On Thu, 23 Nov 2006 08:34:34 +1100
Benjamin Herrenschmidt [off-list ref] wrote:

quoted

+BEGIN_FTR_SECTION
+/*
+ * certain freescale cores treat 'normal' floating point instructions
+ * as FP Unavail exception.  Redirect to normal illegal/emulation handling.
+ */
+	b 	ProgramCheck
+END_FTR_SECTION_IFSET(CPU_FTR_FP_TAKES_FPUNAVAIL)
 	EXCEPTION_PROLOG
 	bne	load_up_fpu		/* if from user, just load it up */
 	addi	r3,r1,STACK_FRAME_OVERHEAD

Do you absolutely need that ? Is there any way those cores will actually

The feature section provides a means of distinguishing among other processors (i.e. those with FPUs) at runtime.

send a "normal" FPUnavail exception ? If not, don't bother. There aren't

no, it never takes the Illegal instruction/ProgramCheck exception by itself when a FP insn is in the pipe.

that many CPU feature bits left so let's not use one for something that
never happens.

this happens when executing a binary with FP instructions compiled in.  This feature will be reused when support for other FPUless core variants coming from freescale are added.

Kim