ST20-C1 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST20-C1' PDF : 205 Pages View PDF
8 Instruction Set Reference
enqueue
enqueue a process
Code: 23 F7
Description: Add the process indicated by the process descriptor in Breg to the
queue structure in Areg. The queue control block is defined in Chapter 7.
Definition:
if (word[Areg @ q.FPtrLoc] = NotProcess)
{
word′[Areg @ q.FPtrLoc] ← Breg
word′[Areg @ q.BPtrLoc] ← Breg
}
else
{
word′[word[Areg @ q.BPtrLoc] @ pw.Link]
word′[Areg @ q.BPtrLoc] ← Breg
}
-- queue is empty
← Breg
Areg′ ← undefined
Breg′ ← undefined
Creg′ ← undefined
Status Register:
No effect
Comments:
Secondary instruction.
This instruction may require 4 memory accesses. If the queue structure is in off-
chip memory then interrupt latency may be affected.
Areg must be word aligned (i.e. divisible by 4).
See also: dequeue, stop
Chapter 7.
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