Re: CVS commit: src/sys/arch/atari/stand/installboot

[Taylor R Campbell <campbell+netbsd-source-changes-d%mumble.net@localhost>]

   Date: Mon, 24 Nov 2014 04:46:31 +0900
   From: Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>

   Christos said "it is legally converting a void * pointer."
    http://mail-index.netbsd.org/source-changes-d/2014/11/16/msg007356.html
   You guys have different opinions.  Which is correct?

   Which C99 specification you think the existing abcksum violates?

Casting to void * is valid.  Converting a pointer to a uint8_t object
to uint16_t * and then dereferencing the uint16_t * is not valid, even
if you converted to uint16_t * via some void * casts.

See C99 Section 6.5 `Expressions', Clause 7, p. 68: `An object shall
have its stored value accessed only by an lvalue expression that has
one of the following types: ...'.  Casts through void * are irrelevant
here: if the object's effective type is uint8_t (as is the case for an
element of the bb_xxboot member of a struct bootblock), uint16_t is
not one of the allowed types for accessing the object.