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Additional T800 FPU Not-A-Number value
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Mike B.
May 23, 2012, 10:35:21 AM5/23/12
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During anatomizing the fpremfirst instruction (still in progress),
I’ve discovered an additional NAN value returning from the T800 FPU.
When FAreg contains a NAN (Remainder from Infinity, ...) as an result
from the fpremfirst instruction, FBreg contains 0x7F801000.
As this value is not documented in the TIS-ACWG I've called it
"Quotient undefined".
The corresponding double value is 0x7FF00200'00000000.
-Mike
PS: It is also documented that the FCreg will be modified. This can
not be confirmed.
I’ve discovered an additional NAN value returning from the T800 FPU.
When FAreg contains a NAN (Remainder from Infinity, ...) as an result
from the fpremfirst instruction, FBreg contains 0x7F801000.
As this value is not documented in the TIS-ACWG I've called it
"Quotient undefined".
The corresponding double value is 0x7FF00200'00000000.
-Mike
PS: It is also documented that the FCreg will be modified. This can
not be confirmed.
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