James West le escribe a Junichi Uekawa:

JW> True, that's what it's meant to do, but OS/2 uses it as a
JW> command word as  well.  Whenever OS/2 switches away from the
JW> task (which the HLT instruction  will wait for.) it looks at
JW> the current instruction, and if it was a HLT  instruction,
JW> then it will do various things based on current register 
JW> contents and the contents of the bytes following the HLT
JW> instruction. 

What exactly can it do? List of commands, please?

loSmaH cha'

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