solution day 2 - AdventOfCode/AdventOfCode2018 - solutions for Advent of Code 2018

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author	Brian Chu <brianmchu42@gmail.com>	2022-08-21 16:41:02 -0700
committer	Brian Chu <brianmchu42@gmail.com>	2022-08-21 16:41:02 -0700
commit	2e9342c1f28264d7ef609f0bb15a1c3792f7a352 (patch)
tree	625ea9bc256fcead53b983ebfcf67aea526ef139 /lib/day22.ml
parent	c9a6741617eb28834674a5ef84daae4366ac4101 (diff)
download	AdventOfCode2018-2e9342c1f28264d7ef609f0bb15a1c3792f7a352.tar.gz

solution day 2 main

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Mu - subx/052kernel_string_equal.subx</title> <meta name="Generator" content="Vim/8.0"> <meta name="plugin-version" content="vim7.4_v2"> <meta name="syntax" content="none"> <meta name="settings" content="number_lines,use_css,no_foldcolumn,expand_tabs,line_ids,prevent_copy="> <meta name="colorscheme" content="minimal"> <style type="text/css">  </style> <script type='text/javascript'>  </script> </head> <body onload='JumpToLine();'> <a href='https://github.com/akkartik/mu/blob/master/subx/052kernel_string_equal.subx'>https://github.com/akkartik/mu/blob/master/subx/052kernel_string_equal.subx</a> <pre id='vimCodeElement'> 1 # Checking null-terminated ascii strings. 2 # 3 # By default we create strings with a 4-byte length prefix rather than a null suffix. 4 # However we still need null-prefixed strings when interacting with the Linux 5 # kernel in a few places. This layer implements a function for comparing 6 # a null-terminated 'kernel string' with a length-prefixed 'SubX string'. 7 # 8 # To run (from the subx directory): 9 # $ subx translate 05[0-2]*.subx -o /tmp/tmp52 10 # $ subx run /tmp/tmp52 # runs a series of tests 11 # ...... # all tests pass 12 # 13 # (We can't yet run the tests when given a "test" commandline argument, 14 # because checking for it would require the function being tested! Breakage 15 # would cause tests to not run, rather than to fail as we'd like.) 16 17 == code 18 # instruction effective address register displacement immediate 19 # . op subop mod rm32 base index scale r32 20 # . 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes 21 22 # main: 23 e8/call run-tests/disp32 # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'. 24 # syscall(exit, Num-test-failures) 25 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 3/r32/EBX Num-test-failures/disp32 # copy *Num-test-failures to EBX 26 b8/copy-to-EAX 1/imm32 27 cd/syscall 0x80/imm8 28 29 # compare a null-terminated ascii string with a more idiomatic length-prefixed byte array 30 # reason for the name: the only place we should have null-terminated ascii strings is from commandline args 31 kernel-string-equal: # s : null-terminated ascii string, benchmark : length-prefixed ascii string -> EAX : boolean 32 # . prolog 33 55/push-EBP 34 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP 35 # . save registers 36 51/push-ECX 37 52/push-EDX 38 53/push-EBX 39 56/push-ESI 40 57/push-EDI 41 42 # pseudocode: 43 # initialize n = b.length 44 # initialize s1 = s 45 # initialize s2 = b.data 46 # i = 0 47 # for (i = 0; i < n; ++n) 48 # c1 = *s1 49 # c2 = *s2 50 # if c1 == 0 51 # return false 52 # if c1 != c2 53 # return false 54 # return *s1 == 0 55 # 56 # initialize s into EDI 57 8b/copy 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none . 7/r32/EDI 8/disp8 . # copy *(EBP+8) to EDI 58 # initialize benchmark length n into EDX 59 8b/copy 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none . 2/r32/EDX 0xc/disp8 . # copy *(EBP+12) to EDX 60 8b/copy 0/mod/indirect 2/rm32/EDX . . . 2/r32/EDX . . # copy *EDX to EDX 61 # initialize benchmark data into ESI 62 8b/copy 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none . 6/r32/ESI 0xc/disp8 . # copy *(EBP+12) to ESI 63 81 0/subop/add 3/mod/direct 6/rm32/ESI . . . . . 4/imm32 # add to ESI 64 # initialize loop counter i into ECX 65 b9/copy-to-ECX 0/imm32/exit 66 # while (i/ECX < n/EDX) 67 $kernel-string-equal:loop: 68 39/compare 3/mod/direct 1/rm32/ECX . . . 2/r32/EDX . . # compare ECX with EDX 69 74/jump-if-equal $kernel-string-equal:break/disp8 70 # c1/EAX, c2/EBX = *s, *benchmark 71 b8/copy-to-EAX 0/imm32 72 8a/copy 0/mod/indirect 7/rm32/EDI . . . 0/r32/EAX . . # copy byte at *EDI to lower byte of EAX 73 bb/copy-to-EBX 0/imm32 74 8a/copy 0/mod/indirect 6/rm32/ESI . . . 3/r32/EBX . . # copy byte at *ESI to lower byte of EBX 75 # if (c1 == 0) return false 76 3d/compare-EAX 0/imm32 77 74/jump-if-equal $kernel-string-equal:false/disp8 78 # if (c1 != c2) return false 79 39/compare 3/mod/direct 0/rm32/EAX . . . 3/r32/EBX . . # compare EAX with EBX 80 75/jump-if-not-equal $kernel-string-equal:false/disp8 81 # ++s1, ++s2, ++i 82 41/inc-ECX 83 46/inc-ESI 84 47/inc-EDI 85 # end while 86 eb/jump $kernel-string-equal:loop/disp8 87 $kernel-string-equal:break: 88 # if (*s/EDI == 0) return true 89 b8/copy-to-EAX 0/imm32 90 8a/copy 0/mod/indirect 7/rm32/EDI . . . 0/r32/EAX . . # copy byte at *EDI to lower byte of EAX 91 3d/compare-EAX 0/imm32 92 75/jump-if-not-equal $kernel-string-equal:false/disp8 93 $kernel-string-equal:true: 94 b8/copy-to-EAX 1/imm32 95 eb/jump $kernel-string-equal:end/disp8 96 # return false 97 $kernel-string-equal:false: 98 b8/copy-to-EAX 0/imm32 99 100 $kernel-string-equal:end: 101 # . restore registers 102 5f/pop-to-EDI 103 5e/pop-to-ESI 104 5b/pop-to-EBX 105 5a/pop-to-EDX 106 59/pop-to-ECX 107 # . epilog 108 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP 109 5d/pop-to-EBP 110 c3/return 111 112 # - tests 113 114 test-compare-null-kernel-string-with-empty-array: 115 # EAX = kernel-string-equal(Null-kernel-string, "") 116 # . . push args 117 68/push ""/imm32 118 68/push Null-kernel-string/imm32 119 # . . call 120 e8/call kernel-string-equal/disp32 121 # . . discard args 122 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP 123 # check-ints-equal(EAX, 1, msg) 124 # . . push args 125 68/push "F - test-compare-null-kernel-string-with-empty-array"/imm32 126 68/push 1/imm32/true 127 50/push-EAX 128 # . . call 129 e8/call check-ints-equal/disp32 130 # . . discard args 131 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP 132 c3/return 133 134 test-compare-null-kernel-string-with-non-empty-array: 135 # EAX = kernel-string-equal(Null-kernel-string, "Abc") 136 # . . push args 137 68/push "Abc"/imm32 138 68/push Null-kernel-string/imm32 139 # . . call 140 e8/call kernel-string-equal/disp32 141 # . . discard args 142 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP 143 # check-ints-equal(EAX, 0, msg) 144 # . . push args 145 68/push "F - test-compare-null-kernel-string-with-non-empty-array"/imm32 146 68/push 0/imm32/false 147 50/push-EAX 148 # . . call 149 e8/call check-ints-equal/disp32 150 # . . discard args 151 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP 152 c3/return 153 154 test-compare-kernel-string-with-equal-array: 155 # EAX = kernel-string-equal(Abc-kernel-string, "Abc") 156 # . . push args 157 68/push "Abc"/imm32 158 68/push Abc-kernel-string/imm32 159 # . . call 160 e8/call kernel-string-equal/disp32 161 # . . discard args 162 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP 163 # check-ints-equal(EAX, 1, msg) 164 # . . push args 165 68/push "F - test-compare-kernel-string-with-equal-array"/imm32 166 68/push 1/imm32/true 167 50/push-EAX 168 # . . call 169 e8/call check-ints-equal/disp32 170 # . . discard args 171 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP 172 c3/return 173 174 test-compare-kernel-string-with-inequal-array: 175 # EAX = kernel-string-equal(Abc-kernel-string, "Adc") 176 # . . push args 177 68/push "Adc"/imm32 178 68/push Abc-kernel-string/imm32 179 # . . call 180 e8/call kernel-string-equal/disp32 181 # . . discard args 182 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP 183 # check-ints-equal(EAX, 0, msg) 184 # . . push args 185 68/push "F - test-compare-kernel-string-with-equal-array"/imm32 186 68/push 0/imm32/false 187 50/push-EAX 188 # . . call 189 e8/call check-ints-equal/disp32 190 # . . discard args 191 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP 192 c3/return 193 194 test-compare-kernel-string-with-empty-array: 195 # EAX = kernel-string-equal(Abc-kernel-string, "") 196 # . . push args 197 68/push ""/imm32 198 68/push Abc-kernel-string/imm32 199 # . . call 200 e8/call kernel-string-equal/disp32 201 # . . discard args 202 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP 203 # check-ints-equal(EAX, 0) 204 # . . push args 205 68/push "F - test-compare-kernel-string-with-equal-array"/imm32 206 68/push 0/imm32/false 207 50/push-EAX 208 # . . call 209 e8/call check-ints-equal/disp32 210 # . . discard args 211 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP 212 c3/return 213 214 test-compare-kernel-string-with-shorter-array: 215 # EAX = kernel-string-equal(Abc-kernel-string, "Ab") 216 # . . push args 217 68/push "Ab"/imm32 218 68/push Abc-kernel-string/imm32 219 # . . call 220 e8/call kernel-string-equal/disp32 221 # . . discard args 222 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP 223 # check-ints-equal(EAX, 0) 224 # . . push args 225 68/push "F - test-compare-kernel-string-with-shorter-array"/imm32 226 68/push 0/imm32/false 227 50/push-EAX 228 # . . call 229 e8/call check-ints-equal/disp32 230 # . . discard args 231 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP 232 c3/return 233 234 test-compare-kernel-string-with-longer-array: 235 # EAX = kernel-string-equal(Abc-kernel-string, "Abcd") 236 # . . push args 237 68/push "Abcd"/imm32 238 68/push Abc-kernel-string/imm32 239 # . . call 240 e8/call kernel-string-equal/disp32 241 # . . discard args 242 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP 243 # check-ints-equal(EAX, 0) 244 # . . push args 245 68/push "F - test-compare-kernel-string-with-longer-array"/imm32 246 68/push 0/imm32/false 247 50/push-EAX 248 # . . call 249 e8/call check-ints-equal/disp32 250 # . . discard args 251 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP 252 c3/return 253 254 == data 255 256 Null-kernel-string: 257 00/null 258 Abc-kernel-string: 259 41/A 62/b 63/c 00/null 260 261 # . . vim:nowrap:textwidth=0 </pre> </body> </html>


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