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string.asm (3789B)
1 get_string_length: ; rdi = pointer, ret rax
2 stackpush
3 cld
4 mov r10, -1
5 mov rsi, rdi
6 get_string_length_start:
7 inc r10
8 lodsb
9 cmp al, 0x00
10 jne get_string_length_start
11 mov rax, r10
12 stackpop
13 ret
14
15 string_copy: ; rdi = dest, rsi = source, rdx = bytes to copy
16 stackpush
17 mov rcx, rdx
18 inc rcx ; to get null
19 cld
20 rep movsb
21 stackpop
22 ret
23
24 string_atoi: ; rdi = string, rax = int
25 stackpush
26
27 mov r8, 0 ; ;return
28
29 call get_string_length
30 mov r10, rax ; length
31 cmp rax, 0
32 je string_atoi_ret_empty
33
34 mov r9, 1 ; multiplier
35
36 dec r10
37 string_atoi_loop:
38 xor rbx, rbx
39 mov bl, BYTE [rdi+r10]
40 sub bl, 0x30 ;get byte, subtract to get real from ascii value
41 mov rax, r9
42 mul rbx ; multiply value by multiplier
43 add r8, rax ; add result to running total
44 dec r10 ; next digit
45 mov rax, 10 ; multiply r9 ( multiplier ) by 10
46 mul r9
47 mov r9, rax
48 cmp r10, -1
49 jne string_atoi_loop
50 jmp string_atoi_ret
51
52 string_atoi_ret_empty:
53 mov rax, -1
54 stackpop
55 ret
56
57 string_atoi_ret:
58 mov rax, r8
59 stackpop
60 ret
61
62 string_contains: ;rdi = haystack, rsi = needle, ret = rax: location of string, else -1
63 stackpush
64
65 xor r10, r10 ; total length from beginning
66 xor r8, r8 ; count from offset
67
68 string_contains_start:
69 mov dl, BYTE [rdi]
70 cmp dl, 0x00
71 je string_contains_ret_no
72 cmp dl, BYTE [rsi]
73 je string_contains_check
74 inc rdi
75 inc r10 ; count from base ( total will be r10 + r8 )
76 jmp string_contains_start
77
78 string_contains_check:
79 inc r8 ; already checked at pos 0
80 cmp BYTE [rsi+r8], 0x00
81 je string_contains_ret_ok
82 mov dl, [rdi+r8]
83 cmp dl ,0x00
84 je string_contains_ret_no
85 cmp dl, [rsi+r8]
86 je string_contains_check
87
88 inc rdi
89 inc r10
90 xor r8, r8
91 jmp string_contains_start
92
93 string_contains_ret_ok:
94 mov rax, r10
95 jmp string_contains_ret
96
97 string_contains_ret_no:
98 mov rax, -1
99
100 string_contains_ret:
101 stackpop
102 ret
103
104 ;Removes first instance of string
105 string_remove: ;rdi = source, rsi = string to remove, ret = 1 for removed, 0 for not found
106 stackpush
107
108 mov r9, 0 ; return flag
109
110 call get_string_length
111 mov r8, rax ; r8: source length
112 cmp r8, 0
113 mov rax, 0
114 jle string_remove_ret ; source string empty?
115
116 push rdi
117 mov rdi, rsi
118 call get_string_length
119 mov r10, rax ; r10: string to remove length
120 pop rdi
121 cmp r10, 0
122 mov rax, 0
123 jle string_remove_ret ; string to remove is blank?
124
125 string_remove_start:
126
127 call string_contains
128
129 cmp rax,-1
130 je string_remove_ret
131
132 ;Shift source string over
133 add rdi, rax
134 mov rsi, rdi
135 add rsi, r10 ; copying to itself sans found string
136
137 cld
138 string_remove_do_copy:
139 lodsb
140 stosb
141 cmp al, 0x00
142 jne string_remove_do_copy
143
144 mov r9, 1
145
146 string_remove_ret:
147 mov rax, r9
148 stackpop
149 ret
150
151 string_ends_with:;rdi = haystack, rsi = needle, ret = rax: 0 false, 1 true
152 stackpush
153
154 ;Get length of haystack, store in r8
155 call get_string_length
156 mov r8, rax
157
158 ;Get length of needle, store in r10
159 push rdi
160 mov rdi, rsi
161 call get_string_length
162 mov r10, rax
163 pop rdi
164
165 add rdi, r8
166 add rsi, r10
167
168 xor rax, rax
169 xor rdx, rdx
170
171 string_ends_with_loop:
172 ;Start from end, dec r10 till 0
173 mov dl, BYTE [rdi]
174 cmp dl, BYTE [rsi]
175 jne string_ends_with_ret
176 dec rdi
177 dec rsi
178 dec r10
179 cmp r10, 0
180 jne string_ends_with_loop
181 mov rax, 1
182
183 string_ends_with_ret:
184 stackpop
185 ret
186
187 print_line: ; rdi = pointer, rsi = length
188 stackpush
189 call sys_write
190 mov rdi, new_line
191 mov rsi, 1
192 call sys_write
193 stackpop
194 ret
195