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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 | |
21 | ENTRY(__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 | |
87 | ENDPROC(__c6xabi_divremu) |