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  to-hex-char/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  append-byte/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  to-hex-char/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  append-byte/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  _test-stream/imm32
 68     # . . call
 69     e8/call  clear-stream/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  _test-stream/imm32
 76     # . . call
 77     e8/call  append-byte-hex/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  _test-stream/imm32
 85     # . . call
 86     e8/call  check-stream-equal/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  to-hex-char/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  write-byte-buffered/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  to-hex-char/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  write-byte-buffered/disp32
124     # . . discard args
125     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
126 $write-byte-hex-buffered:end:
127     # . restore registers
128     58/pop-to-eax
129     # . epilogue
130     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
131     5d/pop-to-ebp
132     c3/return
133 
134 test-write-byte-hex-buffered:
135     # - check that write-byte-hex-buffered prints the hex textual representation
136     # setup
137     # . clear-stream(_test-stream)
138     # . . push args
139     68/push  _test-stream/imm32
140     # . . call
141     e8/call  clear-stream/disp32
142     # . . discard args
143     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
144     # . clear-stream($_test-buffered-file->buffer)
145     # . . push args
146     68/push  $_test-buffered-file->buffer/imm32
147     # . . call
148     e8/call  clear-stream/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  _test-buffered-file/imm32
155     # . . call
156     e8/call  write-byte-hex-buffered/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  _test-buffered-file/imm32
162     # . . call
163     e8/call  flush/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  _test-stream/imm32
171     # . . call
172     e8/call  check-stream-equal/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  write/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  write-int32-hex-bits/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  to-hex-char/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  append-byte/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  _test-stream/imm32
264     # . . call
265     e8/call  clear-stream/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  _test-stream/imm32
272     # . . call
273     e8/call  write-int32-hex/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  _test-stream/imm32
281     # . . call
282     e8/call  check-stream-equal/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  write-buffered/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  write-int32-hex-bits-buffered/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  to-hex-char/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  write-byte-buffered/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 $write-int32-hex-bits-buffered:end:
360     # . restore registers
361     59/pop-to-ecx
362     58/pop-to-eax
363     # . epilogue
364     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
365     5d/pop-to-ebp
366     c3/return
367 
368 test-write-int32-hex-buffered:
369     # - check that write-int32-hex-buffered prints the hex textual representation
370     # setup
371     # . clear-stream(_test-stream)
372     # . . push args
373     68/push  _test-stream/imm32
374     # . . call
375     e8/call  clear-stream/disp32
376     # . . discard args
377     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
378     # . clear-stream($_test-buffered-file->buffer)
379     # . . push args
380     68/push  $_test-buffered-file->buffer/imm32
381     # . . call
382     e8/call  clear-stream/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  _test-buffered-file/imm32
389     # . . call
390     e8/call  write-int32-hex-buffered/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  _test-buffered-file/imm32
396     # . . call
397     e8/call  flush/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  _test-stream/imm32
423     # . . call
424     e8/call  check-stream-equal/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