flat assembler
Message board for the users of flat assembler.
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l4m2
Code: use64 mov [es:rbx],ax |
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revolution
l4m2 wrote: Why mov [es:rbx],ax complies? |
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l4m2
Document say es: is invalid in 64 bit mode. Is there a time when it still work?(like POP CS)
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revolution
The segment registers are still valid and must point to valid descriptors but the base and limit fields are ignored, only the access rights are used.
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revolution
You posted an ES override. That is different from POP ES. The POP ES instruction might not be valid, but the ES register is valid.
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l4m2
Quote: If an instruction uses base registers RSP/RBP and uses a segment override prefix to specify a non-SS segment, a So here treat ignore as allowed Oh it seems the ES: is also not complied out |
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revolution
That is for the stack registers RBP/RSP. For ordinary registers like RBX that paragraph does not apply.
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