| blob | d30cb7625215b4704784faef449855a7f5c6b62b |
1 # Helper to print an int32 in decimal.
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
8 write-int32-decimal: # out: (addr stream byte), n: int
9 # works by generating characters from lowest to highest and pushing them
10 # to the stack, before popping them one by one into the stream
11 #
12 # pseudocode:
13 # push sentinel
14 # eax = abs(n)
15 # while true
16 # sign-extend eax into edx
17 # eax, edx = eax/10, eax%10
18 # edx += '0'
19 # push edx
20 # if (eax == 0) break
21 # if n < 0
22 # push '-'
23 # w = out->write
24 # curr = &out->data[out->write]
25 # max = &out->data[out->size]
26 # while true
27 # pop into eax
28 # if (eax == sentinel) break
29 # if (curr >= max) abort
30 # *curr = AL
31 # ++curr
32 # ++w
33 # out->write = w
34 # (based on K&R itoa: https://en.wikibooks.org/wiki/C_Programming/stdlib.h/itoa)
35 # (this pseudocode contains registers because operations like division
36 # require specific registers in x86)
37 #
38 # . prologue
39 55/push-ebp
40 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp
41 # . save registers
42 50/push-eax
43 51/push-ecx
44 52/push-edx
45 53/push-ebx
46 57/push-edi
47 # const ten/ecx = 10
48 b9/copy-to-ecx 0xa/imm32
49 # push sentinel
50 68/push 0/imm32/sentinel
51 # var eax: int = abs(n)
52 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax
53 3d/compare-eax-with 0/imm32
54 7d/jump-if->= $write-int32-decimal:read-loop/disp8
55 $write-int32-decimal:negative:
56 f7 3/subop/negate 3/mod/direct 0/rm32/eax . . . . . . # negate eax
57 $write-int32-decimal:read-loop:
58 # eax, edx = eax / 10, eax % 10
59 99/sign-extend-eax-into-edx
60 f7 7/subop/idiv 3/mod/direct 1/rm32/ecx . . . . . . # divide edx:eax by ecx, storing quotient in eax and remainder in edx
61 # edx += '0'
62 81 0/subop/add 3/mod/direct 2/rm32/edx . . . . . 0x30/imm32 # add to edx
63 # push edx
64 52/push-edx
65 # if (eax == 0) break
66 3d/compare-eax-and 0/imm32
67 7f/jump-if-> $write-int32-decimal:read-loop/disp8
68 $write-int32-decimal:read-break:
69 # if (n < 0) push('-')
70 81 7/subop/compare 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 0/imm32 # compare *(ebp+12)
71 7d/jump-if->= $write-int32-decimal:write/disp8
72 $write-int32-decimal:push-negative:
73 68/push 0x2d/imm32/-
74 $write-int32-decimal:write:
75 # edi = out
76 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 7/r32/edi 8/disp8 . # copy *(ebp+8) to edi
77 # var w/edx: int = out->write
78 8b/copy 0/mod/indirect 7/rm32/edi . . . 2/r32/edx . . # copy *edi to edx
79 # var curr/ecx: (addr byte) = &out->data[out->write]
80 8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/edi 2/index/edx . 1/r32/ecx 0xc/disp8 . # copy ebx+edx+12 to ecx
81 # var max/ebx: (addr byte) = &out->data[out->size]
82 8b/copy 1/mod/*+disp8 7/rm32/edi . . . 3/r32/ebx 8/disp8 . # copy *(edi+8) to ebx
83 8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/edi 3/index/ebx . 3/r32/ebx 0xc/disp8 . # copy edi+ebx+12 to ebx
84 $write-int32-decimal:write-loop:
85 # pop into eax
86 58/pop-to-eax
87 # if (eax == sentinel) break
88 3d/compare-eax-and 0/imm32/sentinel
89 74/jump-if-= $write-int32-decimal:write-break/disp8
90 # if (curr >= max) abort
91 39/compare 3/mod/direct 1/rm32/ecx . . . 3/r32/ebx . . # compare ecx with ebx
92 73/jump-if-addr>= $write-int32-decimal:abort/disp8
93 $write-int32-decimal:write-char:
94 # *curr = AL
95 88/copy-byte 0/mod/indirect 1/rm32/ecx . . . 0/r32/AL . . # copy AL to byte at *ecx
96 # ++curr
97 41/increment-ecx
98 # ++w
99 42/increment-edx
100 eb/jump $write-int32-decimal:write-loop/disp8
101 $write-int32-decimal:write-break:
102 # out->write = w
103 89/copy 0/mod/indirect 7/rm32/edi . . . 2/r32/edx . . # copy edx to *edi
104 $write-int32-decimal:end:
105 # . restore registers
106 5f/pop-to-edi
107 5b/pop-to-ebx
108 5a/pop-to-edx
109 59/pop-to-ecx
110 58/pop-to-eax
111 # . epilogue
112 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp
113 5d/pop-to-ebp
114 c3/return
116 $write-int32-decimal:abort:
117 (abort "write-int32-decimal: stream out of space")
118 # never gets here
120 test-write-int32-decimal:
121 # - check that a single-digit number converts correctly
122 # setup
123 # . clear-stream(_test-stream)
124 # . . push args
125 68/push _test-stream/imm32
126 # . . call
127 e8/call clear-stream/disp32
128 # . . discard args
129 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
130 # write-int32-decimal(_test-stream, 9)
131 # . . push args
132 68/push 9/imm32
133 68/push _test-stream/imm32
134 # . . call
135 e8/call write-int32-decimal/disp32
136 # . . discard args
137 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
138 # check-stream-equal(_test-stream, "9", msg)
139 # . . push args
140 68/push "F - test-write-int32-decimal"/imm32
141 68/push "9"/imm32
142 68/push _test-stream/imm32
143 # . . call
144 e8/call check-stream-equal/disp32
145 # . . discard args
146 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
147 # . end
148 c3/return
150 test-write-int32-decimal-zero:
151 # - check that 0 converts correctly
152 # setup
153 # . clear-stream(_test-stream)
154 # . . push args
155 68/push _test-stream/imm32
156 # . . call
157 e8/call clear-stream/disp32
158 # . . discard args
159 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
160 # write-int32-decimal(_test-stream, 0)
161 # . . push args
162 68/push 0/imm32
163 68/push _test-stream/imm32
164 # . . call
165 e8/call write-int32-decimal/disp32
166 # . . discard args
167 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
168 # check-stream-equal(_test-stream, "0", msg)
169 # . . push args
170 68/push "F - test-write-int32-decimal-zero"/imm32
171 68/push "0"/imm32
172 68/push _test-stream/imm32
173 # . . call
174 e8/call check-stream-equal/disp32
175 # . . discard args
176 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
177 # . end
178 c3/return
180 test-write-int32-decimal-multiple-digits:
181 # - check that a multi-digit number converts correctly
182 # setup
183 # . clear-stream(_test-stream)
184 # . . push args
185 68/push _test-stream/imm32
186 # . . call
187 e8/call clear-stream/disp32
188 # . . discard args
189 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
190 # write-int32-decimal(_test-stream, 10)
191 # . . push args
192 68/push 0xa/imm32
193 68/push _test-stream/imm32
194 # . . call
195 e8/call write-int32-decimal/disp32
196 # . . discard args
197 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
198 # check-stream-equal(_test-stream, "10", msg)
199 # . . push args
200 68/push "F - test-write-int32-decimal-multiple-digits"/imm32
201 68/push "10"/imm32
202 68/push _test-stream/imm32
203 # . . call
204 e8/call check-stream-equal/disp32
205 # . . discard args
206 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
207 # . end
208 c3/return
210 test-write-int32-decimal-negative:
211 # - check that a negative single-digit number converts correctly
212 # setup
213 # . clear-stream(_test-stream)
214 # . . push args
215 68/push _test-stream/imm32
216 # . . call
217 e8/call clear-stream/disp32
218 # . . discard args
219 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
220 # write-int32-decimal(_test-stream, -9)
221 # . . push args
222 68/push -9/imm32
223 68/push _test-stream/imm32
224 # . . call
225 e8/call write-int32-decimal/disp32
226 # . . discard args
227 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
228 #? # dump _test-stream {{{
229 #? # . write(2/stderr, "^")
230 #? # . . push args
231 #? 68/push "^"/imm32
232 #? 68/push 2/imm32/stderr
233 #? # . . call
234 #? e8/call write/disp32
235 #? # . . discard args
236 #? 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
237 #? # . write-stream(2/stderr, _test-stream)
238 #? # . . push args
239 #? 68/push _test-stream/imm32
240 #? 68/push 2/imm32/stderr
241 #? # . . call
242 #? e8/call write-stream/disp32
243 #? # . . discard args
244 #? 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
245 #? # . write(2/stderr, "$\n")
246 #? # . . push args
247 #? 68/push "$\n"/imm32
248 #? 68/push 2/imm32/stderr
249 #? # . . call
250 #? e8/call write/disp32
251 #? # . . discard args
252 #? 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
253 #? # }}}
254 # check-stream-equal(_test-stream, "-9", msg)
255 # . . push args
256 68/push "F - test-write-int32-decimal-negative"/imm32
257 68/push "-9"/imm32
258 68/push _test-stream/imm32
259 # . . call
260 e8/call check-stream-equal/disp32
261 # . . discard args
262 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
263 # . end
264 c3/return
266 # There's a special bit pattern that corresponds to no 2's complement integer.
267 # There doesn't seem to be a widespread convention for representing it.
268 test-write-int32-decimal-indefinite-integer:
269 # setup
270 # . clear-stream(_test-stream)
271 # . . push args
272 68/push _test-stream/imm32
273 # . . call
274 e8/call clear-stream/disp32
275 # . . discard args
276 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
277 # write-int32-decimal(_test-stream, 0x80000000)
278 # . . push args
279 68/push 0x80000000/imm32
280 68/push _test-stream/imm32
281 # . . call
282 e8/call write-int32-decimal/disp32
283 # . . discard args
284 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
285 # check-stream-equal(_test-stream, "-(", msg)
286 # . . push args
287 68/push "F - test-write-int32-decimal-indefinite-integer"/imm32
288 68/push "-("/imm32
289 68/push _test-stream/imm32
290 # . . call
291 e8/call check-stream-equal/disp32
292 # . . discard args
293 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
294 # . end
295 c3/return
297 test-write-int32-decimal-negative-multiple-digits:
298 # - check that a multi-digit number converts correctly
299 # setup
300 # . clear-stream(_test-stream)
301 # . . push args
302 68/push _test-stream/imm32
303 # . . call
304 e8/call clear-stream/disp32
305 # . . discard args
306 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
307 # write-int32-decimal(_test-stream, -10)
308 # . . push args
309 68/push -0xa/imm32
310 68/push _test-stream/imm32
311 # . . call
312 e8/call write-int32-decimal/disp32
313 # . . discard args
314 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
315 # check-stream-equal(_test-stream, "-10", msg)
316 # . . push args
317 68/push "F - test-write-int32-decimal-negative-multiple-digits"/imm32
318 68/push "-10"/imm32
319 68/push _test-stream/imm32
320 # . . call
321 e8/call check-stream-equal/disp32
322 # . . discard args
323 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
324 # . end
325 c3/return
327 decimal-digit?: # c: grapheme -> result/eax: boolean
328 # . prologue
329 55/push-ebp
330 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp
331 # . save registers
332 51/push-ecx
333 # ecx = c
334 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 8/disp8 . # copy *(ebp+8) to ecx
335 # result = false
336 b8/copy-to-eax 0/imm32/false
337 # return false if c < '0'
338 81 7/subop/compare 3/mod/direct 1/rm32/ecx . . . . . 0x30/imm32 # compare ecx
339 7c/jump-if-< $decimal-digit?:end/disp8
340 # return (c <= '9')
341 81 7/subop/compare 3/mod/direct 1/rm32/ecx . . . . . 0x39/imm32 # compare ecx
342 7f/jump-if-> $decimal-digit?:end/disp8
343 $decimal-digit?:true:
344 b8/copy-to-eax 1/imm32/true
345 $decimal-digit?:end:
346 # . restore registers
347 59/pop-to-ecx
348 # . epilogue
349 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp
350 5d/pop-to-ebp
351 c3/return
353 test-decimal-digit-below-0:
354 # eax = decimal-digit?(0x2f)
355 # . . push args
356 68/push 0x2f/imm32
357 # . . call
358 e8/call decimal-digit?/disp32
359 # . . discard args
360 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
361 # check-ints-equal(eax, 0, msg)
362 # . . push args
363 68/push "F - test-decimal-digit-below-0"/imm32
364 68/push 0/imm32/false
365 50/push-eax
366 # . . call
367 e8/call check-ints-equal/disp32
368 # . . discard args
369 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
370 c3/return
372 test-decimal-digit-0-to-9:
373 # eax = decimal-digit?(0x30)
374 # . . push args
375 68/push 0x30/imm32
376 # . . call
377 e8/call decimal-digit?/disp32
378 # . . discard args
379 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
380 # check-ints-equal(eax, 1, msg)
381 # . . push args
382 68/push "F - test-decimal-digit-at-0"/imm32
383 68/push 1/imm32/true
384 50/push-eax
385 # . . call
386 e8/call check-ints-equal/disp32
387 # . . discard args
388 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
389 # eax = decimal-digit?(0x39)
390 # . . push args
391 68/push 0x39/imm32
392 # . . call
393 e8/call decimal-digit?/disp32
394 # . . discard args
395 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
396 # check-ints-equal(eax, 1, msg)
397 # . . push args
398 68/push "F - test-decimal-digit-at-9"/imm32
399 68/push 1/imm32/true
400 50/push-eax
401 # . . call
402 e8/call check-ints-equal/disp32
403 # . . discard args
404 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
405 c3/return
407 test-decimal-digit-above-9:
408 # eax = decimal-digit?(0x3a)
409 # . . push args
410 68/push 0x3a/imm32
411 # . . call
412 e8/call decimal-digit?/disp32
413 # . . discard args
414 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp
415 # check-ints-equal(eax, 0, msg)
416 # . . push args
417 68/push "F - test-decimal-digit-above-9"/imm32
418 68/push 0/imm32/false
419 50/push-eax
420 # . . call
421 e8/call check-ints-equal/disp32
422 # . . discard args
423 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
424 c3/return
426 to-decimal-digit: # in: grapheme -> out/eax: int
427 # . prologue
428 55/push-ebp
429 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp
430 # eax = in
431 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 8/disp8 . # copy *(ebp+8) to eax
432 $to-decimal-digit:check0:
433 # if (eax < '0') goto abort
434 3d/compare-eax-with 0x30/imm32/0
435 7c/jump-if-< $to-decimal-digit:abort/disp8
436 $to-decimal-digit:check1:
437 # if (eax > '9') goto abort
438 3d/compare-eax-with 0x39/imm32/f
439 7f/jump-if-> $to-decimal-digit:abort/disp8
440 $to-decimal-digit:digit:
441 # return eax - '0'
442 2d/subtract-from-eax 0x30/imm32/0
443 $to-decimal-digit:end:
444 # . epilogue
445 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp
446 5d/pop-to-ebp
447 c3/return
449 $to-decimal-digit:abort:
450 (abort "to-decimal-digit: not a digit character")
451 # never gets here
453 # . . vim:nowrap:textwidth=0