Program Logic Manual - All about the IBM 1130 Computing System

0 U) ®COMMA,SkeletonSupervisorCOMMA,SkeletonSupervisorCOMMA,SkeletonSupervisorDISKZ DISKZ DISKZPhase0Phase1Phase0Phase2DiskI/0BuffersLoadTab leThatPortionofCore LoadAbove5056Phase0Phase2Phases3,4,5,6,12,13Phase7,8,9,10,11LoadTableThatPortionofCore LoadAbove5056Figure 9. Core Layout During Core Load Builder Operationlast so that they may be overlaid by phase 3. Phase 3includes the subroutines required to choose a subroutine(as opposed to a mainline) from the Load'Table and relocate it. Phases 4 and 6 round out theone-pass core load building process. Phase 4determines whether or not SOCALs are required,and, if so, whether or not they can be employed tomake the core load fit into core storage. It alsoprocesses ILSs. Phase 6 performs the miscellaneousjobs, such as creating the transfer vector, that canbe done only at the end of the process of building acore load. Phase 5 is executed only during pass 2in a two•pass building process. It organizes theLOCALs and SOCALs for relocation, including theirspecial linkages.DISK BUFFERSThere are three buffers used by the Core LoadBuilder. Each is 320 words long, not counting theword count and sector address, and each has aprimary use, although it may be used temporarilyfor something else. For example, the LET searchbuffer is used primarily to hold a sector of LET/FLET when searching that table. However, it containsone of the message phases (phases 7-10)whenever a message is printed.The data buffer is a buffer for the User Area.The program currently being incorporated into thecore load is read into this buffer, one sector at atime. For example, after a sector of the mainlineis read into this buffer from the User Area orWorking Storage, the relocation of the mainline canbegin. When this sector of the mainline has beenrelocated, another sector (if any) is fetched, andso on until the entire mainline is relocated.The main use of the CIB buffer is to contain theCIB, one sector at a time. For example, if a coreload is to occupy locations 1000 - 1639, then the firstsector of the CIB contains the part of the core loadthat is to occupy 1000 - 1319 and the second sector1320 - 1639. As the core load is built, the LocationAssignment Counter (LAC) reflects the ultimate coreaddress of the data word currently being relocated.In this example, the LAC would start at 1000, thuscausing sector 1 of the CIB to be read into the CIBbuffer. This first word of the core load would beplaced in the first word of the CIB buffer and theLAC advanced by 1. Assuming no data breaks, theLAC will eventually be incremented to 1320. Thenthe contents of the CIB buffer will be written outon sector 1 of the CIB, and sector 2 will replacesector 1 in the CIB buffer. In short, each word ora core load is always transferred to the CIB via theCIB buffer.The data and CIB buffers are combined into asingle 640-word buffer for the purpose of fetchingthe LOCAL, NOCAL, FILES, and G2250 informationfrom the SCRA.CORE IMAGE BUFFER (CIB)The Core Image Buffer is used by the Core LoadBuilder, the Core Image Loader, and the SkeletonSupervisor. The Core Load Builder uses it to storeany part of the core load that is to reside (when the34