I'm going to try and summarize the current state of 128-bit floating point on the PowerPC here.
There are 2 switches that control long double support in the compiler, but without supporting libraries, it isn't useful to users: -mabi=ieeelongdouble vs. -mabi=ibmlongdouble: These switches control which 128-bit format to use. If you use either switch, you get two warning messages (one from the gcc drive, one from the compiler proper). -mlong-double-128 vs. -mlong-double 64 These switches control whether long double is 128-bits (either ibm/ieee formats), or 64-bits. AIX and Darwin hardwires the choice to -mabi=ibmlongdouble, and you cannot use the switch to override things. Linux and Freebsd set the default to -mabi=ibmlongdouble. Any PowerPC system that is not AIX, Darwin, Linux, nor Freebsd appears to default to IEEE 128-bit (vxworks?). In terms of places where TFmode is mentioned in GCC, it is the following files: predicates.md, rs6000.c, rs6000.h, rs6000.md, rs6000-modes.def, spe.md -- Michael Meissner, IBM IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA email: meiss...@linux.vnet.ibm.com, phone: +1 (978) 899-4797