91 lines
2.3 KiB
NASM
91 lines
2.3 KiB
NASM
dnl X86_64 mpn_divrem_hensel_1
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dnl Copyright 2009 Jason Moxham
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dnl This file is part of the MPIR Library.
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dnl The MPIR Library is free software; you can redistribute it and/or modify
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dnl it under the terms of the GNU Lesser General Public License as published
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dnl by the Free Software Foundation; either version 2.1 of the License, or (at
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dnl your option) any later version.
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dnl The MPIR Library is distributed in the hope that it will be useful, but
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dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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dnl License for more details.
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dnl You should have received a copy of the GNU Lesser General Public License
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dnl along with the MPIR Library; see the file COPYING.LIB. If not, write
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dnl to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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dnl Boston, MA 02110-1301, USA.
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include(`../config.m4')
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C (rdi,rdx)=(rsi,rdx) / rcx inverse is r8
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C rax=remainder
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C This is divrem_hensel_1 with shifting on the output of the quotient
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C On k8/k10 the shifting comes for free so no need to have different
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C fn for that. And on K8/K10 this runs at 10c/l which is optimal
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C This function "replaces" divexact_1 and modexact_1_odd
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DONT USE until we have sorted out the return value
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ASM_START()
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PROLOGUE(mpn_divrem_hensel_1)
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mov $1,%r9
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sub %rdx,%r9
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lea (%rdi,%rdx,8),%rdi
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lea (%rsi,%rdx,8),%rsi
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mov %rcx,%r10
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mov %r8,%r11
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mov $64,%rax
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bsf %r10,%rcx
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sub %rcx,%rax
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movq %rcx,%mm0
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movq %rax,%mm1
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shr %cl,%r10
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mov -8(%rsi,%r9,8),%rax
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imul %r11,%rax
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movq %rax,%mm4
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movq %mm4,%mm5
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psrlq %mm0,%mm4
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psllq %mm1,%mm5
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psrlq %mm1,%mm5
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mul %r10
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mov $1,%r8
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# cmp below clears carry
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cmp $0,%r9
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jz skiploop
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ALIGN(16)
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loop:
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movq %mm4,%mm2
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mov (%rsi,%r9,8),%rax
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sbb %rdx,%rax
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sbb %r8,%r8
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imul %r11,%rax
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movq %rax,%mm3
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movq %mm3,%mm4
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psllq %mm1,%mm3
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psrlq %mm0,%mm4
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por %mm3,%mm2
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movq %mm2,-8(%rdi,%r9,8)
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mul %r10
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add $1,%r8
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inc %r9
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jnz loop
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skiploop:
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movq %mm4,-8(%rdi,%r9,8)
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movq %mm5,%rax
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dec %r8
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sub %r8,%rdx
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shl %cl,%rdx
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add %rdx,%rax
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emms
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ret
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# so (xp,n) = low_s_bitsof(ret)*d/2^s + (qp,n)*(d) - (ret>>s)*B^n and 0 <= (ret>>s) < d/2^s
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# the return value is overly complicated , simplify this when we are clearer
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# about what we need
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EPILOGUE()
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