/* Subtract two limb vectors of equal, non-zero length for PowerPC.   Copyright (C) 1997, 1999, 2000 Free Software Foundation, Inc.   This file is part of the GNU C Library.   The GNU C Library is free software; you can redistribute it and/or   modify it under the terms of the GNU Lesser General Public   License as published by the Free Software Foundation; either   version 2.1 of the License, or (at your option) any later version.   The GNU C Library is distributed in the hope that it will be useful,   but WITHOUT ANY WARRANTY; without even the implied warranty of   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU   Lesser General Public License for more details.   You should have received a copy of the GNU Lesser General Public   License along with the GNU C Library; if not, write to the Free   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA   02111-1307 USA.  */#include <sysdep.h>#include <bp-sym.h>#include <bp-asm.h>/* mp_limb_t mpn_sub_n (mp_ptr res_ptr, mp_srcptr s1_ptr, mp_srcptr s2_ptr,                        mp_size_t size)   Calculate s1-s2 and put result in res_ptr; return borrow, 0 or 1.  *//* Note on optimisation: This code is optimal for the 601.  Almost every other   possible 2-unrolled inner loop will not be.  Also, watch out for the   alignment...  */EALIGN (BP_SYM (__mpn_sub_n), 3, 1)#if __BOUNDED_POINTERS__	slwi r10,r6,2		/* convert limbs to bytes */	CHECK_BOUNDS_BOTH_WIDE (r3, r8, r9, r10)	CHECK_BOUNDS_BOTH_WIDE (r4, r8, r9, r10)	CHECK_BOUNDS_BOTH_WIDE (r5, r8, r9, r10)#endif/* Set up for loop below.  */	mtcrf 0x01,r6	srwi. r7,r6,1	mtctr r7	bt    31,L(2)/* Set the carry (clear the borrow).  */	subfc r0,r0,r0/* Adjust pointers for loop.  */	addi  r3,r3,-4	addi  r4,r4,-4	addi  r5,r5,-4	b     L(0)L(2):	lwz   r7,0(r5)	lwz   r6,0(r4)	subfc r6,r7,r6	stw   r6,0(r3)        beq   L(1)/* Align start of loop to an odd word boundary to guarantee that the   last two words can be fetched in one access (for 601).  This turns   out to be important.  */L(0):	lwz   r9,4(r4)	lwz   r8,4(r5)	lwzu  r6,8(r4)	lwzu  r7,8(r5)	subfe r8,r8,r9	stw   r8,4(r3)	subfe r6,r7,r6	stwu  r6,8(r3)	bdnz  L(0)/* Return the borrow. */L(1):	subfe r3,r3,r3	neg   r3,r3	blrEND (BP_SYM (__mpn_sub_n))