On Mon, Jun 14, 2010 at 11:07:16PM +0200, Marius Tennøe wrote: > There is a bug in AS, where AS translates fdivp and fsubp incorrectly, by > translating fdivp (DE F9) to fdivrp (DE F1), and fsubp (DE E9) to fsubrp > (DE E1).
This is deliberate. See this include/opcode/i386.h comment: /* The SystemV/386 SVR3.2 assembler, and probably all AT&T derived ix86 Unix assemblers, generate floating point instructions with reversed source and destination registers in certain cases. Unfortunately, gcc and possibly many other programs use this reversed syntax, so we're stuck with it. eg. `fsub %st(3),%st' results in st = st - st(3) as expected, but `fsub %st,%st(3)' results in st(3) = st - st(3), rather than the expected st(3) = st(3) - st This happens with all the non-commutative arithmetic floating point operations with two register operands, where the source register is %st, and destination register is %st(i). The affected opcode map is dceX, dcfX, deeX, defX. */ -- Alan Modra Australia Development Lab, IBM _______________________________________________ bug-binutils mailing list bug-binutils@gnu.org http://lists.gnu.org/mailman/listinfo/bug-binutils
