Topic       : The ATARI Compendium
Author      : Scott Sanders / JAY Software
Version     : 1.25 (20/6/2003)
Subject     : Documentation
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HCP-Version : 6
Compiled on : Atari
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View Ref-FileSetexc()                                                               BIOS

Syntax

(VOIDP)() Setexc( num, newvec )
WORD num;
VOID (*newvec)();

Function      Setexc() reads or modifies system exception vectors.

Opcode        5 (0x05)

Availability  All TOS versions.

Parameters    num indicates the vector number you are interested in. To
              obtain the vector number divide the address of the vector by
              4. Some common vectors are:

              Name                     num     Vector

              VEC_BUSERROR             0x02    Bomb errors (Bus, Address,
              VEC_ADDRESSERROR         0x03    Instruction)
              VEC_ILLEGALINSTRUCTION   0x04

              VEC_GEMDOS               0x21    trap   #1 (GEMDOS)

              VEC_GEM                  0x22    trap   #2 (AES/VDI)

              VEC_BIOS                 0x2D    trap   #13 (BIOS)

              VEC_XBIOS                0x2E    trap   #14 (XBIOS)

              VEC_TIMER                0x100   System timer (etv_timer)

              VEC_CRITICALERROR        0x101   Critical error handler
              (VEC_CRITICALERR)                (etv_critic)

              VEC_TERMINATE            0x102   Process terminate handle
              (VEC_PROCTERM)                   (etv_term)

              newvec should be the address of your new vector handler.
              Passing a value of VEC_INQUIRE ((VOIDP)-1) will not modify
              the vector.

Binding       pea      newvec
              move.w   num,-(sp)
              move.w   #$05,-(sp)
              trap     #13
              addq.l   #8,sp

Return Value  The original value of the vector is returned by the call.

Comments      You must reinstate old vector handlers you changed prior to
              your process exiting. Programs which modify replace system
              vector code should install themselves following the
              conventions of the XBRA protocol. For details, consult the
              overview portion of this chapter.