summaryrefslogtreecommitdiff
path: root/thumb2divmod.s
blob: 3343db6a2af183a75ddbc66a7e820690ae2e07ab (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
	.arch	armv7-a
	.syntax unified
	.thumb
	.fpu	vfpv3-d16
	.text

	.globl	divide
	.thumb_func
divide:
	eor	r12,r3,r4
	cmp	r4,#0
	it lt
	neglt	r4,r4
	cmp	r3,#0
	it lt
	neglt	r3,r3

	cmp	r4,#32
	bls	divide_by_small_number

	clz	r1,r4
	clz	r2,r3
	rsb	r1,r1,#31-5-11
	add	r1,r1,r2
	mov	r2,#0

	cmp	r1,#32-5-11
	bhs	divide_large_result

	add	r1,r1,r1,lsl #1
	mov	r14,pc
	add	r14,r14,r1,lsl #2
	mov	pc,r14
	nop

	.set	shift,32-5-11
	.rept	32-5-11
	.set	shift,shift-1
	subs	r1,r3,r4,lsl #shift
	it cs
	movcs	r3,r1
	it cs
	orrcs	r2,r2,#1<<shift
	.endr

	mov	r4,r2
	cmp	r12,#0
	it lt
	neglt	r4,r4
	ldr	pc,[sp],#4

	.thumb_func
divide_large_result:
	bpl	divide_result_0

	vmov    s13,r3
	vmov    s15,r4
	vcvt.f64.u32	d6,s13
	vcvt.f64.u32	d7,s15
	vdiv.f64	d7,d6,d7
	vcvt.u32.f64	s15,d7
	vmov	r4,s15
	cmp	r12,#0
	it lt
	neglt	r4,r4
	ldr	pc,[sp],#4

divide_result_0:
	mov	r4,#0
	ldr	pc,[sp],#4

	.thumb_func
divide_by_small_number:
	mov	r1,pc
	add	r1,r1,r4,lsl #3
	ldrb	r4,[r1,#(div_mod_table+1)-(divide_by_small_number+8)]
	ldr	r2,[r1,#(div_mod_table+4)-(divide_by_small_number+8)]
	ldrb	r1,[r1,#div_mod_table-(divide_by_small_number+8)]
	adds	r3,r3,r4
	it cc
	umullcc	r4,r2,r3,r2
	lsr	r4,r2,r1
	cmp	r12,#0
	it lt
	neglt	r4,r4
	ldr	pc,[sp],#4

	.globl	modulo	
	.thumb_func
modulo:
	cmp	r4,#0
	it lt
	neglt	r4,r4
	movs	r12,r3
	it lt
	neglt	r3,r3

	cmp	r4,#32
	bls	modulo_of_small_number

	clz	r1,r4
	clz	r2,r3
	rsb	r1,r1,#31-5-11
	add	r1,r1,r2

	cmp	r1,#32-5-11
	bhs	modulo_large_divide_result

	mov	r14,pc
	add	r14,r14,r1,lsl #3
	mov	pc,r14
	nop

	.set	shift,32
	.rept	32
	.set	shift,shift-1
	subs	r1,r3,r4,lsl #shift
	it cs
	movcs	r3,r1
	.endr

	.thumb_func
modulo_large_divide_result:
	bpl	modulo_divide_result_0

	vmov    s13,r3
	vmov    s15,r4
	vcvt.f64.u32	d6,s13
	vcvt.f64.u32	d7,s15
	vdiv.f64	d7,d6,d7
	vcvt.u32.f64	s15,d7
	vmov	r2,s15
	b	modulo_from_quotient

modulo_divide_result_0:
	mov	r4,r3
	cmp	r12,#0
	it lt
	neglt	r4,r4
	ldr	pc,[sp],#4

	.thumb_func
modulo_of_small_number:
	mov	r1,pc
	add	r1,r1,r4,lsl #3
	ldrb	r0,[r1,#(div_mod_table+1)-(modulo_of_small_number+8)]
	ldr	r2,[r1,#(div_mod_table+4)-(modulo_of_small_number+8)]
	ldrb	r1,[r1,#div_mod_table-(modulo_of_small_number+8)]
	adds	r14,r3,r0
	it cc
	umullcc	r0,r2,r14,r2
	lsr	r2,r2,r1
	.thumb_func
modulo_from_quotient:
@	mls	r4,r4,r2,r3
	neg	r3,r3
	mla	r4,r4,r2,r3
	cmp	r12,#0
	it lt
	neglt	r4,r4
	ldr	pc,[sp],#4

	.thumb_func
div_mod_table:
	.long	0,0
	.long	0x100,0xffffffff
	.long	0,0x80000000
	.long	1,0xaaaaaaab
	.long	0,0x40000000
	.long	2,0xcccccccd
	.long	2,0xaaaaaaab
	.long	0x102,0x92492492
	.long	0,0x20000000
	.long	1,0x38e38e39
	.long	3,0xcccccccd
	.long	3,0xba2e8ba3
	.long	3,0xaaaaaaab
	.long	2,0x4ec4ec4f
	.long	0x103,0x92492492
	.long	3,0x88888889
	.long	0,0x10000000
	.long	4,0xf0f0f0f1
	.long	2,0x38e38e39
	.long	0x104,0xd79435e5
	.long	4,0xcccccccd
	.long	0x104,0xc30c30c3
	.long	4,0xba2e8ba3
	.long	4,0xb21642c9
	.long	4,0xaaaaaaab
	.long	3,0x51eb851f
	.long	3,0x4ec4ec4f
	.long	0x104,0x97b425ed	
	.long	0x104,0x92492492
	.long	4,0x8d3dcb09
	.long	4,0x88888889
	.long	0x104,0x84210842
	.long	0,0x08000000