MAXDSIZ limits

Hello,

I am sorry if this is an ignorant question, but I am having difficulty
finding info regarding MAXSIZD.

A look through /sys/arch/amd64/include/vmparam.h reveals a 32GB maximum
per-process limit. A look through some of the other arches I own reveals:


amd64 MAXDSIZ : ((paddr_t)32*1024*1024*1024)
i386 MAXDSIZ : (3UL*1024*1024*1024)
sparc64 MAXDSIZ : (8L*1024*1024*1024)
mips64 MAXDSIZ : 16UL*1024*1024*1024
hppa MAXDSIZ : 1*1024*1024*1024UL
arm64 MAXDSIZ : ((paddr_t)16*1024*1024*1024)

Could anyone tell me what the 'U' , "L' and '((paddr_t)' means?

I hope I'm reading this wrong, but does sparc64 have an 8GB per-process
limit? I will be shocked if a mips64 box can allocate more memory
per-process than a sparc64 T-series.

Any info would be much appreciated.

Cheers,

Jordan