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c906108c SS |
1 | /**************************************************************************** |
2 | ||
3 | THIS SOFTWARE IS NOT COPYRIGHTED | |
4 | ||
5 | HP offers the following for use in the public domain. HP makes no | |
6 | warranty with regard to the software or it's performance and the | |
7 | user accepts the software "AS IS" with all faults. | |
8 | ||
9 | HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD | |
10 | TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES | |
11 | OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. | |
12 | ||
13 | ****************************************************************************/ | |
14 | ||
15 | /**************************************************************************** | |
16 | * Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $ | |
17 | * | |
18 | * Module name: remcom.c $ | |
19 | * Revision: 1.34 $ | |
20 | * Date: 91/03/09 12:29:49 $ | |
21 | * Contributor: Lake Stevens Instrument Division$ | |
22 | * | |
23 | * Description: low level support for gdb debugger. $ | |
24 | * | |
25 | * Considerations: only works on target hardware $ | |
26 | * | |
27 | * Written by: Glenn Engel $ | |
28 | * ModuleState: Experimental $ | |
29 | * | |
30 | * NOTES: See Below $ | |
31 | * | |
32 | * To enable debugger support, two things need to happen. One, a | |
33 | * call to set_debug_traps() is necessary in order to allow any breakpoints | |
34 | * or error conditions to be properly intercepted and reported to gdb. | |
35 | * Two, a breakpoint needs to be generated to begin communication. This | |
36 | * is most easily accomplished by a call to breakpoint(). Breakpoint() | |
37 | * simulates a breakpoint by executing a trap #1. The breakpoint instruction | |
38 | * is hardwired to trap #1 because not to do so is a compatibility problem-- | |
39 | * there either should be a standard breakpoint instruction, or the protocol | |
40 | * should be extended to provide some means to communicate which breakpoint | |
41 | * instruction is in use (or have the stub insert the breakpoint). | |
42 | * | |
43 | * Some explanation is probably necessary to explain how exceptions are | |
44 | * handled. When an exception is encountered the 68000 pushes the current | |
45 | * program counter and status register onto the supervisor stack and then | |
46 | * transfers execution to a location specified in it's vector table. | |
47 | * The handlers for the exception vectors are hardwired to jmp to an address | |
48 | * given by the relation: (exception - 256) * 6. These are decending | |
49 | * addresses starting from -6, -12, -18, ... By allowing 6 bytes for | |
50 | * each entry, a jsr, jmp, bsr, ... can be used to enter the exception | |
51 | * handler. Using a jsr to handle an exception has an added benefit of | |
52 | * allowing a single handler to service several exceptions and use the | |
53 | * return address as the key differentiation. The vector number can be | |
54 | * computed from the return address by [ exception = (addr + 1530) / 6 ]. | |
55 | * The sole purpose of the routine _catchException is to compute the | |
56 | * exception number and push it on the stack in place of the return address. | |
57 | * The external function exceptionHandler() is | |
58 | * used to attach a specific handler to a specific m68k exception. | |
59 | * For 68020 machines, the ability to have a return address around just | |
60 | * so the vector can be determined is not necessary because the '020 pushes an | |
61 | * extra word onto the stack containing the vector offset | |
62 | * | |
63 | * Because gdb will sometimes write to the stack area to execute function | |
64 | * calls, this program cannot rely on using the supervisor stack so it | |
65 | * uses it's own stack area reserved in the int array remcomStack. | |
66 | * | |
67 | ************* | |
68 | * | |
69 | * The following gdb commands are supported: | |
70 | * | |
71 | * command function Return value | |
72 | * | |
73 | * g return the value of the CPU registers hex data or ENN | |
74 | * G set the value of the CPU registers OK or ENN | |
75 | * | |
76 | * mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN | |
77 | * MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN | |
78 | * | |
79 | * c Resume at current address SNN ( signal NN) | |
80 | * cAA..AA Continue at address AA..AA SNN | |
81 | * | |
82 | * s Step one instruction SNN | |
83 | * sAA..AA Step one instruction from AA..AA SNN | |
84 | * | |
85 | * k kill | |
86 | * | |
87 | * ? What was the last sigval ? SNN (signal NN) | |
88 | * | |
89 | * All commands and responses are sent with a packet which includes a | |
90 | * checksum. A packet consists of | |
91 | * | |
92 | * $<packet info>#<checksum>. | |
93 | * | |
94 | * where | |
95 | * <packet info> :: <characters representing the command or response> | |
96 | * <checksum> :: < two hex digits computed as modulo 256 sum of <packetinfo>> | |
97 | * | |
98 | * When a packet is received, it is first acknowledged with either '+' or '-'. | |
99 | * '+' indicates a successful transfer. '-' indicates a failed transfer. | |
100 | * | |
101 | * Example: | |
102 | * | |
103 | * Host: Reply: | |
104 | * $m0,10#2a +$00010203040506070809101112131415#42 | |
105 | * | |
106 | ****************************************************************************/ | |
107 | ||
108 | #include <stdio.h> | |
109 | #include <string.h> | |
110 | #include <setjmp.h> | |
111 | ||
112 | /************************************************************************ | |
113 | * | |
114 | * external low-level support routines | |
115 | */ | |
116 | typedef void (*ExceptionHook)(int); /* pointer to function with int parm */ | |
117 | typedef void (*Function)(); /* pointer to a function */ | |
118 | ||
119 | extern void putDebugChar(); /* write a single character */ | |
120 | extern int getDebugChar(); /* read and return a single char */ | |
121 | ||
122 | extern Function exceptionHandler(); /* assign an exception handler */ | |
123 | extern ExceptionHook exceptionHook; /* hook variable for errors/exceptions */ | |
124 | ||
125 | /************************/ | |
126 | /* FORWARD DECLARATIONS */ | |
127 | /************************/ | |
128 | static void | |
129 | initializeRemcomErrorFrame (); | |
130 | ||
131 | /************************************************************************/ | |
132 | /* BUFMAX defines the maximum number of characters in inbound/outbound buffers*/ | |
133 | /* at least NUMREGBYTES*2 are needed for register packets */ | |
134 | #define BUFMAX 400 | |
135 | ||
136 | static char initialized; /* boolean flag. != 0 means we've been initialized */ | |
137 | ||
138 | int remote_debug; | |
139 | /* debug > 0 prints ill-formed commands in valid packets & checksum errors */ | |
140 | ||
141 | static const char hexchars[]="0123456789abcdef"; | |
142 | ||
143 | /* there are 180 bytes of registers on a 68020 w/68881 */ | |
144 | /* many of the fpa registers are 12 byte (96 bit) registers */ | |
145 | #define NUMREGBYTES 180 | |
146 | enum regnames {D0,D1,D2,D3,D4,D5,D6,D7, | |
147 | A0,A1,A2,A3,A4,A5,A6,A7, | |
148 | PS,PC, | |
149 | FP0,FP1,FP2,FP3,FP4,FP5,FP6,FP7, | |
150 | FPCONTROL,FPSTATUS,FPIADDR | |
151 | }; | |
152 | ||
153 | \f | |
154 | /* We keep a whole frame cache here. "Why?", I hear you cry, "doesn't | |
155 | GDB handle that sort of thing?" Well, yes, I believe the only | |
156 | reason for this cache is to save and restore floating point state | |
157 | (fsave/frestore). A cleaner way to do this would be to make the | |
158 | fsave data part of the registers which GDB deals with like any | |
159 | other registers. This should not be a performance problem if the | |
160 | ability to read individual registers is added to the protocol. */ | |
161 | ||
162 | typedef struct FrameStruct | |
163 | { | |
164 | struct FrameStruct *previous; | |
165 | int exceptionPC; /* pc value when this frame created */ | |
166 | int exceptionVector; /* cpu vector causing exception */ | |
167 | short frameSize; /* size of cpu frame in words */ | |
168 | short sr; /* for 68000, this not always sr */ | |
169 | int pc; | |
170 | short format; | |
171 | int fsaveHeader; | |
172 | int morejunk[0]; /* exception frame, fp save... */ | |
173 | } Frame; | |
174 | ||
175 | #define FRAMESIZE 500 | |
176 | int gdbFrameStack[FRAMESIZE]; | |
177 | static Frame *lastFrame; | |
178 | ||
179 | /* | |
180 | * these should not be static cuz they can be used outside this module | |
181 | */ | |
182 | int registers[NUMREGBYTES/4]; | |
183 | int superStack; | |
184 | ||
185 | #define STACKSIZE 10000 | |
186 | int remcomStack[STACKSIZE/sizeof(int)]; | |
187 | static int* stackPtr = &remcomStack[STACKSIZE/sizeof(int) - 1]; | |
188 | ||
189 | /* | |
190 | * In many cases, the system will want to continue exception processing | |
191 | * when a continue command is given. | |
192 | * oldExceptionHook is a function to invoke in this case. | |
193 | */ | |
194 | ||
195 | static ExceptionHook oldExceptionHook; | |
196 | ||
197 | #ifdef mc68020 | |
198 | /* the size of the exception stack on the 68020 varies with the type of | |
199 | * exception. The following table is the number of WORDS used | |
200 | * for each exception format. | |
201 | */ | |
202 | const short exceptionSize[] = { 4,4,6,4,4,4,4,4,29,10,16,46,12,4,4,4 }; | |
203 | #endif | |
204 | ||
205 | #ifdef mc68332 | |
206 | static const short exceptionSize[] = { 4,4,6,4,4,4,4,4,4,4,4,4,16,4,4,4 }; | |
207 | #endif | |
208 | ||
209 | /************* jump buffer used for setjmp/longjmp **************************/ | |
210 | jmp_buf remcomEnv; | |
211 | ||
212 | /*************************** ASSEMBLY CODE MACROS *************************/ | |
213 | /* */ | |
214 | ||
215 | #ifdef __HAVE_68881__ | |
216 | /* do an fsave, then remember the address to begin a restore from */ | |
217 | #define SAVE_FP_REGS() asm(" fsave a0@-"); \ | |
218 | asm(" fmovemx fp0-fp7,_registers+72"); \ | |
219 | asm(" fmoveml fpcr/fpsr/fpi,_registers+168"); | |
220 | #define RESTORE_FP_REGS() \ | |
221 | asm(" \n\ | |
222 | fmoveml _registers+168,fpcr/fpsr/fpi \n\ | |
223 | fmovemx _registers+72,fp0-fp7 \n\ | |
224 | cmpl #-1,a0@ | skip frestore flag set ? \n\ | |
225 | beq skip_frestore \n\ | |
226 | frestore a0@+ \n\ | |
227 | skip_frestore: \n\ | |
228 | "); | |
229 | ||
230 | #else | |
231 | #define SAVE_FP_REGS() | |
232 | #define RESTORE_FP_REGS() | |
233 | #endif /* __HAVE_68881__ */ | |
234 | ||
235 | void return_to_super(); | |
236 | void return_to_user(); | |
237 | ||
238 | asm(" | |
239 | .text | |
240 | .globl _return_to_super | |
241 | _return_to_super: | |
242 | movel _registers+60,sp /* get new stack pointer */ | |
243 | movel _lastFrame,a0 /* get last frame info */ | |
244 | bra return_to_any | |
245 | ||
246 | .globl _return_to_user | |
247 | _return_to_user: | |
248 | movel _registers+60,a0 /* get usp */ | |
249 | movel a0,usp /* set usp */ | |
250 | movel _superStack,sp /* get original stack pointer */ | |
251 | ||
252 | return_to_any: | |
253 | movel _lastFrame,a0 /* get last frame info */ | |
254 | movel a0@+,_lastFrame /* link in previous frame */ | |
255 | addql #8,a0 /* skip over pc, vector#*/ | |
256 | movew a0@+,d0 /* get # of words in cpu frame */ | |
257 | addw d0,a0 /* point to end of data */ | |
258 | addw d0,a0 /* point to end of data */ | |
259 | movel a0,a1 | |
260 | # | |
261 | # copy the stack frame | |
262 | subql #1,d0 | |
263 | copyUserLoop: | |
264 | movew a1@-,sp@- | |
265 | dbf d0,copyUserLoop | |
266 | "); | |
267 | RESTORE_FP_REGS() | |
268 | asm(" moveml _registers,d0-d7/a0-a6"); | |
269 | asm(" rte"); /* pop and go! */ | |
270 | ||
271 | #define DISABLE_INTERRUPTS() asm(" oriw #0x0700,sr"); | |
272 | #define BREAKPOINT() asm(" trap #1"); | |
273 | ||
274 | /* this function is called immediately when a level 7 interrupt occurs */ | |
275 | /* if the previous interrupt level was 7 then we're already servicing */ | |
276 | /* this interrupt and an rte is in order to return to the debugger. */ | |
277 | /* For the 68000, the offset for sr is 6 due to the jsr return address */ | |
278 | asm(" | |
279 | .text | |
280 | .globl __debug_level7 | |
281 | __debug_level7: | |
282 | movew d0,sp@-"); | |
283 | #if defined (mc68020) || defined (mc68332) | |
284 | asm(" movew sp@(2),d0"); | |
285 | #else | |
286 | asm(" movew sp@(6),d0"); | |
287 | #endif | |
288 | asm(" andiw #0x700,d0 | |
289 | cmpiw #0x700,d0 | |
290 | beq _already7 | |
291 | movew sp@+,d0 | |
292 | bra __catchException | |
293 | _already7: | |
294 | movew sp@+,d0"); | |
295 | #if !defined (mc68020) && !defined (mc68332) | |
296 | asm(" lea sp@(4),sp"); /* pull off 68000 return address */ | |
297 | #endif | |
298 | asm(" rte"); | |
299 | ||
300 | extern void _catchException (); | |
301 | ||
302 | #if defined (mc68020) || defined (mc68332) | |
303 | /* This function is called when a 68020 exception occurs. It saves | |
304 | * all the cpu and fpcp regs in the _registers array, creates a frame on a | |
305 | * linked list of frames which has the cpu and fpcp stack frames needed | |
306 | * to properly restore the context of these processors, and invokes | |
307 | * an exception handler (remcom_handler). | |
308 | * | |
309 | * stack on entry: stack on exit: | |
310 | * N bytes of junk exception # MSWord | |
311 | * Exception Format Word exception # MSWord | |
312 | * Program counter LSWord | |
313 | * Program counter MSWord | |
314 | * Status Register | |
315 | * | |
316 | * | |
317 | */ | |
318 | asm(" | |
319 | .text | |
320 | .globl __catchException | |
321 | __catchException:"); | |
322 | DISABLE_INTERRUPTS(); | |
323 | asm(" | |
324 | moveml d0-d7/a0-a6,_registers /* save registers */ | |
325 | movel _lastFrame,a0 /* last frame pointer */ | |
326 | "); | |
327 | SAVE_FP_REGS(); | |
328 | asm(" | |
329 | lea _registers,a5 /* get address of registers */ | |
330 | movew sp@,d1 /* get status register */ | |
331 | movew d1,a5@(66) /* save sr */ | |
332 | movel sp@(2),a4 /* save pc in a4 for later use */ | |
333 | movel a4,a5@(68) /* save pc in _regisers[] */ | |
334 | ||
335 | # | |
336 | # figure out how many bytes in the stack frame | |
337 | movew sp@(6),d0 /* get '020 exception format */ | |
338 | movew d0,d2 /* make a copy of format word */ | |
339 | andiw #0xf000,d0 /* mask off format type */ | |
340 | rolw #5,d0 /* rotate into the low byte *2 */ | |
341 | lea _exceptionSize,a1 | |
342 | addw d0,a1 /* index into the table */ | |
343 | movew a1@,d0 /* get number of words in frame */ | |
344 | movew d0,d3 /* save it */ | |
345 | subw d0,a0 /* adjust save pointer */ | |
346 | subw d0,a0 /* adjust save pointer(bytes) */ | |
347 | movel a0,a1 /* copy save pointer */ | |
348 | subql #1,d0 /* predecrement loop counter */ | |
349 | # | |
350 | # copy the frame | |
351 | saveFrameLoop: | |
352 | movew sp@+,a1@+ | |
353 | dbf d0,saveFrameLoop | |
354 | # | |
355 | # now that the stack has been clenaed, | |
356 | # save the a7 in use at time of exception | |
357 | movel sp,_superStack /* save supervisor sp */ | |
358 | andiw #0x2000,d1 /* were we in supervisor mode ? */ | |
359 | beq userMode | |
360 | movel a7,a5@(60) /* save a7 */ | |
361 | bra a7saveDone | |
362 | userMode: | |
363 | movel usp,a1 | |
364 | movel a1,a5@(60) /* save user stack pointer */ | |
365 | a7saveDone: | |
366 | ||
367 | # | |
368 | # save size of frame | |
369 | movew d3,a0@- | |
370 | ||
371 | # | |
372 | # compute exception number | |
373 | andl #0xfff,d2 /* mask off vector offset */ | |
374 | lsrw #2,d2 /* divide by 4 to get vect num */ | |
375 | movel d2,a0@- /* save it */ | |
376 | # | |
377 | # save pc causing exception | |
378 | movel a4,a0@- | |
379 | # | |
380 | # save old frame link and set the new value | |
381 | movel _lastFrame,a1 /* last frame pointer */ | |
382 | movel a1,a0@- /* save pointer to prev frame */ | |
383 | movel a0,_lastFrame | |
384 | ||
385 | movel d2,sp@- /* push exception num */ | |
386 | movel _exceptionHook,a0 /* get address of handler */ | |
387 | jbsr a0@ /* and call it */ | |
388 | clrl sp@ /* replace exception num parm with frame ptr */ | |
389 | jbsr __returnFromException /* jbsr, but never returns */ | |
390 | "); | |
391 | #else /* mc68000 */ | |
392 | /* This function is called when an exception occurs. It translates the | |
393 | * return address found on the stack into an exception vector # which | |
394 | * is then handled by either handle_exception or a system handler. | |
395 | * _catchException provides a front end for both. | |
396 | * | |
397 | * stack on entry: stack on exit: | |
398 | * Program counter MSWord exception # MSWord | |
399 | * Program counter LSWord exception # MSWord | |
400 | * Status Register | |
401 | * Return Address MSWord | |
402 | * Return Address LSWord | |
403 | */ | |
404 | asm(" | |
405 | .text | |
406 | .globl __catchException | |
407 | __catchException:"); | |
408 | DISABLE_INTERRUPTS(); | |
409 | asm(" | |
410 | moveml d0-d7/a0-a6,_registers /* save registers */ | |
411 | movel _lastFrame,a0 /* last frame pointer */ | |
412 | "); | |
413 | SAVE_FP_REGS(); | |
414 | asm(" | |
415 | lea _registers,a5 /* get address of registers */ | |
416 | movel sp@+,d2 /* pop return address */ | |
417 | addl #1530,d2 /* convert return addr to */ | |
418 | divs #6,d2 /* exception number */ | |
419 | extl d2 | |
420 | ||
421 | moveql #3,d3 /* assume a three word frame */ | |
422 | ||
423 | cmpiw #3,d2 /* bus error or address error ? */ | |
424 | bgt normal /* if >3 then normal error */ | |
425 | movel sp@+,a0@- /* copy error info to frame buff*/ | |
426 | movel sp@+,a0@- /* these are never used */ | |
427 | moveql #7,d3 /* this is a 7 word frame */ | |
428 | ||
429 | normal: | |
430 | movew sp@+,d1 /* pop status register */ | |
431 | movel sp@+,a4 /* pop program counter */ | |
432 | movew d1,a5@(66) /* save sr */ | |
433 | movel a4,a5@(68) /* save pc in _regisers[] */ | |
434 | movel a4,a0@- /* copy pc to frame buffer */ | |
435 | movew d1,a0@- /* copy sr to frame buffer */ | |
436 | ||
437 | movel sp,_superStack /* save supervisor sp */ | |
438 | ||
439 | andiw #0x2000,d1 /* were we in supervisor mode ? */ | |
440 | beq userMode | |
441 | movel a7,a5@(60) /* save a7 */ | |
442 | bra saveDone | |
443 | userMode: | |
444 | movel usp,a1 /* save user stack pointer */ | |
445 | movel a1,a5@(60) /* save user stack pointer */ | |
446 | saveDone: | |
447 | ||
448 | movew d3,a0@- /* push frame size in words */ | |
449 | movel d2,a0@- /* push vector number */ | |
450 | movel a4,a0@- /* push exception pc */ | |
451 | ||
452 | # | |
453 | # save old frame link and set the new value | |
454 | movel _lastFrame,a1 /* last frame pointer */ | |
455 | movel a1,a0@- /* save pointer to prev frame */ | |
456 | movel a0,_lastFrame | |
457 | ||
458 | movel d2,sp@- /* push exception num */ | |
459 | movel _exceptionHook,a0 /* get address of handler */ | |
460 | jbsr a0@ /* and call it */ | |
461 | clrl sp@ /* replace exception num parm with frame ptr */ | |
462 | jbsr __returnFromException /* jbsr, but never returns */ | |
463 | "); | |
464 | #endif | |
465 | ||
466 | ||
467 | /* | |
468 | * remcomHandler is a front end for handle_exception. It moves the | |
469 | * stack pointer into an area reserved for debugger use in case the | |
470 | * breakpoint happened in supervisor mode. | |
471 | */ | |
472 | asm("_remcomHandler:"); | |
473 | asm(" addl #4,sp"); /* pop off return address */ | |
474 | asm(" movel sp@+,d0"); /* get the exception number */ | |
475 | asm(" movel _stackPtr,sp"); /* move to remcom stack area */ | |
476 | asm(" movel d0,sp@-"); /* push exception onto stack */ | |
477 | asm(" jbsr _handle_exception"); /* this never returns */ | |
478 | asm(" rts"); /* return */ | |
479 | ||
480 | void _returnFromException( Frame *frame ) | |
481 | { | |
482 | /* if no passed in frame, use the last one */ | |
483 | if (! frame) | |
484 | { | |
485 | frame = lastFrame; | |
486 | frame->frameSize = 4; | |
487 | frame->format = 0; | |
488 | frame->fsaveHeader = -1; /* restore regs, but we dont have fsave info*/ | |
489 | } | |
490 | ||
491 | #if !defined (mc68020) && !defined (mc68332) | |
492 | /* a 68000 cannot use the internal info pushed onto a bus error | |
493 | * or address error frame when doing an RTE so don't put this info | |
494 | * onto the stack or the stack will creep every time this happens. | |
495 | */ | |
496 | frame->frameSize=3; | |
497 | #endif | |
498 | ||
499 | /* throw away any frames in the list after this frame */ | |
500 | lastFrame = frame; | |
501 | ||
502 | frame->sr = registers[(int) PS]; | |
503 | frame->pc = registers[(int) PC]; | |
504 | ||
505 | if (registers[(int) PS] & 0x2000) | |
506 | { | |
507 | /* return to supervisor mode... */ | |
508 | return_to_super(); | |
509 | } | |
510 | else | |
511 | { /* return to user mode */ | |
512 | return_to_user(); | |
513 | } | |
514 | } | |
515 | ||
516 | int hex(ch) | |
517 | char ch; | |
518 | { | |
519 | if ((ch >= 'a') && (ch <= 'f')) return (ch-'a'+10); | |
520 | if ((ch >= '0') && (ch <= '9')) return (ch-'0'); | |
521 | if ((ch >= 'A') && (ch <= 'F')) return (ch-'A'+10); | |
522 | return (-1); | |
523 | } | |
524 | ||
525 | ||
526 | /* scan for the sequence $<data>#<checksum> */ | |
527 | void getpacket(buffer) | |
528 | char * buffer; | |
529 | { | |
530 | unsigned char checksum; | |
531 | unsigned char xmitcsum; | |
532 | int i; | |
533 | int count; | |
534 | char ch; | |
535 | ||
536 | do { | |
537 | /* wait around for the start character, ignore all other characters */ | |
538 | while ((ch = (getDebugChar() & 0x7f)) != '$'); | |
539 | checksum = 0; | |
540 | xmitcsum = -1; | |
541 | ||
542 | count = 0; | |
543 | ||
544 | /* now, read until a # or end of buffer is found */ | |
545 | while (count < BUFMAX) { | |
546 | ch = getDebugChar() & 0x7f; | |
547 | if (ch == '#') break; | |
548 | checksum = checksum + ch; | |
549 | buffer[count] = ch; | |
550 | count = count + 1; | |
551 | } | |
552 | buffer[count] = 0; | |
553 | ||
554 | if (ch == '#') { | |
555 | xmitcsum = hex(getDebugChar() & 0x7f) << 4; | |
556 | xmitcsum += hex(getDebugChar() & 0x7f); | |
557 | if ((remote_debug ) && (checksum != xmitcsum)) { | |
558 | fprintf (stderr,"bad checksum. My count = 0x%x, sent=0x%x. buf=%s\n", | |
559 | checksum,xmitcsum,buffer); | |
560 | } | |
561 | ||
562 | if (checksum != xmitcsum) putDebugChar('-'); /* failed checksum */ | |
563 | else { | |
564 | putDebugChar('+'); /* successful transfer */ | |
565 | /* if a sequence char is present, reply the sequence ID */ | |
566 | if (buffer[2] == ':') { | |
567 | putDebugChar( buffer[0] ); | |
568 | putDebugChar( buffer[1] ); | |
569 | /* remove sequence chars from buffer */ | |
570 | count = strlen(buffer); | |
571 | for (i=3; i <= count; i++) buffer[i-3] = buffer[i]; | |
572 | } | |
573 | } | |
574 | } | |
575 | } while (checksum != xmitcsum); | |
576 | ||
577 | } | |
578 | ||
579 | /* send the packet in buffer. The host get's one chance to read it. | |
580 | This routine does not wait for a positive acknowledge. */ | |
581 | ||
582 | ||
583 | void putpacket(buffer) | |
584 | char * buffer; | |
585 | { | |
586 | unsigned char checksum; | |
587 | int count; | |
588 | char ch; | |
589 | ||
590 | /* $<packet info>#<checksum>. */ | |
591 | do { | |
592 | putDebugChar('$'); | |
593 | checksum = 0; | |
594 | count = 0; | |
595 | ||
596 | while (ch=buffer[count]) { | |
597 | putDebugChar(ch); | |
598 | checksum += ch; | |
599 | count += 1; | |
600 | } | |
601 | ||
602 | putDebugChar('#'); | |
603 | putDebugChar(hexchars[checksum >> 4]); | |
604 | putDebugChar(hexchars[checksum % 16]); | |
605 | ||
606 | } while (1 == 0); /* (getDebugChar() != '+'); */ | |
607 | ||
608 | } | |
609 | ||
610 | char remcomInBuffer[BUFMAX]; | |
611 | char remcomOutBuffer[BUFMAX]; | |
612 | static short error; | |
613 | ||
614 | ||
615 | void debug_error(format, parm) | |
616 | char * format; | |
617 | char * parm; | |
618 | { | |
619 | if (remote_debug) fprintf (stderr,format,parm); | |
620 | } | |
621 | ||
622 | /* convert the memory pointed to by mem into hex, placing result in buf */ | |
623 | /* return a pointer to the last char put in buf (null) */ | |
624 | char* mem2hex(mem, buf, count) | |
625 | char* mem; | |
626 | char* buf; | |
627 | int count; | |
628 | { | |
629 | int i; | |
630 | unsigned char ch; | |
631 | for (i=0;i<count;i++) { | |
632 | ch = *mem++; | |
633 | *buf++ = hexchars[ch >> 4]; | |
634 | *buf++ = hexchars[ch % 16]; | |
635 | } | |
636 | *buf = 0; | |
637 | return(buf); | |
638 | } | |
639 | ||
640 | /* convert the hex array pointed to by buf into binary to be placed in mem */ | |
641 | /* return a pointer to the character AFTER the last byte written */ | |
642 | char* hex2mem(buf, mem, count) | |
643 | char* buf; | |
644 | char* mem; | |
645 | int count; | |
646 | { | |
647 | int i; | |
648 | unsigned char ch; | |
649 | for (i=0;i<count;i++) { | |
650 | ch = hex(*buf++) << 4; | |
651 | ch = ch + hex(*buf++); | |
652 | *mem++ = ch; | |
653 | } | |
654 | return(mem); | |
655 | } | |
656 | ||
657 | /* a bus error has occurred, perform a longjmp | |
658 | to return execution and allow handling of the error */ | |
659 | ||
660 | void handle_buserror() | |
661 | { | |
662 | longjmp(remcomEnv,1); | |
663 | } | |
664 | ||
665 | /* this function takes the 68000 exception number and attempts to | |
666 | translate this number into a unix compatible signal value */ | |
667 | int computeSignal( exceptionVector ) | |
668 | int exceptionVector; | |
669 | { | |
670 | int sigval; | |
671 | switch (exceptionVector) { | |
672 | case 2 : sigval = 10; break; /* bus error */ | |
673 | case 3 : sigval = 10; break; /* address error */ | |
674 | case 4 : sigval = 4; break; /* illegal instruction */ | |
675 | case 5 : sigval = 8; break; /* zero divide */ | |
676 | case 6 : sigval = 8; break; /* chk instruction */ | |
677 | case 7 : sigval = 8; break; /* trapv instruction */ | |
678 | case 8 : sigval = 11; break; /* privilege violation */ | |
679 | case 9 : sigval = 5; break; /* trace trap */ | |
680 | case 10: sigval = 4; break; /* line 1010 emulator */ | |
681 | case 11: sigval = 4; break; /* line 1111 emulator */ | |
682 | ||
683 | /* Coprocessor protocol violation. Using a standard MMU or FPU | |
684 | this cannot be triggered by software. Call it a SIGBUS. */ | |
685 | case 13: sigval = 10; break; | |
686 | ||
687 | case 31: sigval = 2; break; /* interrupt */ | |
688 | case 33: sigval = 5; break; /* breakpoint */ | |
689 | ||
690 | /* This is a trap #8 instruction. Apparently it is someone's software | |
691 | convention for some sort of SIGFPE condition. Whose? How many | |
692 | people are being screwed by having this code the way it is? | |
693 | Is there a clean solution? */ | |
694 | case 40: sigval = 8; break; /* floating point err */ | |
695 | ||
696 | case 48: sigval = 8; break; /* floating point err */ | |
697 | case 49: sigval = 8; break; /* floating point err */ | |
698 | case 50: sigval = 8; break; /* zero divide */ | |
699 | case 51: sigval = 8; break; /* underflow */ | |
700 | case 52: sigval = 8; break; /* operand error */ | |
701 | case 53: sigval = 8; break; /* overflow */ | |
702 | case 54: sigval = 8; break; /* NAN */ | |
703 | default: | |
704 | sigval = 7; /* "software generated"*/ | |
705 | } | |
706 | return (sigval); | |
707 | } | |
708 | ||
709 | /**********************************************/ | |
710 | /* WHILE WE FIND NICE HEX CHARS, BUILD AN INT */ | |
711 | /* RETURN NUMBER OF CHARS PROCESSED */ | |
712 | /**********************************************/ | |
713 | int hexToInt(char **ptr, int *intValue) | |
714 | { | |
715 | int numChars = 0; | |
716 | int hexValue; | |
717 | ||
718 | *intValue = 0; | |
719 | ||
720 | while (**ptr) | |
721 | { | |
722 | hexValue = hex(**ptr); | |
723 | if (hexValue >=0) | |
724 | { | |
725 | *intValue = (*intValue <<4) | hexValue; | |
726 | numChars ++; | |
727 | } | |
728 | else | |
729 | break; | |
730 | ||
731 | (*ptr)++; | |
732 | } | |
733 | ||
734 | return (numChars); | |
735 | } | |
736 | ||
737 | /* | |
738 | * This function does all command procesing for interfacing to gdb. | |
739 | */ | |
740 | void handle_exception(int exceptionVector) | |
741 | { | |
742 | int sigval; | |
743 | int addr, length; | |
744 | char * ptr; | |
745 | int newPC; | |
746 | Frame *frame; | |
747 | ||
748 | if (remote_debug) printf("vector=%d, sr=0x%x, pc=0x%x\n", | |
749 | exceptionVector, | |
750 | registers[ PS ], | |
751 | registers[ PC ]); | |
752 | ||
753 | /* reply to host that an exception has occurred */ | |
754 | sigval = computeSignal( exceptionVector ); | |
755 | remcomOutBuffer[0] = 'S'; | |
756 | remcomOutBuffer[1] = hexchars[sigval >> 4]; | |
757 | remcomOutBuffer[2] = hexchars[sigval % 16]; | |
758 | remcomOutBuffer[3] = 0; | |
759 | ||
760 | putpacket(remcomOutBuffer); | |
761 | ||
762 | while (1==1) { | |
763 | error = 0; | |
764 | remcomOutBuffer[0] = 0; | |
765 | getpacket(remcomInBuffer); | |
766 | switch (remcomInBuffer[0]) { | |
767 | case '?' : remcomOutBuffer[0] = 'S'; | |
768 | remcomOutBuffer[1] = hexchars[sigval >> 4]; | |
769 | remcomOutBuffer[2] = hexchars[sigval % 16]; | |
770 | remcomOutBuffer[3] = 0; | |
771 | break; | |
772 | case 'd' : remote_debug = !(remote_debug); /* toggle debug flag */ | |
773 | break; | |
774 | case 'g' : /* return the value of the CPU registers */ | |
775 | mem2hex((char*) registers, remcomOutBuffer, NUMREGBYTES); | |
776 | break; | |
777 | case 'G' : /* set the value of the CPU registers - return OK */ | |
778 | hex2mem(&remcomInBuffer[1], (char*) registers, NUMREGBYTES); | |
779 | strcpy(remcomOutBuffer,"OK"); | |
780 | break; | |
781 | ||
782 | /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ | |
783 | case 'm' : | |
784 | if (setjmp(remcomEnv) == 0) | |
785 | { | |
786 | exceptionHandler(2,handle_buserror); | |
787 | ||
788 | /* TRY TO READ %x,%x. IF SUCCEED, SET PTR = 0 */ | |
789 | ptr = &remcomInBuffer[1]; | |
790 | if (hexToInt(&ptr,&addr)) | |
791 | if (*(ptr++) == ',') | |
792 | if (hexToInt(&ptr,&length)) | |
793 | { | |
794 | ptr = 0; | |
795 | mem2hex((char*) addr, remcomOutBuffer, length); | |
796 | } | |
797 | ||
798 | if (ptr) | |
799 | { | |
800 | strcpy(remcomOutBuffer,"E01"); | |
801 | debug_error("malformed read memory command: %s",remcomInBuffer); | |
802 | } | |
803 | } | |
804 | else { | |
805 | exceptionHandler(2,_catchException); | |
806 | strcpy(remcomOutBuffer,"E03"); | |
807 | debug_error("bus error"); | |
808 | } | |
809 | ||
810 | /* restore handler for bus error */ | |
811 | exceptionHandler(2,_catchException); | |
812 | break; | |
813 | ||
814 | /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */ | |
815 | case 'M' : | |
816 | if (setjmp(remcomEnv) == 0) { | |
817 | exceptionHandler(2,handle_buserror); | |
818 | ||
819 | /* TRY TO READ '%x,%x:'. IF SUCCEED, SET PTR = 0 */ | |
820 | ptr = &remcomInBuffer[1]; | |
821 | if (hexToInt(&ptr,&addr)) | |
822 | if (*(ptr++) == ',') | |
823 | if (hexToInt(&ptr,&length)) | |
824 | if (*(ptr++) == ':') | |
825 | { | |
826 | hex2mem(ptr, (char*) addr, length); | |
827 | ptr = 0; | |
828 | strcpy(remcomOutBuffer,"OK"); | |
829 | } | |
830 | if (ptr) | |
831 | { | |
832 | strcpy(remcomOutBuffer,"E02"); | |
833 | debug_error("malformed write memory command: %s",remcomInBuffer); | |
834 | } | |
835 | } | |
836 | else { | |
837 | exceptionHandler(2,_catchException); | |
838 | strcpy(remcomOutBuffer,"E03"); | |
839 | debug_error("bus error"); | |
840 | } | |
841 | ||
842 | /* restore handler for bus error */ | |
843 | exceptionHandler(2,_catchException); | |
844 | break; | |
845 | ||
846 | /* cAA..AA Continue at address AA..AA(optional) */ | |
847 | /* sAA..AA Step one instruction from AA..AA(optional) */ | |
848 | case 'c' : | |
849 | case 's' : | |
850 | /* try to read optional parameter, pc unchanged if no parm */ | |
851 | ptr = &remcomInBuffer[1]; | |
852 | if (hexToInt(&ptr,&addr)) | |
853 | registers[ PC ] = addr; | |
854 | ||
855 | newPC = registers[ PC]; | |
856 | ||
857 | /* clear the trace bit */ | |
858 | registers[ PS ] &= 0x7fff; | |
859 | ||
860 | /* set the trace bit if we're stepping */ | |
861 | if (remcomInBuffer[0] == 's') registers[ PS ] |= 0x8000; | |
862 | ||
863 | /* | |
864 | * look for newPC in the linked list of exception frames. | |
865 | * if it is found, use the old frame it. otherwise, | |
866 | * fake up a dummy frame in returnFromException(). | |
867 | */ | |
868 | if (remote_debug) printf("new pc = 0x%x\n",newPC); | |
869 | frame = lastFrame; | |
870 | while (frame) | |
871 | { | |
872 | if (remote_debug) | |
873 | printf("frame at 0x%x has pc=0x%x, except#=%d\n", | |
874 | frame,frame->exceptionPC, | |
875 | frame->exceptionVector); | |
876 | if (frame->exceptionPC == newPC) break; /* bingo! a match */ | |
877 | /* | |
878 | * for a breakpoint instruction, the saved pc may | |
879 | * be off by two due to re-executing the instruction | |
880 | * replaced by the trap instruction. Check for this. | |
881 | */ | |
882 | if ((frame->exceptionVector == 33) && | |
883 | (frame->exceptionPC == (newPC+2))) break; | |
884 | if (frame == frame->previous) | |
885 | { | |
886 | frame = 0; /* no match found */ | |
887 | break; | |
888 | } | |
889 | frame = frame->previous; | |
890 | } | |
891 | ||
892 | /* | |
893 | * If we found a match for the PC AND we are not returning | |
894 | * as a result of a breakpoint (33), | |
895 | * trace exception (9), nmi (31), jmp to | |
896 | * the old exception handler as if this code never ran. | |
897 | */ | |
898 | if (frame) | |
899 | { | |
900 | if ((frame->exceptionVector != 9) && | |
901 | (frame->exceptionVector != 31) && | |
902 | (frame->exceptionVector != 33)) | |
903 | { | |
904 | /* | |
905 | * invoke the previous handler. | |
906 | */ | |
907 | if (oldExceptionHook) | |
908 | (*oldExceptionHook) (frame->exceptionVector); | |
909 | newPC = registers[ PC ]; /* pc may have changed */ | |
910 | if (newPC != frame->exceptionPC) | |
911 | { | |
912 | if (remote_debug) | |
913 | printf("frame at 0x%x has pc=0x%x, except#=%d\n", | |
914 | frame,frame->exceptionPC, | |
915 | frame->exceptionVector); | |
916 | /* re-use the last frame, we're skipping it (longjump?)*/ | |
917 | frame = (Frame *) 0; | |
918 | _returnFromException( frame ); /* this is a jump */ | |
919 | } | |
920 | } | |
921 | } | |
922 | ||
923 | /* if we couldn't find a frame, create one */ | |
924 | if (frame == 0) | |
925 | { | |
926 | frame = lastFrame -1 ; | |
927 | ||
928 | /* by using a bunch of print commands with breakpoints, | |
929 | it's possible for the frame stack to creep down. If it creeps | |
930 | too far, give up and reset it to the top. Normal use should | |
931 | not see this happen. | |
932 | */ | |
933 | if ((unsigned int) (frame-2) < (unsigned int) &gdbFrameStack) | |
934 | { | |
935 | initializeRemcomErrorFrame(); | |
936 | frame = lastFrame; | |
937 | } | |
938 | frame->previous = lastFrame; | |
939 | lastFrame = frame; | |
940 | frame = 0; /* null so _return... will properly initialize it */ | |
941 | } | |
942 | ||
943 | _returnFromException( frame ); /* this is a jump */ | |
944 | ||
945 | break; | |
946 | ||
947 | /* kill the program */ | |
948 | case 'k' : /* do nothing */ | |
949 | break; | |
950 | } /* switch */ | |
951 | ||
952 | /* reply to the request */ | |
953 | putpacket(remcomOutBuffer); | |
954 | } | |
955 | } | |
956 | ||
957 | ||
958 | void | |
959 | initializeRemcomErrorFrame() | |
960 | { | |
961 | lastFrame = ((Frame *) &gdbFrameStack[FRAMESIZE-1]) - 1; | |
962 | lastFrame->previous = lastFrame; | |
963 | } | |
964 | ||
965 | /* this function is used to set up exception handlers for tracing and | |
966 | breakpoints */ | |
967 | void set_debug_traps() | |
968 | { | |
969 | extern void _debug_level7(); | |
970 | extern void remcomHandler(); | |
971 | int exception; | |
972 | ||
973 | initializeRemcomErrorFrame(); | |
974 | stackPtr = &remcomStack[STACKSIZE/sizeof(int) - 1]; | |
975 | ||
976 | for (exception = 2; exception <= 23; exception++) | |
977 | exceptionHandler(exception,_catchException); | |
978 | ||
979 | /* level 7 interrupt */ | |
980 | exceptionHandler(31,_debug_level7); | |
981 | ||
982 | /* breakpoint exception (trap #1) */ | |
983 | exceptionHandler(33,_catchException); | |
984 | ||
985 | /* This is a trap #8 instruction. Apparently it is someone's software | |
986 | convention for some sort of SIGFPE condition. Whose? How many | |
987 | people are being screwed by having this code the way it is? | |
988 | Is there a clean solution? */ | |
989 | exceptionHandler(40,_catchException); | |
990 | ||
991 | /* 48 to 54 are floating point coprocessor errors */ | |
992 | for (exception = 48; exception <= 54; exception++) | |
993 | exceptionHandler(exception,_catchException); | |
994 | ||
995 | if (oldExceptionHook != remcomHandler) | |
996 | { | |
997 | oldExceptionHook = exceptionHook; | |
998 | exceptionHook = remcomHandler; | |
999 | } | |
1000 | ||
1001 | initialized = 1; | |
1002 | ||
1003 | } | |
1004 | ||
1005 | /* This function will generate a breakpoint exception. It is used at the | |
1006 | beginning of a program to sync up with a debugger and can be used | |
1007 | otherwise as a quick means to stop program execution and "break" into | |
1008 | the debugger. */ | |
1009 | ||
1010 | void breakpoint() | |
1011 | { | |
1012 | if (initialized) BREAKPOINT(); | |
1013 | } | |
1014 |