1 # Port of https://github.com/akkartik/crenshaw/blob/master/tutor2.1.pas
  2 # which corresponds to the section "single digits" in https://compilers.iecc.com/crenshaw/tutor2.txt
  3 # except that we support hex numbers of multiple digits.
  4 #
  5 # To run:
  6 #   $ bootstrap/bootstrap translate [01]*.subx crenshaw2-1b.subx -o crenshaw2-1b
  7 #   $ echo '1a'  |bootstrap/bootstrap run crenshaw2-1b
  8 # Expected output:
  9 #   # syscall(exit, 1a)
 10 #   bb/copy-to-ebx  3/imm32
 11 #   b8/copy-to-eax  1/imm32/exit
 12 #   cd/syscall  0x80/imm8
 13 #
 14 # To run the generated output:
 15 #   $ echo '1a'  |bootstrap/bootstrap run crenshaw2-1b > z1.subx
 16 #   $ bootstrap/bootstrap translate z1.subx -o z1
 17 #   $ bootstrap/bootstrap run z1
 18 #   $ echo $?
 19 #   26  # 0x1a in decimal
 20 #
 21 # Stdin must contain just a single hex digit. Other input will print an error:
 22 #   $ echo 'xyz'  |bootstrap/bootstrap run crenshaw2-1b
 23 #   Error: integer expected
 24 #
 25 # Names in this file sometimes follow Crenshaw's original rather than my usual
 26 # naming conventions.
 27 
 28 == code
 29 #   instruction                     effective address                                                   register    displacement    immediate
 30 # . op          subop               mod             rm32          base        index         scale       r32
 31 # . 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
 32 
 33 Entry:  # run tests if necessary, call 'compile' if not
 34     # . prologue
 35     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
 36 
 37     # initialize heap
 38     # . Heap = new-segment(Heap-size)
 39     # . . push args
 40     68/push  Heap/imm32
 41     ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Heap-size/disp32                  # push *Heap-size
 42     # . . call
 43     e8/call  new-segment/disp32
 44     # . . discard args
 45     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
 46 
 47     # - if argc > 1 and argv[1] == "test", then return run_tests()
 48     # if (argc <= 1) goto run-main
 49     81          7/subop/compare     1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0/disp8         1/imm32           # compare *ebp
 50     7e/jump-if-<=  $run-main/disp8
 51     # if (!kernel-string-equal?(argv[1], "test")) goto run-main
 52     # . eax = kernel-string-equal?(argv[1], "test")
 53     # . . push args
 54     68/push  "test"/imm32
 55     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
 56     # . . call
 57     e8/call  kernel-string-equal?/disp32
 58     # . . discard args
 59     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
 60     # . if (eax == false) goto run-main
 61     3d/compare-eax-and  0/imm32/false
 62     74/jump-if-=  $run-main/disp8
 63     # run-tests()
 64     e8/call  run-tests/disp32
 65     # syscall(exit, *Num-test-failures)
 66     8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/ebx   Num-test-failures/disp32          # copy *Num-test-failures to ebx
 67     eb/jump  $main:end/disp8
 68 $run-main:
 69     # - otherwise read a program from stdin and emit its translation to stdout
 70     # . compile(Stdin, 1/stdout, 2/stderr, 0)
 71     # . . push args
 72     68/push  0/imm32/exit-descriptor
 73     68/push  2/imm32/stderr
 74     68/push  1/imm32/stdout
 75     68/push  Stdin/imm32
 76     # . . call
 77     e8/call  compile/disp32
 78     # . . discard args
 79     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0x10/imm32        # add to esp
 80     # syscall(exit, 0)
 81     bb/copy-to-ebx  0/imm32
 82 $main:end:
 83     e8/call  syscall_exit/disp32
 84 
 85 # the main entry point
 86 compile:  # in: (addr buffered-file), out: fd or (addr stream byte), err: fd or (addr stream byte), ed: (addr exit-descriptor)
 87     # . prologue
 88     55/push-ebp
 89     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
 90     # . save registers
 91     50/push-eax
 92     51/push-ecx
 93     # prime the pump
 94     # . Look = get-char(in)
 95     # . . push args
 96     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8      .                    # push *(ebp+8)
 97     # . . call
 98     e8/call  get-char/disp32
 99     # . . discard args
100     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
101     # var num/ecx: (stream byte 7)
102     # Numbers can be 32 bits or 8 hex bytes long. One of them will be in 'Look', so we need space for 7 bytes.
103     # Sizing the stream just right buys us overflow-handling for free inside 'get-num'.
104     # Add 12 bytes for 'read', 'write' and 'size' fields, for a total of 19 bytes, or 0x13 in hex.
105     # The stack pointer is no longer aligned, so dump_stack() can be misleading past this point.
106     81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               0x13/imm32        # subtract from esp
107     89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
108     # initialize the stream
109     # . num->size = 7
110     c7          0/subop/copy        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           8/disp8         7/imm32           # copy to *(ecx+8)
111     # . clear-stream(num)
112     # . . push args
113     51/push-ecx
114     # . . call
115     e8/call  clear-stream/disp32
116     # . . discard args
117     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
118     # read a digit from 'in' into 'num'
119     # . get-num(in, num, err, ed)
120     # . . push args
121     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0x14/disp8      .                 # push *(ebp+20)
122     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0x10/disp8      .                 # push *(ebp+16)
123     51/push-ecx/num
124     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8      .                    # push *(ebp+8)
125     # . . call
126     e8/call  get-num/disp32
127     # . . discard args
128     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0x10/imm32        # add to esp
129     # render 'num' into the following template on 'out':
130     #   bb/copy-to-ebx  _num_
131     #   b8/copy-to-eax  1/imm32/exit
132     #   cd/syscall  0x80/imm8
133     #
134     # . write(out, "bb/copy-to-ebx  ")
135     # . . push args
136     68/push  "bb/copy-to-ebx  "/imm32
137     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
138     # . . call
139     e8/call  write/disp32
140     # . . discard args
141     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
142     # . write-stream(out, num)
143     # . . push args
144     51/push-ecx/num
145     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
146     # . . call
147     e8/call  write-stream/disp32
148     # . . discard args
149     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
150     # . write(out, Newline)
151     # . . push args
152     68/push  Newline/imm32
153     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
154     # . . call
155     e8/call  write/disp32
156     # . . discard args
157     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
158     # . write(out, "b8/copy-to-eax  1/imm32/exit\n")
159     # . . push args
160     68/push  "b8/copy-to-eax  1/imm32/exit\n"/imm32
161     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
162     # . . call
163     e8/call  write/disp32
164     # . . discard args
165     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
166     # . write(out, "cd/syscall  0x80/imm8\n")
167     # . . push args
168     68/push  "cd/syscall  0x80/imm8\n"/imm32
169     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
170     # . . call
171     e8/call  write/disp32
172     # . . discard args
173     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
174 $compile:end:
175     # . restore registers
176     59/pop-to-ecx
177     58/pop-to-eax
178     # . epilogue
179     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
180     5d/pop-to-ebp
181     c3/return
182 
183 # Read a sequence of digits into 'out'. Abort if there are none, or if there is
184 # no space in 'out'.
185 # Input comes from the global variable 'Look' (first byte) and the argument
186 # 'in' (rest). We leave the next byte from 'in' into 'Look' on exit.
187 get-num:  # in: (addr buffered-file), out: (addr stream byte), err: fd or (addr stream byte), ed: (addr exit-descriptor)
188     # pseudocode:
189     #   if (!digit?(Look)) expected(ed, err, "integer")
190     #   do
191     #     if out->write >= out->size
192     #       write(err, "Error: too many digits in number\n")
193     #       stop(ed, 1)
194     #     out->data[out->write] = LSB(Look)
195     #     ++out->write
196     #     Look = get-char(in)
197     #   while digit?(Look)
198     # This is complicated because I don't want to hard-code the error strategy in
199     # a general helper like write-byte-buffered. Maybe I should just create a
200     # local helper.
201     #
202     # within the loop we'll try to keep things in registers:
203     #   in: esi
204     #   out: edi
205     #   out->write: ecx (cached copy; need to keep in sync)
206     #   out->size: edx
207     #   temporaries: eax, ebx
208     # We can't allocate Look to a register because it gets written implicitly in
209     # get-char in each iteration of the loop. (Thereby demonstrating that it's
210     # not the right interface for us. But we'll keep it just to follow Crenshaw.)
211     #
212     # . prologue
213     55/push-ebp
214     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
215     # - if (digit?(Look)) expected(ed, err, "integer")
216     # . eax = digit?(Look)
217     # . . push args
218     ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Look/disp32     .                 # push *Look
219     # . . call
220     e8/call  digit?/disp32
221     # . . discard args
222     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
223     # . if (eax == false)
224     3d/compare-eax-and  0/imm32/false
225     75/jump-if-!=  $get-num:main/disp8
226     # . expected(ed, err, "integer")
227     # . . push args
228     68/push  "integer"/imm32
229     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0x10/disp8      .                 # push *(ebp+16)
230     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0x14/disp8      .                 # push *(ebp+20)
231     # . . call
232     e8/call  expected/disp32  # never returns
233     # . . discard args
234     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
235 $get-num:main:
236     # - otherwise read a digit
237     # . save registers
238     50/push-eax
239     51/push-ecx
240     52/push-edx
241     53/push-ebx
242     56/push-esi
243     57/push-edi
244     # read necessary variables to registers
245     # esi = in
246     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           6/r32/esi   8/disp8         .                 # copy *(ebp+8) to esi
247     # edi = out
248     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           7/r32/edi   0xc/disp8       .                 # copy *(ebp+12) to edi
249     # ecx = out->write
250     8b/copy                         0/mod/indirect  7/rm32/edi    .           .             .           1/r32/ecx   .               .                 # copy *edi to ecx
251     # edx = out->size
252     8b/copy                         1/mod/*+disp8   7/rm32/edi    .           .             .           2/r32/edx   8/disp8         .                 # copy *(edi+8) to edx
253 $get-num:loop:
254     # if (out->write >= out->size) error
255     39/compare                      3/mod/direct    2/rm32/edx    .           .             .           1/r32/ecx   .               .                 # compare edx with ecx
256     7d/jump-if-<  $get-num:loop-stage2/disp8
257     # . error(ed, err, msg)  # TODO: show full number
258     # . . push args
259     68/push  "get-num: too many digits in number"/imm32
260     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0x10/disp8      .                 # push *(ebp+16)
261     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0x14/disp8      .                 # push *(ebp+20)
262     # . . call
263     e8/call  error/disp32  # never returns
264     # . . discard args
265     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
266 $get-num:loop-stage2:
267     # out->data[out->write] = LSB(Look)
268     8d/copy-address                 1/mod/*+disp8   4/rm32/sib    7/base/edi  1/index/ecx   .           3/r32/ebx   0xc/disp8       .                 # copy edi+ecx+12 to ebx
269     8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           0/r32/eax   Look/disp32     .                 # copy *Look to eax
270     88/copy-byte                    0/mod/indirect  3/rm32/ebx    .           .             .           0/r32/AL    .               .                 # copy byte at AL to *ebx
271     # ++out->write
272     41/increment-ecx
273     # Look = get-char(in)
274     # . . push args
275     56/push-esi
276     # . . call
277     e8/call  get-char/disp32
278     # . . discard args
279     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
280     # if (digit?(Look)) loop
281     # . eax = digit?(Look)
282     # . . push args
283     ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Look/disp32     .                 # push *Look
284     # . . call
285     e8/call  digit?/disp32
286     # . . discard args
287     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
288     # . if (eax != false) loop
289     3d/compare-eax-and  0/imm32/false
290     0f 85/jump-if-!=  $get-num:loop/disp32
291 $get-num:loop-end:
292     # persist necessary variables from registers
293     89/copy                         0/mod/indirect  7/rm32/edi    .           .             .           1/r32/ecx   .               .                 # copy ecx to *edi
294 $get-num:end:
295     # . restore registers
296     5f/pop-to-edi
297     5e/pop-to-esi
298     5b/pop-to-ebx
299     5a/pop-to-edx
300     59/pop-to-ecx
301     58/pop-to-eax
302     # . epilogue
303     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
304     5d/pop-to-ebp
305     c3/return
306 
307 test-get-num-reads-single-digit:
308     # - check that get-num returns first character if it's a digit
309     # This test uses exit-descriptors. Use ebp for setting up local variables.
310     55/push-ebp
311     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
312     # clear all streams
313     # . clear-stream(_test-stream)
314     # . . push args
315     68/push  _test-stream/imm32
316     # . . call
317     e8/call  clear-stream/disp32
318     # . . discard args
319     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
320     # . clear-stream($_test-buffered-file->buffer)
321     # . . push args
322     68/push  $_test-buffered-file->buffer/imm32
323     # . . call
324     e8/call  clear-stream/disp32
325     # . . discard args
326     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
327     # . clear-stream(_test-output-stream)
328     # . . push args
329     68/push  _test-output-stream/imm32
330     # . . call
331     e8/call  clear-stream/disp32
332     # . . discard args
333     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
334     # . clear-stream(_test-error-stream)
335     # . . push args
336     68/push  _test-error-stream/imm32
337     # . . call
338     e8/call  clear-stream/disp32
339     # . . discard args
340     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
341     # initialize 'in'
342     # . write(_test-stream, "3")
343     # . . push args
344     68/push  "3"/imm32
345     68/push  _test-stream/imm32
346     # . . call
347     e8/call  write/disp32
348     # . . discard args
349     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
350     # initialize exit-descriptor 'ed' for the call to 'get-num' below
351     # . var ed/eax: exit-descriptor
352     81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
353     89/copy                         3/mod/direct    0/rm32/eax    .           .             .           4/r32/esp   .               .                 # copy esp to eax
354     # . tailor-exit-descriptor(ed, 16)
355     # . . push args
356     68/push  0x10/imm32/nbytes-of-args-for-get-num
357     50/push-eax/ed
358     # . . call
359     e8/call  tailor-exit-descriptor/disp32
360     # . . discard args
361     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
362     # prime the pump
363     # . get-char(_test-buffered-file)
364     # . . push args
365     68/push  _test-buffered-file/imm32
366     # . . call
367     e8/call  get-char/disp32
368     # . . discard args
369     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
370     # get-num(in, out, err, ed)
371     # . . push args
372     50/push-eax/ed
373     68/push  _test-error-stream/imm32
374     68/push  _test-output-stream/imm32
375     68/push  _test-buffered-file/imm32
376     # . . call
377     e8/call  get-num/disp32
378     # registers except esp may be clobbered at this point
379     # . . discard args
380     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0x10/imm32        # add to esp
381     # check-ints-equal(*_test-output-stream->data, '3', msg)
382     # . . push args
383     68/push  "F - test-get-num-reads-single-digit"/imm32
384     68/push  0x33/imm32
385     b8/copy-to-eax  _test-output-stream/imm32
386     ff          6/subop/push        1/mod/*+disp8   0/rm32/eax    .           .             .           .           0xc/disp8       .                 # push *(eax+12)
387     # . . call
388     e8/call  check-ints-equal/disp32
389     # . . discard args
390     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
391     # . reclaim locals
392     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
393     5d/pop-to-ebp
394     c3/return
395 
396 test-get-num-aborts-on-non-digit-in-Look:
397     # - check that get-num returns first character if it's a digit
398     # This test uses exit-descriptors. Use ebp for setting up local variables.
399     55/push-ebp
400     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
401     # clear all streams
402     # . clear-stream(_test-stream)
403     # . . push args
404     68/push  _test-stream/imm32
405     # . . call
406     e8/call  clear-stream/disp32
407     # . . discard args
408     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
409     # . clear-stream($_test-buffered-file->buffer)
410     # . . push args
411     68/push  $_test-buffered-file->buffer/imm32
412     # . . call
413     e8/call  clear-stream/disp32
414     # . . discard args
415     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
416     # . clear-stream(_test-output-stream)
417     # . . push args
418     68/push  _test-output-stream/imm32
419     # . . call
420     e8/call  clear-stream/disp32
421     # . . discard args
422     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
423     # . clear-stream(_test-error-stream)
424     # . . push args
425     68/push  _test-error-stream/imm32
426     # . . call
427     e8/call  clear-stream/disp32
428     # . . discard args
429     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
430     # initialize 'in'
431     # . write(_test-stream, "3")
432     # . . push args
433     68/push  "3"/imm32
434     68/push  _test-stream/imm32
435     # . . call
436     e8/call  write/disp32
437     # . . discard args
438     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
439     # initialize exit-descriptor 'ed' for the call to 'get-num' below
440     # . var ed/eax: exit-descriptor
441     81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
442     89/copy                         3/mod/direct    0/rm32/eax    .           .             .           4/r32/esp   .               .                 # copy esp to eax
443     # . tailor-exit-descriptor(ed, 16)
444     # . . push args
445     68/push  0x10/imm32/nbytes-of-args-for-get-num
446     50/push-eax/ed
447     # . . call
448     e8/call  tailor-exit-descriptor/disp32
449     # . . discard args
450     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
451     # *don't* prime the pump
452     # get-num(in, out, err, ed)
453     # . . push args
454     50/push-eax/ed
455     68/push  _test-error-stream/imm32
456     68/push  _test-output-stream/imm32
457     68/push  _test-buffered-file/imm32
458     # . . call
459     e8/call  get-num/disp32
460     # registers except esp may be clobbered at this point
461     # . . discard args
462     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0x10/imm32        # add to esp
463     # check that get-num tried to call exit(1)
464     # . check-ints-equal(ed->value, 2, msg)  # i.e. stop was called with value 1
465     # . . push args
466     68/push  "F - test-get-num-aborts-on-non-digit-in-Look"/imm32
467     68/push  2/imm32
468     # . . push ed->value
469     ff          6/subop/push        1/mod/*+disp8   0/rm32/eax    .           .             .           .           4/disp8         .                 # push *(eax+4)
470     # . . call
471     e8/call  check-ints-equal/disp32
472     # . . discard args
473     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
474     # . reclaim locals
475     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
476     5d/pop-to-ebp
477     c3/return
478 
479 test-get-num-reads-multiple-digits:
480     # - check that get-num returns all initial digits until it encounters a non-digit
481     # This test uses exit-descriptors. Use ebp for setting up local variables.
482     55/push-ebp
483     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
484     # clear all streams
485     # . clear-stream(_test-stream)
486     # . . push args
487     68/push  _test-stream/imm32
488     # . . call
489     e8/call  clear-stream/disp32
490     # . . discard args
491     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
492     # . clear-stream($_test-buffered-file->buffer)
493     # . . push args
494     68/push  $_test-buffered-file->buffer/imm32
495     # . . call
496     e8/call  clear-stream/disp32
497     # . . discard args
498     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
499     # . clear-stream(_test-output-stream)
500     # . . push args
501     68/push  _test-output-stream/imm32
502     # . . call
503     e8/call  clear-stream/disp32
504     # . . discard args
505     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
506     # . clear-stream(_test-error-stream)
507     # . . push args
508     68/push  _test-error-stream/imm32
509     # . . call
510     e8/call  clear-stream/disp32
511     # . . discard args
512     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
513     # initialize 'in'
514     # . write(_test-stream, "3456 x")
515     # . . push args
516     68/push  "3456"/imm32
517     68/push  _test-stream/imm32
518     # . . call
519     e8/call  write/disp32
520     # . . discard args
521     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
522     # initialize exit-descriptor 'ed' for the call to 'get-num' below
523     # . var ed/eax: exit-descriptor
524     81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
525     89/copy                         3/mod/direct    0/rm32/eax    .           .             .           4/r32/esp   .               .                 # copy esp to eax
526     # . tailor-exit-descriptor(ed, 16)
527     # . . push args
528     68/push  0x10/imm32/nbytes-of-args-for-get-num
529     50/push-eax/ed
530     # . . call
531     e8/call  tailor-exit-descriptor/disp32
532     # . . discard args
533     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
534     # prime the pump
535     # . get-char(_test-buffered-file)
536     # . . push args
537     68/push  _test-buffered-file/imm32
538     # . . call
539     e8/call  get-char/disp32
540     # . . discard args
541     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
542     # get-num(in, out, err, ed)
543     # . . push args
544     50/push-eax/ed
545     68/push  _test-error-stream/imm32
546     68/push  _test-output-stream/imm32
547     68/push  _test-buffered-file/imm32
548     # . . call
549     e8/call  get-num/disp32
550     # registers except esp may be clobbered at this point
551     # . . discard args
552     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0x10/imm32        # add to esp
553     # check-ints-equal(*_test-output-stream->data, '3456', msg)
554     # . . push args
555     68/push  "F - test-get-num-reads-multiple-digits"/imm32
556     68/push  0x36353433/imm32
557     b8/copy-to-eax  _test-output-stream/imm32
558     ff          6/subop/push        1/mod/*+disp8   0/rm32/eax    .           .             .           .           0xc/disp8       .                 # push *(eax+12)
559     # . . call
560     e8/call  check-ints-equal/disp32
561     # . . discard args
562     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
563     # . reclaim locals
564     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
565     5d/pop-to-ebp
566     c3/return
567 
568 test-get-num-reads-multiple-digits-followed-by-nondigit:
569     # - check that get-num returns all initial digits until it encounters a non-digit
570     # This test uses exit-descriptors. Use ebp for setting up local variables.
571     55/push-ebp
572     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
573     # clear all streams
574     # . clear-stream(_test-stream)
575     # . . push args
576     68/push  _test-stream/imm32
577     # . . call
578     e8/call  clear-stream/disp32
579     # . . discard args
580     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
581     # . clear-stream($_test-buffered-file->buffer)
582     # . . push args
583     68/push  $_test-buffered-file->buffer/imm32
584     # . . call
585     e8/call  clear-stream/disp32
586     # . . discard args
587     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
588     # . clear-stream(_test-output-stream)
589     # . . push args
590     68/push  _test-output-stream/imm32
591     # . . call
592     e8/call  clear-stream/disp32
593     # . . discard args
594     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
595     # . clear-stream(_test-error-stream)
596     # . . push args
597     68/push  _test-error-stream/imm32
598     # . . call
599     e8/call  clear-stream/disp32
600     # . . discard args
601     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
602     # initialize 'in'
603     # . write(_test-stream, "3456 x")
604     # . . push args
605     68/push  "3456 x"/imm32
606     68/push  _test-stream/imm32
607     # . . call
608     e8/call  write/disp32
609     # . . discard args
610     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
611     # initialize exit-descriptor 'ed' for the call to 'get-num' below
612     # . var ed/eax: exit-descriptor
613     81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
614     89/copy                         3/mod/direct    0/rm32/eax    .           .             .           4/r32/esp   .               .                 # copy esp to eax
615     # . tailor-exit-descriptor(ed, 16)
616     # . . push args
617     68/push  0x10/imm32/nbytes-of-args-for-get-num
618     50/push-eax/ed
619     # . . call
620     e8/call  tailor-exit-descriptor/disp32
621     # . . discard args
622     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
623     # prime the pump
624     # . get-char(_test-buffered-file)
625     # . . push args
626     68/push  _test-buffered-file/imm32
627     # . . call
628     e8/call  get-char/disp32
629     # . . discard args
630     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
631     # get-num(in, out, err, ed)
632     # . . push args
633     50/push-eax/ed
634     68/push  _test-error-stream/imm32
635     68/push  _test-output-stream/imm32
636     68/push  _test-buffered-file/imm32
637     # . . call
638     e8/call  get-num/disp32
639     # registers except esp may be clobbered at this point
640     # . . discard args
641     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0x10/imm32        # add to esp
642     # check-ints-equal(*_test-output-stream->data, '3456', msg)
643     # . . push args
644     68/push  "F - test-get-num-reads-multiple-digits-followed-by-nondigit"/imm32
645     68/push  0x36353433/imm32
646     b8/copy-to-eax  _test-output-stream/imm32
647     ff          6/subop/push        1/mod/*+disp8   0/rm32/eax    .           .             .           .           0xc/disp8       .                 # push *(eax+12)
648     # . . call
649     e8/call  check-ints-equal/disp32
650     # . . discard args
651     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
652     # . reclaim locals
653     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
654     5d/pop-to-ebp
655     c3/return
656 
657 ## helpers
658 
659 # write(f, "Error: "+s+" expected\n") then stop(ed, 1)
660 expected:  # ed: (addr exit-descriptor), f: fd or (addr stream byte), s: (addr array byte)
661     # . prologue
662     55/push-ebp
663     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
664     # write(f, "Error: ")
665     # . . push args
666     68/push  "Error: "/imm32
667     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
668     # . . call
669     e8/call  write/disp32
670     # . . discard args
671     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
672     # write(f, s)
673     # . . push args
674     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0x10/disp8      .                 # push *(ebp+16)
675     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
676     # . . call
677     e8/call  write/disp32
678     # . . discard args
679     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
680     # write(f, " expected\n")
681     # . . push args
682     68/push  " expected\n"/imm32
683     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
684     # . . call
685     e8/call  write/disp32
686     # . . discard args
687     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
688     # stop(ed, 1)
689     # . . push args
690     68/push  1/imm32
691     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
692     # . . call
693     e8/call  stop/disp32
694     # should never get past this point
695 $expected:dead-end:
696     # . epilogue
697     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
698     5d/pop-to-ebp
699     c3/return
700 
701 # read a byte from 'f', and save it in 'Look'
702 get-char:  # f: (addr buffered-file)
703     # . prologue
704     55/push-ebp
705     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
706     # . save registers
707     50/push-eax
708     # eax = read-byte-buffered(f)
709     # . . push args
710     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
711     # . . call
712     e8/call  read-byte-buffered/disp32
713     # . . discard args
714     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
715     # save eax to Look
716     89/copy                         0/mod/indirect  5/rm32/.disp32            .             .           0/r32/eax   Look/disp32     .                 # copy eax to *Look
717 $get-char:end:
718     # . restore registers
719     58/pop-to-eax
720     # . epilogue
721     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
722     5d/pop-to-ebp
723     c3/return
724 
725 digit?:  # c: int -> eax: boolean
726     # . prologue
727     55/push-ebp
728     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
729     # eax = false
730     b8/copy-to-eax  0/imm32
731     # if (c < '0') return false
732     81          7/subop/compare     1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         0x30/imm32        # compare *(ebp+8)
733     7c/jump-if-<  $digit?:end/disp8
734     # if (c > '9') return false
735     81          7/subop/compare     1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         0x39/imm32        # compare *(ebp+8)
736     7f/jump-if->  $digit?:end/disp8
737     # otherwise return true
738     b8/copy-to-eax  1/imm32
739 $digit?:end:
740     # . epilogue
741     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
742     5d/pop-to-ebp
743     c3/return
744 
745 == data
746 
747 Look:  # (char with some extra padding)
748     0/imm32
749 
750 # . . vim:nowrap:textwidth=0