24 lines
760 B
Text
24 lines
760 B
Text
$!
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$! This procedure patches KA41A.BIN (V1.6) Boot ROM image to work under
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$! the SIMH simulator
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$!
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$ PATCH /ABSOLUTE /NEW_VERSION /OUTPUT=KA41A.BIN KA41A_ORIG.BIN
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!
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! Test D - NVR
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!
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! - This appears to be a bug in the ROM code, which
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! causes an endless loop if the NVR is not initialised.
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! The subroutine loops until a particular value is found
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! in the SIE register however the SIE is a constant and
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! never matches the expected value. There are no other
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! exit conditions from this loop. The KA41-D V1.0 ROM
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! has the same subroutine however the loop is exited
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! when the expected value is not found in the SIE.
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!
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REPLACE/INSTRUCTION 0284C = 'BNEQ 0000280E'
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'BNEQ 0000285B'
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EXIT
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!
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UPDATE
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EXIT
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$
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