1dnl  ARM mpn_sub_n -- Subtract two limb vectors of the same length > 0 and
2dnl  store difference in a third limb vector.
3dnl  Contributed by Robert Harley.
4
5dnl  Copyright 1997, 2000, 2001 Free Software Foundation, Inc.
6
7dnl  This file is part of the GNU MP Library.
8
9dnl  The GNU MP Library is free software; you can redistribute it and/or modify
10dnl  it under the terms of the GNU Lesser General Public License as published
11dnl  by the Free Software Foundation; either version 3 of the License, or (at
12dnl  your option) any later version.
13
14dnl  The GNU MP Library is distributed in the hope that it will be useful, but
15dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
17dnl  License for more details.
18
19dnl  You should have received a copy of the GNU Lesser General Public License
20dnl  along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.
21
22include(`../config.m4')
23
24C This code runs at 5 cycles/limb.
25
26define(`rp',`r0')
27define(`up',`r1')
28define(`vp',`r2')
29define(`n',`r3')
30
31
32ASM_START()
33PROLOGUE(mpn_sub_n)
34	stmfd	sp!, { r8, r9, lr }
35	subs	r12, r12, r12
36	tst	n, #1
37	beq	L(skip1)
38	ldr	r12, [up], #4
39	ldr	lr, [vp], #4
40	subs	r12, r12, lr
41	str	r12, [rp], #4
42L(skip1):
43	tst	n, #2
44	beq	L(skip2)
45	ldmia	up!, { r8, r9 }
46	ldmia	vp!, { r12, lr }
47	sbcs	r8, r8, r12
48	sbcs	r9, r9, lr
49	stmia	rp!, { r8, r9 }
50L(skip2):
51	bics	n, n, #3
52	beq	L(return)
53	stmfd	sp!, { r4, r5, r6, r7 }
54L(sub_n_loop):
55	ldmia	up!, { r4, r5, r6, r7 }
56	ldmia	vp!, { r8, r9, r12, lr }
57	sbcs	r4, r4, r8
58	ldr	r8, [rp, #12]			C cache allocate
59	sbcs	r5, r5, r9
60	sbcs	r6, r6, r12
61	sbcs	r7, r7, lr
62	stmia	rp!, { r4, r5, r6, r7 }
63	sub	n, n, #4
64	teq	n, #0
65	bne	L(sub_n_loop)
66	ldmfd	sp!, { r4, r5, r6, r7 }
67L(return):
68	sbc	r0, r0, r0
69	and	r0, r0, #1
70	ldmfd	sp!, { r8, r9, pc }
71EPILOGUE(mpn_sub_n)
72