4187119d |
1 | # This is a shell archive. Remove anything before this line, |
2 | # then unpack it by saving it in a file and typing "sh file". |
3 | # |
4 | # Wrapped by Glenn Engel <glenne@labgre> on Mon Jun 12 15:19:20 1989 |
5 | # |
6 | # This archive contains: |
7 | # remcom.c |
8 | # |
9 | |
10 | LANG=""; export LANG |
11 | PATH=/bin:/usr/bin:$PATH; export PATH |
12 | |
13 | echo x - remcom.c |
14 | cat >remcom.c <<'@EOF' |
15 | |
16 | /**************************************************************************** |
17 | |
18 | THIS SOFTWARE IS NOT COPYRIGHTED |
19 | |
20 | HP offers the following for use in the public domain. HP makes no |
21 | warranty with regard to the software or it's performance and the |
22 | user accepts the software "AS IS" with all faults. |
23 | |
24 | HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD |
25 | TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES |
26 | OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
27 | |
28 | ****************************************************************************/ |
29 | |
30 | /**************************************************************************** |
31 | * $Header: remcom.c,v 1.25 89/05/16 14:34:00 glenne Exp $ |
32 | * |
33 | * $Module name: remcom.c $ |
34 | * $Revision: 1.25 $ |
35 | * $Date: 89/05/16 14:34:00 $ |
36 | * $Contributor: Lake Stevens Instrument Division$ |
37 | * |
38 | * $Description: low level support for gdb debugger. $ |
39 | * |
40 | * $Considerations: only works on target hardware $ |
41 | * |
42 | * $Written by: Glenn Engel $ |
43 | * $ModuleState: Experimental $ |
44 | * |
45 | * $NOTES: See Below $ |
46 | * |
47 | * To enable debugger support, two things need to happen. One, a |
48 | * call to set_debug_traps() is necessary in order to allow any breakpoints |
49 | * or error conditions to be properly intercepted and reported to gdb. |
50 | * Two, a breakpoint needs to be generated to begin communication. This |
51 | * is most easily accomplished by a call to breakpoint(). Breakpoint() |
52 | * simulates a breakpoint by executing a trap #1. |
53 | * |
54 | * Some explanation is probably necessary to explain how exceptions are |
55 | * handled. When an exception is encountered the 68000 pushes the current |
56 | * program counter and status register onto the supervisor stack and then |
57 | * transfers execution to a location specified in it's vector table. |
58 | * The handlers for the exception vectors are hardwired to jmp to an address |
59 | * given by the relation: (exception - 256) * 6. These are decending |
60 | * addresses starting from -6, -12, -18, ... By allowing 6 bytes for |
61 | * each entry, a jsr, jmp, bsr, ... can be used to enter the exception |
62 | * handler. Using a jsr to handle an exception has an added benefit of |
63 | * allowing a single handler to service several exceptions and use the |
64 | * return address as the key differentiation. The vector number can be |
65 | * computed from the return address by [ exception = (addr + 1530) / 6 ]. |
66 | * The sole purpose of the routine _catchException is to compute the |
67 | * exception number and push it on the stack in place of the return address. |
68 | * The external function exceptionHandler() is |
69 | * used to attach a specific handler to a specific 68k exception. |
70 | * For 68020 machines, the ability to have a return address around just |
71 | * so the vector can be determined is not necessary because the '020 pushes an |
72 | * extra word onto the stack containing the vector offset |
73 | * |
74 | * Because gdb will sometimes write to the stack area to execute function |
75 | * calls, this program cannot rely on using the supervisor stack so it |
76 | * uses it's own stack area reserved in the int array remcomStack. |
77 | * |
78 | ************* |
79 | * |
80 | * The following gdb commands are supported: |
81 | * |
82 | * command function Return value |
83 | * |
84 | * g return the value of the CPU registers hex data or ENN |
85 | * G set the value of the CPU registers OK or ENN |
86 | * |
87 | * mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN |
88 | * MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN |
89 | * |
90 | * c Resume at current address SNN ( signal NN) |
91 | * cAA..AA Continue at address AA..AA SNN |
92 | * |
93 | * s Step one instruction SNN |
94 | * sAA..AA Step one instruction from AA..AA SNN |
95 | * |
96 | * k kill |
97 | * |
98 | * ? What was the last sigval ? SNN (signal NN) |
99 | * |
100 | * All commands and responses are sent with a packet which includes a |
101 | * checksum. A packet consists of |
102 | * |
103 | * $<packet info>#<checksum>. |
104 | * |
105 | * where |
106 | * <packet info> :: <characters representing the command or response> |
107 | * <checksum> :: < two hex digits computed as modulo 256 sum of <packetinfo>> |
108 | * |
109 | * When a packet is received, it is first acknowledged with either '+' or '-'. |
110 | * '+' indicates a successful transfer. '-' indicates a failed transfer. |
111 | * |
112 | * Example: |
113 | * |
114 | * Host: Reply: |
115 | * $m0,10#2a +$00010203040506070809101112131415#42 |
116 | * |
117 | ****************************************************************************/ |
118 | |
119 | #include <stdio.h> |
120 | #include <string.h> |
121 | #include <setjmp.h> |
122 | |
123 | /************************************************************************ |
124 | * |
125 | * external low-level support routines |
126 | */ |
127 | typedef void (*ExceptionHook)(int); /* pointer to function with int parm */ |
128 | typedef void (*Function)(); /* pointer to a function */ |
129 | |
130 | extern putDebugChar(); /* write a single character */ |
131 | extern getDebugChar(); /* read and return a single char */ |
132 | |
133 | extern Function exceptionHandler(); /* assign an exception handler */ |
134 | extern ExceptionHook exceptionHook; /* hook variable for errors/exceptions */ |
135 | |
136 | |
137 | /************************************************************************/ |
138 | /* BUFMAX defines the maximum number of characters in inbound/outbound buffers*/ |
139 | /* at least NUMREGBYTES*2 are needed for register packets */ |
140 | #define BUFMAX 400 |
141 | |
142 | static char initialized; /* boolean flag. != 0 means we've been initialized */ |
143 | |
144 | int remote_debug = 0; |
145 | /* debug > 0 prints ill-formed commands in valid packets & checksum errors */ |
146 | |
147 | char hexchars[]="0123456789abcdef"; |
148 | |
149 | /* there are 180 bytes of registers on a 68020 w/68881 */ |
150 | /* many of the fpa registers are 12 byte (96 bit) registers */ |
151 | #define NUMREGBYTES 180 |
152 | enum regnames {D0,D1,D2,D3,D4,D5,D6,D7, |
153 | A0,A1,A2,A3,A4,A5,A6,A7, |
154 | PS,PC, |
155 | FP0,FP1,FP2,FP3,FP4,FP5,FP6,FP7, |
156 | FPCONTROL,FPSTATUS,FPIADDR |
157 | }; |
158 | |
159 | typedef struct FrameStruct |
160 | { |
161 | struct FrameStruct *previous; |
162 | int exceptionPC; /* pc value when this frame created */ |
163 | int exceptionVector; /* cpu vector causing exception */ |
164 | short frameSize; /* size of cpu frame in words */ |
165 | short sr; /* for 68000, this not always sr */ |
166 | int pc; |
167 | short format; |
168 | int fsaveHeader; |
169 | int morejunk[0]; /* exception frame, fp save... */ |
170 | } Frame; |
171 | |
172 | #define FRAMESIZE 500 |
173 | static Frame *lastFrame; |
174 | static int frameStack[FRAMESIZE]; |
175 | |
176 | /* |
177 | * these should not be static cuz they can be used outside this module |
178 | */ |
179 | int registers[NUMREGBYTES/4]; |
180 | int superStack; |
181 | |
182 | static int remcomStack[400]; |
183 | static int* stackPtr = &remcomStack[399]; |
184 | |
185 | /* |
186 | * In many cases, the system will want to continue exception processing |
187 | * when a continue command is given. |
188 | * oldExceptionHook is a function to invoke in this case. |
189 | */ |
190 | |
191 | static ExceptionHook oldExceptionHook; |
192 | |
193 | /* the size of the exception stack on the 68020 varies with the type of |
194 | * exception. The following table is the number of WORDS used |
195 | * for each exception format. |
196 | */ |
197 | static short exceptionSize[] = { 4,4,6,4,4,4,4,4,29,10,16,46,4,4,4,4 }; |
198 | |
199 | /************* jump buffer used for setjmp/longjmp **************************/ |
200 | jmp_buf env; |
201 | |
202 | /*************************** ASSEMBLY CODE MACROS *************************/ |
203 | /* */ |
204 | |
205 | #ifdef __HAVE_68881__ |
206 | /* do an fsave, then remember the address to begin a restore from */ |
207 | #define SAVE_FP_REGS() asm(" fsave a0@-"); \ |
208 | asm(" fmovemx fp0-fp7,_registers+72"); \ |
209 | asm(" fmoveml fpcr/fpsr/fpi,_registers+168"); |
210 | #define RESTORE_FP_REGS() asm(" fmoveml _registers+168,fpcr/fpsr/fpi"); \ |
211 | asm(" fmovemx _registers+72,fp0-fp7"); \ |
212 | asm(" frestore a0@+"); |
213 | #else |
214 | #define SAVE_FP_REGS() |
215 | #define RESTORE_FP_REGS() |
216 | #endif /* __HAVE_68881__ */ |
217 | |
218 | asm(" |
219 | .text |
220 | .globl _return_to_super |
221 | _return_to_super: |
222 | movel _registers+60,sp /* get new stack pointer */ |
223 | movel _lastFrame,a0 /* get last frame info */ |
224 | bra return_to_any |
225 | |
226 | .globl _return_to_user |
227 | _return_to_user: |
228 | movel _registers+60,a0 /* get usp */ |
229 | movel a0,usp /* set usp */ |
230 | movel _superStack,sp /* get original stack pointer */ |
231 | |
232 | return_to_any: |
233 | movel _lastFrame,a0 /* get last frame info */ |
234 | movel a0@+,_lastFrame /* link in previous frame */ |
235 | addql #8,a0 /* skip over pc, vector#*/ |
236 | movew a0@+,d0 /* get # of words in cpu frame */ |
237 | addw d0,a0 /* point to end of data */ |
238 | addw d0,a0 /* point to end of data */ |
239 | movel a0,a1 |
240 | # |
241 | # copy the stack frame |
242 | subql #1,d0 |
243 | copyUserLoop: |
244 | movew a1@-,sp@- |
245 | dbf d0,copyUserLoop |
246 | "); |
247 | RESTORE_FP_REGS() |
248 | asm(" moveml _registers,d0-d7/a0-a6"); |
249 | asm(" rte"); /* pop and go! */ |
250 | |
251 | #define DISABLE_INTERRUPTS() asm(" oriw #0x0700,sr"); |
252 | #define BREAKPOINT() asm(" trap #1"); |
253 | |
254 | /* this function is called immediately when a level 7 interrupt occurs */ |
255 | /* if the previous interrupt level was 7 then we're already servicing */ |
256 | /* this interrupt and an rte is in order to return to the debugger. */ |
257 | /* For the 68000, the offset for sr is 6 due to the jsr return address */ |
258 | asm(" |
259 | .text |
260 | .globl __debug_level7 |
261 | __debug_level7: |
262 | movew d0,sp@-"); |
263 | #ifdef mc68020 |
264 | asm(" movew sp@(2),d0"); |
265 | #else |
266 | asm(" movew sp@(6),d0"); |
267 | #endif |
268 | asm(" andiw #0x700,d0 |
269 | cmpiw #0x700,d0 |
270 | beq _already7 |
271 | movew sp@+,d0 |
272 | bra __catchException |
273 | _already7: |
274 | movew sp@+,d0"); |
275 | #ifndef mc68020 |
276 | asm(" lea sp@(4),sp"); /* pull off 68000 return address */ |
277 | #endif |
278 | asm(" rte"); |
279 | |
280 | extern void _catchException(); |
281 | |
282 | #ifdef mc68020 |
283 | /* This function is called when a 68020 exception occurs. It saves |
284 | * all the cpu and fpcp regs in the _registers array, creates a frame on a |
285 | * linked list of frames which has the cpu and fpcp stack frames needed |
286 | * to properly restore the context of these processors, and invokes |
287 | * an exception handler (remcom_handler). |
288 | * |
289 | * stack on entry: stack on exit: |
290 | * N bytes of junk exception # MSWord |
291 | * Exception Format Word exception # MSWord |
292 | * Program counter LSWord |
293 | * Program counter MSWord |
294 | * Status Register |
295 | * |
296 | * |
297 | */ |
298 | asm(" |
299 | .text |
300 | .globl __catchException |
301 | __catchException:"); |
302 | DISABLE_INTERRUPTS(); |
303 | asm(" |
304 | moveml d0-d7/a0-a6,_registers /* save registers */ |
305 | movel _lastFrame,a0 /* last frame pointer */ |
306 | "); |
307 | SAVE_FP_REGS(); |
308 | asm(" |
309 | lea _registers,a5 /* get address of registers */ |
310 | movew sp@,d1 /* get status register */ |
311 | movew d1,a5@(66) /* save sr */ |
312 | movel sp@(2),a4 /* save pc in a4 for later use */ |
313 | movel a4,a5@(68) /* save pc in _regisers[] */ |
314 | |
315 | # |
316 | # figure out how many bytes in the stack frame |
317 | movew sp@(6),d0 /* get '020 exception format */ |
318 | movew d0,d2 /* make a copy of format word */ |
319 | andiw #0xf000,d0 /* mask off format type */ |
320 | rolw #5,d0 /* rotate into the low byte *2 */ |
321 | lea _exceptionSize,a1 |
322 | addw d0,a1 /* index into the table */ |
323 | movew a1@,d0 /* get number of words in frame */ |
324 | movew d0,d3 /* save it */ |
325 | subw d0,a0 /* adjust save pointer */ |
326 | subw d0,a0 /* adjust save pointer(bytes) */ |
327 | movel a0,a1 /* copy save pointer */ |
328 | subql #1,d0 /* predecrement loop counter */ |
329 | # |
330 | # copy the frame |
331 | saveFrameLoop: |
332 | movew sp@+,a1@+ |
333 | dbf d0,saveFrameLoop |
334 | # |
335 | # now that the stack has been clenaed, |
336 | # save the a7 in use at time of exception |
337 | movel sp,_superStack /* save supervisor sp */ |
338 | andiw #0x2000,d1 /* were we in supervisor mode ? */ |
339 | beq userMode |
340 | movel a7,a5@(60) /* save a7 */ |
341 | bra a7saveDone |
342 | userMode: |
343 | movel usp,a1 |
344 | movel a1,a5@(60) /* save user stack pointer */ |
345 | a7saveDone: |
346 | |
347 | # |
348 | # save size of frame |
349 | movew d3,a0@- |
350 | |
351 | # |
352 | # compute exception number |
353 | andl #0xfff,d2 /* mask off vector offset */ |
354 | lsrw #2,d2 /* divide by 4 to get vect num */ |
355 | movel d2,a0@- /* save it */ |
356 | # |
357 | # save pc causing exception |
358 | movel a4,a0@- |
359 | # |
360 | # save old frame link and set the new value |
361 | movel _lastFrame,a1 /* last frame pointer */ |
362 | movel a1,a0@- /* save pointer to prev frame */ |
363 | movel a0,_lastFrame |
364 | |
365 | movel d2,sp@- /* push exception num */ |
366 | movel _exceptionHook,a0 /* get address of handler */ |
367 | jbsr a0@ /* and call it */ |
368 | jmp __returnFromException /* now, return */ |
369 | "); |
370 | #else /* mc68000 */ |
371 | /* This function is called when an exception occurs. It translates the |
372 | * return address found on the stack into an exception vector # which |
373 | * is then handled by either handle_exception or a system handler. |
374 | * _catchException provides a front end for both. |
375 | * |
376 | * stack on entry: stack on exit: |
377 | * Program counter MSWord exception # MSWord |
378 | * Program counter LSWord exception # MSWord |
379 | * Status Register |
380 | * Return Address MSWord |
381 | * Return Address LSWord |
382 | */ |
383 | asm(" |
384 | .text |
385 | .globl __catchException |
386 | __catchException:"); |
387 | DISABLE_INTERRUPTS(); |
388 | asm(" |
389 | moveml d0-d7/a0-a6,_registers /* save registers */ |
390 | movel _lastFrame,a0 /* last frame pointer */ |
391 | "); |
392 | SAVE_FP_REGS(); |
393 | asm(" |
394 | lea _registers,a5 /* get address of registers */ |
395 | movel sp@+,d2 /* pop return address */ |
396 | addl #1530,d2 /* convert return addr to */ |
397 | divs #6,d2 /* exception number */ |
398 | extl d2 |
399 | |
400 | moveql #3,d3 /* assume a three word frame */ |
401 | |
402 | cmpiw #3,d2 /* bus error or address error ? */ |
403 | bgt normal /* if >3 then normal error */ |
404 | movel sp@+,a0@- /* copy error info to frame buff*/ |
405 | movel sp@+,a0@- /* these are never used */ |
406 | moveql #7,d3 /* this is a 7 word frame */ |
407 | |
408 | normal: |
409 | movew sp@+,d1 /* pop status register */ |
410 | movel sp@+,a4 /* pop program counter */ |
411 | movew d1,a5@(66) /* save sr */ |
412 | movel a4,a5@(68) /* save pc in _regisers[] */ |
413 | movel a4,a0@- /* copy pc to frame buffer */ |
414 | movew d1,a0@- /* copy sr to frame buffer */ |
415 | |
416 | movel sp,_superStack /* save supervisor sp */ |
417 | |
418 | andiw #0x2000,d1 /* were we in supervisor mode ? */ |
419 | beq userMode |
420 | movel a7,a5@(60) /* save a7 */ |
421 | bra saveDone |
422 | userMode: |
423 | movel usp,a1 /* save user stack pointer */ |
424 | movel a1,a5@(60) /* save user stack pointer */ |
425 | saveDone: |
426 | |
427 | movew d3,a0@- /* push frame size in words */ |
428 | movel d2,a0@- /* push vector number */ |
429 | movel a4,a0@- /* push exception pc */ |
430 | |
431 | # |
432 | # save old frame link and set the new value |
433 | movel _lastFrame,a1 /* last frame pointer */ |
434 | movel a1,a0@- /* save pointer to prev frame */ |
435 | movel a0,_lastFrame |
436 | |
437 | movel d2,sp@- /* push exception num */ |
438 | movel _exceptionHook,a0 /* get address of handler */ |
439 | jbsr a0@ /* and call it */ |
440 | jmp __returnFromException /* now, return */ |
441 | "); |
442 | #endif |
443 | |
444 | |
445 | /* |
446 | * remcomHandler is a front end for handle_exception. It moves the |
447 | * stack pointer into an area reserved for debugger use in case the |
448 | * breakpoint happened in supervisor mode. |
449 | */ |
450 | asm("_remcomHandler:"); |
451 | asm(" addl #4,sp"); /* pop off return address */ |
452 | asm(" movel sp@+,d0"); /* get the exception number */ |
453 | asm(" movel _stackPtr,sp"); /* move to remcom stack area */ |
454 | asm(" movel d0,sp@-"); /* push exception onto stack */ |
455 | asm(" jbsr _handle_exception"); /* this never returns */ |
456 | asm(" rts"); /* return */ |
457 | |
458 | void _returnFromException( Frame *frame ) |
459 | { |
460 | /* if no existing frame, dummy one up */ |
461 | if (! frame) |
462 | { |
463 | frame = lastFrame -1; |
464 | frame->frameSize = 4; |
465 | frame->format = 0; |
466 | frame->fsaveHeader = 0; |
467 | frame->previous = lastFrame; |
468 | } |
469 | |
470 | #ifndef mc68020 |
471 | /* a 68000 cannot use the internal info pushed onto a bus error |
472 | * or address error frame when doing an RTE so don't put this info |
473 | * onto the stack or the stack will creep every time this happens. |
474 | */ |
475 | frame->frameSize=3; |
476 | #endif |
477 | |
478 | /* throw away any frames in the list after this frame */ |
479 | lastFrame = frame; |
480 | |
481 | frame->sr = registers[(int) PS]; |
482 | frame->pc = registers[(int) PC]; |
483 | |
484 | if (registers[(int) PS] & 0x2000) |
485 | { |
486 | /* return to supervisor mode... */ |
487 | return_to_super(); |
488 | } |
489 | else |
490 | { /* return to user mode */ |
491 | return_to_user(); |
492 | } |
493 | } |
494 | |
495 | int hex(ch) |
496 | char ch; |
497 | { |
498 | if ((ch >= 'a') && (ch <= 'f')) return (ch-'a'+10); |
499 | if ((ch >= '0') && (ch <= '9')) return (ch-'0'); |
500 | return (0); |
501 | } |
502 | |
503 | |
504 | /* scan for the sequence $<data>#<checksum> */ |
505 | void getpacket(buffer) |
506 | char * buffer; |
507 | { |
508 | unsigned char checksum; |
509 | unsigned char xmitcsum; |
510 | int i; |
511 | int count; |
512 | char ch; |
513 | |
514 | do { |
515 | /* wait around for the start character, ignore all other characters */ |
516 | while ((ch = getDebugChar()) != '$'); |
517 | checksum = 0; |
518 | count = 0; |
519 | |
520 | /* now, read until a # or end of buffer is found */ |
521 | while (count < BUFMAX) { |
522 | ch = getDebugChar(); |
523 | if (ch == '#') break; |
524 | checksum = checksum + ch; |
525 | buffer[count] = ch; |
526 | count = count + 1; |
527 | } |
528 | buffer[count] = 0; |
529 | |
530 | if (ch == '#') { |
531 | xmitcsum = hex(getDebugChar()) << 4; |
532 | xmitcsum += hex(getDebugChar()); |
533 | if ((remote_debug ) && (checksum != xmitcsum)) { |
534 | fprintf(stderr,"bad checksum. My count = 0x%x, sent=0x%x. buf=%s\n", |
535 | checksum,xmitcsum,buffer); |
536 | } |
537 | |
538 | if (checksum != xmitcsum) putDebugChar('-'); /* failed checksum */ |
539 | else { |
540 | putDebugChar('+'); /* successful transfer */ |
541 | /* if a sequence char is present, reply the sequence ID */ |
542 | if (buffer[2] == ':') { |
543 | putDebugChar( buffer[0] ); |
544 | putDebugChar( buffer[1] ); |
545 | /* remove sequence chars from buffer */ |
546 | count = strlen(buffer); |
547 | for (i=3; i <= count; i++) buffer[i-3] = buffer[i]; |
548 | } |
549 | } |
550 | } |
551 | } while (checksum != xmitcsum); |
552 | |
553 | } |
554 | |
555 | /* send the packet in buffer. The host get's one chance to read it. |
556 | This routine does not wait for a positive acknowledge. */ |
557 | |
558 | |
559 | void putpacket(buffer) |
560 | char * buffer; |
561 | { |
562 | unsigned char checksum; |
563 | int count; |
564 | char ch; |
565 | |
566 | /* $<packet info>#<checksum>. */ |
567 | do { |
568 | putDebugChar('$'); |
569 | checksum = 0; |
570 | count = 0; |
571 | |
572 | while (ch=buffer[count]) { |
573 | if (! putDebugChar(ch)) return; |
574 | checksum += ch; |
575 | count += 1; |
576 | } |
577 | |
578 | putDebugChar('#'); |
579 | putDebugChar(hexchars[checksum >> 4]); |
580 | putDebugChar(hexchars[checksum % 16]); |
581 | |
582 | } while (1 == 0); /* (getDebugChar() != '+'); */ |
583 | |
584 | } |
585 | |
586 | static char inbuffer[BUFMAX]; |
587 | static char outbuffer[BUFMAX]; |
588 | static short error; |
589 | |
590 | |
591 | void debug_error(format, parm) |
592 | char * format; |
593 | char * parm; |
594 | { |
595 | if (remote_debug) fprintf(stderr,format,parm); |
596 | } |
597 | |
598 | /* convert the memory pointed to by mem into hex, placing result in buf */ |
599 | /* return a pointer to the last char put in buf (null) */ |
600 | char* mem2hex(mem, buf, count) |
601 | char* mem; |
602 | char* buf; |
603 | int count; |
604 | { |
605 | int i; |
606 | unsigned char ch; |
607 | for (i=0;i<count;i++) { |
608 | ch = *mem++; |
609 | *buf++ = hexchars[ch >> 4]; |
610 | *buf++ = hexchars[ch % 16]; |
611 | } |
612 | *buf = 0; |
613 | return(buf); |
614 | } |
615 | |
616 | /* convert the hex array pointed to by buf into binary to be placed in mem */ |
617 | /* return a pointer to the character AFTER the last byte written */ |
618 | char* hex2mem(buf, mem, count) |
619 | char* buf; |
620 | char* mem; |
621 | int count; |
622 | { |
623 | int i; |
624 | unsigned char ch; |
625 | for (i=0;i<count;i++) { |
626 | ch = hex(*buf++) << 4; |
627 | ch = ch + hex(*buf++); |
628 | *mem++ = ch; |
629 | } |
630 | return(mem); |
631 | } |
632 | |
633 | /* a bus error has occurred, perform a longjmp |
634 | to return execution and allow handling of the error */ |
635 | |
636 | void handle_buserror() |
637 | { |
638 | longjmp(env,1); |
639 | } |
640 | |
641 | /* this function takes the 68000 exception number and attempts to |
642 | translate this number into a unix compatible signal value */ |
643 | int computeSignal( exceptionVector ) |
644 | int exceptionVector; |
645 | { |
646 | int sigval; |
647 | switch (exceptionVector) { |
648 | case 2 : sigval = 10; break; /* bus error */ |
649 | case 3 : sigval = 10; break; /* address error */ |
650 | case 4 : sigval = 4; break; /* illegal instruction */ |
651 | case 5 : sigval = 8; break; /* zero divide */ |
652 | case 6 : sigval = 16; break; /* chk instruction */ |
653 | case 7 : sigval = 16; break; /* trapv instruction */ |
654 | case 8 : sigval = 11; break; /* privilege violation */ |
655 | case 9 : sigval = 5; break; /* trace trap */ |
656 | case 10: sigval = 4; break; /* line 1010 emulator */ |
657 | case 11: sigval = 4; break; /* line 1111 emulator */ |
658 | case 31: sigval = 2; break; /* interrupt */ |
659 | case 33: sigval = 5; break; /* breakpoint */ |
660 | case 40: sigval = 8; break; /* floating point err */ |
661 | case 48: sigval = 8; break; /* floating point err */ |
662 | case 49: sigval = 8; break; /* floating point err */ |
663 | case 50: sigval = 8; break; /* zero divide */ |
664 | case 51: sigval = 8; break; /* underflow */ |
665 | case 52: sigval = 8; break; /* operand error */ |
666 | case 53: sigval = 8; break; /* overflow */ |
667 | case 54: sigval = 8; break; /* NAN */ |
668 | default: |
669 | sigval = 7; /* "software generated"*/ |
670 | } |
671 | return (sigval); |
672 | } |
673 | |
674 | /* |
675 | * This function does all command procesing for interfacing to gdb. |
676 | */ |
677 | void handle_exception(int exceptionVector) |
678 | { |
679 | int sigval; |
680 | int addr, length; |
681 | char * ptr; |
682 | int newPC; |
683 | Frame *frame; |
684 | |
685 | if (remote_debug) printf("vector=%d, sr=0x%x, pc=0x%x\n", |
686 | exceptionVector, |
687 | registers[ PS ], |
688 | registers[ PC ]); |
689 | |
690 | /* reply to host that an exception has occurred */ |
691 | sigval = computeSignal( exceptionVector ); |
692 | sprintf(outbuffer,"S%02x",sigval); |
693 | putpacket(outbuffer); |
694 | |
695 | while (1==1) { |
696 | error = 0; |
697 | outbuffer[0] = 0; |
698 | getpacket(inbuffer); |
699 | switch (inbuffer[0]) { |
700 | case '?' : sprintf(outbuffer,"S%02x",sigval); |
701 | break; |
702 | case 'd' : remote_debug = !(remote_debug); /* toggle debug flag */ |
703 | break; |
704 | case 'g' : /* return the value of the CPU registers */ |
705 | mem2hex((char*) registers, outbuffer, NUMREGBYTES); |
706 | break; |
707 | case 'G' : /* set the value of the CPU registers - return OK */ |
708 | hex2mem(&inbuffer[1], (char*) registers, NUMREGBYTES); |
709 | strcpy(outbuffer,"OK"); |
710 | break; |
711 | |
712 | /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ |
713 | case 'm' : |
714 | if (setjmp(env) == 0) { |
715 | exceptionHandler(2,handle_buserror); |
716 | |
717 | if (2 == sscanf(&inbuffer[1],"%x,%x",&addr,&length)) { |
718 | mem2hex((char*) addr, outbuffer, length); |
719 | } |
720 | else { |
721 | strcpy(outbuffer,"E01"); |
722 | debug_error("malformed read memory command: %s",inbuffer); |
723 | } |
724 | } |
725 | else { |
726 | exceptionHandler(2,_catchException); |
727 | strcpy(outbuffer,"E03"); |
728 | debug_error("bus error"); |
729 | } |
730 | |
731 | /* restore handler for bus error */ |
732 | exceptionHandler(2,_catchException); |
733 | break; |
734 | |
735 | /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */ |
736 | case 'M' : |
737 | if (setjmp(env) == 0) { |
738 | exceptionHandler(2,handle_buserror); |
739 | |
740 | if (2 == sscanf(&inbuffer[1],"%x,%x:",&addr,&length)) { |
741 | ptr = strchr(inbuffer,':'); |
742 | ptr += 1; /* point 1 past the colon */ |
743 | hex2mem(ptr, (char*) addr, length); |
744 | strcpy(outbuffer,"OK"); |
745 | } |
746 | else { |
747 | strcpy(outbuffer,"E02"); |
748 | debug_error("malformed write memory command: %s",inbuffer); |
749 | } |
750 | } |
751 | else { |
752 | exceptionHandler(2,_catchException); |
753 | strcpy(outbuffer,"E03"); |
754 | debug_error("bus error"); |
755 | } |
756 | break; |
757 | |
758 | /* cAA..AA Continue at address AA..AA(optional) */ |
759 | /* sAA..AA Step one instruction from AA..AA(optional) */ |
760 | case 'c' : |
761 | case 's' : |
762 | /* try to read optional parameter, addr unchanged if no parm */ |
763 | if (1 == sscanf(&inbuffer[1],"%x",®isters[ PC ])); |
764 | newPC = registers[ PC]; |
765 | |
766 | /* clear the trace bit */ |
767 | registers[ PS ] &= 0x7fff; |
768 | |
769 | /* set the trace bit if we're stepping */ |
770 | if (inbuffer[0] == 's') registers[ PS ] |= 0x8000; |
771 | |
772 | /* |
773 | * look for newPC in the linked list of exception frames. |
774 | * if it is found, use the old frame it. otherwise, |
775 | * fake up a dummy frame in returnFromException(). |
776 | */ |
777 | if (remote_debug) printf("new pc = 0x%x\n",newPC); |
778 | frame = lastFrame; |
779 | while (frame) |
780 | { |
781 | if (remote_debug) |
782 | printf("frame at 0x%x has pc=0x%x, except#=%d\n", |
783 | frame,frame->exceptionPC, |
784 | frame->exceptionVector); |
785 | if (frame->exceptionPC == newPC) break; /* bingo! a match */ |
786 | /* |
787 | * for a breakpoint instruction, the saved pc may |
788 | * be off by two due to re-executing the instruction |
789 | * replaced by the trap instruction. Check for this. |
790 | */ |
791 | if ((frame->exceptionVector == 33) && |
792 | (frame->exceptionPC == (newPC+2))) break; |
793 | frame = frame->previous; |
794 | } |
795 | |
796 | /* |
797 | * If we found a match for the PC AND we are not returning |
798 | * as a result of a breakpoint (33), |
799 | * trace exception (9), nmi (31), jmp to |
800 | * the old exception handler as if this code never ran. |
801 | */ |
802 | if (frame) |
803 | { |
804 | if ((frame->exceptionVector != 9) && |
805 | (frame->exceptionVector != 31) && |
806 | (frame->exceptionVector != 33)) |
807 | { |
808 | /* |
809 | * invoke the previous handler. |
810 | */ |
811 | if (oldExceptionHook) |
812 | (*oldExceptionHook) (frame->exceptionVector); |
813 | newPC = registers[ PC ]; /* pc may have changed */ |
814 | if (newPC != frame->exceptionPC) |
815 | { |
816 | if (remote_debug) |
817 | printf("frame at 0x%x has pc=0x%x, except#=%d\n", |
818 | frame,frame->exceptionPC, |
819 | frame->exceptionVector); |
820 | /* dispose of this frame, we're skipping it (longjump?)*/ |
821 | lastFrame = frame->previous; |
822 | frame = (Frame *) 0; |
823 | } |
824 | } |
825 | } |
826 | |
827 | _returnFromException( frame ); |
828 | |
829 | break; |
830 | |
831 | /* kill the program */ |
832 | case 'k' : /* do nothing */ |
833 | break; |
834 | } /* switch */ |
835 | |
836 | /* reply to the request */ |
837 | putpacket(outbuffer); |
838 | } |
839 | } |
840 | |
841 | |
842 | /* this function is used to set up exception handlers for tracing and |
843 | breakpoints */ |
844 | void set_debug_traps() |
845 | { |
846 | extern void _debug_level7(); |
847 | extern void remcomHandler(); |
848 | int exception; |
849 | |
850 | for (exception = 2; exception <= 23; exception++) |
851 | exceptionHandler(exception,_catchException); |
852 | |
853 | /* level 7 interrupt */ |
854 | exceptionHandler(31,_debug_level7); |
855 | |
856 | /* breakpoint exception (trap #1) */ |
857 | exceptionHandler(33,_catchException); |
858 | |
859 | /* floating point error (trap #8) */ |
860 | exceptionHandler(40,_catchException); |
861 | |
862 | /* 48 to 54 are floating point coprocessor errors */ |
863 | for (exception = 48; exception <= 54; exception++) |
864 | exceptionHandler(exception,_catchException); |
865 | |
866 | if (oldExceptionHook != remcomHandler) |
867 | { |
868 | oldExceptionHook = exceptionHook; |
869 | exceptionHook = remcomHandler; |
870 | } |
871 | |
872 | initialized = 1; |
873 | |
874 | lastFrame = (Frame *) &frameStack[FRAMESIZE-1]; |
875 | lastFrame->previous = (Frame *) 0; |
876 | } |
877 | |
878 | /* This function will generate a breakpoint exception. It is used at the |
879 | beginning of a program to sync up with a debugger and can be used |
880 | otherwise as a quick means to stop program execution and "break" into |
881 | the debugger. */ |
882 | |
883 | void breakpoint() |
884 | { |
885 | if (initialized) BREAKPOINT(); |
886 | } |
887 | |
888 | @EOF |
889 | |
890 | chmod 444 remcom.c |
891 | |
892 | exit 0 |
893 | |