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1;; Copyright 2011 Free Software Foundation, Inc.
2;; Contributed by Bernd Schmidt <bernds@codesourcery.com>.
3;;
4;; This program is free software; you can redistribute it and/or modify
5;; it under the terms of the GNU General Public License as published by
6;; the Free Software Foundation; either version 2 of the License, or
7;; (at your option) any later version.
8;;
9;; This program is distributed in the hope that it will be useful,
10;; but WITHOUT ANY WARRANTY; without even the implied warranty of
11;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12;; GNU General Public License for more details.
13;;
14;; You should have received a copy of the GNU General Public License
15;; along with this program; if not, write to the Free Software
16;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17
18#include <linux/linkage.h>
19
20 .text
21ENTRY(__c6xabi_divremu)
22 ;; We use a series of up to 31 subc instructions. First, we find
23 ;; out how many leading zero bits there are in the divisor. This
24 ;; gives us both a shift count for aligning (shifting) the divisor
25 ;; to the, and the number of times we have to execute subc.
26
27 ;; At the end, we have both the remainder and most of the quotient
28 ;; in A4. The top bit of the quotient is computed first and is
29 ;; placed in A2.
30
31 ;; Return immediately if the dividend is zero. Setting B4 to 1
32 ;; is a trick to allow us to leave the following insns in the jump
33 ;; delay slot without affecting the result.
34 mv .s2x A4, B1
35
36 [b1] lmbd .l2 1, B4, B1
37||[!b1] b .s2 B3 ; RETURN A
38||[!b1] mvk .d2 1, B4
39
40||[!b1] zero .s1 A5
41 mv .l1x B1, A6
42|| shl .s2 B4, B1, B4
43
44 ;; The loop performs a maximum of 28 steps, so we do the
45 ;; first 3 here.
46 cmpltu .l1x A4, B4, A2
47 [!A2] sub .l1x A4, B4, A4
48|| shru .s2 B4, 1, B4
49|| xor .s1 1, A2, A2
50
51 shl .s1 A2, 31, A2
52|| [b1] subc .l1x A4,B4,A4
53|| [b1] add .s2 -1, B1, B1
54 [b1] subc .l1x A4,B4,A4
55|| [b1] add .s2 -1, B1, B1
56
57 ;; RETURN A may happen here (note: must happen before the next branch)
58__divremu0:
59 cmpgt .l2 B1, 7, B0
60|| [b1] subc .l1x A4,B4,A4
61|| [b1] add .s2 -1, B1, B1
62 [b1] subc .l1x A4,B4,A4
63|| [b1] add .s2 -1, B1, B1
64|| [b0] b .s1 __divremu0
65 [b1] subc .l1x A4,B4,A4
66|| [b1] add .s2 -1, B1, B1
67 [b1] subc .l1x A4,B4,A4
68|| [b1] add .s2 -1, B1, B1
69 [b1] subc .l1x A4,B4,A4
70|| [b1] add .s2 -1, B1, B1
71 [b1] subc .l1x A4,B4,A4
72|| [b1] add .s2 -1, B1, B1
73 [b1] subc .l1x A4,B4,A4
74|| [b1] add .s2 -1, B1, B1
75 ;; loop backwards branch happens here
76
77 ret .s2 B3
78|| mvk .s1 32, A1
79 sub .l1 A1, A6, A6
80|| extu .s1 A4, A6, A5
81 shl .s1 A4, A6, A4
82 shru .s1 A4, 1, A4
83|| sub .l1 A6, 1, A6
84 or .l1 A2, A4, A4
85 shru .s1 A4, A6, A4
86 nop
87ENDPROC(__c6xabi_divremu)
1;; SPDX-License-Identifier: GPL-2.0-or-later
2;; Copyright 2011 Free Software Foundation, Inc.
3;; Contributed by Bernd Schmidt <bernds@codesourcery.com>.
4;;
5
6#include <linux/linkage.h>
7
8 .text
9ENTRY(__c6xabi_divremu)
10 ;; We use a series of up to 31 subc instructions. First, we find
11 ;; out how many leading zero bits there are in the divisor. This
12 ;; gives us both a shift count for aligning (shifting) the divisor
13 ;; to the, and the number of times we have to execute subc.
14
15 ;; At the end, we have both the remainder and most of the quotient
16 ;; in A4. The top bit of the quotient is computed first and is
17 ;; placed in A2.
18
19 ;; Return immediately if the dividend is zero. Setting B4 to 1
20 ;; is a trick to allow us to leave the following insns in the jump
21 ;; delay slot without affecting the result.
22 mv .s2x A4, B1
23
24 [b1] lmbd .l2 1, B4, B1
25||[!b1] b .s2 B3 ; RETURN A
26||[!b1] mvk .d2 1, B4
27
28||[!b1] zero .s1 A5
29 mv .l1x B1, A6
30|| shl .s2 B4, B1, B4
31
32 ;; The loop performs a maximum of 28 steps, so we do the
33 ;; first 3 here.
34 cmpltu .l1x A4, B4, A2
35 [!A2] sub .l1x A4, B4, A4
36|| shru .s2 B4, 1, B4
37|| xor .s1 1, A2, A2
38
39 shl .s1 A2, 31, A2
40|| [b1] subc .l1x A4,B4,A4
41|| [b1] add .s2 -1, B1, B1
42 [b1] subc .l1x A4,B4,A4
43|| [b1] add .s2 -1, B1, B1
44
45 ;; RETURN A may happen here (note: must happen before the next branch)
46__divremu0:
47 cmpgt .l2 B1, 7, B0
48|| [b1] subc .l1x A4,B4,A4
49|| [b1] add .s2 -1, B1, B1
50 [b1] subc .l1x A4,B4,A4
51|| [b1] add .s2 -1, B1, B1
52|| [b0] b .s1 __divremu0
53 [b1] subc .l1x A4,B4,A4
54|| [b1] add .s2 -1, B1, B1
55 [b1] subc .l1x A4,B4,A4
56|| [b1] add .s2 -1, B1, B1
57 [b1] subc .l1x A4,B4,A4
58|| [b1] add .s2 -1, B1, B1
59 [b1] subc .l1x A4,B4,A4
60|| [b1] add .s2 -1, B1, B1
61 [b1] subc .l1x A4,B4,A4
62|| [b1] add .s2 -1, B1, B1
63 ;; loop backwards branch happens here
64
65 ret .s2 B3
66|| mvk .s1 32, A1
67 sub .l1 A1, A6, A6
68|| extu .s1 A4, A6, A5
69 shl .s1 A4, A6, A4
70 shru .s1 A4, 1, A4
71|| sub .l1 A6, 1, A6
72 or .l1 A2, A4, A4
73 shru .s1 A4, A6, A4
74 nop
75ENDPROC(__c6xabi_divremu)