1 # write: write to in-memory streams
  2 #
  3 # We need to do this in machine code because streams need to be opaque types,
  4 # and we don't yet support opaque types in Mu.
  5 
  6 == code
  7 #   instruction                     effective address                                                   register    displacement    immediate
  8 # . op          subop               mod             rm32          base        index         scale       r32
  9 # . 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
 10 
 11 write:  # f: (addr stream byte), s: (addr array byte)
 12     # . prologue
 13     55/push-ebp
 14     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
 15     # if (s == 0) return
 16     81          7/subop/compare     1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       0/imm32           # compare *(ebp+12)
 17     74/jump-if-=  $write:end/disp8
 18     # . save registers
 19     50/push-eax
 20     51/push-ecx
 21     52/push-edx
 22     53/push-ebx
 23     # ecx = f
 24     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .                         1/r32/ecx   8/disp8         .                 # copy *(ebp+8) to ecx
 25     # edx = f->write
 26     8b/copy                         0/mod/indirect  1/rm32/ecx    .           .             .           2/r32/edx   .               .                 # copy *ecx to edx
 27     # ebx = f->size
 28     8b/copy                         1/mod/*+disp8   1/rm32/ecx    .           .             .           3/r32/ebx   8/disp8         .                 # copy *(ecx+8) to ebx
 29     # eax = _append-3(&f->data[f->write], &f->data[f->size], s)
 30     # . . push s
 31     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
 32     # . . push &f->data[f->size]
 33     8d/copy-address                 1/mod/*+disp8   4/rm32/sib    1/base/ecx  3/index/ebx   .           3/r32/ebx   0xc/disp8       .                 # copy ecx+ebx+12 to ebx
 34     53/push-ebx
 35     # . . push &f->data[f->write]
 36     8d/copy-address                 1/mod/*+disp8   4/rm32/sib    1/base/ecx  2/index/edx   .           3/r32/ebx   0xc/disp8       .                 # copy ecx+edx+12 to ebx
 37     53/push-ebx
 38     # . . call
 39     e8/call  _append-3/disp32
 40     # . . discard args
 41     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
 42     # f->write += eax
 43     01/add                          0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # add eax to *ecx
 44     # . restore registers
 45     5b/pop-to-ebx
 46     5a/pop-to-edx
 47     59/pop-to-ecx
 48     58/pop-to-eax
 49 $write:end:
 50     # . epilogue
 51     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
 52     5d/pop-to-ebp
 53     c3/return
 54 
 55 test-write-single:
 56     # clear-stream(_test-stream)
 57     # . . push args
 58     68/push  _test-stream/imm32
 59     # . . call
 60     e8/call  clear-stream/disp32
 61     # . . discard args
 62     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
 63     # write(_test-stream, "Ab")
 64     # . . push args
 65     68/push  "Ab"/imm32
 66     68/push  _test-stream/imm32
 67     # . . call
 68     e8/call  write/disp32
 69     # . . discard args
 70     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
 71     # check-ints-equal(*_test-stream->data, 41/A 62/b 00 00, msg)
 72     # . . push args
 73     68/push  "F - test-write-single"/imm32
 74     68/push  0x006241/imm32/Ab
 75     # . . push *_test-stream->data
 76     b8/copy-to-eax  _test-stream/imm32
 77     ff          6/subop/push        1/mod/*+disp8   0/rm32/eax    .           .             .           .           0xc/disp8       .                 # push *(eax+12)
 78     # . . call
 79     e8/call  check-ints-equal/disp32
 80     # . . discard args
 81     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
 82     # end
 83     c3/return
 84 
 85 test-write-appends:
 86     # clear-stream(_test-stream)
 87     # . . push args
 88     68/push  _test-stream/imm32
 89     # . . call
 90     e8/call  clear-stream/disp32
 91     # . . discard args
 92     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
 93     # write(_test-stream, "C")
 94     # . . push args
 95     68/push  "C"/imm32
 96     68/push  _test-stream/imm32
 97     # . . call
 98     e8/call  write/disp32
 99     # . . discard args
100     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
101     # write(_test-stream, "D")
102     # . . push args
103     68/push  "D"/imm32
104     68/push  _test-stream/imm32
105     # . . call
106     e8/call  write/disp32
107     # . . discard args
108     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
109     # check-ints-equal(*_test-stream->data, 43/C 44/D 00 00, msg)
110     # . . push args
111     68/push  "F - test-write-appends"/imm32
112     68/push  0x00004443/imm32/C-D
113     # . . push *_test-stream->data
114     b8/copy-to-eax  _test-stream/imm32
115     ff          6/subop/push        1/mod/*+disp8   0/rm32/eax    .           .             .           .           0xc/disp8       .                 # push *(eax+12)
116     # . . call
117     e8/call  check-ints-equal/disp32
118     # . . discard args
119     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
120     # end
121     c3/return
122 
123 == data
124 
125 _test-stream:  # (stream byte)
126     # current write index
127     0/imm32
128     # current read index
129     0/imm32
130     # size
131     0x10/imm32
132     # data (2 lines x 8 bytes/line)
133     00 00 00 00 00 00 00 00
134     00 00 00 00 00 00 00 00
135 
136 == code
137 
138 try-write:  # f: (addr stream byte), s: (addr array byte) -> overflow?/eax: boolean
139     # . prologue
140     55/push-ebp
141     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
142     # if (s == 0) return
143     81          7/subop/compare     1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       0/imm32           # compare *(ebp+12)
144     74/jump-if-=  $try-write:end/disp8
145     # . save registers
146     51/push-ecx
147     # if (f->size - f->write < s->size) return
148     # . eax = f->size - f->write - s->size
149     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .                         1/r32/ecx   8/disp8         .                 # copy *(ebp+8) to ecx
150     8b/copy                         1/mod/*+disp8   1/rm32/ecx    .           .             .           0/r32/eax   8/disp8         .                 # copy *(ecx+8) to eax
151     2b/subtract                     0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # subtract *ecx from eax
152     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .                         1/r32/ecx   0xc/disp8       .                 # copy *(ebp+12) to ecx
153     2b/subtract                     0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # subtract *ecx from eax
154     # . if (eax < 0) return
155     3d/compare-eax-and  0/imm32
156     7c/jump-if-<  $try-write:end/disp8
157     # write(f, s)
158     # . . push args
159     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
160     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
161     # . . call
162     e8/call  write/disp32
163     # . . discard args
164     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
165     # . restore registers
166     59/pop-to-ecx
167     # return 0
168     b8/copy-to-eax  0/imm32
169 $try-write:end:
170     # . epilogue
171     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
172     5d/pop-to-ebp
173     c3/return
174 
175 # probably a bad idea
176 space-remaining-in-stream:  # f: (addr stream byte) -> n/eax: int
177     # . prologue
178     55/push-ebp
179     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
180     # . save registers
181     51/push-ecx
182     # return f->size - f->write
183     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .                         1/r32/ecx   8/disp8         .                 # copy *(ebp+8) to ecx
184     8b/copy                         1/mod/*+disp8   1/rm32/ecx    .           .             .           0/r32/eax   8/disp8         .                 # copy *(ecx+8) to eax
185     2b/subtract                     0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # subtract *ecx from eax
186     # . restore registers
187     59/pop-to-ecx
188 $space-remaining-in-stream:end:
189     # . epilogue
190     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
191     5d/pop-to-ebp
192     c3/return
193 
194 stream-size:  # f: (addr stream byte) -> n/eax: int
195     # . prologue
196     55/push-ebp
197     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
198     # . save registers
199     51/push-ecx
200     # return f->write
201     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .                         1/r32/ecx   8/disp8         .                 # copy *(ebp+8) to ecx
202     8b/copy                         0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # copy *ecx to eax
203     # . restore registers
204     59/pop-to-ecx
205 $stream-size:end:
206     # . epilogue
207     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
208     5d/pop-to-ebp
209     c3/return
210 
211 # 3-argument variant of _append
212 _append-3:  # out: (addr byte), outend: (addr byte), s: (addr array byte) -> num_bytes_appended/eax
213     # . prologue
214     55/push-ebp
215     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
216     # . save registers
217     51/push-ecx
218     # if (outend - out < s->size) abort
219     # . eax = f->size - f->write - s->size
220     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .                         0/r32/eax   0xc/disp8       .                 # copy *(ebp+12) to eax
221     2b/subtract                     1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/eax   8/disp8         .                 # subtract *(ebp+8) from eax
222     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .                         1/r32/ecx   0x10/disp8      .                 # copy *(ebp+16) to ecx
223     2b/subtract                     0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # subtract *ecx from eax
224     # . if (eax < 0) abort
225     3d/compare-eax-and  0/imm32
226     7c/jump-if-<  $_append-3:abort/disp8
227     # eax = _append-4(out, outend, &s->data[0], &s->data[s->size])
228     # . . push &s->data[s->size]
229     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .                         0/r32/eax   0x10/disp8      .                 # copy *(ebp+16) to eax
230     8b/copy                         0/mod/indirect  0/rm32/eax    .           .             .           1/r32/ecx   .               .                 # copy *eax to ecx
231     8d/copy-address                 1/mod/*+disp8   4/rm32/sib    0/base/eax  1/index/ecx   .           1/r32/ecx   4/disp8         .                 # copy eax+ecx+4 to ecx
232     51/push-ecx
233     # . . push &s->data[0]
234     8d/copy-address                 1/mod/*+disp8   0/rm32/eax    .           .             .           1/r32/ecx   4/disp8         .                 # copy eax+4 to ecx
235     51/push-ecx
236     # . . push outend
237     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
238     # . . push out
239     ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
240     # . . call
241     e8/call  _append-4/disp32
242     # . . discard args
243     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0x10/imm32        # add to esp
244 $_append-3:end:
245     # . restore registers
246     59/pop-to-ecx
247     # . epilogue
248     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
249     5d/pop-to-ebp
250     c3/return
251 
252 $_append-3:abort:
253     (abort "_append-3 about to overflow")  # 3=cyan
254     # never gets here
255 
256 # 4-argument variant of _append
257 _append-4:  # out: (addr byte), outend: (addr byte), in: (addr byte), inend: (addr byte) -> num_bytes_appended/eax: int
258     # . prologue
259     55/push-ebp
260     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
261     # . save registers
262     51/push-ecx
263     52/push-edx
264     53/push-ebx
265     56/push-esi
266     57/push-edi
267     # num_bytes_appended = 0
268     b8/copy-to-eax  0/imm32
269     # edi = out
270     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           7/r32/edi   8/disp8         .                 # copy *(ebp+8) to edi
271     # edx = outend
272     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           2/r32/edx   0xc/disp8       .                 # copy *(ebp+12) to edx
273     # esi = in
274     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           6/r32/esi   0x10/disp8      .                 # copy *(ebp+16) to esi
275     # ecx = inend
276     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           1/r32/ecx   0x14/disp8      .                 # copy *(ebp+20) to ecx
277 $_append-4:loop:
278     # if (in >= inend) break
279     39/compare                      3/mod/direct    6/rm32/esi    .           .             .           1/r32/ecx   .               .                 # compare esi with ecx
280     73/jump-if-addr>=  $_append-4:end/disp8
281     # if (out >= outend) abort  # just to catch test failures fast
282     39/compare                      3/mod/direct    7/rm32/edi    .           .             .           2/r32/edx   .               .                 # compare edi with edx
283     0f 83/jump-if-addr>=  $_append-4:abort/disp32
284     # *out = *in
285     8a/copy-byte                    0/mod/indirect  6/rm32/esi    .           .             .           3/r32/BL    .               .                 # copy byte at *esi to BL
286     88/copy-byte                    0/mod/indirect  7/rm32/edi    .           .             .           3/r32/BL    .               .                 # copy byte at BL to *edi
287     # ++num_bytes_appended
288     40/increment-eax
289     # ++in
290     46/increment-esi
291     # ++out
292     47/increment-edi
293     eb/jump  $_append-4:loop/disp8
294 $_append-4: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     # . epilogue
302     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
303     5d/pop-to-ebp
304     c3/return
305 
306 $_append-4:abort:
307     (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "_append-4: stream full at " 3 0)  # 3=cyan
308     (draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0 %eax 3 0)
309     (abort "")
310     # never gets here
311 
312 # . . vim:nowrap:textwidth=0