mdw@git.distorted.org.uk Git - ssr/blob - StraySrc/Libraries/Steel/s/calltrace

   1 ;
   2 ; calltrace
   3 ;
   4 ; Display a backtrace of the call stack
   5 ;
   6 ; © 1994-1998 Straylight
   7 ;
   8
   9 ;----- Licensing note -------------------------------------------------------
  10 ;
  11 ; This file is part of Straylight's Steel library.
  12 ;
  13 ; Steel is free software; you can redistribute it and/or modify
  14 ; it under the terms of the GNU General Public License as published by
  15 ; the Free Software Foundation; either version 2, or (at your option)
  16 ; any later version.
  17 ;
  18 ; Steel is distributed in the hope that it will be useful,
  19 ; but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ; GNU General Public License for more details.
  22 ;
  23 ; You should have received a copy of the GNU General Public License
  24 ; along with Steel.  If not, write to the Free Software Foundation,
  25 ; 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  26
  27                 GET     libs:header
  28                 GET     libs:swis
  29
  30                 IMPORT  |_kernel_unwind|
  31                 IMPORT  |_kernel_procname|
  32
  33                 AREA    |C$$Code|,CODE,READONLY
  34
  35 99
  36                 DCB     "_calltrace",0
  37                 ALIGN
  38                 DCD     &FF000000+{PC}-%b99
  39
  40                 EXPORT  |_calltrace|
  41 |_calltrace|    ROUT
  42
  43                 MOV     ip,sp
  44                 STMFD   sp!,{fp,ip,lr,pc}
  45                 SUB     fp,ip,#4
  46                 SUB     sp,sp,#20               ;Make a small buffer
  47
  48                 ; --- Start displaying the command window ---
  49
  50                 ADR     a1,wintitle
  51                 SWI     Wimp_CommandWindow
  52                 SWI     XOS_WriteI+14
  53
  54                 ; --- Set up dunny `frame pointer' ---
  55
  56                 MOV     ip,fp
  57
  58 00              ; --- Print address from which it's called ---
  59
  60                 LDR     a1,[ip,#-4]             ;Get the link regiser
  61                 BIC     a1,a1,#&FC000003        ;Strip off saved PSR
  62                 SUB     a1,a1,#4                ;Find the call address
  63                 MOV     a2,sp                   ;Point to the buffer
  64                 MOV     a3,#20                  ;Buffer size
  65                 SWI     XOS_ConvertHex8         ;Convert the address
  66                 SWI     XOS_Write0              ;Display it on screen
  67                 SWI     XOS_WriteI+' '
  68                 SWI     XOS_WriteI+'('
  69
  70                 ; --- Print procedure name ---
  71
  72                 LDR     ip,[ip,#-12]
  73                 LDR     a4,[ip,#0]              ;Where's the stacked pc?
  74                 BIC     a4,a4,#&FC000003        ;Mask off the PSR bits
  75                 SUB     a4,a4,#20               ;Point to procedure word
  76                 LDR     a2,[a4,#0]              ;And load it
  77                 AND     a3,a2,#&FF000000        ;Check the top byte is right
  78                 CMP     a3,#&FF000000           ;Is it the right pattern?
  79                 BICEQ   a3,a2,#&FF000000        ;Yes: Find the string length
  80                 SUBEQ   a1,a4,a3                ;     Point to the proc name
  81                 ADRNE   a1,anon                 ;No:  Point to `anonymous'
  82                 SWI     XOS_Write0              ;Display the procedure name
  83                 SWI     XOS_WriteI+')'
  84                 SWI     XOS_NewLine             ;Move on to next line
  85
  86                 ; --- Unwind the stack another level ---
  87
  88                 LDR     a1,[ip,#-12]            ;Get the stacked frame ptr
  89                 CMP     a1,#0                   ;Is there a real stack frame?
  90                 BNE     %00                     ;Yes -- dump that one out
  91
  92                 ; --- Turn the command window off ---
  93
  94 01              SWI     Wimp_CommandWindow
  95
  96                 LDMDB   fp,{fp,sp,pc}^
  97
  98 wintitle        DCB     "Stack backtrace",0
  99 anon            DCB     "Anonymous function",0
 100
 101                 LTORG
 102
 103                 END