc r9
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dec r9
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jz end
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sbb rax, [rdx]
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mov [rcx], rax
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dec r9
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jz end
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sbb rax, [rdx+8]
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mov [rcx+8], rax
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dec r9
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jz end
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sbb rax, [rdx+16]
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mov [rcx+16], rax
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dec r9
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end:
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sbb rax, 0
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ret
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