sub_n.asm revision 1.1.1.1 
1dnl  PowerPC-64/mode32 mpn_sub_n -- Subtract two limb vectors of the same
2dnl  length and store difference in a third limb vector.
3
4dnl  Copyright 1999, 2000, 2001, 2003, 2005 Free Software Foundation, Inc.
5
6dnl  This file is part of the GNU MP Library.
7
8dnl  The GNU MP Library is free software; you can redistribute it and/or modify
9dnl  it under the terms of the GNU Lesser General Public License as published
10dnl  by the Free Software Foundation; either version 3 of the License, or (at
11dnl  your option) any later version.
12
13dnl  The GNU MP Library is distributed in the hope that it will be useful, but
14dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
16dnl  License for more details.
17
18dnl  You should have received a copy of the GNU Lesser General Public License
19dnl  along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.
20
21include(`../config.m4')
22
23C		cycles/limb
24C POWER3/PPC630:     ?
25C POWER4/PPC970:     4.25
26
27C INPUT PARAMETERS
28C rp	r3
29C up	r4
30C vp	r5
31C n	r6
32
33ASM_START()
34PROLOGUE(mpn_sub_n)
35	mtctr	r6		C copy size into CTR
36	addic	r0, r6, -1	C set cy
37	ld	r8, 0(r4)	C load least significant s1 limb
38	ld	r0, 0(r5)	C load least significant s2 limb
39	addi	r3, r3, -8	C offset res_ptr, it's updated before it's used
40	bdz	L(end)		C If done, skip loop
41
42L(oop):	ld	r9, 8(r4)	C load s1 limb
43	ld	r10, 8(r5)	C load s2 limb
44	subfe	r7, r0, r8	C subtract limbs with cy, set cy
45	srdi	r6, r0, 32
46	srdi	r11, r8, 32
47	subfe	r6, r6, r11
48	std	r7, 8(r3)	C store result limb
49	bdz	L(exit)		C decrement CTR and exit if done
50	ldu	r8, 16(r4)	C load s1 limb and update s1_ptr
51	ldu	r0, 16(r5)	C load s2 limb and update s2_ptr
52	subfe	r7, r10, r9	C subtract limbs with cy, set cy
53	srdi	r6, r10, 32
54	srdi	r11, r9, 32
55	subfe	r6, r6, r11
56	stdu	r7, 16(r3)	C store result limb and update res_ptr
57	bdnz	L(oop)		C decrement CTR and loop back
58
59L(end):	subfe	r7, r0, r8
60	srdi	r6, r0, 32
61	srdi	r11, r8, 32
62	subfe	r6, r6, r11
63	std	r7, 8(r3)	C store ultimate result limb
64	subfe	r3, r0, r0	C load !cy into ...
65	subfic	r4, r3, 0	C ... return value register
66	li	r3, 0		C zero extend return value
67	blr
68L(exit):	subfe	r7, r10, r9
69	srdi	r6, r10, 32
70	srdi	r11, r9, 32
71	subfe	r6, r6, r11
72	std	r7, 16(r3)
73	subfe	r3, r0, r0	C load !cy into ...
74	subfic	r4, r3, 0	C ... return value register
75	li	r3, 0		C zero extend return value
76	blr
77EPILOGUE()
78