RtlpBreakWithStatusInstruction is just a label for KD. On machines that have register calling conventions (basically all except x86), the `Status` parameter for `DbgBreakPointWithStatus` is stored in the first argument register. https://learn.microsoft.com/en-us/windows-hardware/drivers/ddi/wdm/nf-wdm-dbgbreakpointwithstatus On the x64 platform, `DbgBreakPointWithStatus` only uses the ECX register and leaves EAX untouched. Verified on Windows.