iAPX 286 Operating System Writers Guide 1983

REAL MEMORY MANAGEMENTPL/M-286 COMPILER 960-501 date PAGE 1system-ID PL/M-286 DEBUG Vx.y COMPILATION OF MODULE MEMORYOBJECT MODULE PLACED IN :Fl:MEMORY.OBJCOMPILER INVOKED BY: :F3:PLM286.86 :Fl:MEMORY.PLM CODE DEBUG$ PAGEWIDTH(71) TITLE('960-501') INCLUDE (:Fl:NUCSUB.PLM)$ NOLIST12345678910111213141221221221111MEMORY:DO;/*******************************************************//* Externals. */POINT AT: PROCEDURE (SLOT, RIGHTS, PHYS ADDR PTR, LIMIT)EXTERNAL;DECLARE SLOT SELECTOR, RIGHTS BYTE,PHYS ADDR PTR POINTER, LIMIT WORD;END POINT AT; -NULLIFY: PROCEDURE (SLOT) EXTERNAL;DECLARE SLOT SELECTOR;END NULL IFY;GETSEGMENTBASE: PROCEDURE (SEL, BASE ADDR PTR) EXTERNAL;DECLARE SEL SELECTOR, BASE ADDR PTR-POINTER;END GETSEGMENTBASE; --/*******************************************************//* Space-management definitions. */DECLARE PARAGRAPH LITERALLY '16';/* To run under SIM286, all segments must have a baseaddress equal to zero mod PARAGRAPH. This is notrequired when running on iAPX 286 hardware. */DECLARE MEM LINK LITERALLY'PADDING (8) BYTE,START DWORD,HI TAG WORD,LO-TAG WORD,PRIOR DWORD,NEXT DWORD,SIZE DWORD';/* Base address of link descriptor is always PARAGRAPHless than address of PRIOR field. Address of PRIORfield is always 0 mod PARAGRAPH. PRIOR, NEXT, andSIZE fields always point to a PRIOR - PARAGRAPHaddress. */DECLARE TAGS SIZE LITERALLY '4';/* The space used by both tag words */DECLARE LINK LIMIT LITERALLY '27';/* Limit used to construct descriptors for MEM_LINK */151DECLARE BLOCK MODULUS LITERALLY '32';/* All memory blocks are an integral multiple ofBLOCK_MODULUS in length.*/Figure 3-9. Code for Memory-Management Example3-15121960-001