mu - Soul of a tiny new machine. More thorough tests → More comprehensible and rewrite-friendly software → More resilient society.

	Commit message (Expand)	Author	Age	Files	Lines
*	.	Kartik Agaram	2021-06-26	1	-4/+4
*	.	Kartik Agaram	2021-06-24	1	-3/+3
*	.	Kartik Agaram	2021-05-18	1	-167/+165
*	.	Kartik Agaram	2021-04-21	1	-3/+3
*	.	Kartik Agaram	2021-03-23	1	-0/+230

<!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 - linux/117write-int-hex.subx</title> <meta name="Generator" content="Vim/8.1"> <meta name="plugin-version" content="vim8.1_v1"> <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-light"> <style type="text/css">  </style> <script type='text/javascript'>  </script> </head> <body onload='JumpToLine();'> <a href='https://github.com/akkartik/mu/blob/main/linux/117write-int-hex.subx'>https://github.com/akkartik/mu/blob/main/linux/117write-int-hex.subx</a> <pre id='vimCodeElement'> 1 # Write out the (hex) textual representation of numbers. 2 3 == code 4 # instruction effective address register displacement immediate 5 # . op subop mod rm32 base index scale r32 6 # . 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 7 8 # convert the lowest nibble of eax to ascii and return it in the lowest byte of eax 9 to-hex-char: # in/eax: int -> out/eax: int 10 # no error checking; accepts argument in eax 11 # if (eax <= 9) return eax + '0' 12 3d/compare-eax-with 0x9/imm32/9 13 7f/jump-if-> $to-hex-char:else/disp8 14 05/add-to-eax 0x30/imm32/0 15 c3/return 16 $to-hex-char:else: 17 # otherwise return eax + 'a' - 10 18 05/add-to-eax 0x57/imm32/a-10 19 c3/return 20 21 append-byte-hex: # f: (addr stream byte), n: int 22 # . prologue 23 55/push-ebp 24 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp 25 # . save registers 26 50/push-eax 27 # AL = convert upper nibble to hex 28 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax 29 c1/shift 5/subop/logic-right 3/mod/direct 0/rm32/eax . . . . . 4/imm8 # shift eax right by 4 bits, while padding zeroes 30 25/and-eax 0xf/imm32 31 # . AL = to-hex-char(AL) 32 e8/call <a href='117write-int-hex.subx.html#L9'>to-hex-char</a>/disp32 33 # append-byte(f, AL) 34 # . . push args 35 50/push-eax 36 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) 37 # . . call 38 e8/call <a href='115write-byte.subx.html#L208'>append-byte</a>/disp32 39 # . . discard args 40 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 41 # AL = convert lower nibble to hex 42 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax 43 25/and-eax 0xf/imm32 44 # . AL = to-hex-char(AL) 45 e8/call <a href='117write-int-hex.subx.html#L9'>to-hex-char</a>/disp32 46 # append-byte(f, AL) 47 # . . push args 48 50/push-eax 49 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) 50 # . . call 51 e8/call <a href='115write-byte.subx.html#L208'>append-byte</a>/disp32 52 # . . discard args 53 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 54 $append-byte-hex:end: 55 # . restore registers 56 58/pop-to-eax 57 # . epilogue 58 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp 59 5d/pop-to-ebp 60 c3/return 61 62 test-append-byte-hex: 63 # - check that append-byte-hex adds the hex textual representation 64 # setup 65 # . clear-stream(_test-stream) 66 # . . push args 67 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 68 # . . call 69 e8/call <a href='106stream.subx.html#L17'>clear-stream</a>/disp32 70 # . . discard args 71 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp 72 # append-byte-hex(_test-stream, 0xa) # exercises digit, non-digit as well as leading zero 73 # . . push args 74 68/push 0xa/imm32 75 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 76 # . . call 77 e8/call <a href='117write-int-hex.subx.html#L21'>append-byte-hex</a>/disp32 78 # . . discard args 79 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 80 # check-stream-equal(_test-stream, "0a", msg) 81 # . . push args 82 68/push "F - test-append-byte-hex"/imm32 83 68/push "0a"/imm32 84 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 85 # . . call 86 e8/call <a href='109stream-equal.subx.html#L194'>check-stream-equal</a>/disp32 87 # . . discard args 88 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp 89 # . end 90 c3/return 91 92 # print the hex representation for the lowest byte of a number 93 write-byte-hex-buffered: # f: (addr buffered-file), n: int 94 # . prologue 95 55/push-ebp 96 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp 97 # . save registers 98 50/push-eax 99 # AL = convert upper nibble to hex 100 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax 101 c1/shift 5/subop/logic-right 3/mod/direct 0/rm32/eax . . . . . 4/imm8 # shift eax right by 4 bits, while padding zeroes 102 25/and-eax 0xf/imm32 103 # . AL = to-hex-char(AL) 104 e8/call <a href='117write-int-hex.subx.html#L9'>to-hex-char</a>/disp32 105 # write-byte-buffered(f, AL) 106 # . . push args 107 50/push-eax 108 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) 109 # . . call 110 e8/call <a href='115write-byte.subx.html#L33'>write-byte-buffered</a>/disp32 111 # . . discard args 112 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 113 # AL = convert lower nibble to hex 114 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax 115 25/and-eax 0xf/imm32 116 # . AL = to-hex-char(AL) 117 e8/call <a href='117write-int-hex.subx.html#L9'>to-hex-char</a>/disp32 118 # write-byte-buffered(f, AL) 119 # . . push args 120 50/push-eax 121 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) 122 # . . call 123 e8/call <a href='115write-byte.subx.html#L33'>write-byte-buffered</a>/disp32 124 # . . discard args 125 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 126 $write-byte-hex-buffered:end: 127 # . restore registers 128 58/pop-to-eax 129 # . epilogue 130 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp 131 5d/pop-to-ebp 132 c3/return 133 134 test-write-byte-hex-buffered: 135 # - check that write-byte-hex-buffered prints the hex textual representation 136 # setup 137 # . clear-stream(_test-stream) 138 # . . push args 139 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 140 # . . call 141 e8/call <a href='106stream.subx.html#L17'>clear-stream</a>/disp32 142 # . . discard args 143 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp 144 # . clear-stream($_test-buffered-file->buffer) 145 # . . push args 146 68/push $_test-buffered-file->buffer/imm32 147 # . . call 148 e8/call <a href='106stream.subx.html#L17'>clear-stream</a>/disp32 149 # . . discard args 150 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp 151 # write-byte-hex-buffered(_test-buffered-file, 0xa) # exercises digit, non-digit as well as leading zero 152 # . . push args 153 68/push 0xa/imm32 154 68/push <a href='112read-byte.subx.html#L318'>_test-buffered-file</a>/imm32 155 # . . call 156 e8/call <a href='117write-int-hex.subx.html#L93'>write-byte-hex-buffered</a>/disp32 157 # . . discard args 158 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 159 # flush(_test-buffered-file) 160 # . . push args 161 68/push <a href='112read-byte.subx.html#L318'>_test-buffered-file</a>/imm32 162 # . . call 163 e8/call <a href='115write-byte.subx.html#L81'>flush</a>/disp32 164 # . . discard args 165 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp 166 # check-stream-equal(_test-stream, "0a", msg) 167 # . . push args 168 68/push "F - test-write-byte-hex-buffered"/imm32 169 68/push "0a"/imm32 170 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 171 # . . call 172 e8/call <a href='109stream-equal.subx.html#L194'>check-stream-equal</a>/disp32 173 # . . discard args 174 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp 175 # . end 176 c3/return 177 178 write-int32-hex: # f: (addr stream byte), n: int 179 # . prologue 180 55/push-ebp 181 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp 182 $write-int32-hex:hex-prefix: 183 # write(f, "0x") 184 # . . push args 185 68/push "0x"/imm32 186 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) 187 # . . call 188 e8/call <a href='108write.subx.html#L24'>write</a>/disp32 189 # . . discard args 190 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 191 $write-int32-hex:rest: 192 # write-int32-hex-bits(f, n, 32) 193 # . . push args 194 68/push 0x20/imm32 195 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) 196 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) 197 # . . call 198 e8/call <a href='117write-int-hex.subx.html#L209'>write-int32-hex-bits</a>/disp32 199 # . . discard args 200 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp 201 $write-int32-hex:end: 202 # . epilogue 203 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp 204 5d/pop-to-ebp 205 c3/return 206 207 # print rightmost 'bits' of 'n' 208 # bits must be multiple of 4 209 write-int32-hex-bits: # f: (addr stream byte), n: int, bits: int 210 # pseudocode: 211 # bits -= 4 212 # while true 213 # if (bits < 0) break 214 # eax = n >> bits 215 # eax = eax & 0xf 216 # append-byte(f, AL) 217 # bits -= 4 218 # 219 # . prologue 220 55/push-ebp 221 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp 222 # . save registers 223 50/push-eax 224 51/push-ecx 225 # ecx = bits-4 226 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 0x10/disp8 . # copy *(ebp+16) to ecx 227 81 5/subop/subtract 3/mod/direct 1/rm32/ecx . . . . . 4/imm32 # subtract from ecx 228 $write-int32-hex-bits:loop: 229 # if (bits < 0) break 230 81 7/subop/compare 3/mod/direct 1/rm32/ecx . . . . . 0/imm32 # compare ecx 231 7c/jump-if-< $write-int32-hex-bits:end/disp8 232 # eax = n >> bits 233 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax 234 d3/>>ecx 5/subop/pad-zeroes 3/mod/direct 0/rm32/eax . . . . . . # shift eax right by ecx bits, padding zeroes 235 # eax = to-hex-char(AL) 236 25/and-eax 0xf/imm32 237 e8/call <a href='117write-int-hex.subx.html#L9'>to-hex-char</a>/disp32 238 # append-byte(f, AL) 239 # . . push args 240 50/push-eax 241 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) 242 # . . call 243 e8/call <a href='115write-byte.subx.html#L208'>append-byte</a>/disp32 244 # . . discard args 245 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 246 # bits -= 4 247 81 5/subop/subtract 3/mod/direct 1/rm32/ecx . . . . . 4/imm32 # subtract from ecx 248 eb/jump $write-int32-hex-bits:loop/disp8 249 $write-int32-hex-bits:end: 250 # . restore registers 251 59/pop-to-ecx 252 58/pop-to-eax 253 # . epilogue 254 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp 255 5d/pop-to-ebp 256 c3/return 257 258 test-write-int32-hex: 259 # - check that write-int32-hex prints the hex textual representation 260 # setup 261 # . clear-stream(_test-stream) 262 # . . push args 263 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 264 # . . call 265 e8/call <a href='106stream.subx.html#L17'>clear-stream</a>/disp32 266 # . . discard args 267 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp 268 # write-int32-hex(_test-stream, 0x8899aa) 269 # . . push args 270 68/push 0x8899aa/imm32 271 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 272 # . . call 273 e8/call <a href='117write-int-hex.subx.html#L178'>write-int32-hex</a>/disp32 274 # . . discard args 275 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 276 # check-stream-equal(_test-stream, "0x008899aa", msg) 277 # . . push args 278 68/push "F - test-write-int32-hex"/imm32 279 68/push "0x008899aa"/imm32 280 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 281 # . . call 282 e8/call <a href='109stream-equal.subx.html#L194'>check-stream-equal</a>/disp32 283 # . . discard args 284 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp 285 # . end 286 c3/return 287 288 write-int32-hex-buffered: # f: (addr buffered-file), n: int 289 # . prologue 290 55/push-ebp 291 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp 292 $write-int32-hex-buffered:hex-prefix: 293 # write-buffered(f, "0x") 294 # . . push args 295 68/push "0x"/imm32 296 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) 297 # . . call 298 e8/call <a href='116write-buffered.subx.html#L8'>write-buffered</a>/disp32 299 # . . discard args 300 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 301 $write-int32-hex-buffered:rest: 302 # write-int32-hex-bits-buffered(f, n, 32) 303 # . . push args 304 68/push 0x20/imm32 305 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) 306 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) 307 # . . call 308 e8/call <a href='117write-int-hex.subx.html#L319'>write-int32-hex-bits-buffered</a>/disp32 309 # . . discard args 310 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp 311 $write-int32-hex-buffered:end: 312 # . epilogue 313 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp 314 5d/pop-to-ebp 315 c3/return 316 317 # print rightmost 'bits' of 'n' 318 # bits must be multiple of 4 319 write-int32-hex-bits-buffered: # f: (addr buffered-file), n: int, bits: int 320 # pseudocode: 321 # bits -= 4 322 # while true 323 # if (bits < 0) break 324 # eax = n >> bits 325 # eax = eax & 0xf 326 # write-byte-buffered(f, AL) 327 # bits -= 4 328 # 329 # . prologue 330 55/push-ebp 331 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp 332 # . save registers 333 50/push-eax 334 51/push-ecx 335 # ecx = bits-4 336 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 0x10/disp8 . # copy *(ebp+16) to ecx 337 81 5/subop/subtract 3/mod/direct 1/rm32/ecx . . . . . 4/imm32 # subtract from ecx 338 $write-int32-hex-bits-buffered:loop: 339 # if (bits < 0) break 340 81 7/subop/compare 3/mod/direct 1/rm32/ecx . . . . . 0/imm32 # compare ecx 341 7c/jump-if-< $write-int32-hex-bits-buffered:end/disp8 342 # eax = n >> bits 343 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax 344 d3/>>ecx 5/subop/pad-zeroes 3/mod/direct 0/rm32/eax . . . . . . # shift eax right by ecx bits, padding zeroes 345 # eax = to-hex-char(AL) 346 25/and-eax 0xf/imm32 347 e8/call <a href='117write-int-hex.subx.html#L9'>to-hex-char</a>/disp32 348 # write-byte-buffered(f, AL) 349 # . . push args 350 50/push-eax 351 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) 352 # . . call 353 e8/call <a href='115write-byte.subx.html#L33'>write-byte-buffered</a>/disp32 354 # . . discard args 355 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 356 # bits -= 4 357 81 5/subop/subtract 3/mod/direct 1/rm32/ecx . . . . . 4/imm32 # subtract from ecx 358 eb/jump $write-int32-hex-bits-buffered:loop/disp8 359 $write-int32-hex-bits-buffered:end: 360 # . restore registers 361 59/pop-to-ecx 362 58/pop-to-eax 363 # . epilogue 364 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp 365 5d/pop-to-ebp 366 c3/return 367 368 test-write-int32-hex-buffered: 369 # - check that write-int32-hex-buffered prints the hex textual representation 370 # setup 371 # . clear-stream(_test-stream) 372 # . . push args 373 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 374 # . . call 375 e8/call <a href='106stream.subx.html#L17'>clear-stream</a>/disp32 376 # . . discard args 377 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp 378 # . clear-stream($_test-buffered-file->buffer) 379 # . . push args 380 68/push $_test-buffered-file->buffer/imm32 381 # . . call 382 e8/call <a href='106stream.subx.html#L17'>clear-stream</a>/disp32 383 # . . discard args 384 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp 385 # write-int32-hex-buffered(_test-buffered-file, 0x8899aa) 386 # . . push args 387 68/push 0x8899aa/imm32 388 68/push <a href='112read-byte.subx.html#L318'>_test-buffered-file</a>/imm32 389 # . . call 390 e8/call <a href='117write-int-hex.subx.html#L288'>write-int32-hex-buffered</a>/disp32 391 # . . discard args 392 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 393 # flush(_test-buffered-file) 394 # . . push args 395 68/push <a href='112read-byte.subx.html#L318'>_test-buffered-file</a>/imm32 396 # . . call 397 e8/call <a href='115write-byte.subx.html#L81'>flush</a>/disp32 398 # . . discard args 399 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp 400 +-- 18 lines: #? # dump line -------------------------------------------------------------------------------------------------------------------------------------------------------- 418 # check-stream-equal(_test-stream, "0x008899aa", msg) 419 # . . push args 420 68/push "F - test-write-int32-hex-buffered"/imm32 421 68/push "0x008899aa"/imm32 422 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 423 # . . call 424 e8/call <a href='109stream-equal.subx.html#L194'>check-stream-equal</a>/disp32 425 # . . discard args 426 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp 427 # . end 428 c3/return 429 430 # . . vim:nowrap:textwidth=0 </pre> </body> </html>