struct _BootConfig is ... strange...

I've spent about 4 days in total in the last few months debugging a
strange startup problem with the Jornada 820 which runs out to having
been caused by this part of hpcarm/include/bootconfig.h:

#define DRAM_BLOCKS     1

typedef struct _BootConfig {
        PhysMem dram[DRAM_BLOCKS];
	u_int dramblocks;
	u_int kernsize;
} BootConfig;

Why exactly is this written that way?

	-is