>Number:         21558
>Category:       port-i386
>Synopsis:       cpu_switch() allways returns value 0
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    port-i386-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue May 13 01:29:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Stephan Uphoff
>Release:        1.6T
>Organization:
>Environment:
NetBSD giant 1.6T NetBSD 1.6T (GIANT) #0: Mon May 12 20:17:34 EDT 2003  ups@giant:/usr/home/ups/sources/build/makeobjectdirprefix/usr/home/ups/sources/src/sys/arch/i386/compile/GIANT i386

>Description:
The return value is written too early to the eax register.
The register is overwritten by function calls later in the code.
( The last function called is Xspllower() which sets the eax register to 0)
>How-To-Repeat:

>Fix:
Use the ebx register to hold the value until
it is save to store it to the eax register. 


RCS file: /cvsroot/src/sys/arch/i386/i386/locore.S,v
retrieving revision 1.8
diff -r1.8 locore.S
1856c1856
<       movl    $1, %eax
---
>       movl    $1, %ebx
1964c1964
<       xor     %eax,%eax
---
>       xorl    %ebx,%ebx
1974c1974,1975
<       
---
> 
>       movl    %ebx,%eax

>Release-Note:
>Audit-Trail:
>Unformatted: