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instruction: 0.970
runtime: 0.018
syscall: 0.012
incorrect handling of [r32] address (long mode)
while executing in Long Mode (x86-64) instructions such as
mov eax,[r15d]
end up executing as
mov eax,[r15]
according to x86 programmer manuals the behavior of using the Address-Size override (in long mode) is supposed to ignore the high 32bits of the register. I use this fact in my operating system to reduce register usage (the high 32 bits of r15 holds other data). consequently a general protection exception occurs since the memory address isn't "canonical". this error doesn't always appear since the high 32 bits might not be zero in those conditions.
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