QEMU is currently lacking support for the Decimal Floating Point category of instructions (see Power ISA V2.07 Chapter 6). I intend to add this support.
Has this topic been investigated before and if so can anyone point me to that discussion? A Google search came up empty for me. My proposal is to incorporate the libdecnumber component of libdfp (http://www.eglibc.org/cgi-bin/viewvc.cgi/libdfp/trunk/) in a manner analogous to how softfloat is used for binary floating point. So, for example, the helper for the dadd instruction would look something like the following: - map FPSCR state to a decContext. - convert the contents of the source FPRs to decNumbers (decimal64ToNumber). - call decNumberAdd - convert the resultant decNumber to DPD (decimal64FromNumber) - update FPSCR per the decContext.status and result. Comments?
