ST20-C1 datasheet(101/205 Pages) STMICROELECTRONICS

101 / 205 page

101/205

8 Instruction Set Reference

dequeue

dequeue a process

Code: 23 F8

Description: Load into Breg a pointer to the first process from the queue control

block pointed to by Areg. Load into Areg a boolean value indicating whether a

process was found. The queue control block is defined in Chapter 7.

Definition:

if (frontptr = NotProcess)

-- queue is empty

{

Areg

′← false

Breg

′← undefined

}

else

-- queue is not empty

{

Areg

′← true

Breg

′← frontptr

if (frontptr = backptr)

-- one process on queue

word

′[Areg @ q.FPtrLoc]← NotProcess

else

-- many processes on queue

word

′[Areg @ q.FPtrLoc]← word[ frontptr @ pw.Link ]

}

Creg

′← undefined

where frontptr = word[Areg @ q.FPtrLoc]

backptr = word[Areg @ q.BPtrLoc]

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).

ST20-C1 데이터시트(PDF) 101 Page - STMicroelectronics

ST20-C1 데이터시트(HTML) 101 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

데이터시트 다운로드

링크 URL