>Number:         34571
>Category:       pkg
>Synopsis:       TME sun3 emulator doesn't consider floating point infinities to be equal
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Sep 20 17:05:00 +0000 2006
>Originator:     Arthur Townsend
>Release:        3.0
>Organization:
>Environment:
3.0 for i386
>Description:
TME doesn't consider extended floating point infinities to be equal (whereas a real sun3 does).

>How-To-Repeat:
gcc-3.3.3 testcase 960405-1.c, compiled with hard float on a real sun3 passes.  compiled with hard float inside the emulator, it fails.  compiled with -msoft-float on either a real sun3 or inside TME it fails.  This is likely a softfloat implementation, as both -msoft-float and TME's emulation of hardware floating point use the same softfloat routines.

The assembly code below (modified from the output of gcc -S 960405-1.c) clearly shows comparing infinity to itself.

	.file	"a.c"
	.globl	x
	.data
	.align	4
	.type	x, @object
	.size	x, 12
x:
	.long	0x7fff0000
	.long	0
	.long	0
	.text
	.align	2
	.globl	main
	.type	main, @function
main:
	link.w %fp,#0
	fmove.x x,%fp0
	fcmp.x x,%fp0
	fbne .L3
	jbra .L2
	.align	2
.L3:
	jbsr abort
	.align	2
.L2:
	clr.l -(%sp)
	jbsr exit
	nop
	.size	main, .-main
	.ident	"GCC: (GNU) 3.3.3 (NetBSD nb3 20040520)"

Also note that a real sun3 considers
0x7fff00008000000000000000 infinity the same as 
0x7fff00000000000000000000 infinity.

>Fix:
Modify TME's softfloat routines.  Arguably, its not a problem with the original softfloat routines themselves, since different operating systems and processors may implement infinity comparisons differently, but since TME is designed to emulate a Sun3, then it should do exactly what a Sun3 does, and consider infinities equal.