On 29.07.2009 00:36, Robert Millan wrote: > The Multiboot spec is a bit too permissive about this, as it doesn't > specify the state of direction flag when payload is called. Some payloads > (we found this in ReactOS FreeLDR) assume it is cleared, and fail otherwise. > > We adjusted GRUB to be sure it's always cleared. I think coreboot should do > the same. Here's a patch for v3. >
AFAIK this patch is unneeded. The GCC ABI on x86 and x86_64 states that the direction flag must always be cleared before running any gcc compiled code, so if you need to execute cld in the middle of C code, it means that all C code before that cld had undefined behaviour. The correct place for cld is early asm startup code before any C code gets executed. Regards, Carl-Daniel -- http://www.hailfinger.org/ -- coreboot mailing list: [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
