sqr_basecase.asm
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上传日期:2022-08-06
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- dnl AMD K7 mpn_sqr_basecase -- square an mpn number.
- dnl Copyright 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
- dnl
- dnl This file is part of the GNU MP Library.
- dnl
- dnl The GNU MP Library is free software; you can redistribute it and/or
- dnl modify it under the terms of the GNU Lesser General Public License as
- dnl published by the Free Software Foundation; either version 3 of the
- dnl License, or (at your option) any later version.
- dnl
- dnl The GNU MP Library is distributed in the hope that it will be useful,
- dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
- dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- dnl Lesser General Public License for more details.
- dnl
- dnl You should have received a copy of the GNU Lesser General Public License
- dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/.
- include(`../config.m4')
- C K7: approx 2.3 cycles/crossproduct, or 4.55 cycles/triangular product
- C (measured on the speed difference between 25 and 50 limbs, which is
- C roughly the Karatsuba recursing range).
- dnl These are the same as mpn/x86/k6/sqr_basecase.asm, see that code for
- dnl some comments.
- deflit(SQR_TOOM2_THRESHOLD_MAX, 66)
- ifdef(`SQR_TOOM2_THRESHOLD_OVERRIDE',
- `define(`SQR_TOOM2_THRESHOLD',SQR_TOOM2_THRESHOLD_OVERRIDE)')
- m4_config_gmp_mparam(`SQR_TOOM2_THRESHOLD')
- deflit(UNROLL_COUNT, eval(SQR_TOOM2_THRESHOLD-3))
- C void mpn_sqr_basecase (mp_ptr dst, mp_srcptr src, mp_size_t size);
- C
- C With a SQR_TOOM2_THRESHOLD around 50 this code is about 1500 bytes,
- C which is quite a bit, but is considered good value since squares big
- C enough to use most of the code will be spending quite a few cycles in it.
- defframe(PARAM_SIZE,12)
- defframe(PARAM_SRC, 8)
- defframe(PARAM_DST, 4)
- TEXT
- ALIGN(32)
- PROLOGUE(mpn_sqr_basecase)
- deflit(`FRAME',0)
- movl PARAM_SIZE, %ecx
- movl PARAM_SRC, %eax
- cmpl $2, %ecx
- movl PARAM_DST, %edx
- je L(two_limbs)
- ja L(three_or_more)
- C------------------------------------------------------------------------------
- C one limb only
- C eax src
- C ecx size
- C edx dst
- movl (%eax), %eax
- movl %edx, %ecx
- mull %eax
- movl %edx, 4(%ecx)
- movl %eax, (%ecx)
- ret
- C------------------------------------------------------------------------------
- C
- C Using the read/modify/write "add"s seems to be faster than saving and
- C restoring registers. Perhaps the loads for the first set hide under the
- C mul latency and the second gets store to load forwarding.
- ALIGN(16)
- L(two_limbs):
- C eax src
- C ebx
- C ecx size
- C edx dst
- deflit(`FRAME',0)
- pushl %ebx FRAME_pushl()
- movl %eax, %ebx C src
- movl (%eax), %eax
- movl %edx, %ecx C dst
- mull %eax C src[0]^2
- movl %eax, (%ecx) C dst[0]
- movl 4(%ebx), %eax
- movl %edx, 4(%ecx) C dst[1]
- mull %eax C src[1]^2
- movl %eax, 8(%ecx) C dst[2]
- movl (%ebx), %eax
- movl %edx, 12(%ecx) C dst[3]
- mull 4(%ebx) C src[0]*src[1]
- popl %ebx
- addl %eax, 4(%ecx)
- adcl %edx, 8(%ecx)
- adcl $0, 12(%ecx)
- ASSERT(nc)
- addl %eax, 4(%ecx)
- adcl %edx, 8(%ecx)
- adcl $0, 12(%ecx)
- ASSERT(nc)
- ret
- C------------------------------------------------------------------------------
- defframe(SAVE_EBX, -4)
- defframe(SAVE_ESI, -8)
- defframe(SAVE_EDI, -12)
- defframe(SAVE_EBP, -16)
- deflit(STACK_SPACE, 16)
- L(three_or_more):
- subl $STACK_SPACE, %esp
- cmpl $4, %ecx
- jae L(four_or_more)
- deflit(`FRAME',STACK_SPACE)
- C------------------------------------------------------------------------------
- C Three limbs
- C
- C Writing out the loads and stores separately at the end of this code comes
- C out about 10 cycles faster than using adcls to memory.
- C eax src
- C ecx size
- C edx dst
- movl %ebx, SAVE_EBX
- movl %eax, %ebx C src
- movl (%eax), %eax
- movl %edx, %ecx C dst
- movl %esi, SAVE_ESI
- movl %edi, SAVE_EDI
- mull %eax C src[0] ^ 2
- movl %eax, (%ecx)
- movl 4(%ebx), %eax
- movl %edx, 4(%ecx)
- mull %eax C src[1] ^ 2
- movl %eax, 8(%ecx)
- movl 8(%ebx), %eax
- movl %edx, 12(%ecx)
- mull %eax C src[2] ^ 2
- movl %eax, 16(%ecx)
- movl (%ebx), %eax
- movl %edx, 20(%ecx)
- mull 4(%ebx) C src[0] * src[1]
- movl %eax, %esi
- movl (%ebx), %eax
- movl %edx, %edi
- mull 8(%ebx) C src[0] * src[2]
- addl %eax, %edi
- movl %ebp, SAVE_EBP
- movl $0, %ebp
- movl 4(%ebx), %eax
- adcl %edx, %ebp
- mull 8(%ebx) C src[1] * src[2]
- xorl %ebx, %ebx
- addl %eax, %ebp
- adcl $0, %edx
- C eax
- C ebx zero, will be dst[5]
- C ecx dst
- C edx dst[4]
- C esi dst[1]
- C edi dst[2]
- C ebp dst[3]
- adcl $0, %edx
- addl %esi, %esi
- adcl %edi, %edi
- movl 4(%ecx), %eax
- adcl %ebp, %ebp
- adcl %edx, %edx
- adcl $0, %ebx
- addl %eax, %esi
- movl 8(%ecx), %eax
- adcl %eax, %edi
- movl 12(%ecx), %eax
- movl %esi, 4(%ecx)
- adcl %eax, %ebp
- movl 16(%ecx), %eax
- movl %edi, 8(%ecx)
- movl SAVE_ESI, %esi
- movl SAVE_EDI, %edi
- adcl %eax, %edx
- movl 20(%ecx), %eax
- movl %ebp, 12(%ecx)
- adcl %ebx, %eax
- ASSERT(nc)
- movl SAVE_EBX, %ebx
- movl SAVE_EBP, %ebp
- movl %edx, 16(%ecx)
- movl %eax, 20(%ecx)
- addl $FRAME, %esp
- ret
- C------------------------------------------------------------------------------
- L(four_or_more):
- C First multiply src[0]*src[1..size-1] and store at dst[1..size].
- C Further products are added in rather than stored.
- C eax src
- C ebx
- C ecx size
- C edx dst
- C esi
- C edi
- C ebp
- defframe(`VAR_COUNTER',-20)
- defframe(`VAR_JMP', -24)
- deflit(EXTRA_STACK_SPACE, 8)
- movl %ebx, SAVE_EBX
- movl %edi, SAVE_EDI
- leal (%edx,%ecx,4), %edi C &dst[size]
- movl %esi, SAVE_ESI
- movl %ebp, SAVE_EBP
- leal (%eax,%ecx,4), %esi C &src[size]
- movl (%eax), %ebp C multiplier
- movl $0, %ebx
- decl %ecx
- negl %ecx
- subl $EXTRA_STACK_SPACE, %esp
- FRAME_subl_esp(EXTRA_STACK_SPACE)
- L(mul_1):
- C eax scratch
- C ebx carry
- C ecx counter
- C edx scratch
- C esi &src[size]
- C edi &dst[size]
- C ebp multiplier
- movl (%esi,%ecx,4), %eax
- mull %ebp
- addl %ebx, %eax
- movl %eax, (%edi,%ecx,4)
- movl $0, %ebx
- adcl %edx, %ebx
- incl %ecx
- jnz L(mul_1)
- C Add products src[n]*src[n+1..size-1] at dst[2*n-1...], for each n=1..size-2.
- C
- C The last two products, which are the bottom right corner of the product
- C triangle, are left to the end. These are src[size-3]*src[size-2,size-1]
- C and src[size-2]*src[size-1]. If size is 4 then it's only these corner
- C cases that need to be done.
- C
- C The unrolled code is the same as in mpn_addmul_1, see that routine for
- C some comments.
- C
- C VAR_COUNTER is the outer loop, running from -size+4 to -1, inclusive.
- C
- C VAR_JMP is the computed jump into the unrolled code, stepped by one code
- C chunk each outer loop.
- C
- C K7 does branch prediction on indirect jumps, which is bad since it's a
- C different target each time. There seems no way to avoid this.
- dnl This value also hard coded in some shifts and adds
- deflit(CODE_BYTES_PER_LIMB, 17)
- dnl With the unmodified &src[size] and &dst[size] pointers, the
- dnl displacements in the unrolled code fit in a byte for UNROLL_COUNT
- dnl values up to 31, but above that an offset must be added to them.
- deflit(OFFSET,
- ifelse(eval(UNROLL_COUNT>31),1,
- eval((UNROLL_COUNT-31)*4),
- 0))
- dnl Because the last chunk of code is generated differently, a label placed
- dnl at the end doesn't work. Instead calculate the implied end using the
- dnl start and how many chunks of code there are.
- deflit(UNROLL_INNER_END,
- `L(unroll_inner_start)+eval(UNROLL_COUNT*CODE_BYTES_PER_LIMB)')
- C eax
- C ebx carry
- C ecx
- C edx
- C esi &src[size]
- C edi &dst[size]
- C ebp
- movl PARAM_SIZE, %ecx
- movl %ebx, (%edi)
- subl $4, %ecx
- jz L(corner)
- negl %ecx
- ifelse(OFFSET,0,,`subl $OFFSET, %edi')
- ifelse(OFFSET,0,,`subl $OFFSET, %esi')
- movl %ecx, %edx
- shll $4, %ecx
- ifdef(`PIC',`
- call L(pic_calc)
- L(here):
- ',`
- leal UNROLL_INNER_END-eval(2*CODE_BYTES_PER_LIMB)(%ecx,%edx), %ecx
- ')
- C The calculated jump mustn't come out to before the start of the
- C code available. This is the limit UNROLL_COUNT puts on the src
- C operand size, but checked here directly using the jump address.
- ASSERT(ae,
- `movl_text_address(L(unroll_inner_start), %eax)
- cmpl %eax, %ecx')
- C------------------------------------------------------------------------------
- ALIGN(16)
- L(unroll_outer_top):
- C eax
- C ebx high limb to store
- C ecx VAR_JMP
- C edx VAR_COUNTER, limbs, negative
- C esi &src[size], constant
- C edi dst ptr, high of last addmul
- C ebp
- movl -12+OFFSET(%esi,%edx,4), %ebp C next multiplier
- movl -8+OFFSET(%esi,%edx,4), %eax C first of multiplicand
- movl %edx, VAR_COUNTER
- mull %ebp
- define(cmovX,`ifelse(eval(UNROLL_COUNT%2),0,`cmovz($@)',`cmovnz($@)')')
- testb $1, %cl
- movl %edx, %ebx C high carry
- movl %ecx, %edx C jump
- movl %eax, %ecx C low carry
- cmovX( %ebx, %ecx) C high carry reverse
- cmovX( %eax, %ebx) C low carry reverse
- leal CODE_BYTES_PER_LIMB(%edx), %eax
- xorl %edx, %edx
- leal 4(%edi), %edi
- movl %eax, VAR_JMP
- jmp *%eax
- ifdef(`PIC',`
- L(pic_calc):
- addl (%esp), %ecx
- addl $UNROLL_INNER_END-eval(2*CODE_BYTES_PER_LIMB)-L(here), %ecx
- addl %edx, %ecx
- ret_internal
- ')
- C Must be an even address to preserve the significance of the low
- C bit of the jump address indicating which way around ecx/ebx should
- C start.
- ALIGN(2)
- L(unroll_inner_start):
- C eax next limb
- C ebx carry high
- C ecx carry low
- C edx scratch
- C esi src
- C edi dst
- C ebp multiplier
- forloop(`i', UNROLL_COUNT, 1, `
- deflit(`disp_src', eval(-i*4 + OFFSET))
- deflit(`disp_dst', eval(disp_src - 4))
- m4_assert(`disp_src>=-128 && disp_src<128')
- m4_assert(`disp_dst>=-128 && disp_dst<128')
- ifelse(eval(i%2),0,`
- Zdisp( movl, disp_src,(%esi), %eax)
- adcl %edx, %ebx
- mull %ebp
- Zdisp( addl, %ecx, disp_dst,(%edi))
- movl $0, %ecx
- adcl %eax, %ebx
- ',`
- dnl this bit comes out last
- Zdisp( movl, disp_src,(%esi), %eax)
- adcl %edx, %ecx
- mull %ebp
- Zdisp( addl, %ebx, disp_dst,(%edi))
- ifelse(forloop_last,0,
- ` movl $0, %ebx')
- adcl %eax, %ecx
- ')
- ')
- C eax next limb
- C ebx carry high
- C ecx carry low
- C edx scratch
- C esi src
- C edi dst
- C ebp multiplier
- adcl $0, %edx
- addl %ecx, -4+OFFSET(%edi)
- movl VAR_JMP, %ecx
- adcl $0, %edx
- movl %edx, m4_empty_if_zero(OFFSET) (%edi)
- movl VAR_COUNTER, %edx
- incl %edx
- jnz L(unroll_outer_top)
- ifelse(OFFSET,0,,`
- addl $OFFSET, %esi
- addl $OFFSET, %edi
- ')
- C------------------------------------------------------------------------------
- L(corner):
- C esi &src[size]
- C edi &dst[2*size-5]
- movl -12(%esi), %ebp
- movl -8(%esi), %eax
- movl %eax, %ecx
- mull %ebp
- addl %eax, -4(%edi)
- movl -4(%esi), %eax
- adcl $0, %edx
- movl %edx, %ebx
- movl %eax, %esi
- mull %ebp
- addl %ebx, %eax
- adcl $0, %edx
- addl %eax, (%edi)
- movl %esi, %eax
- adcl $0, %edx
- movl %edx, %ebx
- mull %ecx
- addl %ebx, %eax
- movl %eax, 4(%edi)
- adcl $0, %edx
- movl %edx, 8(%edi)
- C Left shift of dst[1..2*size-2], high bit shifted out becomes dst[2*size-1].
- L(lshift_start):
- movl PARAM_SIZE, %eax
- movl PARAM_DST, %edi
- xorl %ecx, %ecx C clear carry
- leal (%edi,%eax,8), %edi
- notl %eax C -size-1, preserve carry
- leal 2(%eax), %eax C -(size-1)
- L(lshift):
- C eax counter, negative
- C ebx
- C ecx
- C edx
- C esi
- C edi dst, pointing just after last limb
- C ebp
- rcll -4(%edi,%eax,8)
- rcll (%edi,%eax,8)
- incl %eax
- jnz L(lshift)
- setc %al
- movl PARAM_SRC, %esi
- movl %eax, -4(%edi) C dst most significant limb
- movl PARAM_SIZE, %ecx
- C Now add in the squares on the diagonal, src[0]^2, src[1]^2, ...,
- C src[size-1]^2. dst[0] hasn't yet been set at all yet, and just gets the
- C low limb of src[0]^2.
- movl (%esi), %eax C src[0]
- mull %eax
- leal (%esi,%ecx,4), %esi C src point just after last limb
- negl %ecx
- movl %eax, (%edi,%ecx,8) C dst[0]
- incl %ecx
- L(diag):
- C eax scratch
- C ebx scratch
- C ecx counter, negative
- C edx carry
- C esi src just after last limb
- C edi dst just after last limb
- C ebp
- movl (%esi,%ecx,4), %eax
- movl %edx, %ebx
- mull %eax
- addl %ebx, -4(%edi,%ecx,8)
- adcl %eax, (%edi,%ecx,8)
- adcl $0, %edx
- incl %ecx
- jnz L(diag)
- movl SAVE_ESI, %esi
- movl SAVE_EBX, %ebx
- addl %edx, -4(%edi) C dst most significant limb
- movl SAVE_EDI, %edi
- movl SAVE_EBP, %ebp
- addl $FRAME, %esp
- ret
- EPILOGUE()