Densely packed decimal is a refinement of this, by Mike Cowlishaw, which was incorporated into the IEEE 754-2008 standard for decimal floating-point.

Decimal Floating-Point: Algorism for Computers, Proceedings of the 16th IEEE Symposium on Computer Arithmetic (Cowlishaw, M. F., 2003)

It is based on Power ISA v.2.04 and includes changes primarily to Book I and Book III-S, including significant enhancements such as decimal arithmetic (Category: Decimal Floating-Point in Book I) and server hypervisor improvements.