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Aurelien Jacquiot09831ca2011-10-04 11:15:51 -04001;; Copyright 2010 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 ;; ABI considerations for the divide functions
21 ;; The following registers are call-used:
22 ;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5
23 ;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4
24 ;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4
25 ;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4
26 ;;
27 ;; In our implementation, divu and remu are leaf functions,
28 ;; while both divi and remi call into divu.
29 ;; A0 is not clobbered by any of the functions.
30 ;; divu does not clobber B2 either, which is taken advantage of
31 ;; in remi.
32 ;; divi uses B5 to hold the original return address during
33 ;; the call to divu.
34 ;; remi uses B2 and A5 to hold the input values during the
35 ;; call to divu. It stores B3 in on the stack.
36
37
38 .text
39
40ENTRY(__c6xabi_remu)
41 ;; The ABI seems designed to prevent these functions calling each other,
42 ;; so we duplicate most of the divsi3 code here.
43 mv .s2x A4, B1
44 lmbd .l2 1, B4, B1
45|| [!B1] b .s2 B3 ; RETURN A
46|| [!B1] mvk .d2 1, B4
47
48 mv .l1x B1, A7
49|| shl .s2 B4, B1, B4
50
51 cmpltu .l1x A4, B4, A1
52 [!A1] sub .l1x A4, B4, A4
53 shru .s2 B4, 1, B4
54
55_remu_loop:
56 cmpgt .l2 B1, 7, B0
57|| [B1] subc .l1x A4,B4,A4
58|| [B1] add .s2 -1, B1, B1
59 ;; RETURN A may happen here (note: must happen before the next branch)
60 [B1] subc .l1x A4,B4,A4
61|| [B1] add .s2 -1, B1, B1
62|| [B0] b .s1 _remu_loop
63 [B1] subc .l1x A4,B4,A4
64|| [B1] add .s2 -1, B1, B1
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 ;; loop backwards branch happens here
74
75 ret .s2 B3
76 [B1] subc .l1x A4,B4,A4
77|| [B1] add .s2 -1, B1, B1
78 [B1] subc .l1x A4,B4,A4
79
80 extu .s1 A4, A7, A4
81 nop 2
82ENDPROC(__c6xabi_remu)