Comment by csense

In x86-world, floating point hardware was an add-on chip before the 486DX was introduced in 1989 [1] [2].

I think the BCD instructions were never intended to be used outside of software arithmetic libraries, but they provide speedups for crucial operations in such libraries. Sort of like Intel's recently introduced AES instructions, which will probably only be used in encryption libraries.

Of course, it turns out that BCD-based arithmetic isn't much used, because IEEE-style floating-point has a fundamental advantage (you can store more precision in a given amount of space) and is also compatible with hardware FPU's.

[1] http://en.wikipedia.org/wiki/Floating-point_unit#Add-on_FPUs

[2] http://en.wikipedia.org/wiki/I486