Group DebugStub

# Todo: Change these to a group level var
var .DebugBPs int[256]
var .DebugWaitMsg = 'Waiting for debugger connection...'

# Called before Kernel runs. Inits debug stub, etc
procedure Init {
    Cls()
	# Display message before even trying to init serial
    DisplayWaitMsg()
    InitSerial()
    WaitForDbgHandshake()
    Cls()
}

procedure WaitForSignature {
    EBX = 0
Read:
    ComReadAL()
    BL = AL
    EBX ~> 8
    if EBX != $19740807 goto Read
}

# QEMU (and possibly others) send some garbage across the serial line first.
# Actually they send the garbage inbound, but garbage could be inbound as well so we 
# keep this.
# To work around this we send a signature. DC then discards everything before the signature.
# QEMU has other serial issues too, and we dont support it anymore, but this signature is a good
# feature so we kept it.
procedure WaitForDbgHandshake {
    # "Clear" the UART out
    AL = 0
    ComWriteAL()

    # Cosmos.Debug.Consts.Consts.SerialSignature
	+$19740807
    ESI = ESP

    # TODO pass a count register
    ComWrite8()
    ComWrite8()
    ComWrite8()
    ComWrite8()

    # Restore ESP, we actually dont care about EAX or the value on the stack anymore.
    -EAX

    # We could use the signature as the start signal, but I prefer
    # to keep the logic separate, especially in DC.

	# Send the actual started signal
	# DsVsip.Started = 6
    AL = 6
    ComWriteAL()

    WaitForSignature()
    ProcessCommandBatch()
}