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
|
###################################-
#
# Copyright (C) 2009-2016 Free Software Foundation, Inc.
#
# Contributed by Michael Eager <eager@eagercon.com>.
#
# This file 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 3, or (at your option) any
# later version.
#
# GCC 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.
#
# Under Section 7 of GPL version 3, you are granted additional
# permissions described in the GCC Runtime Library Exception, version
# 3.1, as published by the Free Software Foundation.
#
# You should have received a copy of the GNU General Public License and
# a copy of the GCC Runtime Library Exception along with this program;
# see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
# <http://www.gnu.org/licenses/>.
#
# udivsi3.S
#
# Unsigned divide operation.
# Input : Divisor in Reg r5
# Dividend in Reg r6
# Output: Result in Reg r3
#
#######################################
.globl __udivsi3
.ent __udivsi3
.type __udivsi3,@function
__udivsi3:
.frame r1,0,r15
ADDIK r1,r1,-12
SWI r29,r1,0
SWI r30,r1,4
SWI r31,r1,8
BEQI r6,$LaDiv_By_Zero # Div_by_Zero # Division Error
BEQID r5,$LaResult_Is_Zero # Result is Zero
ADDIK r30,r0,0 # Clear mod
ADDIK r29,r0,32 # Initialize the loop count
# Check if r6 and r5 are equal # if yes, return 1
RSUB r18,r5,r6
BEQID r18,$LaRETURN_HERE
ADDIK r3,r0,1
# Check if (uns)r6 is greater than (uns)r5. In that case, just return 0
XOR r18,r5,r6
BGEID r18,16
ADD r3,r0,r0 # We would anyways clear r3
BLTI r6,$LaRETURN_HERE # r6[bit 31 = 1] hence is greater
BRI $LCheckr6
RSUB r18,r6,r5 # MICROBLAZEcmp
BLTI r18,$LaRETURN_HERE
# If r6 [bit 31] is set, then return result as 1
$LCheckr6:
BGTI r6,$LaDIV0
BRID $LaRETURN_HERE
ADDIK r3,r0,1
# First part try to find the first '1' in the r5
$LaDIV0:
BLTI r5,$LaDIV2
$LaDIV1:
ADD r5,r5,r5 # left shift logical r5
BGTID r5,$LaDIV1
ADDIK r29,r29,-1
$LaDIV2:
ADD r5,r5,r5 # left shift logical r5 get the '1' into the Carry
ADDC r30,r30,r30 # Move that bit into the Mod register
RSUB r31,r6,r30 # Try to subtract (r30 a r6)
BLTI r31,$LaMOD_TOO_SMALL
OR r30,r0,r31 # Move the r31 to mod since the result was positive
ADDIK r3,r3,1
$LaMOD_TOO_SMALL:
ADDIK r29,r29,-1
BEQi r29,$LaLOOP_END
ADD r3,r3,r3 # Shift in the '1' into div
BRI $LaDIV2 # Div2
$LaLOOP_END:
BRI $LaRETURN_HERE
$LaDiv_By_Zero:
$LaResult_Is_Zero:
OR r3,r0,r0 # set result to 0
$LaRETURN_HERE:
# Restore values of CSRs and that of r3 and the divisor and the dividend
LWI r29,r1,0
LWI r30,r1,4
LWI r31,r1,8
RTSD r15,8
ADDIK r1,r1,12
.end __udivsi3
.size __udivsi3, . - __udivsi3
|
