summaryrefslogtreecommitdiffstats
path: root/c/src/lib/libbsp/m68k/gen68360/start/start.S
blob: c5f76ec803c58b87a272a9a40d32fad21c116a7e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
/*
 *
 *  This file contains the entry point for the application.
 *  It jumps to the BSP which is responsible for performing
 *  all initialization.
 *
 *  COPYRIGHT (c) 1989-1999.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may in
 *  the file LICENSE in this distribution or at
 *  http://www.OARcorp.com/rtems/license.html.
 *
 * Based on the `gen68302' board support package, and covered by the
 * original distribution terms.
 *
 * W. Eric Norum
 * Saskatchewan Accelerator Laboratory
 * University of Saskatchewan
 * Saskatoon, Saskatchewan, CANADA
 * eric@skatter.usask.ca
 *
 *  $Id$
 */

#include "asm.h"

BEGIN_CODE
	/*
	 * Step 1: Decide on Reset Stack Pointer and Initial Program Counter
	 */
Entry:
	.long	m360+1024		|   0: Initial SSP
	.long	start			|   1: Initial PC
	.long	_uhoh			|   2: Bus error
	.long	_uhoh			|   3: Address error
	.long	_uhoh			|   4: Illegal instruction
	.long	_uhoh			|   5: Zero division
	.long	_uhoh			|   6: CHK, CHK2 instruction
	.long	_uhoh			|   7: TRAPcc, TRAPV instructions
	.long	_uhoh			|   8: Privilege violation
	.long	_uhoh			|   9: Trace
	.long	_uhoh			|  10: Line 1010 emulator
	.long	_uhoh			|  11: Line 1111 emulator
	.long	_uhoh			|  12: Hardware breakpoint
	.long	_uhoh			|  13: Reserved for coprocessor violation
	.long	_uhoh			|  14: Format error
	.long	_uhoh			|  15: Uninitialized interrupt
	.long	_uhoh			|  16: Unassigned, reserved
	.long	_uhoh			|  17:
	.long	_uhoh			|  18:
	.long	_uhoh			|  19:
	.long	_uhoh			|  20:
	.long	_uhoh			|  21:
	.long	_uhoh			|  22:
	.long	_uhoh			|  23:
	.long	_spuriousInterrupt	|  24: Spurious interrupt
	.long	_uhoh			|  25: Level 1 interrupt autovector
	.long	_uhoh			|  26: Level 2 interrupt autovector
	.long	_uhoh			|  27: Level 3 interrupt autovector
	.long	_uhoh			|  28: Level 4 interrupt autovector
	.long	_uhoh			|  29: Level 5 interrupt autovector
	.long	_uhoh			|  30: Level 6 interrupt autovector
	.long	_uhoh			|  31: Level 7 interrupt autovector
	.long	_uhoh			|  32: Trap instruction (0-15)
	.long	_uhoh			|  33:
	.long	_uhoh			|  34:
	.long	_uhoh			|  35:
	.long	_uhoh			|  36:
	.long	_uhoh			|  37:
	.long	_uhoh			|  38:
	.long	_uhoh			|  39:
	.long	_uhoh			|  40:
	.long	_uhoh			|  41:
	.long	_uhoh			|  42:
	.long	_uhoh			|  43:
	.long	_uhoh			|  44:
	.long	_uhoh			|  45:
	.long	_uhoh			|  46:
	.long	_uhoh			|  47:
	.long	_uhoh			|  48: Reserved for coprocessor
	.long	_uhoh			|  49:
	.long	_uhoh			|  50:
	.long	_uhoh			|  51:
	.long	_uhoh			|  52:
	.long	_uhoh			|  53:
	.long	_uhoh			|  54:
	.long	_uhoh			|  55:
	.long	_uhoh			|  56:
	.long	_uhoh			|  57:
	.long	_uhoh			|  58:
	.long	_uhoh			|  59: Unassigned, reserved
	.long	_uhoh			|  60:
	.long	_uhoh			|  61:
	.long	_uhoh			|  62:
	.long	_uhoh			|  63:
	.long	_uhoh			|  64: User defined vectors (192)
	.long	_uhoh			|  65:
	.long	_uhoh			|  66:
	.long	_uhoh			|  67:
	.long	_uhoh			|  68:
	.long	_uhoh			|  69:
	.long	_uhoh			|  70:
	.long	_uhoh			|  71:
	.long	_uhoh			|  72:
	.long	_uhoh			|  73:
	.long	_uhoh			|  74:
	.long	_uhoh			|  75:
	.long	_uhoh			|  76:
	.long	_uhoh			|  77:
	.long	_uhoh			|  78:
	.long	_uhoh			|  79:
	.long	_uhoh			|  80:
	.long	_uhoh			|  81:
	.long	_uhoh			|  82:
	.long	_uhoh			|  83:
	.long	_uhoh			|  84:
	.long	_uhoh			|  85:
	.long	_uhoh			|  86:
	.long	_uhoh			|  87:
	.long	_uhoh			|  88:
	.long	_uhoh			|  89:
	.long	_uhoh			|  90:
	.long	_uhoh			|  91:
	.long	_uhoh			|  92:
	.long	_uhoh			|  93:
	.long	_uhoh			|  94:
	.long	_uhoh			|  95:
	.long	_uhoh			|  96:
	.long	_uhoh			|  97:
	.long	_uhoh			|  98:
	.long	_uhoh			|  99:
	.long	_uhoh			| 100:
	.long	_uhoh			| 101:
	.long	_uhoh			| 102:
	.long	_uhoh			| 103:
	.long	_uhoh			| 104:
	.long	_uhoh			| 105:
	.long	_uhoh			| 106:
	.long	_uhoh			| 107:
	.long	_uhoh			| 108:
	.long	_uhoh			| 109:
	.long	_uhoh			| 110:
	.long	_uhoh			| 111:
	.long	_uhoh			| 112:
	.long	_uhoh			| 113:
	.long	_uhoh			| 114:
	.long	_uhoh			| 115:
	.long	_uhoh			| 116:
	.long	_uhoh			| 117:
	.long	_uhoh			| 118:
	.long	_uhoh			| 119:
	.long	_uhoh			| 120:
	.long	_uhoh			| 121:
	.long	_uhoh			| 122:
	.long	_uhoh			| 123:
	.long	_uhoh			| 124:
	.long	_uhoh			| 125:
	.long	_uhoh			| 126:
	.long	_uhoh			| 127:
	.long	_uhoh			| 128:
	.long	_uhoh			| 129:
	.long	_uhoh			| 130:
	.long	_uhoh			| 131:
	.long	_uhoh			| 132:
	.long	_uhoh			| 133:
	.long	_uhoh			| 134:
	.long	_uhoh			| 135:
	.long	_uhoh			| 136:
	.long	_uhoh			| 137:
	.long	_uhoh			| 138:
	.long	_uhoh			| 139:
	.long	_uhoh			| 140:
	.long	_uhoh			| 141:
	.long	_uhoh			| 142:
	.long	_uhoh			| 143:
	.long	_uhoh			| 144:
	.long	_uhoh			| 145:
	.long	_uhoh			| 146:
	.long	_uhoh			| 147:
	.long	_uhoh			| 148:
	.long	_uhoh			| 149:
	.long	_uhoh			| 150:
	.long	_uhoh			| 151:
	.long	_uhoh			| 152:
	.long	_uhoh			| 153:
	.long	_uhoh			| 154:
	.long	_uhoh			| 155:
	.long	_uhoh			| 156:
	.long	_uhoh			| 157:
	.long	_uhoh			| 158:
	.long	_uhoh			| 159:
	.long	_uhoh			| 160:
	.long	_uhoh			| 161:
	.long	_uhoh			| 162:
	.long	_uhoh			| 163:
	.long	_uhoh			| 164:
	.long	_uhoh			| 165:
	.long	_uhoh			| 166:
	.long	_uhoh			| 167:
	.long	_uhoh			| 168:
	.long	_uhoh			| 169:
	.long	_uhoh			| 170:
	.long	_uhoh			| 171:
	.long	_uhoh			| 172:
	.long	_uhoh			| 173:
	.long	_uhoh			| 174:
	.long	_uhoh			| 175:
	.long	_uhoh			| 176:
	.long	_uhoh			| 177:
	.long	_uhoh			| 178:
	.long	_uhoh			| 179:
	.long	_uhoh			| 180:
	.long	_uhoh			| 181:
	.long	_uhoh			| 182:
	.long	_uhoh			| 183:
	.long	_uhoh			| 184:
	.long	_uhoh			| 185:
	.long	_uhoh			| 186:
	.long	_uhoh			| 187:
	.long	_uhoh			| 188:
	.long	_uhoh			| 189:
	.long	_uhoh			| 190:
	.long	_uhoh			| 191:
	.long	_uhoh			| 192:
	.long	_uhoh			| 193:
	.long	_uhoh			| 194:
	.long	_uhoh			| 195:
	.long	_uhoh			| 196:
	.long	_uhoh			| 197:
	.long	_uhoh			| 198:
	.long	_uhoh			| 199:
	.long	_uhoh			| 200:
	.long	_uhoh			| 201:
	.long	_uhoh			| 202:
	.long	_uhoh			| 203:
	.long	_uhoh			| 204:
	.long	_uhoh			| 205:
	.long	_uhoh			| 206:
	.long	_uhoh			| 207:
	.long	_uhoh			| 208:
	.long	_uhoh			| 209:
	.long	_uhoh			| 210:
	.long	_uhoh			| 211:
	.long	_uhoh			| 212:
	.long	_uhoh			| 213:
	.long	_uhoh			| 214:
	.long	_uhoh			| 215:
	.long	_uhoh			| 216:
	.long	_uhoh			| 217:
	.long	_uhoh			| 218:
	.long	_uhoh			| 219:
	.long	_uhoh			| 220:
	.long	_uhoh			| 221:
	.long	_uhoh			| 222:
	.long	_uhoh			| 223:
	.long	_uhoh			| 224:
	.long	_uhoh			| 225:
	.long	_uhoh			| 226:
	.long	_uhoh			| 227:
	.long	_uhoh			| 228:
	.long	_uhoh			| 229:
	.long	_uhoh			| 230:
	.long	_uhoh			| 231:
	.long	_uhoh			| 232:
	.long	_uhoh			| 233:
	.long	_uhoh			| 234:
	.long	_uhoh			| 235:
	.long	_uhoh			| 236:
	.long	_uhoh			| 237:
	.long	_uhoh			| 238:
	.long	_uhoh			| 239:
	.long	_uhoh			| 240:
	.long	_uhoh			| 241:
	.long	_uhoh			| 242:
	.long	_uhoh			| 243:
	.long	_uhoh			| 244:
	.long	_uhoh			| 245:
	.long	_uhoh			| 246:
	.long	_uhoh			| 247:
	.long	_uhoh			| 248:
	.long	_uhoh			| 249:
	.long	_uhoh			| 250:
	.long	_uhoh			| 251:
	.long	_uhoh			| 252:
	.long	_uhoh			| 253:
	.long	_uhoh			| 254:
	.long	_uhoh			| 255:

/*
 * Default trap handler
 * With an oscilloscope you can see AS* stop
 */
	PUBLIC (_uhoh)
_uhoh:	nop				| Leave spot for breakpoint
	stop	#0x2700			| Stop with interrupts disabled
	bra.l	_uhoh			| Stuck forever

/*
 * Log, but otherwise ignore, spurious interrupts
 */
	PUBLIC (_spuriousInterrupt)
_spuriousInterrupt:
	addql	#1,_M68kSpuriousInterruptCount
	rte

/*
 * Place the low-order 3 octets of the board's ethernet address at
 * a `well-known' fixed location relative to the startup location.
 */
	.align 2
	.word	0			| Padding
ethernet_address_buffer:
	.word	0x08F3			| Default address
	.word	0xDEAD
	.word	0xCAFE

/*
 * Initial PC
 */
.globl start
start:
	/*
	 * Step 2: Stay in Supervisor Mode
	 */
#if ( M68K_HAS_SEPARATE_STACKS == 1 )
	oriw	#0x3000,sr		| Switch to Master Stack Pointer
	lea	SYM(m360)+1024-64,a7	| Put stack in dual-port ram
					| a little below the interrupt stack
#endif

	/*
	 * Step 3: Write the VBR
	 */
	lea	Entry,a0		| Get base of vector table
	movec	a0,vbr			| Set up the VBR

	/*
	 * Step 4: Write the MBAR
	 */
	movec	dfc,d1			| Save destination register
	moveq	#7,d0			| CPU-space funcction code
	movec	d0,dfc			| Set destination function code register
	movel	#m360+0x101,d0		| MBAR value (mask CPU space accesses)
	movesl	d0,0x3FF00		| Set MBAR
	movec	d1,dfc			| Restore destination register

	/*
	 * Step 5: Verify a dual-port RAM location
	 */
	lea	m360,a0			| Point a0 to first DPRAM location
	moveb	#0x33,d0		| Set the test value
	moveb	d0,a0@			| Set the memory location
	cmpb	a0@,d0			| Does it read back?
	bne	_uhoh			| If not, bad news!
	notb	d0			| Flip bits
	moveb	d0,a0@			| Set the memory location
	cmpb	a0@,d0			| Does it read back?
	bne	_uhoh			| If not, bad news!

	/*
	 * Remaining steps are handled by C code
	 */
	jmp	_Init68360		| Start C code (which never returns)

/*
 * Copy DATA segment, clear BSS segment, set up real stack, start C program.
 * Assume that DATA and BSS sizes are multiples of 4.
 */
	PUBLIC (_CopyDataClearBSSAndStart)
_CopyDataClearBSSAndStart:
	lea	_copy_start,a0		| Get start of DATA in RAM
	lea	etext,a2		| Get start of DATA in ROM
	cmpl	a0,a2			| Are they the same?
	beq.s	NOCOPY			| Yes, no copy necessary
	lea	_copy_end,a1		| Get end of DATA in RAM
	bra.s	COPYLOOPTEST		| Branch into copy loop
COPYLOOP:
	movel	a2@+,a0@+		| Copy word from ROM to RAM
COPYLOOPTEST:
	cmpl	a1,a0			| Done?
	bcs.s	COPYLOOP		| No, skip
NOCOPY:

	lea	_clear_start,a0		| Get start of BSS
	lea	_clear_end,a1		| Get end of BSS
	clrl	d0			| Value to set
	bra.s	ZEROLOOPTEST		| Branch into clear loop
ZEROLOOP:
	movel	d0,a0@+			| Clear a word
ZEROLOOPTEST:
	cmpl	a1,a0			| Done?
	bcs.s	ZEROLOOP		| No, skip

	movel	4(a7),_RamSize		| Set RAM size

	movel	#_stack_init,a7		| set master stack pointer
	pea	env			| envp
	pea	arg			| argv
	movel	d0,a7@-			| argc
	jsr	boot_card		| Call C main

	PUBLIC (_mainDone)
_mainDone:
	nop				| Leave spot for breakpoint
	movew	#1,a7			| Force a double bus error
	movel	d0,a7@-			| This should cause a RESET
	stop	#0x2700			| Stop with interrupts disabled
	bra.l	_mainDone		| Stuck forever

        .align 2
END_CODE

BEGIN_DATA_DCL
        .align 2
	PUBLIC (environ)
environ:
	.long	env
	PUBLIC (_M68kSpuriousInterruptCount)
_M68kSpuriousInterruptCount:
	.long	0
END_DATA_DCL

BEGIN_BSS
env:	.long	0
arg:	.long	0
END_BSS

END