1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
/* mc68020 __mpn_rshift -- Shift right a low-level natural-number integer.
Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Library General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
The GNU MP 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 Library General Public
License for more details.
You should have received a copy of the GNU Library General Public License
along with the GNU MP Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
/*
INPUT PARAMETERS
res_ptr (sp + 4)
s_ptr (sp + 8)
s_size (sp + 16)
cnt (sp + 12)
*/
#include "sysdep.h"
#include "asm-syntax.h"
#define res_ptr a1
#define s_ptr a0
#define s_size d6
#define cnt d4
TEXT
ALIGN
GLOBL C_SYMBOL_NAME(__mpn_rshift)
C_SYMBOL_NAME(__mpn_rshift:)
PROLOG(__mpn_rshift)
/* Save used registers on the stack. */
moveml R(d2)-R(d6)/R(a2),MEM_PREDEC(sp)
/* Copy the arguments to registers. */
movel MEM_DISP(sp,28),R(res_ptr)
movel MEM_DISP(sp,32),R(s_ptr)
movel MEM_DISP(sp,36),R(s_size)
movel MEM_DISP(sp,40),R(cnt)
moveql #1,R(d5)
cmpl R(d5),R(cnt)
bne L(Lnormal)
cmpl R(res_ptr),R(s_ptr)
bls L(Lspecial) /* jump if res_ptr >= s_ptr */
#if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020))
lea MEM_INDX1(res_ptr,s_size,l,4),R(a2)
#else /* not mc68020 */
movel R(s_size),R(d0)
asll #2,R(d0)
lea MEM_INDX(res_ptr,d0,l),R(a2)
#endif
cmpl R(s_ptr),R(a2)
bls L(Lspecial) /* jump if s_ptr >= res_ptr + s_size */
L(Lnormal:)
moveql #32,R(d5)
subl R(cnt),R(d5)
movel MEM_POSTINC(s_ptr),R(d2)
movel R(d2),R(d0)
lsll R(d5),R(d0) /* compute carry limb */
lsrl R(cnt),R(d2)
movel R(d2),R(d1)
subql #1,R(s_size)
beq L(Lend)
lsrl #1,R(s_size)
bcs L(L1)
subql #1,R(s_size)
L(Loop:)
movel MEM_POSTINC(s_ptr),R(d2)
movel R(d2),R(d3)
lsll R(d5),R(d3)
orl R(d3),R(d1)
movel R(d1),MEM_POSTINC(res_ptr)
lsrl R(cnt),R(d2)
L(L1:)
movel MEM_POSTINC(s_ptr),R(d1)
movel R(d1),R(d3)
lsll R(d5),R(d3)
orl R(d3),R(d2)
movel R(d2),MEM_POSTINC(res_ptr)
lsrl R(cnt),R(d1)
dbf R(s_size),L(Loop)
subl #0x10000,R(s_size)
bcc L(Loop)
L(Lend:)
movel R(d1),MEM(res_ptr) /* store most significant limb */
/* Restore used registers from stack frame. */
moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2)
rts
/* We loop from most significant end of the arrays, which is only
permissable if the source and destination don't overlap, since the
function is documented to work for overlapping source and destination. */
L(Lspecial:)
#if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020))
lea MEM_INDX1(s_ptr,s_size,l,4),R(s_ptr)
lea MEM_INDX1(res_ptr,s_size,l,4),R(res_ptr)
#else /* not mc68000 */
movel R(s_size),R(d0)
asll #2,R(d0)
addl R(s_size),R(s_ptr)
addl R(s_size),R(res_ptr)
#endif
clrl R(d0) /* initialize carry */
eorw #1,R(s_size)
lsrl #1,R(s_size)
bcc L(LL1)
subql #1,R(s_size)
L(LLoop:)
movel MEM_PREDEC(s_ptr),R(d2)
roxrl #1,R(d2)
movel R(d2),MEM_PREDEC(res_ptr)
L(LL1:)
movel MEM_PREDEC(s_ptr),R(d2)
roxrl #1,R(d2)
movel R(d2),MEM_PREDEC(res_ptr)
dbf R(s_size),L(LLoop)
roxrl #1,R(d0) /* save cy in msb */
subl #0x10000,R(s_size)
bcs L(LLend)
addl R(d0),R(d0) /* restore cy */
bra L(LLoop)
L(LLend:)
/* Restore used registers from stack frame. */
moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2)
rts
EPILOG(__mpn_rshift)
|
