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gerrit-public.fairphone.software / toolchain / llvm-project / 8f6cf7085a261e8eea5061c094c540358f3af970 / . / compiler-rt / lib / builtins / arm / udivsi3.S
blob: 8fb1dca0f0d25ff6196738c9b436563e64b1614d [file] [log] [blame]
Joerg Sonnenbergerdde27002014-01-30 18:41:32 +0000[diff] [blame]1/*===-- udivsi3.S - 32-bit unsigned integer divide ------------------------===//
Stephen Canon5abb5c12011-03-18 16:35:02 +0000[diff] [blame]2 *
3 * The LLVM Compiler Infrastructure
4 *
5 * This file is dual licensed under the MIT and the University of Illinois Open
6 * Source Licenses. See LICENSE.TXT for details.
7 *
8 *===----------------------------------------------------------------------===//
9 *
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]10 * This file implements the __udivsi3 (32-bit unsigned integer divide)
11 * function for the ARM 32-bit architecture.
Stephen Canon5abb5c12011-03-18 16:35:02 +0000[diff] [blame]12 *
13 *===----------------------------------------------------------------------===*/
14
15#include "../assembly.h"
16
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]17 .syntax unified
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]18 .text
Saleem Abdulrasool8f2efc32014-06-16 16:36:25 +0000[diff] [blame]19
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]20 .p2align 2
Anton Korobeynikov75e3c192011-04-19 17:51:24 +0000[diff] [blame]21DEFINE_AEABI_FUNCTION_ALIAS(__aeabi_uidiv, __udivsi3)
Stephen Canon5abb5c12011-03-18 16:35:02 +0000[diff] [blame]22DEFINE_COMPILERRT_FUNCTION(__udivsi3)
Stephen Hines7633afc2013-10-25 06:26:44 +0000[diff] [blame]23#if __ARM_ARCH_EXT_IDIV__
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]24 tst r1, r1
25 beq LOCAL_LABEL(divby0)
26 mov r3, r0
27 udiv r0, r3, r1
28 mls r1, r0, r1, r3
Bob Wilsona4cefbd2012-09-29 23:37:01 +0000[diff] [blame]29 bx lr
Bob Wilsona4cefbd2012-09-29 23:37:01 +0000[diff] [blame]30#else
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]31 cmp r1, #1
32 bcc LOCAL_LABEL(divby0)
33 JMPc(lr, eq)
34 cmp r0, r1
35 movcc r0, #0
36 JMPc(lr, cc)
37 /*
38 * Implement division using binary long division algorithm.
39 *
40 * r0 is the numerator, r1 the denominator.
41 *
42 * The code before JMP computes the correct shift I, so that
43 * r0 and (r1 << I) have the highest bit set in the same position.
44 * At the time of JMP, ip := .Ldiv0block - 12 * I.
45 * This depends on the fixed instruction size of block.
46 *
47 * block(shift) implements the test-and-update-quotient core.
48 * It assumes (r0 << shift) can be computed without overflow and
49 * that (r0 << shift) < 2 * r1. The quotient is stored in r3.
50 */
Stephen Canon5abb5c12011-03-18 16:35:02 +0000[diff] [blame]51
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]52# ifdef __ARM_FEATURE_CLZ
53 clz ip, r0
54 clz r3, r1
55 /* r0 >= r1 implies clz(r0) <= clz(r1), so ip <= r3. */
56 sub r3, r3, ip
Joerg Sonnenberger8f6cf702014-07-20 20:00:26 +0000[diff] [blame^]57 adr ip, LOCAL_LABEL(div0block)
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]58 sub ip, ip, r3, lsl #2
59 sub ip, ip, r3, lsl #3
60 mov r3, #0
61 bx ip
62# else
63 mov r2, r0
Joerg Sonnenberger8f6cf702014-07-20 20:00:26 +0000[diff] [blame^]64 adr ip, LOCAL_LABEL(div0block)
Stephen Canon5abb5c12011-03-18 16:35:02 +0000[diff] [blame]65
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]66 lsr r3, r2, #16
67 cmp r3, r1
68 movhs r2, r3
69 subhs ip, ip, #(16 * 12)
Stephen Canon5abb5c12011-03-18 16:35:02 +0000[diff] [blame]70
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]71 lsr r3, r2, #8
72 cmp r3, r1
73 movhs r2, r3
74 subhs ip, ip, #(8 * 12)
75
76 lsr r3, r2, #4
77 cmp r3, r1
78 movhs r2, r3
79 subhs ip, #(4 * 12)
80
81 lsr r3, r2, #2
82 cmp r3, r1
83 movhs r2, r3
84 subhs ip, ip, #(2 * 12)
85
86 /* Last block, no need to update r2 or r3. */
87 cmp r1, r2, lsr #1
88 subls ip, ip, #(1 * 12)
89
90 mov r3, #0
91
92 JMP(ip)
93# endif
94
95#define IMM #
96
Joerg Sonnenberger8f6cf702014-07-20 20:00:26 +0000[diff] [blame^]97#define block(shift) \
98 cmp r0, r1, lsl IMM shift; \
99 addhs r3, r3, IMM (1 << shift); \
100 subhs r0, r0, r1, lsl IMM shift
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]101
102 block(31)
103 block(30)
104 block(29)
105 block(28)
106 block(27)
107 block(26)
108 block(25)
109 block(24)
110 block(23)
111 block(22)
112 block(21)
113 block(20)
114 block(19)
115 block(18)
116 block(17)
117 block(16)
118 block(15)
119 block(14)
120 block(13)
121 block(12)
122 block(11)
123 block(10)
124 block(9)
125 block(8)
126 block(7)
127 block(6)
128 block(5)
129 block(4)
130 block(3)
131 block(2)
132 block(1)
Joerg Sonnenberger8f6cf702014-07-20 20:00:26 +0000[diff] [blame^]133LOCAL_LABEL(div0block):
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]134 block(0)
135
136 mov r0, r3
137 JMP(lr)
138#endif /* __ARM_ARCH_EXT_IDIV__ */
139
140LOCAL_LABEL(divby0):
141 mov r0, #0
142#ifdef __ARM_EABI__
143 b __aeabi_idiv0
144#else
145 JMP(lr)
Bob Wilsona4cefbd2012-09-29 23:37:01 +0000[diff] [blame]146#endif
Joerg Sonnenberger59611a82014-01-24 13:43:35 +0000[diff] [blame]147
148END_COMPILERRT_FUNCTION(__udivsi3)