IBM 5280 Distributed Data System - Index of

Allocate Keyboard/Display Storage (KEYOP)! ISource: KEYOP (12 BRa)I ! Object: C7I I 12 @1 0 00Ii0 8I15 ; 23 31DfJIo Keyboard operation number: The number that the main microprocessorstores in the keyboard/display lOB starting at hex displacement 1 F.fJ Length address: The address of the binary register that contains, in the rightmostbyte, the length in K-bytes to allocate for each area, as follows:BitsMeaning0-1 Number of K bytes (in binary) to allocate to section F (unit 1).2-3 Number of K bytes (in binary) to allocate to section B (unit 2).4-5 Number of K bytes (in binary) to allocate to section 7 (unit 3).6-7 Number of K bytes (in binary) to allocate to section 3 (unit 4).This instruction should be issued only at IPL time to allocate keyboard/display storage.The storage address range for one to three K bytes is as follows if the specifiedamount of storage is available:BinarySpecification011011Number of KBytes123Address Range inKeyboard/Display StoragexCOO through xFFFx800 through xF F Fx400 through xFFFWhere x is hex F, B, 7, or 3 for keyboard/display units 1,2,3, or 4 respectively.If 3 K of storage is specified for a section and only 1 or 2 K is available, the storageis allocated beginning at x400. If 2 K of storage is specified for a section and only1 K of storage is available, the storage is allocated beginning at x800.If the amount of storage specified for allocation to sections F, B, 7, and 3 is lessthan the total amount available, the remaining storage is allocated in section 0starting at address hex 0000 to a maximum of 4 K bytes.Notes:1. Certain 5280 models have keyboard/display storage that is not dynamicallyallocatable. On these models, execution of this instruction does not changethe storage allocation.2. Regardless of how the allocation is specified, the hardware will not allocatestorage in a section if that section does not have a corresponding displayattachment.See Chapter 3 for more information about keyboard/display storage.Object Code I nst ruct ion Format 285