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/*
2
 *  startsis.s
3
 *
4
 *  Start code for the ERC32.
5
 *
6
 *  This is based on the file srt0.s provided with the binary
7
 *  distribution of the SPARC Instruction Simulator (SIS) found
8
 *  at ftp://ftp.estec.esa.nl/pub/ws/wsd/erc32.
9
 *
10
 *  $Id: start.S,v 1.2 2001-09-27 12:01:13 chris Exp $
11
 */
12
 
13
#include 
14
#include 
15
 
16
/*
17
 *  Unexpected trap will halt the processor by forcing it to error state
18
 */
19
 
20
#define BAD_TRAP \
21
  ta 0; \
22
  nop; \
23
  nop; \
24
  nop;
25
 
26
/*
27
 *  Software trap. Treat as BAD_TRAP for the time being...
28
 */
29
 
30
#define SOFT_TRAP BAD_TRAP
31
 
32
 
33
  .seg    "text"
34
  PUBLIC(start)
35
  .global start
36
 
37
SYM(start):
38
start:
39
 
40
/*
41
 *  The trap table has to be the first code in a boot PROM.  But because
42
 *  the Memory Configuration comes up thinking we only have 4K of PROM, we
43
 *  cannot have a full trap table and still have room left over to
44
 *  reprogram the Memory Configuration register correctly.  This file
45
 *  uses an abbreviated trap which has every entry which might be used
46
 *  before RTEMS installs its own trap table.
47
 */
48
 
49
 
50
  PUBLIC(trap_table)
51
SYM(trap_table):
52
 
53
  RTRAP( 0, SYM(hard_reset) );                   ! 00 reset trap
54
  BAD_TRAP;                                     ! 01 instruction access
55
                                                !    exception
56
  BAD_TRAP;                                     ! 02 illegal instruction
57
  BAD_TRAP;                                     ! 03 privileged instruction
58
  BAD_TRAP;                                     ! 04 fp disabled
59
  TRAP( 5, SYM(window_overflow_trap_handler) ); ! 05 window overflow
60
  TRAP( 6, SYM(window_underflow_trap_handler) );! 06 window underflow
61
  BAD_TRAP;                                     ! 07 memory address not aligned
62
  BAD_TRAP;                                     ! 08 fp exception
63
  BAD_TRAP;                                     ! 09 data access exception
64
  BAD_TRAP;                                     ! 0A tag overflow
65
  BAD_TRAP;                                     ! 0B undefined
66
  BAD_TRAP;                                     ! 0C undefined
67
  BAD_TRAP;                                     ! 0D undefined
68
  BAD_TRAP;                                     ! 0E undefined
69
  BAD_TRAP;                                     ! 0F undefined
70
  BAD_TRAP;                                     ! 10 undefined
71
 
72
  /*
73
   *  ERC32 defined traps
74
   */
75
 
76
  BAD_TRAP;                                     ! 11 masked errors
77
  BAD_TRAP;                                     ! 12 external 1
78
  BAD_TRAP;                                     ! 13 external 2
79
  BAD_TRAP;                                     ! 14 UART A RX/TX
80
  BAD_TRAP;                                     ! 15 UART B RX/TX
81
  BAD_TRAP;                                     ! 16 correctable memory error
82
  BAD_TRAP;                                     ! 17 UART error
83
  BAD_TRAP;                                     ! 18 DMA access error
84
  BAD_TRAP;                                     ! 19 DMA timeout
85
  BAD_TRAP;                                     ! 1A external 3
86
  BAD_TRAP;                                     ! 1B external 4
87
  BAD_TRAP;                                     ! 1C general purpose timer
88
  BAD_TRAP;                                     ! 1D real time clock
89
  BAD_TRAP;                                     ! 1E external 5
90
  BAD_TRAP;                                     ! 1F watchdog timeout
91
 
92
 
93
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 20 - 23 undefined
94
  BAD_TRAP;                                     ! 24 cp_disabled
95
            BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 25 - 27 undefined
96
  BAD_TRAP;                                     ! 28 cp_exception
97
            BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 29 - 2B undefined
98
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 2C - 2F undefined
99
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 30 - 33 undefined
100
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 34 - 37 undefined
101
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 38 - 3B undefined
102
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 3C - 3F undefined
103
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 40 - 43 undefined
104
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 44 - 47 undefined
105
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 48 - 4B undefined
106
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 4C - 4F undefined
107
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 50 - 53 undefined
108
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 54 - 57 undefined
109
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 58 - 5B undefined
110
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 5C - 5F undefined
111
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 60 - 63 undefined
112
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 64 - 67 undefined
113
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 68 - 6B undefined
114
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 6C - 6F undefined
115
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 70 - 73 undefined
116
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 74 - 77 undefined
117
  BAD_TRAP; BAD_TRAP; BAD_TRAP; BAD_TRAP;       ! 78 - 7B undefined
118
 
119
/*
120
   This is a sad patch to make sure that we know where the
121
   MEC timer control register mirror is so we can stop the timers
122
   from an external debugger. It is needed because the control
123
   register is write-only. Trap 0x7C cannot occure in ERC32...
124
 
125
   We also use this location to store the last location of the
126
   usable RAM in order not to overwrite the remote debugger with
127
   the RTEMS work-space area.
128
 
129
*/
130
 
131
        .global __ERC32_MEC_Timer_Control_Mirror, SYM(rdb_start), SYM(CLOCK_SPEED)
132
 
133
SYM(rdb_start):
134
__ERC32_MEC_Timer_Control_Mirror:
135
 
136
  BAD_TRAP; BAD_TRAP;                           ! 7C - 7D undefined
137
 
138
SYM(CLOCK_SPEED):
139
 
140
  .word 0x0a, 0, 0, 0                           ! 7E (10 MHz default)
141
 
142
  BAD_TRAP;                                     ! 7F undefined
143
 
144
  /*
145
   *  Software traps
146
   *
147
   *  NOTE: At the risk of being redundant... this is not a full
148
   *        table.  The setjmp on the SPARC requires a window flush trap
149
   *        handler and RTEMS will preserve the entries that were
150
   *        installed before.
151
   */
152
 
153
  TRAP( 0x80, SYM(syscall) );                   ! 80 syscall SW trap
154
  SOFT_TRAP; SOFT_TRAP;                         ! 81 - 82
155
  TRAP( 0x83, SYM(window_flush_trap_handler) ); ! 83 flush windows SW trap
156
 
157
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! 84 - 87
158
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! 88 - 8B
159
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! 8C - 8F
160
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! 90 - 93
161
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! 94 - 97
162
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! 98 - 9B
163
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! 9C - 9F
164
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! A0 - A3
165
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! A4 - A7
166
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! A8 - AB
167
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! AC - AF
168
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! B0 - B3
169
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! B4 - B7
170
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! B8 - BB
171
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! BC - BF
172
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! C0 - C3
173
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! C4 - C7
174
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! C8 - CB
175
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! CC - CF
176
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! D0 - D3
177
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! D4 - D7
178
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! D8 - DB
179
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! DC - DF
180
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! E0 - E3
181
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! E4 - E7
182
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! E8 - EB
183
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! EC - EF
184
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! F0 - F3
185
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! F4 - F7
186
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! F8 - FB
187
  SOFT_TRAP; SOFT_TRAP; SOFT_TRAP; SOFT_TRAP;   ! FC - FF
188
 
189
/*
190
 *  This is the hard reset code.
191
 */
192
 
193
#define PSR_INIT   0x10c0       /* Disable traps, set s and ps */
194
#define WIM_INIT   2
195
#define STACK_SIZE 16 * 1024
196
 
197
        PUBLIC(hard_reset)
198
SYM(hard_reset):
199
 
200
        set     SYM(trap_table), %g1           ! Initialize TBR
201
        mov     %g1, %tbr
202
 
203
        set     (SYM(rdb_start)), %g6      ! End of work-space area
204
        st      %sp, [%g6]
205
 
206
 
207
/* Check if MEC is initialised. If not, this means that we are
208
   running on the simulator. Initiate some of the parameters
209
   that are done by the boot-prom otherwise.
210
*/
211
 
212
        set     SYM(ERC32_MEC), %g3  ! g3 = base address of peripherals
213
        ld      [%g3], %g2
214
        set     0xfe080000, %g1
215
        andcc   %g1, %g2, %g0
216
        bne     2f
217
 
218
 /* Set the correct memory size in MEC memory config register */
219
 
220
        set     SYM(PROM_SIZE), %l0
221
        set     0, %l1
222
        srl     %l0, 18, %l0
223
1:
224
        tst     %l0
225
        srl     %l0, 1, %l0
226
        bne,a   1b
227
        inc     %l1
228
        sll     %l1, 8, %l1
229
 
230
        set     SYM(RAM_SIZE), %l0
231
        srl     %l0, 19, %l0
232
1:
233
        tst     %l0
234
        srl     %l0, 1, %l0
235
        bne,a   1b
236
        inc     %l1
237
        sll     %l1, 10, %l1
238
 
239
                                           ! set the Memory Configuration
240
        st     %l1, [ %g3 + ERC32_MEC_MEMORY_CONFIGURATION_OFFSET ]
241
 
242
        set     SYM(RAM_START), %l1  ! Cannot use RAM_END due to bug in linker
243
        set     SYM(RAM_SIZE), %l2
244
        add     %l1, %l2, %sp
245
        st      %sp, [%g6]
246
 
247
 
248
        set     SYM(CLOCK_SPEED), %g6   ! Use 14 MHz in simulator
249
        set     14, %g1
250
        st      %g1, [%g6]
251
 
252
/* Common initialisation */
253
2:
254
        set     WIM_INIT, %g1           ! Initialize WIM
255
        mov     %g1, %wim
256
 
257
        set     PSR_INIT, %g1
258
        wr      %g1, 0x20, %psr         ! enable traps
259
 
260
        nop
261
        nop
262
        nop
263
 
264
        sethi   %hi(stack_space + STACK_SIZE), %g1
265
        or      %g1,%lo(stack_space + STACK_SIZE),%g1
266
                                        ! g1 = top of stack
267
        mov     %g1, %sp                ! Set stack pointer
268
        mov     %sp, %fp                ! Set frame pointer
269
        nop
270
 
271
        /*
272
         *  Copy the initialized data to RAM
273
         *
274
         *  FROM:   _endtext
275
         *  TO:     _data_start
276
         *  LENGTH: (__bss_start - _data_start) bytes
277
         */
278
 
279
 
280
        sethi %hi(_endtext),%g2
281
        or    %g2,%lo(_endtext),%g2     ! g2 = start of initialized data in ROM
282
 
283
        sethi %hi(_data_start),%g3
284
        or    %g3,%lo(_data_start),%g3  ! g3 = start of initialized data in RAM
285
 
286
        sethi %hi(__bss_start),%g4
287
        or    %g4,%lo(__bss_start),%g4  ! g4 = end of initialized data in RAM
288
 
289
        cmp   %g2, %g3
290
        be    1f
291
        nop
292
 
293
copy_data:
294
        ldd   [ %g2 ], %g6
295
        std   %g6 , [ %g3 ]             ! copy this double word
296
        add   %g3, 8, %g3               ! bump the destination pointer
297
        add   %g2, 8, %g2               ! bump the source pointer
298
        cmp   %g3, %g4                  ! Is the pointer past the end of dest?
299
        bl    copy_data
300
        nop
301
 
302
        /* clear the bss */
303
1:
304
 
305
        sethi %hi(_edata),%g2
306
        or    %g2,%lo(_edata),%g2       ! g2 = start of bss
307
        sethi %hi(_end),%g3
308
        or    %g3,%lo(_end),%g3         ! g3 = end of bss
309
        mov   %g0,%g1                   ! so std has two zeros
310
zerobss:
311
        std    %g0,[%g2]
312
        add    %g2,8,%g2
313
        cmp    %g2,%g3
314
        bleu,a zerobss
315
        nop
316
 
317
        mov     %0, %o2                 ! environ
318
        mov     %0, %o1                 ! argv
319
        mov     %0, %o0                 ! argc
320
        call    SYM(boot_card)
321
        sub     %sp, 0x60, %sp          ! room for boot_card to save args
322
        nop
323
 
324
        PUBLIC(BSP_fatal_return)
325
SYM(BSP_fatal_return):
326
        mov     1, %g1
327
        ta      0                       ! Halt if _main returns ...
328
        nop
329
 
330
        /*
331
         *  There does not seem to be a way to get this aligned AND
332
         *  in the BSS.
333
         */
334
 
335
        .align  32
336
        .comm   stack_space, STACK_SIZE
337
 
338
/* end of file */

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