1. A computer program product for performing a load page table entry address function in a computer system of a machine architecture, the computer program product comprising: a storage medium readable by said computer system, said computer readable medium storing instructions for performing: obtaining a machine instruction defined for said machine architecture and containing an opcode for a Load Page Table Entry Address instruction, said machine instruction further comprising an M field, a first field identifying a first general register and a second field identifying a second general register; and executing said machine instruction comprising: obtaining from said second register a virtual address to be translated; based on said M field, determining an initial address of a hierarchy of address translation tables, said hierarchy of address translation tables comprising a segment table; based on said initial address, performing dynamic address translation of said virtual address to obtain a segment table entry address of a segment table entry of said segment table; and responsive to an enhanced DAT facility being enabled and a format control field in said segment table entry being enabled, saving said segment table entry address in said first general register, said segment table entry configured to address a large block of data in memory.