@@ -425,23 +425,21 @@ if ( (E < (CAP_MAX_E - 1)) & (t[XLENMAX: XLENMAX - 1] - b[XLENMAX - 1] > 1) )
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That is, invert the most significant bit of _t_ if the decoded length of the
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capability is larger than E.
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- [#section_null_inf_cap]
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- === NULL and Infinite Capabilities
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+ [#section_special_caps]
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+ === Special Capabilities
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+
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+ [#section_null_cap]
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+ ==== NULL Capability
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ifdef::cheri_v9_annotations[]
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NOTE: *CHERI v9 Note:* Encoding <<null-cap>> as zeros removes the need for
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the difference between in-memory and architectural format.
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endif::[]
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- The <<null-cap>> capability is represented with 0 in all fields. This implies
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- that <<null-cap>> has no permissions and its exponent E is CAP_MAX_E e.g. 52
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- when XLENMAX=64, so its bounds cover the entire address space such that the
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- expanded base is 0 and top is 2^XLENMAX^. In contrast, the <<infinite-cap>>
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- capability grants all permissions while its bounds also cover the whole address
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- space.
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-
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- NOTE: The <<infinite-cap>> capability is also known as 'default', 'almighty',
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- or 'root' capability.
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+ The <<null-cap>> capability is represented with 0 in all fields. This implies
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+ that it has no permissions and its exponent E is CAP_MAX_E (52 for XLENMAX=64,
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+ 24 for XLENMAX=32), so its bounds cover the entire address space such that the
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+ expanded base is 0 and top is 2^XLENMAX^.
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.Field values of the NULL capability
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[#null-cap,reftext="NULL",options=header,align=center,width="55%",cols="1,1,3"]
@@ -460,6 +458,15 @@ or 'root' capability.
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| Reserved| zeros | All reserved fields
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|==============================================================================
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+ [#section_infinite_cap]
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+ ==== Infinite Capability
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+
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+ The <<infinite-cap>> capability grants all permissions while its bounds also
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+ cover the whole address space.
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+
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+ NOTE: The <<infinite-cap>> capability is also known as 'default', 'almighty',
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+ or 'root' capability.
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+
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.Field values of the Infinite capability
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[#infinite-cap,reftext="Infinite"]
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[options=header,width="100%",align=center,width="55%",cols="1,1,3"]
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