SHUH

Shared update hint

This instruction signals to the memory system that if the next instruction in program order generates an Explicit Memory Effect, then it is to a location that one or more other threads of execution are likely to subsequently update, and there is a performance benefit to ensuring subsequent updates by other threads of execution complete with minimal latency.

Note

This instruction might increase the latency of subsequent accesses to the location by the executing PE.

System class

(FEAT_CMH)

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1	1	0	1	0	1	0	1	0	0	0	0	0	0	1	1	0	0	1	0	0	1	1	0	0	1	x	1	1	1	1	1
																				CRm				op2

Encoding

SHUH {PH}

Decode

if !IsFeatureImplemented(FEAT_CMH) then EndOfDecode(Decode_NOP); constant boolean priority = op2<0> == '1';

Assembler Symbols

Is a priority hint. If present it additionally provides the same hint as the STCPH instruction, and is encoded in op2<0>:

op2<0>	PH
0	[absent]
1	[present]

Operation

Hint_SharedUpdate(priority);

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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	1	0	1	0	1	0	0	0	0	0	0	1	1	0	0	1	0	0	1	1	0	0	1	x	1	1	1	1	1
																				CRm				op2

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																				CRm				op2