>>>>> Bruce Evans writes:
> The default of 4 for -mpreferred-stack-boundary perfectly preserves
> any initial misaligment of the stack. Under FreeBSD the stack is
> initially misaligned (for doubles) with a probability of 1/2. There
> was some discussion of fixing this when gcc-2.95 was imported, but
> nothing was committed. I use the following local hack:
> diff -c2 kern_exec.c~ kern_exec.c
> *** kern_exec.c~ Mon May 1 15:56:40 2000
> --- kern_exec.c Mon May 1 15:56:42 2000
> ***************
> *** 627,630 ****
> --- 647,659 ----
> vectp = (char **)
> (destp - (imgp->argc + imgp->envc + 2) * sizeof(char*));
> +
> + /*
> + * Align stack to a multiple of 0x20.
> + * XXX vectp has the wrong type; we usually want a vm_offset_t;
> + * the suword() family takes a void *, but should take a vm_offset_t.
> + * XXX should align stack for signals too.
> + * XXX should do this more machine/compiler-independently.
> + */
> + vectp = (char **)(((vm_offset_t)vectp & ~(vm_offset_t)0x1F) - 4);
> /*
Any chance that your fix be committed? :-) The impact of misalignments
on performance is considerable.
Jean-Marc
--
Jean-Marc Zucconi PGP Key: finger [EMAIL PROTECTED]
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