mirror of
https://github.com/danbulant/Cosmos
synced 2026-05-19 12:30:32 +00:00
61 lines
1.5 KiB
Text
61 lines
1.5 KiB
Text
Group DebugStub
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# Todo: Change these to a group level var
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var .DebugBPs int[256]
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var .DebugWaitMsg = 'Waiting for debugger connection...'
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# Called before Kernel runs. Inits debug stub, etc
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procedure Init {
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Cls()
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# Display message before even trying to init serial
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DisplayWaitMsg()
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InitSerial()
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WaitForDbgHandshake()
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Cls()
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}
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procedure WaitForSignature {
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EBX = 0
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Read:
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ComReadAL()
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BL = AL
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EBX ~> 8
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if EBX != $19740807 goto Read
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}
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# QEMU (and possibly others) send some garbage across the serial line first.
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# Actually they send the garbage inbound, but garbage could be inbound as well so we
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# keep this.
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# To work around this we send a signature. DC then discards everything before the signature.
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# QEMU has other serial issues too, and we dont support it anymore, but this signature is a good
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# feature so we kept it.
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procedure WaitForDbgHandshake {
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# "Clear" the UART out
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AL = 0
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ComWriteAL()
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# Cosmos.Debug.Consts.Consts.SerialSignature
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+$19740807
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ESI = ESP
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# TODO pass a count register
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ComWrite8()
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ComWrite8()
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ComWrite8()
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ComWrite8()
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# Restore ESP, we actually dont care about EAX or the value on the stack anymore.
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-EAX
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# We could use the signature as the start signal, but I prefer
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# to keep the logic separate, especially in DC.
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# Send the actual started signal
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# DsVsip.Started = 6
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AL = 6
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ComWriteAL()
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WaitForSignature()
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ProcessCommandBatch()
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}
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