--- /dev/null
+dnl Intel Pentium 4 mpn_mod_34lsub1 -- remainder modulo 2^24-1.
+
+dnl Copyright 2000, 2001, 2002, 2003 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 Pentium4: 1.0 cycles/limb
+
+
+C mp_limb_t mpn_mod_34lsub1 (mp_srcptr src, mp_size_t size)
+C
+C Enhancements:
+C
+C There might a couple of cycles to save by using plain integer code for
+C more small sizes. 2 limbs measures about 20 cycles, but 3 limbs jumps to
+C about 46 (inclusive of some function call overheads).
+
+defframe(PARAM_SIZE, 8)
+defframe(PARAM_SRC, 4)
+
+dnl re-use parameter space
+define(SAVE_EBX, `PARAM_SRC')
+define(SAVE_ESI, `PARAM_SIZE')
+
+ TEXT
+ ALIGN(16)
+PROLOGUE(mpn_mod_34lsub1)
+deflit(`FRAME',0)
+
+ movl PARAM_SIZE, %ecx
+ movl PARAM_SRC, %edx
+ movl (%edx), %eax
+
+ subl $2, %ecx
+ ja L(three_or_more)
+ jne L(one)
+
+ movl 4(%edx), %edx
+ movl %eax, %ecx
+ shrl $24, %eax C src[0] high
+
+ andl $0x00FFFFFF, %ecx C src[0] low
+ addl %ecx, %eax
+
+ movl %edx, %ecx
+ shll $8, %edx
+
+ shrl $16, %ecx C src[1] low
+ addl %ecx, %eax
+
+ andl $0x00FFFF00, %edx C src[1] high
+ addl %edx, %eax
+
+L(one):
+ ret
+
+
+L(three_or_more):
+ pxor %mm0, %mm0
+ pxor %mm1, %mm1
+ pxor %mm2, %mm2
+
+ pcmpeqd %mm7, %mm7
+ psrlq $32, %mm7 C 0x00000000FFFFFFFF, low 32 bits
+
+ pcmpeqd %mm6, %mm6
+ psrlq $40, %mm6 C 0x0000000000FFFFFF, low 24 bits
+
+L(top):
+ C eax
+ C ebx
+ C ecx counter, size-2 to 0, -1 or -2
+ C edx src, incrementing
+ C
+ C mm0 sum 0mod3
+ C mm1 sum 1mod3
+ C mm2 sum 2mod3
+ C mm3
+ C mm4
+ C mm5
+ C mm6 0x0000000000FFFFFF
+ C mm7 0x00000000FFFFFFFF
+
+ movd (%edx), %mm3
+ paddq %mm3, %mm0
+
+ movd 4(%edx), %mm3
+ paddq %mm3, %mm1
+
+ movd 8(%edx), %mm3
+ paddq %mm3, %mm2
+
+ addl $12, %edx
+ subl $3, %ecx
+ ja L(top)
+
+
+ C ecx is -2, -1 or 0 representing 0, 1 or 2 more limbs, respectively
+
+ addl $1, %ecx
+ js L(combine) C 0 more
+
+ movd (%edx), %mm3
+ paddq %mm3, %mm0
+
+ jz L(combine) C 1 more
+
+ movd 4(%edx), %mm3
+ paddq %mm3, %mm1
+
+L(combine):
+ movq %mm7, %mm3 C low halves
+ pand %mm0, %mm3
+
+ movq %mm7, %mm4
+ pand %mm1, %mm4
+
+ movq %mm7, %mm5
+ pand %mm2, %mm5
+
+ psrlq $32, %mm0 C high halves
+ psrlq $32, %mm1
+ psrlq $32, %mm2
+
+ paddq %mm0, %mm4 C fold high halves to give 33 bits each
+ paddq %mm1, %mm5
+ paddq %mm2, %mm3
+
+ psllq $8, %mm4 C combine at respective offsets
+ psllq $16, %mm5
+ paddq %mm4, %mm3
+ paddq %mm5, %mm3 C 0x000cxxxxxxxxxxxx, 50 bits
+
+ pand %mm3, %mm6 C fold at 24 bits
+ psrlq $24, %mm3
+
+ paddq %mm6, %mm3
+ movd %mm3, %eax
+
+ ASSERT(z, C nothing left in high dword
+ `psrlq $32, %mm3
+ movd %mm3, %ecx
+ orl %ecx, %ecx')
+
+ emms
+ ret
+
+EPILOGUE()
projects / msp430-gcc.git / blobdiff