Displays the INtime software system calls in a thread's stack.

vu thread-handle

Parameters

thread-handle

The handle of the thread whose stack will be searched for system calls.

Remarks

This command searches a thread's stack for INtime software system calls, starting at the top of the stack. The thread's stack must be inside an INtime software segment. For each system call it finds, vu displays:

• The return address for the call. This is the address of the next instruction to be executed for the thread after the system call has finished running.
• The parameters of the system call. They are shown as if the CALL instruction for the system call were in the CS:EIP register and the displayed stack values were at the top of the stack.

If no system calls are found on the stack, vu attempts to find possible return CS:EIP values. There are two possible displays for this situation; the second can list one or more possible return values:

No system calls on stack
Return cs:eip - xxx:xxx

or

No system calls on stack
Possible Return cs:eip(s) - xxx:xxx
                            xxx:xxx
                            xxx:xxx

The vu command uses internal INtime software data structures to get system call information. The data structures are updated immediately after the system call at the top of the thread's stack completes. Since the monitor interrupt might come after the system call is completed, but before the data structures are updated, some of the information may be obsolete. Therefore, the first system call displayed may not be valid.

System calls can be nested, so some invocations of the vu command produce multiple displays of the type shown here. This is the display format for the vu system call information:

gate #NNNN
Return cs:eip - yyyy:yyyyyyyy
xxxx:xxxxxxxx   XXXXXXXX  XXXXXXXX  XXXXXXXX  XXXXXXXX  XXXXXXXX  XXXXXXXX
xxxx:xxxxxxxx   XXXXXXXX  XXXXXXXX  XXXXXXXX  XXXXXXXX  XXXXXXXX  XXXXXXXX
xxxx:xxxxxxxx   XXXXXXXX  XXXXXXXX  XXXXXXXX  XXXXXXXX  XXXXXXXX  XXXXXXXX
 (subsystem)  system call

|Parameters|.

The fields are as follows:

gate #NNNN

The gate number associated with the system call.

Return cs:eip

The return address for the system call of this display (yyyy:yyyyyyyy).

xxxx:xxxxxxxx

The address of the stack portion devoted to this call.

XXXXXXXX

Values now on the stack.

(subsystem)

The INtime software OS layer containing the system call.

system call

The name of the INtime software system call.

Parameters

The parameter names associated with the stack values. The parameters correspond to the stack values directly above them. If one of the parameters is a string, it displays the string contents below the parameters.

Examples

This example shows how the vu command responds when system calls are nested. The thread for the example has called the EIOS system call s_write_move. s_write_move has called the BIOS system call a_write. a_write has called ReceiveRtHandle to wait for the data transfer to complete.

Suppose that before the message arrives signaling the completion of the transfer, you enter SDM and invoke the vu command:

..vu 21c8   

..vu 2540
gate #0158
Return cs:eip - 2533:004020aa
24f3:0040cca4   00002688    ffffffff    00000000    00000000    00000014    00000000
24f3:0040ccbc   00000004    00000000    00000000    00000000    00000000    00000000
24f3:0040ccd4   00000000    00000000    00000000    00000000    00000000    00000000
(INtime) ReceiveRtHandle
              | Mailbox. |  MillSecs  | Response  |

Error Messages

Syntax Error

You made an error entering the command.

*** INVALID THREAD HANDLE ***

You entered a value that is not a valid thread handle.

HANDLE is not a THREAD

You entered a value that is not a valid thread handle.

See Also

Debugging tools, ReceiveRtHandle