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#BPTR
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Does anybody know what the reasoning is for BPTR's? I know that they exist
because the DOS was written in the language BCPL but I don't see why you
would want pointers to be constantly in need of shifting in order to see
what they actually point at. I guess it would make sense if the memory was
longword addressable but I have the feeling this is not the reason. I
guess it could also be because of a desire to keep what they point at on a
longword boundary but is there in reason for this on the Amiga? Can
anybody out there explain the evolution of AmigaDos? Darrel
BCPL it seems was originally implemented on machines that were linerly word
addressable, versus the liner byte addessability of the 68000. SO if you
use BCPL on a byte addressable machine, you've got to set up the compiler
to produce a model of a word addressable machine in order for BCPL code to
work. It'd be transparent from your BCPL environment but not from C or any
other more flexable language (C not being tied to a particular memory
organization). Had it been written in C you wouldn't have any of this BPTR
stuff to worry about… -Dave
BCPL it seems was originally implemented on machines that were linerly word
addressable, versus the liner byte addessability of the 68000. SO if you
use BCPL on a byte addressable machine, you've got to set up the compiler
to produce a model of a word addressable machine in order for BCPL code to
work. It'd be transparent from your BCPL environment but not from C or any
other more flexable language (C not being tied to a particular memory
organization). Had it been written in C you wouldn't have any of this BPTR
stuff to worry about… -Dave