INtime SDK Help
vc (SDM)

Displays information for an INtime software system call.

vc [pointer]

Parameters

pointer
A selector:offset pair that is the address of a CALL instruction. The address has this form:

ssss:oooooooo

The four-digit hexadecimal value ssss indicates the address selector. The eight-digit hexadecimal value oooooooo indicates the address offset.

If you do not supply a pointer or you specify 0, this parameter defaults to the current CS:EIP. If you specify an EIP value (one eight-digit hexadecimal number) but not a CS value, the default is the current CS.

Remarks

If the CALL instruction is for an INtime software system call, information is displayed about the system call. If the CALL instruction is not an INtime software system call or the instruction is not a CALL instruction, a message is displayed to this effect.

This is the format of the INtime software system call information display:

gate #NNNN
(subsystem) system call

The fields are:

gate #NNNN
Gate number for the INtime software system call.
(subsystem)
INtime kernel layer of the system call.
system call
INtime software system call name.

The gate number determines if the CALL instruction is for an INtime software system call or a C Library call. Information for INtime software system calls usually displays, but occasionally information for a non-system call may display.

Examples

Suppose you disassembled this code:

1e0b:00401060  55                     push   ebp
1e0b:00401061  8bec                   mov    ebp, esp
1e0b:00401063  c705cc30400000000000   mov    dword ptr 04030cc, 0
1e0b:0040106d  c705c430400064000000   mov    dword ptr 04030c4, 064
1e0b:00401077  6820304000             push   0403020
1e0b:0040107c  e8ef020000             call   $+000002f4; a=00401370
1e0b:00401081  83c404                 add    esp, 04
1e0b:00401084  6a00                   push   0
1e0b:00401086  6800100000             push   01000
1e0b:0040108b  6830124000             push   0401230
1e0b:00401090  68c8000000             push   0c8
1e0b:0040109a  83c410                 add    esp, 010

Use vc on the CALL instruction at address 1e0b:0040107c by entering this command:

..vc 1e0b:00401095

This message indicates the call was not an INtime software system call:

Not a system CALL

Use SDM Command vc on the CALL instruction at address 1e0b:0040107c by entering this command:

..vc 1e0b:00401095

This displays the INtime software system call name as:

gate #0158
(INtime) CreateRtThread

The INtime software system call is the kernel system call CreateRtThread with the gate number 0468.

To see if the CALL instruction at 18A0:00000071 is a system call, enter:

..vc 18A0:71

This message indicates the call was not an INtime software system call:

Not a system CALL

To see if the instruction at 18A0:00000074 is a CALL instruction, enter:

..vc 18A0:74

This message indicates the instruction was not a CALL instruction:

Not a CALL instruction

Return Values

Syntax Error
You made an error entering the command.
Not a system CALL
The specified parameter points to a CALL instruction that is not an INtime software system call.
Not a CALL instruction
The CS:EIP does not point to a CALL instruction.

See Also

Debugging tools, SetRtExceptionHandler