1###################################
2#
3#  Copyright (C) 2009-2015 Free Software Foundation, Inc.
4#
5#  Contributed by Michael Eager <eager@eagercon.com>.
6#
7#  This file is free software; you can redistribute it and/or modify it
8#  under the terms of the GNU General Public License as published by the
9#  Free Software Foundation; either version 3, or (at your option) any
10#  later version.
11#
12#  GCC is distributed in the hope that it will be useful, but WITHOUT
13#  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14#  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
15#  License for more details.
16#
17#  Under Section 7 of GPL version 3, you are granted additional
18#  permissions described in the GCC Runtime Library Exception, version
19#  3.1, as published by the Free Software Foundation.
20#
21#  You should have received a copy of the GNU General Public License and
22#  a copy of the GCC Runtime Library Exception along with this program;
23#  see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
24#  <http://www.gnu.org/licenses/>.
25#
26#  umodsi3.S
27#
28#  Unsigned modulo operation for 32 bit integers.
29#	Input :	op1 in Reg r5
30#		op2 in Reg r6
31#	Output: op1 mod op2 in Reg r3
32#
33#######################################
34
35	.globl	__umodsi3
36	.ent	__umodsi3
37	.type	__umodsi3,@function
38__umodsi3:
39	.frame	r1,0,r15
40
41	addik	r1,r1,-12
42	swi	r29,r1,0
43	swi	r30,r1,4
44	swi	r31,r1,8
45
46	BEQI	r6,$LaDiv_By_Zero         # Div_by_Zero   # Division Error
47	BEQId	r5,$LaResult_Is_Zero     # Result is Zero
48	ADDIK 	r3,r0,0                  # Clear div
49	ADDIK 	r30,r0,0     	# clear mod
50	ADDIK 	r29,r0,32       # Initialize the loop count
51
52# Check if r6 and r5 are equal # if yes, return 0
53	rsub 	r18,r5,r6
54	beqi	r18,$LaRETURN_HERE
55
56# Check if (uns)r6 is greater than (uns)r5. In that case, just return r5
57	xor	r18,r5,r6
58	bgeid	r18,16
59	addik	r3,r5,0
60	blti	r6,$LaRETURN_HERE
61	bri	$LCheckr6
62	rsub	r18,r5,r6 # MICROBLAZEcmp
63	bgti	r18,$LaRETURN_HERE
64
65# If r6 [bit 31] is set, then return result as r5-r6
66$LCheckr6:
67	bgtid	r6,$LaDIV0
68	addik	r3,r0,0
69	addik	r18,r0,0x7fffffff
70	and	r5,r5,r18
71	and 	r6,r6,r18
72	brid	$LaRETURN_HERE
73	rsub	r3,r6,r5
74# First part: try to find the first '1' in the r5
75$LaDIV0:
76	BLTI	r5,$LaDIV2
77$LaDIV1:
78	ADD 	r5,r5,r5     # left shift logical r5
79	BGEID 	r5,$LaDIV1   #
80	ADDIK 	r29,r29,-1
81$LaDIV2:
82	ADD 	r5,r5,r5     # left shift logical  r5 get the '1' into the Carry
83	ADDC 	r3,r3,r3     # Move that bit into the Mod register
84	rSUB 	r31,r6,r3    # Try to subtract (r3 a r6)
85	BLTi 	r31,$LaMOD_TOO_SMALL
86	OR  	r3,r0,r31    # Move the r31 to mod since the result was positive
87	ADDIK 	r30,r30,1
88$LaMOD_TOO_SMALL:
89	ADDIK 	r29,r29,-1
90	BEQi 	r29,$LaLOOP_END
91	ADD 	r30,r30,r30 # Shift in the '1' into div
92	BRI 	$LaDIV2     # Div2
93$LaLOOP_END:
94	BRI 	$LaRETURN_HERE
95$LaDiv_By_Zero:
96$LaResult_Is_Zero:
97	or 	r3,r0,r0   # set result to 0
98$LaRETURN_HERE:
99# Restore values of CSRs and that of r3 and the divisor and the dividend
100	lwi 	r29,r1,0
101	lwi 	r30,r1,4
102	lwi 	r31,r1,8
103	rtsd 	r15,8
104	addik 	r1,r1,12
105.end __umodsi3
106	.size	__umodsi3, . - __umodsi3
107