To allocate global memory that will be used by other applications than your own (AV-protocol, BubbleGEM, etc.) you cannot use the standard MALLOC() but should instead implement these routines supplied by Ulli Gruszka of RUN! Software.
Call this function once somewhere in your startup code:
mxmask%=@mxmask FUNCTION mxmask $F% IF GEMDOS(68,L:-1,0)=-32 RETURN 0 ELSE IF GEMDOS(290,-1)=-32 RETURN 3 ELSE RETURN -1 ENDIF ENDFUNCCall this function if you need memory which will be used by other applications (AV-protocol, BubbleGEM)
bubblebuf%=@mxalloc_global(256,3) FUNCTION mxalloc_global(amount%,mode&) $F% ' mode& must be one of the following: ' 0 = ST-RAM only ' 1 = TT-RAM only ' 2 = EITHER, ST-RAM prefered ' 3 = EITHER, TT-RAM prefered ' IF mxmask%<>0 mode&=OR(mode&,&X100000) RETURN GEMDOS(68,L:amount%,mode& AND mxmask%) ELSE RETURN MALLOC(amount%) ENDIF ENDFUNC
Explanation of the problem, by Thomas Binder (snipped from the same thread in CSAS)
There's a problem on TT and Falcon TOS: Both crash or exhibit other strange behaviour when Mxalloc() is called with memory protection flags. Thus, the code Ulli provided ensures that the memory protection flags are masked off before a call to Mxalloc() is being made when there's no memory protection.
Note that the code doesn't actually test for memory protection, but for the existance of the Sysconf()-call. This is a GEMDOS call present in all versions of MiNT supporting memory protection, but not in TOS or MagiC. Andreas Kromke agreed that - if he implemented memory protection - MagiC would get this call, too.
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