BUILD

Build capability from untagged and possibly sealed bit pattern interprets and treats an untagged and possibly sealed bit pattern as a capability, checks this capability against a testing capability and based on the result, writes the built capability to the destination Capability register.

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
1	1	0	0	0	0	1	0	1	1	0	Cm					0	0	0	0	0	1	Cn					Cd
																	opc<1>	opc<0>

Assembler Symbols

<Cd|CSP>

Is the capability name of the destination register or stack pointer, encoded in the "Cd" field.

<Cn|CSP>

Is the capability name of the first source register or stack pointer, encoded in the "Cn" field.

<Cm|CSP>

Is the capability name of the second source register or stack pointer, encoded in the "Cm" field.

Operation

CheckCapabilitiesEnabled(); Capability data = if n == 31 then CSP[] else C[n]; Capability key = if m == 31 then CSP[] else C[m]; Capability result; boolean dataWasSealed = CapIsSealed(data); if dataWasSealed then data = CapUnseal(data); if !CapIsTagSet(key) || CapIsSealed(key) || !CapIsSubSetOf(data,key) || CapIsBaseAboveLimit(data) then if dataWasSealed then result = CapWithTagClear(data); else result = data; else result = CapWithTagSet(data); if d == 31 then CSP[] = result; else C[d] = result;

Internal version only: isa v32.13, AdvSIMD v29.04, pseudocode morello-2022-01_rc2, capabilities morello-2022-01_rc2 ; Build timestamp: 2022-01-11T11:23