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
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
/* mc68020 lshift -- Shift left a low-level natural-number integer.
*
* Copyright (C) 1996, 1998, 2001 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* GnuPG 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*
* Note: This code is heavily based on the GNU MP Library.
* Actually it's the same code with only minor changes in the
* way the data is stored; this is to support the abstraction
* of an optional secure memory allocation which may be used
* to avoid revealing of sensitive data due to paging etc.
* The GNU MP Library itself is published under the LGPL;
* however I decided to publish this code under the plain GPL.
*/
#include "sysdep.h"
#include "asm-syntax.h"
/*******************
* mpi_limb_t
* mpihelp_lshift( mpi_ptr_t wp, (sp + 4)
* mpi_ptr_t up, (sp + 8)
* mpi_size_t usize, (sp + 12)
* unsigned cnt) (sp + 16)
*/
#define res_ptr a1
#define s_ptr a0
#define s_size d6
#define cnt d4
TEXT
ALIGN
GLOBL C_SYMBOL_NAME(mpihelp_lshift)
C_SYMBOL_NAME(mpihelp_lshift:)
PROLOG(mpihelp_lshift)
/* 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(s_ptr),R(res_ptr)
bls L(Lspecial) /* jump if s_ptr >= res_ptr */
#if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020))
lea MEM_INDX1(s_ptr,s_size,l,4),R(a2)
#else /* not mc68020 */
movel R(s_size),R(d0)
asll #2,R(d0)
lea MEM_INDX(s_ptr,d0,l),R(a2)
#endif
cmpl R(res_ptr),R(a2)
bls L(Lspecial) /* jump if res_ptr >= s_ptr + s_size */
L(Lnormal:)
moveql #32,R(d5)
subl R(cnt),R(d5)
#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
movel MEM_PREDEC(s_ptr),R(d2)
movel R(d2),R(d0)
lsrl R(d5),R(d0) /* compute carry limb */
lsll 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_PREDEC(s_ptr),R(d2)
movel R(d2),R(d3)
lsrl R(d5),R(d3)
orl R(d3),R(d1)
movel R(d1),MEM_PREDEC(res_ptr)
lsll R(cnt),R(d2)
L(L1:)
movel MEM_PREDEC(s_ptr),R(d1)
movel R(d1),R(d3)
lsrl R(d5),R(d3)
orl R(d3),R(d2)
movel R(d2),MEM_PREDEC(res_ptr)
lsll R(cnt),R(d1)
dbf R(s_size),L(Loop)
subl #0x10000,R(s_size)
bcc L(Loop)
L(Lend:)
movel R(d1),MEM_PREDEC(res_ptr) /* store least significant limb */
/* Restore used registers from stack frame. */
moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2)
rts
/* We loop from least 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:)
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_POSTINC(s_ptr),R(d2)
addxl R(d2),R(d2)
movel R(d2),MEM_POSTINC(res_ptr)
L(LL1:)
movel MEM_POSTINC(s_ptr),R(d2)
addxl R(d2),R(d2)
movel R(d2),MEM_POSTINC(res_ptr)
dbf R(s_size),L(LLoop)
addxl R(d0),R(d0) /* save cy in lsb */
subl #0x10000,R(s_size)
bcs L(LLend)
lsrl #1,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(mpihelp_lshift)
|
