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[/] [k68/] [trunk/] [sw/] [mon/] [minimon.s] - Blame information for rev 4

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Line No. Rev Author Line
1 2 sybreon
*        Simplified version of a 68000 monitor
2
*        Designed to run with the Teesside 68K simulator
3
*        Version of 3 October 1996
4
*                                   Symbol equates
5
BS       EQU      $08               Back_space
6
CR       EQU      $0D               Carriage_return
7
LF       EQU      $0A               Line_feed
8
SPACE    EQU      $20               Space
9
WAIT     EQU      'W'               Wait character (to suspend output)
10
CTRL_A   EQU      $01               Control_A forces return to monitor
11
*                                   Device addresses
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X_BASE   EQU      $08               Start of exception vector table
13
TRAP_14  EQU      $4E4E             Code for TRAP #14
14
MAXCHR   EQU      64                Length of input line buffer
15
*
16
DATA     EQU      $00000400         Data origin
17
LNBUFF   DS.B     MAXCHR            Input line buffer
18
BUFFEND  EQU      LNBUFF+MAXCHR-1   End of line buffer
19
BUFFPT   DS.L     1                 Pointer to line buffer
20
PARAMTR  DS.L     1                 Last parameter from line buffer
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ECHO     DS.B     1                 When clear this enable input echo
22
U_CASE   DS.B     1                 Flag for upper case conversion
23
TSK_T    DS.W     37                Frame for D0-D7, A0-A6, USP, SSP, SW, PC
24
BP_TAB   DS.W     24                Breakpoint table
25
*
26
*************************************************************************
27
*
28
*  This is the main program which assembles a command in the line
29
*  buffer, removes leading/embedded spaces and interprets it by matching
30
*  it with a command in the user table or the built-in table COMTAB
31
*  All variables are specified with respect to A6
32
*
33
         ORG      $00001000         Monitor origin
34
RESET    EQU      *                 Cold entry point for monitor
35
         LEA.L    DATA,A6           A6 points to data area
36
         MOVE.B   #1,ECHO(A6)       No automatic character echo
37
         CLR.B    U_CASE(A6)        Clear case conversion flag (UC<-LC)
38
         BSR      X_SET             Setup exception table
39
         LEA.L    BANNER(PC),A4     Point to banner
40
         BSR.S    HEADING           and print heading
41
WARM     CLR.L    D7                Warm entry point - clear error flag
42
         BSR.S    NEWLINE           Print a newline
43
         BSR.S    GETLINE           Get a command line
44
         BSR      EXECUTE           Interpret command
45
         BRA      WARM              Repeat indefinitely
46
*
47
*************************************************************************
48
*
49
*  Some initialization and basic routines
50
*
51
NEWLINE  EQU      *                 Move cursor to start of newline
52
         MOVEM.L  A4,-(A7)          Save A4
53
         LEA.L    CRLF(PC),A4       Point to CR/LF string
54
         BSR.S    PSTRING           Print it
55
         MOVEM.L  (A7)+,A4          Restore A4
56
         RTS                        Return
57
*
58
PSTRING  EQU      *                 Display the string pointed at by A4
59
         MOVE.L   D0,-(A7)          Save D0
60
PS1      MOVE.B   (A4)+,D0          Get character to be printed
61
         BEQ.S    PS2               If null then return
62
         BSR      PUTCHAR           Else print it
63
         BRA      PS1               Continue
64
PS2      MOVE.L   (A7)+,D0          Restore D0 and exit
65
         RTS
66
*
67
HEADING  BSR      NEWLINE           Same as PSTRING but with newline
68
         BSR      PSTRING
69
         BRA      NEWLINE
70
*
71
*************************************************************************
72
*
73
*  GETLINE  inputs a string of characters into a line buffer
74
*           A3 points to next free entry in line buffer
75
*           A2 points to end of buffer
76
*           A1 points to start of buffer
77
*           D0 holds character to be stored
78
*
79
GETLINE  LEA.L    LNBUFF(A6),A1     A1 points to start of line buffer
80
         LEA.L    (A1),A3           A3 points to start (initially)
81
         LEA.L    MAXCHR(A1),A2     A2 points to end of buffer
82
GETLN2   BSR      GETCHAR           Get a character
83
         CMP.B    #CTRL_A,D0        If control_A then reject this line
84
         BEQ.S    GETLN5            and get another line
85
         CMP.B    #BS,D0            If back_space then move back pointer
86
         BNE.S    GETLN3            Else skip past wind-back routine
87
         CMP.L    A1,A3             First check for empty buffer
88
         BEQ      GETLN2            If buffer empty then continue
89
         LEA      -1(A3),A3         Else decrement buffer pointer
90
         BRA      GETLN2            and continue with next character
91
GETLN3   MOVE.B   D0,(A3)+          Store character and update pointer
92
         CMP.B    #CR,D0            Test for command terminator
93
         BNE.S    GETLN4            If not CR then skip past exit
94
         BRA      NEWLINE           Else new line before next operation
95
GETLN4   CMP.L    A2,A3             Test for buffer overflow
96
         BNE      GETLN2            If buffer not full then continue
97
GETLN5   BSR      NEWLINE           Else move to next line and
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         BRA      GETLINE           repeat this routine
99
*
100
*************************************************************************
101
*
102
*  EXECUTE matches the first command in the line buffer with the
103
*  commands in a command table.
104
*
105
EXECUTE  LEA.L    COMTAB(PC),A3     Try built-in command table
106
         BSR.S    SEARCH            Look for command in built-in table
107
         BCS.S    EXEC2             If found then execute command
108
         LEA.L    ERMES2(PC),A4     Else print "invalid command"
109
         BRA.L    PSTRING           and return
110
EXEC2    MOVE.L   (A3),A3           Get the relative command address
111
         LEA.L    COMTAB(PC),A4     pointed at by A3 and add it to
112
         ADD.L    A4,A3             the PC to generate the actual
113
*        JMP      (A3)              command address. Then execute it.
114
         LEA      LNBUFF,A2
115
E3       MOVE.B   (A2)+,D0
116
         CMP.B    #$20,D0
117
         BNE      E3
118
         MOVE.L   A2,BUFFPT(A6)
119
         JMP      (A3)
120
*
121
SEARCH   EQU      *                 Match the command in the line buffer
122
         CLR.L    D0                with command table pointed at by A3
123
         MOVE.B   (A3),D0           Get the first character in the
124
         BEQ.S    SRCH7             current entry. If zero then exit
125
         LEA.L    6(A3,D0.W),A4     Else calculate address of next entry
126
         MOVE.B   1(A3),D1          Get number of characters to match
127
         LEA.L    LNBUFF(A6),A5     A5 points to command in line buffer
128
         MOVE.B   2(A3),D2          Get first character in this entry
129
         CMP.B    (A5)+,D2          from the table and match with buffer
130
         BEQ.S    SRCH3             If match then try rest of string
131
SRCH2    MOVE.L   A4,A3             Else get address of next entry
132
         BRA      SEARCH            and try the next entry in the table
133
SRCH3    SUB.B    #1,D1             One less character to match
134
         BEQ.S    SRCH6             If match counter zero then all done
135
         LEA.L    3(A3),A3          Else point to next character in table
136
SRCH4    MOVE.B   (A3)+,D2          Now match a pair of characters
137
         CMP.B    (A5)+,D2
138
         BNE      SRCH2             If no match then try next entry
139
         SUB.B    #1,D1             Else decrement match counter and
140
         BNE      SRCH4             repeat until no chars left to match
141
SRCH6    LEA.L    -4(A4),A3         Calculate address of command entry
142
         OR.B     #1,CCR            point. Mark carry flag as success
143
         RTS                        and return
144
SRCH7    AND.B    #$FE,CCR          Fail - clear carry to indicate
145
         RTS                        command not found and return
146
*
147
*************************************************************************
148
*
149
*  Basic input routines
150
*  HEX    =  Get one   hexadecimal character  into D0
151
*  BYTE   =  Get two   hexadecimal characters into D0
152
*  WORD   =  Get four  hexadecimal characters into D0
153
*  LONGWD =  Get eight hexadecimal characters into D0
154
*  PARAM  =  Get a longword from the line buffer into D0
155
*  Bit 0 of D7 is set to indicate a hexadecimal input error
156
*
157
HEX      BSR      GETCHAR           Get a character from input device
158
         SUB.B    #$30,D0           Convert to binary
159
         BMI.S    NOT_HEX           If less than $30 then exit with error
160
         CMP.B    #$09,D0           Else test for number (0 to 9)
161
         BLE.S    HEX_OK            If number then exit - success
162
         SUB.B    #$07,D0           Else convert letter to hex
163
         CMP.B    #$0F,D0           If character in range "A" to "F"
164
         BLE.S    HEX_OK            then exit successfully
165
NOT_HEX  OR.B     #1,D7             Else set error flag
166
HEX_OK   RTS                        and return
167
*
168
BYTE     MOVE.L   D1,-(A7)          Save D1
169
         BSR      HEX               Get first hex character
170
         ASL.B    #4,D0             Move it to MS nybble position
171
         MOVE.B   D0,D1             Save MS nybble in D1
172
         BSR      HEX               Get second hex character
173
         ADD.B    D1,D0             Merge MS and LS nybbles
174
         MOVE.L   (A7)+,D1          Restore D1
175
         RTS
176
*
177
WORD     BSR      BYTE              Get upper order byte
178
         ASL.W    #8,D0             Move it to MS position
179
         BRA      BYTE              Get LS byte and return
180
*
181
LONGWD   BSR      WORD              Get upper order word
182
         SWAP     D0                Move it to MS position
183
         BRA      WORD              Get lower order word and return
184
*
185
*  PARAM reads a parameter from the line buffer and puts it in both
186
*  PARAMTR(A6) and D0. Bit 1 of D7 is set on error.
187
*
188
PARAM    MOVE.L   D1,-(A7)          Save D1
189
         CLR.L    D1                Clear input accumulator
190
         MOVE.L   BUFFPT(A6),A0     A0 points to parameter in buffer
191
PARAM1   MOVE.B   (A0)+,D0          Read character from line buffer
192
         CMP.B    #SPACE,D0         Test for delimiter
193
         BEQ.S    PARAM4            The permitted delimiter is a
194
         CMP.B    #CR,D0            space or a carriage return
195
         BEQ.S    PARAM4            Exit on either space or C/R
196
         ASL.L    #4,D1             Shift accumulated result 4 bits left
197
         SUB.B    #$30,D0           Convert new character to hex
198
         BMI.S    PARAM5            If less than $30 then not-hex
199
         CMP.B    #$09,D0           If less than 10
200
         BLE.S    PARAM3            then continue
201
         SUB.B    #$07,D0           Else assume $A - $F
202
         CMP.B    #$0F,D0           If more than $F
203
         BGT.S    PARAM5            then exit to error on not-hex
204
PARAM3   ADD.B    D0,D1             Add latest nybble to total in D1
205
         BRA      PARAM1            Repeat until delimiter found
206
PARAM4   MOVE.L   A0,BUFFPT(A6)     Save pointer in memory
207
         MOVE.L   D1,PARAMTR(A6)    Save parameter in memory
208
         MOVE.L   D1,D0             Put parameter in D0 for return
209
         BRA.S    PARAM6            Return without error
210
PARAM5   OR.B     #2,D7             Set error flag before return
211
PARAM6   MOVE.L   (A7)+,D1          Restore working register
212
         RTS                        Return with error
213
*
214
*************************************************************************
215
*
216
*  Output routines
217
*  OUT1X   = print one   hexadecimal character
218
*  OUT2X   = print two   hexadecimal characters
219
*  OUT4X   = print four  hexadecimal characters
220
*  OUT8X   = print eight hexadecimal characters
221
*  In each case, the data to be printed is in D0
222
*
223
OUT1X    MOVE.W   D0,-(A7)          Save D0
224
         AND.B    #$0F,D0           Mask off MS nybble
225
         ADD.B    #$30,D0           Convert to ASCII
226
         CMP.B    #$39,D0           ASCII = HEX + $30
227
         BLS.S    OUT1X1            If ASCII <= $39 then print and exit
228
         ADD.B    #$07,D0           Else ASCII := HEX + 7
229
OUT1X1   BSR      PUTCHAR           Print the character
230
         MOVE.W   (A7)+,D0          Restore D0
231
         RTS
232
*
233
OUT2X    ROR.B    #4,D0             Get MS nybble in LS position
234
         BSR      OUT1X             Print MS nybble
235
         ROL.B    #4,D0             Restore LS nybble
236
         BRA      OUT1X             Print LS nybble and return
237
*
238
OUT4X    ROR.W    #8,D0             Get MS byte in LS position
239
         BSR      OUT2X             Print MS byte
240
         ROL.W    #8,D0             Restore LS byte
241
         BRA      OUT2X             Print LS byte and return
242
*
243
OUT8X    SWAP     D0                Get MS word in LS position
244
         BSR      OUT4X             Print MS word
245
         SWAP     D0                Restore LS word
246
         BRA      OUT4X             Print LS word and return
247
*
248
*************************************************************************
249
*
250
* JUMP causes execution to begin at the address in the line buffer
251
*
252
JUMP     BSR     PARAM              Get address from buffer
253
         TST.B   D7                 Test for input error
254
         BNE.S   JUMP1              If error flag not zero then exit
255
         TST.L   D0                 Else test for missing address
256
         BEQ.S   JUMP1              field. If no address then exit
257
         MOVE.L  D0,A0              Put jump address in A0 and call the
258
         JMP     (A0)               subroutine. User to supply RTS!!
259
JUMP1    LEA.L   ERMES1(PC),A4      Here for error - display error
260
         BRA     PSTRING            message and return
261
*
262
*************************************************************************
263
*
264
*  Display the contents of a memory location and modify it
265
*
266
MEMORY   BSR      PARAM             Get start address from line buffer
267
         TST.B    D7                Test for input error
268
         BNE.S    MEM3              If error then exit
269
         MOVE.L   D0,A3             A3 points to location to be opened
270
MEM1     BSR      NEWLINE
271
         BSR.S    ADR_DAT           Print current address and contents
272
         BSR.S    PSPACE             update pointer, A3, and O/P space
273
         BSR      GETCHAR           Input char to decide next action
274
         CMP.B    #CR,D0            If carriage return then exit
275
         BEQ.S    MEM3              Exit
276
         CMP.B    #'-',D0           If "-" then move back
277
         BNE.S    MEM2              Else skip wind-back procedure
278
         LEA.L    -4(A3),A3         Move pointer back 2+2
279
         BRA      MEM1              Repeat until carriage return
280
MEM2     CMP.B    #SPACE,D0         Test for space (= new entry)
281
         BNE.S    MEM1              If not space then repeat
282
         BSR      WORD              Else get new word to store
283
         TST.B    D7                Test for input error
284
         BNE.S    MEM3              If error then exit
285
         MOVE.W   D0,-2(A3)         Store new word
286
         BRA      MEM1              Repeat until carriage return
287
MEM3     RTS
288
*
289
ADR_DAT  MOVE.L   D0,-(A7)          Print the contents of A3 and the
290
         MOVE.L   A3,D0             word pointed at by A3.
291
         BSR      OUT8X              and print current address
292
         BSR.S    PSPACE            Insert delimiter
293
         MOVE.W   (A3),D0           Get data at this address in D0
294
         BSR      OUT4X              and print it
295
         LEA.L    2(A3),A3          Point to next address to display
296
         MOVE.L   (A7)+,D0          Restore D0
297
         RTS
298
*
299
PSPACE   MOVE.B   D0,-(A7)          Print a single space
300
         MOVE.B   #SPACE,D0
301
         BSR      PUTCHAR
302
         MOVE.B   (A7)+,D0
303
         RTS
304
*
305
*************************************************************************
306
*
307
*  LOAD  Loads data formatted in hexadecimal "S" format
308
*
309
LOAD     MOVE.L   BUFFPT(A6),A4     Any string in the line buffer is
310
LOAD1    MOVE.B   (A4)+,D0          transmitted to the host computer
311
         BSR      PUTCHAR           before the loading begins
312
         CMP.B    #CR,D0            Read from the buffer until EOL
313
         BNE      LOAD1
314
         BSR      NEWLINE           Send newline before loading
315
LOAD2    BSR      GETCHAR           Records from the host must begin
316
         CMP.B    #'S',D0           with S1/S2 (data) or S9/S8 (term)
317
         BNE.S    LOAD2             Repeat GETCHAR until char = "S"
318
         BSR      GETCHAR           Get character after "S"
319
         CMP.B    #'9',D0           Test for the two terminators S9/S8
320
         BEQ.S    LOAD3             If S9 record then exit else test
321
         CMP.B    #'8',D0           for S8 terminator. Fall through to
322
         BNE.S    LOAD6             exit on S8 else continue search
323
LOAD3    EQU      *                 Exit point from LOAD
324
         BTST.B   #0,D7             Test for input errors
325
         BEQ.S    LOAD4             If no I/P error then look at checksum
326
         LEA.L    ERMES1(PC),A4     Else point to error message
327
         BSR      PSTRING           Print it
328
LOAD4    BTST.B   #3,D7             Test for checksum error
329
         BEQ.S    LOAD5             If clear then exit
330
         LEA.L    ERMES3(PC),A4     Else point to error message
331
         BSR      PSTRING           Print it and return
332
LOAD5    RTS
333
*
334
LOAD6    CMP.B    #'1',D0           Test for S1 record
335
         BEQ.S    LOAD6A            If S1 record then read it
336
         CMP.B    #'2',D0           Else test for S2 record
337
         BNE.S    LOAD2             Repeat until valid header found
338
         CLR.B    D3                Read the S2 byte count and address,
339
         BSR.S    LOAD8             clear the checksum
340
         SUB.B    #4,D0             Calculate size of data field
341
         MOVE.B   D0,D2             D2 contains data bytes to read
342
         CLR.L    D0                Clear address accumulator
343
         BSR.S    LOAD8             Read most sig byte of address
344
         ASL.L    #8,D0             Move it one byte left
345
         BSR.S    LOAD8             Read the middle byte of address
346
         ASL.L    #8,D0             Move it one byte left
347
         BSR.S    LOAD8             Read least sig byte of address
348
         MOVE.L   D0,A2             A2 points to destination of record
349
         BRA.S    LOAD7             Skip past S1 header loader
350
LOAD6A   CLR.B    D3                S1 record found - clear checksum
351
         BSR.S    LOAD8             Get byte and update checksum
352
         SUB.B    #3,D0             Subtract 3 from record length
353
         MOVE.B   D0,D2             Save byte count in D2
354
         CLR.L    D0                Clear address accumulator
355
         BSR.S    LOAD8             Get MS byte of load address
356
         ASL.L    #8,D0             Move it to MS position
357
         BSR.S    LOAD8             Get LS byte in D2
358
         MOVE.L   D0,A2             A2 points to destination of data
359
LOAD7    BSR.S    LOAD8             Get byte of data for loading
360
         MOVE.B   D0,(A2)+          Store it
361
         SUB.B    #1,D2             Decrement byte counter
362
         BNE      LOAD7             Repeat until count = 0
363
         BSR.S    LOAD8             Read checksum
364
         ADD.B    #1,D3             Add 1 to total checksum
365
         BEQ      LOAD2             If zero then start next record
366
         OR.B     #%00001000,D7     Else set checksum error bit,
367
         BRA      LOAD3             restore I/O devices and return
368
*
369
LOAD8    BSR     BYTE               Get a byte
370
         ADD.B   D0,D3              Update checksum
371
         RTS                         and return
372
*
373
*************************************************************************
374
*
375
*  DUMP   Transmit S1 formatted records
376
*         A3 = Starting address of data block
377
*         A2 = End address of data block
378
*         D1 = Checksum, D2 = current record length
379
*
380
DUMP     BSR      RANGE             Get start and end address
381
         TST.B    D7                Test for input error
382
         BEQ.S    DUMP1             If no error then continue
383
         LEA.L    ERMES1(PC),A4     Else point to error message,
384
         BRA      PSTRING           print it and return
385
DUMP1    CMP.L    A3,D0             Compare start and end addresses
386
         BPL.S    DUMP2             If positive then start < end
387
         LEA.L    ERMES7(PC),A4     Else print error message
388
         BRA      PSTRING           and return
389
DUMP2    BSR      NEWLINE           Send newline to host and wait
390
         MOVE.L   BUFFPT(A6),A4     Before dumping, send any string
391
DUMP3    MOVE.B   (A4)+,D0          in the input buffer to the host
392
         BSR      PUTCHAR           Repeat
393
         CMP.B    #CR,D0            Transmit char from buffer to host
394
         BNE      DUMP3             Until char = C/R
395
         BSR      NEWLINE
396
         ADDQ.L   #1,A2             A2 contains length of record + 1
397
DUMP4    MOVE.L   A2,D2             D2 points to end address
398
         SUB.L    A3,D2             D2 contains bytes left to print
399
         CMP.L    #17,D2            If this is not a full record of 16
400
         BCS.S    DUMP5             then load D2 with record size
401
         MOVEQ    #16,D2            Else preset byte count to 16
402
DUMP5    LEA.L    HEADER(PC),A4     Point to record header
403
         BSR      PSTRING           Print header
404
         CLR.B    D1                Clear checksum
405
         MOVE.B   D2,D0             Move record length to output register
406
         ADD.B    #3,D0             Length includes address + count
407
         BSR.S    DUMP7             Print number of bytes in record
408
         MOVE.L   A3,D0             Get start address to be printed
409
         ROL.W    #8,D0             Get MS byte in LS position
410
         BSR.S    DUMP7             Print MS byte of address
411
         ROR.W    #8,D0             Restore LS byte
412
         BSR.S    DUMP7             Print LS byte of address
413
DUMP6    MOVE.B   (A3)+,D0          Get data byte to be printed
414
         BSR.S    DUMP7             Print it
415
         SUB.B    #1,D2             Decrement byte count
416
         BNE      DUMP6             Repeat until all this record printed
417
         NOT.B    D1                Complement checksum
418
         MOVE.B   D1,D0             Move to output register
419
         BSR.S    DUMP7             Print checksum
420
         BSR      NEWLINE
421
         CMP.L    A2,A3             Have all records been printed?
422
         BNE      DUMP4             Repeat until all done
423
         LEA.L    TAIL(PC),A4       Point to message tail (S9 record)
424
         BSR      PSTRING           Print it
425
         RTS                        and return
426
*
427
DUMP7    ADD.B    D0,D1             Update checksum, transmit byte
428
         BRA      OUT2X             to host and return
429
*
430
RANGE    EQU      *                 Get the range of addresses to be
431
         CLR.B    D7                transmitted from the buffer
432
         BSR      PARAM             Get starting address
433
         MOVE.L   D0,A3             Set up start address in A3
434
         BSR      PARAM             Get end address
435
         MOVE.L   D0,A2             Set up end address in A2
436
         RTS
437
*
438
*************************************************************************
439
*
440
*  GETCHAR gets a character
441
*
442
GETCHAR  MOVE.B  D0,D1
443
         MOVE.B  #5,D0
444
         TRAP    #15
445
         MOVE.B  D1,D0
446
         AND.B   #$7F,D0         Strip msb of input
447
         TST.B   U_CASE(A6)      Test for upper -> lower case conversion
448
         BNE.S   GETCH2          If flag not zero do not convert case
449
         BTST.B  #6,D0           Test input for lower case
450
         BEQ.S   GETCH2          If upper case then skip conversion
451
         AND.B   #%11011111,D0   Else clear bit 5 for upper case conv
452
GETCH2   TST.B   ECHO(A6)        Do we need to echo the input?
453
         BNE.S   GETCH3          If ECHO not zero then no echo
454
         BSR.S   PUTCHAR         Else echo the input
455
GETCH3   RTS                     and return
456
*
457
*************************************************************************
458
*
459
*  PUTCHAR sends a character to the console device
460
*  The name of the output device is in CN_OVEC.
461
*
462
PUTCHAR  MOVE.L  D1,-(A7)        Save working register
463
         MOVE.B  D0,D1
464
         MOVE.B  #6,D0
465
         TRAP    #15
466
         MOVE.L  (A7)+,D1        Restore working register
467
         RTS
468
*
469
*************************************************************************
470
*
471
*  Exception vector table initialization routine
472
*  All vectors not setup are loaded with uninitialized routine vector
473
*
474
X_SET   LEA.L   X_BASE,A0         Point to base of exception table
475
        MOVE.W  #253,D0           Number of vectors -  3
476
X_SET1  CMPA.L  #188,A0           Avoid TRAP #15 (required by the simulator)
477
        BEQ     X_SET2
478
        MOVE.L  #X_UN,(A0)        Store uninitialized exception vector
479
X_SET2  ADDA.L  #4,A0
480
        DBRA    D0,X_SET1         Repeat until all entries preset
481
        SUB.L   A0,A0             Clear A0 (points to vector table)
482
        MOVE.L  #BUS_ER,8(A0)     Setup bus error vector
483
        MOVE.L  #ADD_ER,12(A0)    Setup address error vector
484
        MOVE.L  #IL_ER,16(A0)     Setup illegal instruction error vect
485
        MOVE.L  #TRACE,36(A0)     Setup trace exception vector
486
        MOVE.L  #BRKPT,184(A0)    Setup TRAP #14 vector = breakpoint
487
        MOVE.W  #7,D0             Now clear the breakpoint table
488
        LEA.L   BP_TAB(A6),A0     Point to table
489
X_SET3  CLR.L   (A0)+             Clear an address entry
490
        CLR.W   (A0)+             Clear the corresponding data
491
        DBRA    D0,X_SET3         Repeat until all 8 cleared
492
        RTS
493
*
494
*
495
*************************************************************************
496
*
497
*  Display exception frame (D0 - D7, A0 - A6, USP, SSP, SR, PC)
498
*  EX_DIS prints registers saved after a breakpoint or exception
499
*  The registers are saved in TSK_T
500
*
501
EX_DIS  LEA.L   TSK_T(A6),A5      A5 points to display frame
502
        LEA.L   MES3(PC),A4       Point to heading
503
        BSR     HEADING           and print it
504
        MOVE.W  #7,D6             8 pairs of registers to display
505
        CLR.B   D5                D5 is the line counter
506
EX_D1   MOVE.B  D5,D0             Put current register number in D0
507
        BSR     OUT1X             and print it
508
        BSR     PSPACE            and a space
509
        ADD.B   #1,D5             Update counter for next pair
510
        MOVE.L  (A5),D0           Get data register to be displayed
511
        BSR     OUT8X             from the frame and print it
512
        LEA.L   MES4(PC),A4       Print string of spaces
513
        BSR.L   PSTRING           between data and address registers
514
        MOVE.L  32(A5),D0         Get address register to be displayed
515
        BSR     OUT8X             which is 32 bytes on from data reg
516
        BSR     NEWLINE
517
        LEA.L   4(A5),A5          Point to next pair (ie Di, Ai)
518
        DBRA    D6,EX_D1          Repeat until all displayed
519
        LEA.L   32(A5),A5         Adjust pointer by 8 longwords
520
        BSR     NEWLINE           to point to SSP
521
        LEA.L   MES2A(PC),A4      Point to "SS ="
522
        BSR     PSTRING           Print it
523
        MOVE.L  (A5)+,D0          Get SSP from frame
524
        BSR     OUT8X             and display it
525
        BSR     NEWLINE
526
        LEA.L   MES1(PC),A4       Point to 'SR ='
527
        BSR     PSTRING           Print it
528
        MOVE.W  (A5)+,D0          Get status register
529
        BSR     OUT4X             Display status
530
        BSR     NEWLINE
531
        LEA.L   MES2(PC),A4       Point to 'PC ='
532
        BSR     PSTRING           Print it
533
        MOVE.L  (A5)+,D0          Get PC
534
        BSR     OUT8X             Display PC
535
        BRA     NEWLINE           Newline and return
536
*
537
*************************************************************************
538
*
539
*  Exception handling routines
540
*
541
IL_ER   EQU      *                Illegal instruction exception
542
        MOVE.L  A4,-(A7)          Save A4
543
        LEA.L   MES10(PC),A4      Point to heading
544
        BSR     HEADING           Print it
545
        MOVE.L  (A7)+,A4          Restore A4
546
        BSR.S   GROUP2            Save registers in display frame
547
        BSR     EX_DIS            Display registers saved in frame
548
        BRA     WARM              Abort from illegal instruction
549
*
550
BUS_ER  EQU     *                 Bus error (group 1) exception
551
        MOVE.L  A4,-(A7)          Save A4
552
        LEA.L   MES8(PC),A4       Point to heading
553
        BSR     HEADING           Print it
554
        MOVE.L  (A7)+,A4          Restore A4
555
        BRA.S   GROUP1            Deal with group 1 exception
556
*
557
ADD_ER  EQU     *                 Address error (group 1) exception
558
        MOVE.L  A4,-(A7)          Save A4
559
        LEA.L   MES9(PC),A4       Point to heading
560
        BSR     HEADING           Print it
561
        MOVE.L  (A7)+,A4          Restore A4
562
        BRA.S   GROUP1            Deal with group 1 exception
563
*
564
BRKPT   EQU     *                   Deal with breakpoint
565
        MOVEM.L D0-D7/A0-A6,-(A7)   Save all registers
566
        BSR     BR_CLR              Clear breakpoints in code
567
        MOVEM.L (A7)+,D0-D7/A0-A6   Restore registers
568
        BSR.S   GROUP2            Treat as group 2 exception
569
        LEA.L   MES11(PC),A4      Point to heading
570
        BSR     HEADING           Print it
571
        BSR     EX_DIS            Display saved registers
572
        BRA     WARM              Return to monitor
573
*
574
*       GROUP1 is called by address and bus error exceptions
575
*       These are "turned into group 2" exceptions (eg TRAP)
576
*       by modifying the stack frame saved by a group 1 exception
577
*
578
GROUP1  MOVEM.L D0/A0,-(A7)       Save working registers
579
        MOVE.L  18(A7),A0         Get PC from group 1 stack frame
580
        MOVE.W  14(A7),D0         Get instruction from stack frame
581
        CMP.W   -(A0),D0          Now backtrack to find the "correct PC"
582
        BEQ.S   GROUP1A           by matching the op-code on the stack
583
        CMP.W   -(A0),D0          with the code in the region of the
584
        BEQ.S   GROUP1A           PC on the stack
585
        CMP.W   -(A0),D0
586
        BEQ.S   GROUP1A
587
        CMP.W   -(A0),D0
588
        BEQ.S   GROUP1A
589
        SUBQ.L  #2,A0
590
GROUP1A MOVE.L  A0,18(A7)          Restore modified PC to stack frame
591
        MOVEM.L (A7)+,D0/A0        Restore working registers
592
        LEA.L   8(A7),A7           Adjust stack pointer to group 1 type
593
        BSR.S   GROUP2             Now treat as group 1 exception
594
        BSR     EX_DIS             Display contents of exception frame
595
        BRA     WARM               Exit to monitor - no RTE from group 2
596
*
597
GROUP2  EQU     *                 Deal with group 2 exceptions
598
        MOVEM.L A0-A7/D0-D7,-(A7) Save all registers on the stack
599
        MOVE.W  #14,D0            Transfer D0 - D7, A0 - A6 from
600
        LEA.L   TSK_T(A6),A0      the stack to the display frame
601
GROUP2A MOVE.L  (A7)+,(A0)+       Move a register from stack to frame
602
        DBRA    D0,GROUP2A        and repeat until D0-D7/A0-A6 moved
603
        MOVE.L  USP,A2            Get the user stack pointer and put it
604
        MOVE.L  A2,(A0)+          in the A7 position in the frame
605
        MOVE.L  (A7)+,D0          Now transfer the SSP to the frame,
606
        SUB.L   #10,D0            remembering to account for the
607
        MOVE.L  D0,(A0)+          data pushed on the stack to this point
608
        MOVE.L  (A7)+,A1          Copy TOS (return address) to A1
609
        MOVE.W  (A7)+,(A0)+       Move SR to display frame
610
        MOVE.L  (A7)+,D0          Get PC in D0
611
        SUBQ.L  #2,D0             Move back to current instruction
612
        MOVE.L  D0,(A0)+          Put adjusted PC in display frame
613
        JMP     (A1)              Return from subroutine
614
*
615
*************************************************************************
616
*
617
*  GO executes a program either from a supplied address or
618
*  by using the data in the display frame
619
GO       BSR     PARAM               Get entry address (if any)
620
         TST.B   D7                  Test for error in input
621
         BEQ.S   GO1                 If D7 zero then OK
622
         LEA.L   ERMES1(PC),A4       Else point to error message,
623
         BRA     PSTRING             print it and return
624
GO1      TST.L   D0                  If no address entered then get
625
         BEQ.S   GO2                 address from display frame
626
         MOVE.L  D0,TSK_T+70(A6)     Else save address in display frame
627
         MOVE.W  #$2700,TSK_T+68(A6) Store dummy status in frame
628
GO2      BRA.S   RESTORE             Restore volatile environment and go
629
*
630
GB       BSR     BR_SET              Same as go but presets breakpoints
631
         BRA.S   GO                  Execute program
632
*
633
*        RESTORE moves the volatile environment from the display
634
*        frame and transfers it to the 68000's registers. This
635
*        re-runs a program suspended after an exception
636
*
637
RESTORE  LEA.L   TSK_T(A6),A3        A3 points to display frame
638
         LEA.L   74(A3),A3           A3 now points to end of frame + 4
639
         LEA.L   4(A7),A7            Remove return address from stack
640
         MOVE.W  #36,D0              Counter for 37 words to be moved
641
REST1    MOVE.W  -(A3),-(A7)         Move word from display frame to stack
642
         DBRA    D0,REST1            Repeat until entire frame moved
643
         MOVEM.L (A7)+,D0-D7         Restore old data registers from stack
644
         MOVEM.L (A7)+,A0-A6         Restore old address registers
645
         LEA.L   8(A7),A7            Except SSP/USP - so adjust stack
646
         RTE                         Return from exception to run program
647
*
648
TRACE    EQU     *                   TRACE exception (rudimentary version)
649
         MOVE.L  MES12(PC),A4        Point to heading
650
         BSR     HEADING             Print it
651
         BSR     GROUP1              Save volatile environment
652
         BSR     EX_DIS              Display it
653
         BRA     WARM                Return to monitor
654
*
655
*************************************************************************
656
*  Breakpoint routines: BR_GET gets the address of a breakpoint and
657
*  puts it in the breakpoint table. It does not plant it in the code.
658
*  BR_SET plants all breakpoints in the code. NOBR removes one or all
659
*  breakpoints from the table. KILL removes breakpoints from the code.
660
*
661
BR_GET   BSR     PARAM               Get breakpoint address in table
662
         TST.B   D7                  Test for input error
663
         BEQ.S   BR_GET1             If no error then continue
664
         LEA.L   ERMES1(PC),A4       Else display error
665
         BRA     PSTRING             and return
666
BR_GET1  LEA.L   BP_TAB(A6),A3       A6 points to breakpoint table
667
         MOVE.L  D0,A5               Save new BP address in A5
668
         MOVE.L  D0,D6               and in D6 because D0 gets corrupted
669
         MOVE.W  #7,D5               Eight entries to test
670
BR_GET2  MOVE.L  (A3)+,D0            Read entry from breakpoint table
671
         BNE.S   BR_GET3             If not zero display existing BP
672
         TST.L   D6                  Only store a non-zero breakpoint
673
         BEQ.S   BR_GET4
674
         MOVE.L  A5,-4(A3)           Store new breakpoint in table
675
         MOVE.W  (A5),(A3)           Save code at BP address in table
676
         CLR.L   D6                  Clear D6 to avoid repetition
677
BR_GET3  BSR     OUT8X               Display this breakpoint
678
         BSR     NEWLINE
679
BR_GET4  LEA.L   2(A3),A3            Step past stored op-code
680
         DBRA    D5,BR_GET2          Repeat until all entries tested
681
         RTS                         Return
682
*
683
BR_SET   EQU     *                   Plant any breakpoints in user code
684
         LEA.L   BP_TAB(A6),A0       A0 points to BP table
685
         LEA.L   TSK_T+70(A6),A2     A2 points to PC in display frame
686
         MOVE.L  (A2),A2             Now A2 contains value of PC
687
         MOVE.W  #7,D0               Up to eight entries to plant
688
BR_SET1  MOVE.L  (A0)+,D1            Read breakpoint address from table
689
         BEQ.S   BR_SET2             If zero then skip planting
690
         CMP.L   A2,D1               Don't want to plant BP at current PC
691
         BEQ.S   BR_SET2             location, so skip planting if same
692
         MOVE.L  D1,A1               Transfer BP address to address reg
693
         MOVE.W  #TRAP_14,(A1)       Plant op-code for TRAP #14 in code
694
BR_SET2  LEA.L   2(A0),A0            Skip past op-code field in table
695
         DBRA    D0,BR_SET1          Repeat until all entries tested
696
         RTS
697
*
698
NOBR     EQU     *                   Clear one or all breakpoints
699
         BSR     PARAM               Get BP address (if any)
700
         TST.B   D7                  Test for input error
701
         BEQ.S   NOBR1               If no error then skip abort
702
         LEA.L   ERMES1(PC),A4       Point to error message
703
         BRA     PSTRING             Display it and return
704
NOBR1    TST.L   D0                  Test for null address (clear all)
705
         BEQ.S   NOBR4               If no address then clear all entries
706
         MOVE.L  D0,A1               Else just clear breakpoint in A1
707
         LEA.L   BP_TAB(A6),A0       A0 points to BP table
708
         MOVE.W  #7,D0               Up to eight entries to test
709
NOBR2    MOVE.L  (A0)+,D1            Get entry and
710
         LEA.L   2(A0),A0            skip past op-code field
711
         CMP.L   A1,D1               Is this the one?
712
         BEQ.S   NOBR3               If so go and clear entry
713
         DBRA    D0,NOBR2            Repeat until all tested
714
         RTS
715
NOBR3    CLR.L   -6(A0)              Clear address in BP table
716
         RTS
717
NOBR4    LEA.L   BP_TAB(A6),A0       Clear all 8 entries in BP table
718
         MOVE.W  #7,D0               Eight entries to clear
719
NOBR5    CLR.L   (A0)+               Clear breakpoint address
720
         CLR.W   (A0)+               Clear op-code field
721
         DBRA    D0,NOBR5            Repeat until all done
722
         RTS
723
*
724
BR_CLR   EQU     *                   Remove breakpoints from code
725
         LEA.L   BP_TAB(A6),A0       A0 points to breakpoint table
726
         MOVE.W  #7,D0               Up to eight entries to clear
727
BR_CLR1  MOVE.L  (A0)+,D1            Get address of BP in D1
728
         MOVE.L  D1,A1               and put copy in A1
729
         TST.L   D1                  Test this breakpoint
730
         BEQ.S   BR_CLR2             If zero then skip BP clearing
731
         MOVE.W  (A0),(A1)           Else restore op-code
732
BR_CLR2  LEA.L   2(A0),A0            Skip past op-code field
733
         DBRA    D0,BR_CLR1          Repeat until all tested
734
         RTS
735
*
736
*  REG_MOD modifies a register in the display frame. The command
737
*  format is REG <reg> <value>. E.g. REG D3 1200
738
*
739
REG_MOD  CLR.L   D1                  D1 to hold name of register
740
         LEA.L   BUFFPT(A6),A0       A0 contains address of buffer pointer
741
         MOVE.L  (A0),A0             A0 now points to next char in buffer
742
         MOVE.B  (A0)+,D1            Put first char of name in D1
743
         ROL.W   #8,D1               Move char one place left
744
         MOVE.B  (A0)+,D1            Get second char in D1
745
         LEA.L   1(A0),A0            Move pointer past space in buffer
746
         MOVE.L  A0,BUFFPT(A6)       Update buffer pointer
747
         CLR.L   D2                  D2 is the character pair counter
748
         LEA.L   REGNAME(PC),A0      A0 points to string of character pairs
749
         LEA.L   (A0),A1             A1 also points to string
750
REG_MD1  CMP.W   (A0)+,D1            Compare a char pair with input
751
         BEQ.S   REG_MD2             If match then exit loop
752
         ADD.L   #1,D2               Else increment match counter
753
         CMP.L   #19,D2              Test for end of loop
754
         BNE     REG_MD1             Continue until all pairs matched
755
         LEA.L   ERMES1(PC),A4       If here then error
756
         BRA     PSTRING             Display error and return
757
REG_MD2  LEA.L   TSK_T(A6),A1        A1 points to display frame
758
         ASL.L   #2,D2               Multiply offset by 4 (4 bytes/entry)
759
         CMP.L   #72,D2              Test for address of PC
760
         BNE.S   REG_MD3             If not PC then all is OK
761
         SUB.L   #2,D2               else dec PC pointer as Sr is a word
762
REG_MD3  LEA.L   (A1,D2),A2          Calculate address of entry in disptable
763
         MOVE.L  (A2),D0             Get old contents
764
         BSR     OUT8X               Display them
765
         BSR     NEWLINE
766
         BSR     PARAM               Get new data
767
         TST.B   D7                  Test for input error
768
         BEQ.S   REG_MD4             If no error then go and store data
769
         LEA.L   ERMES1(PC),A4       Else point to error message
770
         BRA     PSTRING             print it and return
771
REG_MD4  CMP.L   #68,D2              If this address is the SR then
772
         BEQ.S   REG_MD5             we have only a word to store
773
         MOVE.L  D0,(A2)             Else store new data in display frame
774
         RTS
775
REG_MD5  MOVE.W  D0,(A2)             Store SR (one word)
776
         RTS
777
*
778
*************************************************************************
779
*
780
X_UN    EQU     *                 Uninitialized exception vector routine
781
        LEA.L   ERMES6(PC),A4     Point to error message
782
        BSR     PSTRING           Display it
783
        BSR     EX_DIS            Display registers
784
        BRA     WARM              Abort
785
*
786
*************************************************************************
787
*
788
*  All strings and other fixed parameters here
789
*
790
BANNER   DC.B     'TSBUG  Version 3.10.96',0,0
791
CRLF     DC.B     CR,LF,'?',0
792
HEADER   DC.B     CR,LF,'S','1',0,0
793
TAIL     DC.B     'S9  ',0,0
794
MES1     DC.B     ' SR  =  ',0
795
MES2     DC.B     ' PC  =  ',0
796
MES2A    DC.B     ' SS  =  ',0
797
MES3     DC.B     '  Data reg       Address reg',0,0
798
MES4     DC.B     '        ',0,0
799
MES8     DC.B     'Bus error   ',0,0
800
MES9     DC.B     'Address error   ',0,0
801
MES10    DC.B     'Illegal instruction ',0,0
802
MES11    DC.B     'Breakpoint  ',0,0
803
MES12    DC.B     'Trace   ',0
804
REGNAME  DC.B     'D0D1D2D3D4D5D6D7'
805
         DC.B     'A0A1A2A3A4A5A6A7'
806
         DC.B     'SSSR'
807
         DC.B     'PC  ',0
808
ERMES1   DC.B     'Non-valid hexadecimal input  ',0
809
ERMES2   DC.B     'Invalid command  ',0
810
ERMES3   DC.B     'Loading error',0
811
ERMES4   DC.B     'Table full  ',0,0
812
ERMES5   DC.B     'Breakpoint not active   ',0,0
813
ERMES6   DC.B     'Uninitialized exception ',0,0
814
ERMES7   DC.B     ' Range error',0
815
*
816
*  COMTAB is the built-in command table. All entries are made up of
817
*         a string length + number of characters to match + the string
818
*         plus the address of the command relative to COMTAB
819
*
820
         DC.L     0                Force table to even address
821
COMTAB   DC.B     4,4              JUMP <address> causes execution to
822
         DC.B     'JUMP'           begin at <address>
823
         DC.L     JUMP-COMTAB                                          n
824
         DC.B     6,3              MEMORY <address> examines contents of
825
         DC.B     'MEMORY'         <address> and allows them to be changed
826
         DC.L     MEMORY-COMTAB
827
         DC.B     4,2              LOAD <string> loads S1/S2 records
828
         DC.B     'LOAD'           from the host. <string> is sent to host
829
         DC.L     LOAD-COMTAB
830
         DC.B     4,2              DUMP <string> sends S1 records to the
831
         DC.B     'DUMP'           host and is preceeded by <string>.
832
         DC.L     DUMP-COMTAB
833
         DC.B     4,2              NOBR <address> removes the breakpoint
834
         DC.B     'NOBR'           at <address> from the BP table. If
835
         DC.L     NOBR-COMTAB      no address is given all BPs are removed.
836
         DC.B     4,2              DISP displays the contents of the
837
         DC.B     'DISP'           pseudo registers in TSK_T.
838
         DC.L     EX_DIS-COMTAB
839
         DC.B     4,2              GO <address> starts program execution
840
         DC.B    'GO'              at <address> and loads regs from TSK_T
841
         DC.L     GO-COMTAB
842
         DC.B     2,2               BRGT puts a breakpoint in the BP
843
         DC.B    'BRGT'            table - but not in the code
844
         DC.L    BR_GET-COMTAB
845
         DC.B    4,2               PLAN puts the breakpoints in the code
846
         DC.B    'PLAN'
847
         DC.L    BR_SET-COMTAB
848
         DC.B    4,4               KILL removes breakpoints from the code
849
         DC.B    'KILL'
850
         DC.L    BR_CLR-COMTAB
851
         DC.B    4,2               GB <address> sets breakpoints and
852
         DC.B    'GB  '            then calls GO.
853
         DC.L    GB-COMTAB
854
         DC.B    4,3               REG <reg> <value> loads <value>
855
         DC.B    'REG '            into <reg> in TASK_T. Used to preset
856
         DC.L    REG_MOD-COMTAB    registers before a GO or GB
857
         DC.B    0,0
858
*
859
         END $1000
860
 
861
 
862
 
863
 
864
 
865
 
866
 
867
 

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