1/* Copyright (C) 2000-2022 Free Software Foundation, Inc.
2   This file was pretty much copied from newlib.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it
7under the terms of the GNU General Public License as published by the
8Free Software Foundation; either version 3, or (at your option) any
9later version.
10
11GCC is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14General Public License for more details.
15
16Under Section 7 of GPL version 3, you are granted additional
17permissions described in the GCC Runtime Library Exception, version
183.1, as published by the Free Software Foundation.
19
20You should have received a copy of the GNU General Public License and
21a copy of the GCC Runtime Library Exception along with this program;
22see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23<http://www.gnu.org/licenses/>.  */
24
25#include "crt.h"
26
27#ifdef MMU_SUPPORT
28          /* Section used for exception/timer interrupt stack area */
29          .section .data.vbr.stack,"aw"
30          .align 4
31          .global __ST_VBR
32__ST_VBR:
33          .zero 1024 * 2          /* ; 2k for VBR handlers */
34/* Label at the highest stack address where the stack grows from */
35__timer_stack:
36#endif /* MMU_SUPPORT */
37
38          /* ;----------------------------------------
39          Normal newlib crt1.S */
40
41          ! make a place to keep any previous value of the vbr register
42          ! this will only have a value if it has been set by redboot (for example)
43          .section .bss
44old_vbr:
45          .long 0
46#ifdef PROFILE
47profiling_enabled:
48          .long 0
49#endif
50
51
52          .section .text
53          .global   start
54          .import ___rtos_profiler_start_timer
55          .weak   ___rtos_profiler_start_timer
56start:
57          mov.l     stack_k,r15
58
59#if defined (__SH3__) || (defined (__SH_FPU_ANY__) && ! defined (__SH2E__) && ! defined (__SH2A__)) || defined (__SH4_NOFPU__)
60#define VBR_SETUP
61          ! before zeroing the bss ...
62          ! if the vbr is already set to vbr_start then the program has been restarted
63          ! (i.e. it is not the first time the program has been run since reset)
64          ! reset the vbr to its old value before old_vbr (in bss) is wiped
65          ! this ensures that the later code does not create a circular vbr chain
66          stc       vbr, r1
67          mov.l     vbr_start_k, r2
68          cmp/eq    r1, r2
69          bf        0f
70          ! reset the old vbr value
71          mov.l     old_vbr_k, r1
72          mov.l     @r1, r2
73          ldc       r2, vbr
740:
75#endif /* VBR_SETUP */
76
77          ! zero out bss
78          mov.l     edata_k,r0
79          mov.l     end_k,r1
80          mov       #0,r2
81start_l:
82          mov.l     r2,@r0
83          add       #4,r0
84          cmp/ge    r0,r1
85          bt        start_l
86
87#if defined (__SH_FPU_ANY__)
88          mov.l set_fpscr_k, r1
89          mov #4,r4
90          jsr @r1
91          shll16 r4 ! Set DN bit (flush denormal inputs to zero)
92          lds r3,fpscr        ! Switch to default precision
93#endif /* defined (__SH_FPU_ANY__) */
94
95#ifdef VBR_SETUP
96          ! save the existing contents of the vbr
97          ! there will only be a prior value when using something like redboot
98          ! otherwise it will be zero
99          stc       vbr, r1
100          mov.l     old_vbr_k, r2
101          mov.l     r1, @r2
102          ! setup vbr
103          mov.l     vbr_start_k, r1
104          ldc       r1,vbr
105#endif /* VBR_SETUP */
106
107          ! if an rtos is exporting a timer start fn,
108          ! then pick up an SR which does not enable ints
109          ! (the rtos will take care of this)
110          mov.l rtos_start_fn, r0
111          mov.l sr_initial_bare, r1
112          tst       r0, r0
113          bt        set_sr
114
115          mov.l sr_initial_rtos, r1
116
117set_sr:
118          ! Set status register (sr)
119          ldc       r1, sr
120
121          ! arrange for exit to call fini
122          mov.l     atexit_k,r0
123          mov.l     fini_k,r4
124          jsr       @r0
125          nop
126
127#ifdef PROFILE
128          ! arrange for exit to call _mcleanup (via stop_profiling)
129          mova    stop_profiling,r0
130          mov.l   atexit_k,r1
131          jsr     @r1
132          mov       r0, r4
133
134          ! Call profiler startup code
135          mov.l monstartup_k, r0
136          mov.l start_k, r4
137          mov.l etext_k, r5
138          jsr @r0
139          nop
140
141          ! enable profiling trap
142          ! until now any trap 33s will have been ignored
143          ! This means that all library functions called before this point
144          ! (directly or indirectly) may have the profiling trap at the start.
145          ! Therefore, only mcount itself may not have the extra header.
146          mov.l     profiling_enabled_k2, r0
147          mov       #1, r1
148          mov.l     r1, @r0
149#endif /* PROFILE */
150
151          ! call init
152          mov.l     init_k,r0
153          jsr       @r0
154          nop
155
156          ! call the mainline
157          mov.l     main_k,r0
158          jsr       @r0
159          nop
160
161          ! call exit
162          mov       r0,r4
163          mov.l     exit_k,r0
164          jsr       @r0
165          nop
166
167                    .balign 4
168#ifdef PROFILE
169stop_profiling:
170          # stop mcount counting
171          mov.l     profiling_enabled_k2, r0
172          mov       #0, r1
173          mov.l     r1, @r0
174
175          # call mcleanup
176          mov.l     mcleanup_k, r0
177          jmp       @r0
178          nop
179
180                    .balign 4
181mcleanup_k:
182          .long __mcleanup
183monstartup_k:
184          .long ___monstartup
185profiling_enabled_k2:
186          .long profiling_enabled
187start_k:
188          .long _start
189etext_k:
190          .long __etext
191#endif /* PROFILE */
192
193          .align 2
194#if defined (__SH_FPU_ANY__)
195set_fpscr_k:
196          .long     ___set_fpscr
197#endif /*  defined (__SH_FPU_ANY__) */
198
199stack_k:
200          .long     _stack
201edata_k:
202          .long     _edata
203end_k:
204          .long     _end
205main_k:
206          .long     ___setup_argv_and_call_main
207exit_k:
208          .long     _exit
209atexit_k:
210          .long     _atexit
211init_k:
212          .long     GLOBAL(_init)
213fini_k:
214          .long     GLOBAL(_fini)
215#ifdef VBR_SETUP
216old_vbr_k:
217          .long     old_vbr
218vbr_start_k:
219          .long     vbr_start
220#endif /* VBR_SETUP */
221
222sr_initial_rtos:
223          ! Privileged mode RB 1 BL 0. Keep BL 0 to allow default trap handlers to work.
224          ! Whether profiling or not, keep interrupts masked,
225          ! the RTOS will enable these if required.
226          .long 0x600000f1
227
228rtos_start_fn:
229          .long ___rtos_profiler_start_timer
230
231#ifdef PROFILE
232sr_initial_bare:
233          ! Privileged mode RB 1 BL 0. Keep BL 0 to allow default trap handlers to work.
234          ! For bare machine, we need to enable interrupts to get profiling working
235          .long 0x60000001
236#else
237
238sr_initial_bare:
239          ! Privileged mode RB 1 BL 0. Keep BL 0 to allow default trap handlers to work.
240          ! Keep interrupts disabled - the application will enable as required.
241          .long 0x600000f1
242#endif
243
244          ! supplied for backward compatibility only, in case of linking
245          ! code whose main() was compiled with an older version of GCC.
246          .global ___main
247___main:
248          rts
249          nop
250#ifdef VBR_SETUP
251! Exception handlers
252          .section .text.vbr, "ax"
253vbr_start:
254
255          .org 0x100
256vbr_100:
257#ifdef PROFILE
258          ! Note on register usage.
259          ! we use r0..r3 as scratch in this code. If we are here due to a trapa for profiling
260          ! then this is OK as we are just before executing any function code.
261          ! The other r4..r7 we save explicityl on the stack
262          ! Remaining registers are saved by normal ABI conventions and we assert we do not
263          ! use floating point registers.
264          mov.l expevt_k1, r1
265          mov.l @r1, r1
266          mov.l event_mask, r0
267          and r0,r1
268          mov.l trapcode_k, r2
269          cmp/eq r1,r2
270          bt 1f
271          bra handler_100   ! if not a trapa, go to default handler
272          nop
2731:
274          mov.l trapa_k, r0
275          mov.l @r0, r0
276          shlr2 r0      ! trapa code is shifted by 2.
277          cmp/eq #33, r0
278          bt 2f
279          bra handler_100
280          nop
2812:
282
283          ! If here then it looks like we have trap #33
284          ! Now we need to call mcount with the following convention
285          ! Save and restore r4..r7
286          mov.l     r4,@-r15
287          mov.l     r5,@-r15
288          mov.l     r6,@-r15
289          mov.l     r7,@-r15
290          sts.l     pr,@-r15
291
292          ! r4 is frompc.
293          ! r5 is selfpc
294          ! r0 is the branch back address.
295          ! The code sequence emitted by gcc for the profiling trap is
296          ! .align 2
297          ! trapa #33
298          ! .align 2
299          ! .long lab Where lab is planted by the compiler. This is the address
300          ! of a datum that needs to be incremented.
301          sts pr,  r4     ! frompc
302          stc spc, r5         ! selfpc
303          mov #2, r2
304          not r2, r2      ! pattern to align to 4
305          and r2, r5      ! r5 now has aligned address
306!         add #4, r5      ! r5 now has address of address
307          mov r5, r2      ! Remember it.
308!         mov.l @r5, r5   ! r5 has value of lable (lab in above example)
309          add #8, r2
310          ldc r2, spc     ! our return address avoiding address word
311
312          ! only call mcount if profiling is enabled
313          mov.l profiling_enabled_k, r0
314          mov.l @r0, r0
315          cmp/eq #0, r0
316          bt 3f
317          ! call mcount
318          mov.l mcount_k, r2
319          jsr @r2
320          nop
3213:
322          lds.l @r15+,pr
323          mov.l @r15+,r7
324          mov.l @r15+,r6
325          mov.l @r15+,r5
326          mov.l @r15+,r4
327          rte
328          nop
329          .balign 4
330event_mask:
331          .long 0xfff
332trapcode_k:
333          .long 0x160
334expevt_k1:
335          .long 0xff000024 ! Address of expevt
336trapa_k:
337          .long 0xff000020
338mcount_k:
339          .long __call_mcount
340profiling_enabled_k:
341          .long profiling_enabled
342#endif
343          ! Non profiling case.
344handler_100:
345          mov.l 2f, r0     ! load the old vbr setting (if any)
346          mov.l @r0, r0
347          cmp/eq #0, r0
348          bf 1f
349          ! no previous vbr - jump to own generic handler
350          bra handler
351          nop
3521:        ! there was a previous handler - chain them
353          add #0x7f, r0        ! 0x7f
354          add #0x7f, r0        ! 0xfe
355          add #0x2, r0     ! add 0x100 without corrupting another register
356          jmp @r0
357          nop
358          .balign 4
3592:
360          .long old_vbr
361
362          .org 0x400
363vbr_400:  ! Should be at vbr+0x400
364          mov.l 2f, r0     ! load the old vbr setting (if any)
365          mov.l @r0, r0
366          cmp/eq #0, r0
367          ! no previous vbr - jump to own generic handler
368          bt handler
369          ! there was a previous handler - chain them
370          rotcr r0
371          rotcr r0
372          add #0x7f, r0        ! 0x1fc
373          add #0x7f, r0        ! 0x3f8
374          add #0x02, r0        ! 0x400
375          rotcl r0
376          rotcl r0   ! Add 0x400 without corrupting another register
377          jmp @r0
378          nop
379          .balign 4
3802:
381          .long old_vbr
382handler:
383          /* If the trap handler is there call it */
384          mov.l     superh_trap_handler_k, r0
385          cmp/eq    #0, r0       ! True if zero.
386          bf 3f
387          bra   chandler
388          nop
3893:
390          ! Here handler available, call it.
391          /* Now call the trap handler with as much of the context unchanged as possible.
392             Move trapping address into PR to make it look like the trap point */
393          stc spc, r1
394          lds r1, pr
395          mov.l expevt_k, r4
396          mov.l @r4, r4 ! r4 is value of expevt, first parameter.
397          mov r1, r5   ! Remember trapping pc.
398          mov r1, r6   ! Remember trapping pc.
399          mov.l chandler_k, r1
400          mov.l superh_trap_handler_k, r2
401          ! jmp to trap handler to avoid disturbing pr.
402          jmp @r2
403          nop
404
405          .org 0x600
406vbr_600:
407#ifdef PROFILE
408          ! Should be at vbr+0x600
409          ! Now we are in the land of interrupts so need to save more state.
410          ! Save register state
411          mov.l interrupt_stack_k, r15 ! r15 has been saved to sgr.
412          mov.l     r0,@-r15
413          mov.l     r1,@-r15
414          mov.l     r2,@-r15
415          mov.l     r3,@-r15
416          mov.l     r4,@-r15
417          mov.l     r5,@-r15
418          mov.l     r6,@-r15
419          mov.l     r7,@-r15
420          sts.l     pr,@-r15
421          sts.l     mach,@-r15
422          sts.l     macl,@-r15
423#if defined(__SH_FPU_ANY__)
424          ! Save fpul and fpscr, save fr0-fr7 in 64 bit mode
425          ! and set the pervading precision for the timer_handler
426          mov       #0,r0
427          sts.l     fpul,@-r15
428          sts.l     fpscr,@-r15
429          lds       r0,fpscr  ! Clear fpscr
430          fmov      fr0,@-r15
431          fmov      fr1,@-r15
432          fmov      fr2,@-r15
433          fmov      fr3,@-r15
434          mov.l     pervading_precision_k,r0
435          fmov      fr4,@-r15
436          fmov      fr5,@-r15
437          mov.l     @r0,r0
438          fmov      fr6,@-r15
439          fmov      fr7,@-r15
440          lds       r0,fpscr
441#endif /* __SH_FPU_ANY__ */
442          ! Pass interrupted pc to timer_handler as first parameter (r4).
443          stc    spc, r4
444          mov.l timer_handler_k, r0
445          jsr @r0
446          nop
447#if defined(__SH_FPU_ANY__)
448          mov       #0,r0
449          lds       r0,fpscr  ! Clear the fpscr
450          fmov      @r15+,fr7
451          fmov      @r15+,fr6
452          fmov      @r15+,fr5
453          fmov      @r15+,fr4
454          fmov      @r15+,fr3
455          fmov      @r15+,fr2
456          fmov      @r15+,fr1
457          fmov      @r15+,fr0
458          lds.l     @r15+,fpscr
459          lds.l     @r15+,fpul
460#endif /* __SH_FPU_ANY__ */
461          lds.l @r15+,macl
462          lds.l @r15+,mach
463          lds.l @r15+,pr
464          mov.l @r15+,r7
465          mov.l @r15+,r6
466          mov.l @r15+,r5
467          mov.l @r15+,r4
468          mov.l @r15+,r3
469          mov.l @r15+,r2
470          mov.l @r15+,r1
471          mov.l @r15+,r0
472          stc sgr, r15    ! Restore r15, destroyed by this sequence.
473          rte
474          nop
475#if defined(__SH_FPU_ANY__)
476          .balign 4
477pervading_precision_k:
478          .long GLOBAL(__fpscr_values)+4
479#endif
480#else
481          mov.l 2f, r0     ! Load the old vbr setting (if any).
482          mov.l @r0, r0
483          cmp/eq #0, r0
484          ! no previous vbr - jump to own handler
485          bt chandler
486          ! there was a previous handler - chain them
487          rotcr r0
488          rotcr r0
489          add #0x7f, r0        ! 0x1fc
490          add #0x7f, r0        ! 0x3f8
491          add #0x7f, r0        ! 0x5f4
492          add #0x03, r0        ! 0x600
493          rotcl r0
494          rotcl r0   ! Add 0x600 without corrupting another register
495          jmp @r0
496          nop
497          .balign 4
4982:
499          .long old_vbr
500#endif     /* PROFILE code */
501chandler:
502          mov.l expevt_k, r4
503          mov.l @r4, r4 ! r4 is value of expevt hence making this the return code
504          mov.l handler_exit_k,r0
505          jsr   @r0
506          nop
507          ! We should never return from _exit but in case we do we would enter the
508          ! the following tight loop
509limbo:
510          bra limbo
511          nop
512          .balign 4
513#ifdef PROFILE
514interrupt_stack_k:
515          .long __timer_stack ! The high end of the stack
516timer_handler_k:
517          .long __profil_counter
518#endif
519expevt_k:
520          .long 0xff000024 ! Address of expevt
521chandler_k:
522          .long chandler
523superh_trap_handler_k:
524          .long     __superh_trap_handler
525handler_exit_k:
526          .long _exit
527          .align 2
528! Simulated compile of trap handler.
529          .section  .debug_abbrev,"",@progbits
530.Ldebug_abbrev0:
531          .section  .debug_info,"",@progbits
532.Ldebug_info0:
533          .section  .debug_line,"",@progbits
534.Ldebug_line0:
535          .text
536.Ltext0:
537          .align 5
538          .type     __superh_trap_handler,@function
539__superh_trap_handler:
540.LFB1:
541          mov.l     r14,@-r15
542.LCFI0:
543          add       #-4,r15
544.LCFI1:
545          mov       r15,r14
546.LCFI2:
547          mov.l     r4,@r14
548          lds       r1, pr
549          add       #4,r14
550          mov       r14,r15
551          mov.l     @r15+,r14
552          rts
553          nop
554.LFE1:
555.Lfe1:
556          .size     __superh_trap_handler,.Lfe1-__superh_trap_handler
557          .section  .debug_frame,"",@progbits
558.Lframe0:
559          .ualong   .LECIE0-.LSCIE0
560.LSCIE0:
561          .ualong   0xffffffff
562          .byte     0x1
563          .string   ""
564          .uleb128 0x1
565          .sleb128 -4
566          .byte     0x11
567          .byte     0xc
568          .uleb128 0xf
569          .uleb128 0x0
570          .align 2
571.LECIE0:
572.LSFDE0:
573          .ualong   .LEFDE0-.LASFDE0
574.LASFDE0:
575          .ualong   .Lframe0
576          .ualong   .LFB1
577          .ualong   .LFE1-.LFB1
578          .byte     0x4
579          .ualong   .LCFI0-.LFB1
580          .byte     0xe
581          .uleb128 0x4
582          .byte     0x4
583          .ualong   .LCFI1-.LCFI0
584          .byte     0xe
585          .uleb128 0x8
586          .byte     0x8e
587          .uleb128 0x1
588          .byte     0x4
589          .ualong   .LCFI2-.LCFI1
590          .byte     0xd
591          .uleb128 0xe
592          .align 2
593.LEFDE0:
594          .text
595.Letext0:
596          .section  .debug_info
597          .ualong   0xb3
598          .uaword   0x2
599          .ualong   .Ldebug_abbrev0
600          .byte     0x4
601          .uleb128 0x1
602          .ualong   .Ldebug_line0
603          .ualong   .Letext0
604          .ualong   .Ltext0
605          .string   "trap_handler.c"
606          .string   "xxxxxxxxxxxxxxxxxxxxxxxxxxxx"
607          .string   "GNU C 3.2 20020529 (experimental)"
608          .byte     0x1
609          .uleb128 0x2
610          .ualong   0xa6
611          .byte     0x1
612          .string   "_superh_trap_handler"
613          .byte     0x1
614          .byte     0x2
615          .byte     0x1
616          .ualong   .LFB1
617          .ualong   .LFE1
618          .byte     0x1
619          .byte     0x5e
620          .uleb128 0x3
621          .string   "trap_reason"
622          .byte     0x1
623          .byte     0x1
624          .ualong   0xa6
625          .byte     0x2
626          .byte     0x91
627          .sleb128 0
628          .byte     0x0
629          .uleb128 0x4
630          .string   "unsigned int"
631          .byte     0x4
632          .byte     0x7
633          .byte     0x0
634          .section  .debug_abbrev
635          .uleb128 0x1
636          .uleb128 0x11
637          .byte     0x1
638          .uleb128 0x10
639          .uleb128 0x6
640          .uleb128 0x12
641          .uleb128 0x1
642          .uleb128 0x11
643          .uleb128 0x1
644          .uleb128 0x3
645          .uleb128 0x8
646          .uleb128 0x1b
647          .uleb128 0x8
648          .uleb128 0x25
649          .uleb128 0x8
650          .uleb128 0x13
651          .uleb128 0xb
652          .byte     0x0
653          .byte     0x0
654          .uleb128 0x2
655          .uleb128 0x2e
656          .byte     0x1
657          .uleb128 0x1
658          .uleb128 0x13
659          .uleb128 0x3f
660          .uleb128 0xc
661          .uleb128 0x3
662          .uleb128 0x8
663          .uleb128 0x3a
664          .uleb128 0xb
665          .uleb128 0x3b
666          .uleb128 0xb
667          .uleb128 0x27
668          .uleb128 0xc
669          .uleb128 0x11
670          .uleb128 0x1
671          .uleb128 0x12
672          .uleb128 0x1
673          .uleb128 0x40
674          .uleb128 0xa
675          .byte     0x0
676          .byte     0x0
677          .uleb128 0x3
678          .uleb128 0x5
679          .byte     0x0
680          .uleb128 0x3
681          .uleb128 0x8
682          .uleb128 0x3a
683          .uleb128 0xb
684          .uleb128 0x3b
685          .uleb128 0xb
686          .uleb128 0x49
687          .uleb128 0x13
688          .uleb128 0x2
689          .uleb128 0xa
690          .byte     0x0
691          .byte     0x0
692          .uleb128 0x4
693          .uleb128 0x24
694          .byte     0x0
695          .uleb128 0x3
696          .uleb128 0x8
697          .uleb128 0xb
698          .uleb128 0xb
699          .uleb128 0x3e
700          .uleb128 0xb
701          .byte     0x0
702          .byte     0x0
703          .byte     0x0
704          .section  .debug_pubnames,"",@progbits
705          .ualong   0x27
706          .uaword   0x2
707          .ualong   .Ldebug_info0
708          .ualong   0xb7
709          .ualong   0x67
710          .string   "_superh_trap_handler"
711          .ualong   0x0
712          .section  .debug_aranges,"",@progbits
713          .ualong   0x1c
714          .uaword   0x2
715          .ualong   .Ldebug_info0
716          .byte     0x4
717          .byte     0x0
718          .uaword   0x0
719          .uaword   0x0
720          .ualong   .Ltext0
721          .ualong   .Letext0-.Ltext0
722          .ualong   0x0
723          .ualong   0x0
724#endif /* VBR_SETUP */
725