mdw@git.distorted.org.uk Git - ssr/blob - StraySrc/Libraries/Sapphire/sh/seh

   1 ;
   2 ; seh.sh
   3 ;
   4 ; Structured Exception Handling, the Sapphire way
   5 ;
   6 ; © 1995-1998 Straylight
   7 ;
   8
   9 ;----- Licensing note -------------------------------------------------------
  10 ;
  11 ; This file is part of Straylight's Sapphire library.
  12 ;
  13 ; Sapphire 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 ; Sapphire 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 Sapphire.  If not, write to the Free Software Foundation,
  25 ; 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  26
  27 ;----- Overview -------------------------------------------------------------
  28 ;
  29 ; Functions provided:
  30 ;
  31 ;  seh_try
  32 ;  seh_unTry
  33 ;  seh_throw
  34 ;  seh_throwErrors
  35 ;  seh_setListBase
  36 ;  seh_init
  37
  38                 [       :LNOT::DEF:seh__dfn
  39                 GBLL    seh__dfn
  40
  41 ; --- seh_try ---
  42 ;
  43 ; On entry:     R0 == pointer to catch definition block
  44 ;
  45 ; On exit:      R13 dropped by a (small) amount
  46 ;
  47 ; Use:          Inserts an exception handler at the current position.
  48 ;               Exceptions are matched against those described in the catch
  49 ;               block.  If there is a handler for the exception, the
  50 ;               corresponding handler is called, and expected to resume
  51 ;               normally.  Otherwise the tidy-up routine is called and we
  52 ;               unwind the stack further to find an appropriate handler.
  53 ;
  54 ;               The catch block has the following format:
  55 ;
  56 ;               word    B to tidy-up routine
  57 ;               word    1st exception mask
  58 ;               word    1st B to catch routine
  59 ;               word    2nd exception mask
  60 ;               word    2nd B to catch routine
  61 ;               ...
  62 ;               word    0
  63 ;
  64 ;               An exception mask contains two halfwords.  Bits 16-31 are the
  65 ;               class to match, or -1 for all classes.  Bits 0-15 are the
  66 ;               subtype to match, or -1 for all subtypes.  You can do really
  67 ;               odd things if you set bits 16-31 to -1 and leave 0-15
  68 ;               matching specific subtypes -- do this at your own risk.
  69
  70                 IMPORT  seh_try
  71
  72 ; --- seh_unTry ---
  73 ;
  74 ; On entry:     --
  75 ;
  76 ; On exit:      R13 moved to position before corresponding seh_try
  77 ;
  78 ; Use:          Removes the try block marker in the stack at the current
  79 ;               position.  Note that the stack will be unwound to where it
  80 ;               was when seh_try was called.
  81
  82                 IMPORT  seh_unTry
  83
  84 ; --- seh_throw ---
  85 ;
  86 ; On entry:     R0 == exception to match
  87 ;               R1-R3 == useful bits of information
  88 ;
  89 ; On exit:      Doesn't return, unless you've done something /really/ odd
  90 ;
  91 ; Use:          Throws an exception.  The stack is unwound until we find
  92 ;               a handler which can cope.  If there is no handler, we abort
  93 ;               the program.
  94
  95                 IMPORT  seh_throw
  96
  97 ; --- seh_throwErrors ---
  98 ;
  99 ; On entry:     --
 100 ;
 101 ; On exit:      --
 102 ;
 103 ; Use:          Sets up an except-style error handler to throw errors
 104 ;               as SEH exceptions.
 105
 106                 IMPORT  seh_throwErrors
 107
 108 ; --- seh_setListBase ---
 109 ;
 110 ; On entry:     R0 == pointer to try block list base, or 0 to use global
 111 ;
 112 ; On exit:      --
 113 ;
 114 ; Use:          Sets the try block list base.  This should only be used by
 115 ;               coroutine providers, like coRoutine and thread.
 116
 117                 IMPORT  seh_setListBase
 118
 119 ; --- seh_init ---
 120 ;
 121 ; On entry:     --
 122 ;
 123 ; On exit:      --
 124 ;
 125 ; Use:          Initialises SEH's facilities.
 126
 127                 IMPORT  seh_init
 128
 129                 ]
 130
 131 ;----- That's all, folks ----------------------------------------------------
 132
 133                 END