lshift.asm
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上传日期:2022-08-06
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- dnl AMD K7 mpn_lshift -- mpn left shift.
- 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: 1.21 cycles/limb (at 16 limbs/loop).
- dnl K7: UNROLL_COUNT cycles/limb
- dnl 4 1.51
- dnl 8 1.26
- dnl 16 1.21
- dnl 32 1.2
- dnl Maximum possible with the current code is 64.
- deflit(UNROLL_COUNT, 16)
- C mp_limb_t mpn_lshift (mp_ptr dst, mp_srcptr src, mp_size_t size,
- C unsigned shift);
- C
- C Shift src,size left by shift many bits and store the result in dst,size.
- C Zeros are shifted in at the right. The bits shifted out at the left are
- C the return value.
- C
- C The comments in mpn_rshift apply here too.
- ifdef(`PIC',`
- deflit(UNROLL_THRESHOLD, 10)
- ',`
- deflit(UNROLL_THRESHOLD, 10)
- ')
- defframe(PARAM_SHIFT,16)
- defframe(PARAM_SIZE, 12)
- defframe(PARAM_SRC, 8)
- defframe(PARAM_DST, 4)
- defframe(SAVE_EDI, -4)
- defframe(SAVE_ESI, -8)
- defframe(SAVE_EBX, -12)
- deflit(SAVE_SIZE, 12)
- TEXT
- ALIGN(32)
- PROLOGUE(mpn_lshift)
- deflit(`FRAME',0)
- movl PARAM_SIZE, %eax
- movl PARAM_SRC, %edx
- subl $SAVE_SIZE, %esp
- deflit(`FRAME',SAVE_SIZE)
- movl PARAM_SHIFT, %ecx
- movl %edi, SAVE_EDI
- movl PARAM_DST, %edi
- decl %eax
- jnz L(more_than_one_limb)
- movl (%edx), %edx
- shldl( %cl, %edx, %eax) C eax was decremented to zero
- shll %cl, %edx
- movl %edx, (%edi)
- movl SAVE_EDI, %edi
- addl $SAVE_SIZE, %esp
- ret
- C -----------------------------------------------------------------------------
- L(more_than_one_limb):
- C eax size-1
- C ebx
- C ecx shift
- C edx src
- C esi
- C edi dst
- C ebp
- movd PARAM_SHIFT, %mm6
- movd (%edx,%eax,4), %mm5 C src high limb
- cmp $UNROLL_THRESHOLD-1, %eax
- jae L(unroll)
- negl %ecx
- movd (%edx), %mm4 C src low limb
- addl $32, %ecx
- movd %ecx, %mm7
- L(simple_top):
- C eax loop counter, limbs
- C ebx
- C ecx
- C edx src
- C esi
- C edi dst
- C ebp
- C
- C mm0 scratch
- C mm4 src low limb
- C mm5 src high limb
- C mm6 shift
- C mm7 32-shift
- movq -4(%edx,%eax,4), %mm0
- decl %eax
- psrlq %mm7, %mm0
- movd %mm0, 4(%edi,%eax,4)
- jnz L(simple_top)
- psllq %mm6, %mm5
- psllq %mm6, %mm4
- psrlq $32, %mm5
- movd %mm4, (%edi) C dst low limb
- movd %mm5, %eax C return value
- movl SAVE_EDI, %edi
- addl $SAVE_SIZE, %esp
- emms
- ret
- C -----------------------------------------------------------------------------
- ALIGN(16)
- L(unroll):
- C eax size-1
- C ebx (saved)
- C ecx shift
- C edx src
- C esi
- C edi dst
- C ebp
- C
- C mm5 src high limb, for return value
- C mm6 lshift
- movl %esi, SAVE_ESI
- movl %ebx, SAVE_EBX
- leal -4(%edx,%eax,4), %edx C &src[size-2]
- testb $4, %dl
- movq (%edx), %mm1 C src high qword
- jz L(start_src_aligned)
- C src isn't aligned, process high limb (marked xxx) separately to
- C make it so
- C
- C source -4(edx,%eax,4)
- C |
- C +-------+-------+-------+--
- C | xxx |
- C +-------+-------+-------+--
- C 0mod8 4mod8 0mod8
- C
- C dest -4(edi,%eax,4)
- C |
- C +-------+-------+--
- C | xxx | |
- C +-------+-------+--
- psllq %mm6, %mm1
- subl $4, %edx
- movl %eax, PARAM_SIZE C size-1
- psrlq $32, %mm1
- decl %eax C size-2 is new size-1
- movd %mm1, 4(%edi,%eax,4)
- movq (%edx), %mm1 C new src high qword
- L(start_src_aligned):
- leal -4(%edi,%eax,4), %edi C &dst[size-2]
- psllq %mm6, %mm5
- testl $4, %edi
- psrlq $32, %mm5 C return value
- jz L(start_dst_aligned)
- C dst isn't aligned, subtract 4 bytes to make it so, and pretend the
- C shift is 32 bits extra. High limb of dst (marked xxx) handled
- C here separately.
- C
- C source %edx
- C +-------+-------+--
- C | mm1 |
- C +-------+-------+--
- C 0mod8 4mod8
- C
- C dest %edi
- C +-------+-------+-------+--
- C | xxx |
- C +-------+-------+-------+--
- C 0mod8 4mod8 0mod8
- movq %mm1, %mm0
- psllq %mm6, %mm1
- addl $32, %ecx C shift+32
- psrlq $32, %mm1
- movd %mm1, 4(%edi)
- movq %mm0, %mm1
- subl $4, %edi
- movd %ecx, %mm6 C new lshift
- L(start_dst_aligned):
- decl %eax C size-2, two last limbs handled at end
- movq %mm1, %mm2 C copy of src high qword
- negl %ecx
- andl $-2, %eax C round size down to even
- addl $64, %ecx
- movl %eax, %ebx
- negl %eax
- andl $UNROLL_MASK, %eax
- decl %ebx
- shll %eax
- movd %ecx, %mm7 C rshift = 64-lshift
- ifdef(`PIC',`
- call L(pic_calc)
- L(here):
- ',`
- leal L(entry) (%eax,%eax,4), %esi
- ')
- shrl $UNROLL_LOG2, %ebx C loop counter
- leal ifelse(UNROLL_BYTES,256,128) -8(%edx,%eax,2), %edx
- leal ifelse(UNROLL_BYTES,256,128) (%edi,%eax,2), %edi
- movl PARAM_SIZE, %eax C for use at end
- jmp *%esi
- ifdef(`PIC',`
- L(pic_calc):
- C See mpn/x86/README about old gas bugs
- leal (%eax,%eax,4), %esi
- addl $L(entry)-L(here), %esi
- addl (%esp), %esi
- ret_internal
- ')
- C -----------------------------------------------------------------------------
- ALIGN(32)
- L(top):
- C eax size (for use at end)
- C ebx loop counter
- C ecx rshift
- C edx src
- C esi computed jump
- C edi dst
- C ebp
- C
- C mm0 scratch
- C mm1 carry (alternating, mm2 first)
- C mm2 /
- C mm6 lshift
- C mm7 rshift
- C
- C 10 code bytes/limb
- C
- C The two chunks differ in whether mm1 or mm2 hold the carry.
- C The computed jump puts the initial carry in both mm1 and mm2.
- L(entry):
- deflit(CHUNK_COUNT, 4)
- forloop(i, 0, UNROLL_COUNT/CHUNK_COUNT-1, `
- deflit(`disp0', eval(-i*CHUNK_COUNT*4 ifelse(UNROLL_BYTES,256,-128)))
- deflit(`disp1', eval(disp0 - 8))
- Zdisp( movq, disp0,(%edx), %mm0)
- psllq %mm6, %mm2
- movq %mm0, %mm1
- psrlq %mm7, %mm0
- por %mm2, %mm0
- Zdisp( movq, %mm0, disp0,(%edi))
- Zdisp( movq, disp1,(%edx), %mm0)
- psllq %mm6, %mm1
- movq %mm0, %mm2
- psrlq %mm7, %mm0
- por %mm1, %mm0
- Zdisp( movq, %mm0, disp1,(%edi))
- ')
- subl $UNROLL_BYTES, %edx
- subl $UNROLL_BYTES, %edi
- decl %ebx
- jns L(top)
- define(`disp', `m4_empty_if_zero(eval($1 ifelse(UNROLL_BYTES,256,-128)))')
- L(end):
- testb $1, %al
- movl SAVE_EBX, %ebx
- psllq %mm6, %mm2 C wanted left shifted in all cases below
- movd %mm5, %eax
- movl SAVE_ESI, %esi
- jz L(end_even)
- L(end_odd):
- C Size odd, destination was aligned.
- C
- C source edx+8 edx+4
- C --+---------------+-------+
- C | mm2 | |
- C --+---------------+-------+
- C
- C dest edi
- C --+---------------+---------------+-------+
- C | written | | |
- C --+---------------+---------------+-------+
- C
- C mm6 = shift
- C mm7 = ecx = 64-shift
- C Size odd, destination was unaligned.
- C
- C source edx+8 edx+4
- C --+---------------+-------+
- C | mm2 | |
- C --+---------------+-------+
- C
- C dest edi
- C --+---------------+---------------+
- C | written | |
- C --+---------------+---------------+
- C
- C mm6 = shift+32
- C mm7 = ecx = 64-(shift+32)
- C In both cases there's one extra limb of src to fetch and combine
- C with mm2 to make a qword at (%edi), and in the aligned case
- C there's an extra limb of dst to be formed from that extra src limb
- C left shifted.
- movd disp(4) (%edx), %mm0
- testb $32, %cl
- movq %mm0, %mm1
- psllq $32, %mm0
- psrlq %mm7, %mm0
- psllq %mm6, %mm1
- por %mm2, %mm0
- movq %mm0, disp(0) (%edi)
- jz L(end_odd_unaligned)
- movd %mm1, disp(-4) (%edi)
- L(end_odd_unaligned):
- movl SAVE_EDI, %edi
- addl $SAVE_SIZE, %esp
- emms
- ret
- L(end_even):
- C Size even, destination was aligned.
- C
- C source edx+8
- C --+---------------+
- C | mm2 |
- C --+---------------+
- C
- C dest edi
- C --+---------------+---------------+
- C | written | |
- C --+---------------+---------------+
- C
- C mm6 = shift
- C mm7 = ecx = 64-shift
- C Size even, destination was unaligned.
- C
- C source edx+8
- C --+---------------+
- C | mm2 |
- C --+---------------+
- C
- C dest edi+4
- C --+---------------+-------+
- C | written | |
- C --+---------------+-------+
- C
- C mm6 = shift+32
- C mm7 = ecx = 64-(shift+32)
- C The movq for the aligned case overwrites the movd for the
- C unaligned case.
- movq %mm2, %mm0
- psrlq $32, %mm2
- testb $32, %cl
- movd %mm2, disp(4) (%edi)
- jz L(end_even_unaligned)
- movq %mm0, disp(0) (%edi)
- L(end_even_unaligned):
- movl SAVE_EDI, %edi
- addl $SAVE_SIZE, %esp
- emms
- ret
- EPILOGUE()