Annotation of OpenXM_contrib/gmp/mpn/alpha/ev5/sub_n.asm, Revision 1.1.1.1
1.1 maekawa 1: dnl Alpha EV5 __gmpn_sub_n -- Subtract two limb vectors of the same length > 0
2: dnl and store difference in a third limb vector.
3:
4: dnl Copyright (C) 1995, 1999, 2000 Free Software Foundation, Inc.
5:
6: dnl This file is part of the GNU MP Library.
7:
8: dnl The GNU MP Library is free software; you can redistribute it and/or modify
9: dnl it under the terms of the GNU Lesser General Public License as published by
10: dnl the Free Software Foundation; either version 2.1 of the License, or (at your
11: dnl option) any later version.
12:
13: dnl The GNU MP Library is distributed in the hope that it will be useful, but
14: dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15: dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
16: dnl License for more details.
17:
18: dnl You should have received a copy of the GNU Lesser General Public License
19: dnl along with the GNU MP Library; see the file COPYING.LIB. If not, write to
20: dnl the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
21: dnl MA 02111-1307, USA.
22:
23: include(`../config.m4')
24:
25: dnl INPUT PARAMETERS
26: dnl res_ptr r16
27: dnl s1_ptr r17
28: dnl s2_ptr r18
29: dnl size r19
30:
31: ASM_START()
32: PROLOGUE(mpn_sub_n)
33: bis r31,r31,r25 C clear cy
34: subq r19,4,r19 C decr loop cnt
35: blt r19,$Lend2 C if less than 4 limbs, goto 2nd loop
36: C Start software pipeline for 1st loop
37: ldq r0,0(r18)
38: ldq r4,0(r17)
39: ldq r1,8(r18)
40: ldq r5,8(r17)
41: addq r17,32,r17 C update s1_ptr
42: ldq r2,16(r18)
43: subq r4,r0,r20 C 1st main subtract
44: ldq r3,24(r18)
45: subq r19,4,r19 C decr loop cnt
46: ldq r6,-16(r17)
47: cmpult r4,r0,r25 C compute cy from last subtract
48: ldq r7,-8(r17)
49: subq r5,r1,r28 C 2nd main subtract
50: addq r18,32,r18 C update s2_ptr
51: subq r28,r25,r21 C 2nd carry subtract
52: cmpult r5,r1,r8 C compute cy from last subtract
53: blt r19,$Lend1 C if less than 4 limbs remain, jump
54: C 1st loop handles groups of 4 limbs in a software pipeline
55: ALIGN(16)
56: $Loop: cmpult r28,r25,r25 C compute cy from last subtract
57: ldq r0,0(r18)
58: bis r8,r25,r25 C combine cy from the two subtracts
59: ldq r1,8(r18)
60: subq r6,r2,r28 C 3rd main subtract
61: ldq r4,0(r17)
62: subq r28,r25,r22 C 3rd carry subtract
63: ldq r5,8(r17)
64: cmpult r6,r2,r8 C compute cy from last subtract
65: cmpult r28,r25,r25 C compute cy from last subtract
66: stq r20,0(r16)
67: bis r8,r25,r25 C combine cy from the two subtracts
68: stq r21,8(r16)
69: subq r7,r3,r28 C 4th main subtract
70: subq r28,r25,r23 C 4th carry subtract
71: cmpult r7,r3,r8 C compute cy from last subtract
72: cmpult r28,r25,r25 C compute cy from last subtract
73: addq r17,32,r17 C update s1_ptr
74: bis r8,r25,r25 C combine cy from the two subtracts
75: addq r16,32,r16 C update res_ptr
76: subq r4,r0,r28 C 1st main subtract
77: ldq r2,16(r18)
78: subq r28,r25,r20 C 1st carry subtract
79: ldq r3,24(r18)
80: cmpult r4,r0,r8 C compute cy from last subtract
81: ldq r6,-16(r17)
82: cmpult r28,r25,r25 C compute cy from last subtract
83: ldq r7,-8(r17)
84: bis r8,r25,r25 C combine cy from the two subtracts
85: subq r19,4,r19 C decr loop cnt
86: stq r22,-16(r16)
87: subq r5,r1,r28 C 2nd main subtract
88: stq r23,-8(r16)
89: subq r28,r25,r21 C 2nd carry subtract
90: addq r18,32,r18 C update s2_ptr
91: cmpult r5,r1,r8 C compute cy from last subtract
92: bge r19,$Loop
93: C Finish software pipeline for 1st loop
94: $Lend1: cmpult r28,r25,r25 C compute cy from last subtract
95: bis r8,r25,r25 C combine cy from the two subtracts
96: subq r6,r2,r28 C cy add
97: subq r28,r25,r22 C 3rd main subtract
98: cmpult r6,r2,r8 C compute cy from last subtract
99: cmpult r28,r25,r25 C compute cy from last subtract
100: stq r20,0(r16)
101: bis r8,r25,r25 C combine cy from the two subtracts
102: stq r21,8(r16)
103: subq r7,r3,r28 C cy add
104: subq r28,r25,r23 C 4th main subtract
105: cmpult r7,r3,r8 C compute cy from last subtract
106: cmpult r28,r25,r25 C compute cy from last subtract
107: bis r8,r25,r25 C combine cy from the two subtracts
108: addq r16,32,r16 C update res_ptr
109: stq r22,-16(r16)
110: stq r23,-8(r16)
111: $Lend2: addq r19,4,r19 C restore loop cnt
112: beq r19,$Lret
113: C Start software pipeline for 2nd loop
114: ldq r0,0(r18)
115: ldq r4,0(r17)
116: subq r19,1,r19
117: beq r19,$Lend0
118: C 2nd loop handles remaining 1-3 limbs
119: ALIGN(16)
120: $Loop0: subq r4,r0,r28 C main subtract
121: cmpult r4,r0,r8 C compute cy from last subtract
122: ldq r0,8(r18)
123: ldq r4,8(r17)
124: subq r28,r25,r20 C carry subtract
125: addq r18,8,r18
126: addq r17,8,r17
127: stq r20,0(r16)
128: cmpult r28,r25,r25 C compute cy from last subtract
129: subq r19,1,r19 C decr loop cnt
130: bis r8,r25,r25 C combine cy from the two subtracts
131: addq r16,8,r16
132: bne r19,$Loop0
133: $Lend0: subq r4,r0,r28 C main subtract
134: subq r28,r25,r20 C carry subtract
135: cmpult r4,r0,r8 C compute cy from last subtract
136: cmpult r28,r25,r25 C compute cy from last subtract
137: stq r20,0(r16)
138: bis r8,r25,r25 C combine cy from the two subtracts
139:
140: $Lret: bis r25,r31,r0 C return cy
141: ret r31,(r26),1
142: EPILOGUE(mpn_sub_n)
143: ASM_END()
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