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1a59d1b8 | 1 | ;; SPDX-License-Identifier: GPL-2.0-or-later |
09831ca7 AJ |
2 | ;; Copyright 2010 Free Software Foundation, Inc. |
3 | ;; Contributed by Bernd Schmidt <bernds@codesourcery.com>. | |
4 | ;; | |
09831ca7 AJ |
5 | |
6 | #include <linux/linkage.h> | |
7 | ||
8 | ;; ABI considerations for the divide functions | |
9 | ;; The following registers are call-used: | |
10 | ;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5 | |
11 | ;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4 | |
12 | ;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4 | |
13 | ;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4 | |
14 | ;; | |
15 | ;; In our implementation, divu and remu are leaf functions, | |
16 | ;; while both divi and remi call into divu. | |
17 | ;; A0 is not clobbered by any of the functions. | |
18 | ;; divu does not clobber B2 either, which is taken advantage of | |
19 | ;; in remi. | |
20 | ;; divi uses B5 to hold the original return address during | |
21 | ;; the call to divu. | |
22 | ;; remi uses B2 and A5 to hold the input values during the | |
23 | ;; call to divu. It stores B3 in on the stack. | |
24 | ||
25 | ||
26 | .text | |
27 | ||
28 | ENTRY(__c6xabi_remu) | |
29 | ;; The ABI seems designed to prevent these functions calling each other, | |
30 | ;; so we duplicate most of the divsi3 code here. | |
31 | mv .s2x A4, B1 | |
32 | lmbd .l2 1, B4, B1 | |
33 | || [!B1] b .s2 B3 ; RETURN A | |
34 | || [!B1] mvk .d2 1, B4 | |
35 | ||
36 | mv .l1x B1, A7 | |
37 | || shl .s2 B4, B1, B4 | |
38 | ||
39 | cmpltu .l1x A4, B4, A1 | |
40 | [!A1] sub .l1x A4, B4, A4 | |
41 | shru .s2 B4, 1, B4 | |
42 | ||
43 | _remu_loop: | |
44 | cmpgt .l2 B1, 7, B0 | |
45 | || [B1] subc .l1x A4,B4,A4 | |
46 | || [B1] add .s2 -1, B1, B1 | |
47 | ;; RETURN A may happen here (note: must happen before the next branch) | |
48 | [B1] subc .l1x A4,B4,A4 | |
49 | || [B1] add .s2 -1, B1, B1 | |
50 | || [B0] b .s1 _remu_loop | |
51 | [B1] subc .l1x A4,B4,A4 | |
52 | || [B1] add .s2 -1, B1, B1 | |
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 | ;; loop backwards branch happens here | |
62 | ||
63 | ret .s2 B3 | |
64 | [B1] subc .l1x A4,B4,A4 | |
65 | || [B1] add .s2 -1, B1, B1 | |
66 | [B1] subc .l1x A4,B4,A4 | |
67 | ||
68 | extu .s1 A4, A7, A4 | |
69 | nop 2 | |
70 | ENDPROC(__c6xabi_remu) |