mirror of
https://github.com/danbulant/Cosmos
synced 2026-05-19 12:30:32 +00:00
93 lines
No EOL
1.9 KiB
Text
93 lines
No EOL
1.9 KiB
Text
namespace DebugStub
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// Location where INT3 has been injected.
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// 0 if no INT3 is active.
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var AsmBreakEIP
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// Old byte before INT3 was injected.
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// Only 1 byte is used.
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var AsmOrigByte
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function DoAsmBreak {
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// Since our Int3 is temp, we need to adjust return EIP to return to it, not after it.
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ESI = .CallerESP
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EAX = .AsmBreakEIP
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ESI[-12] = EAX
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ClearAsmBreak()
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Break()
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}
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function SetAsmBreak {
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ClearAsmBreak()
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ComReadEAX()
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// Save EIP of the break
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.AsmBreakEIP = EAX
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EDI = EAX
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// Save the old byte
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AL = EDI[0]
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.AsmOrigByte = AL
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// Inject INT3
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// Do in 2 steps to force a byte move to RAM (till X# can do byte in one step)
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AL = $CC
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EDI[0] = AL
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}
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function ClearAsmBreak {
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EDI = .AsmBreakEIP
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// If 0, we don't need to clear an older one.
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if EDI = 0 return
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// Clear old break point and set back to original opcode / partial opcode
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AL = .AsmOrigByte
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EDI[0] = AL
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.AsmBreakEIP = 0
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}
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function SetINT1_TrapFLAG {
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//Push EAX to make sure whatever we do below doesn't affect code afterwards
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+EBP
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+EAX
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//Set base pointer to the caller ESP
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EBP = .CallerESP
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//Set the Trap Flag (http://en.wikipedia.org/wiki/Trap_flag)
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//For EFLAGS we want - the interrupt frame = ESP + 12
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// - The interrupt frame - 8 for correct byte = ESP + 12 - 8 = ESP + 4
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// - Therefore, ESP - 4 to get to the correct position
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EBP - 4
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EAX = [EBP]
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EAX | $0100
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[EBP] = EAX
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//Restore the base pointer
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//Pop EAX - see +EAX at start of method
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-EAX
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-EBP
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}
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function ResetINT1_TrapFLAG {
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//Push EAX to make sure whatever we do below doesn't affect code afterwards
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+EBP
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+EAX
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//Set base pointer to the caller ESP
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EBP = .CallerESP
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//Clear the Trap Flag (http://en.wikipedia.org/wiki/Trap_flag)
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//See comment in SetINT1_TrapFlag
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EBP - 4
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EAX = [EBP]
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EAX & $FEFF
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[EBP] = EAX
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//Pop EAX - see +EAX at start of method
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-EAX
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-EBP
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} |