iAPX 286 Operating System Writers Guide 1983

BINDING AND LOADINGPL/M-2B6 COMPILER 960-515 date PAGE 7145 3147 314B 3149, 3150 4151 4152 4153 4154 3155 215615715B15916016116216316516616716B'"169170171172~ 74175122334444334444444IF EXCEPTION THEN CALL REPORT (@EXCEP);1* Is it marked with Present bit = 0 ? *1IF (SEGDT(LI'X) .RIGHTS AND B0H)=0 THEN1* Is it a call g~te? *1IF (SEGDT(LIX) .RIGHTS AND 0FH)=4 1* Type field *1THEN DO; 1* Insert pointer from BOND table *1CALL FIND BOND (@DESNAM(LIX) .NAME,@GATET(LIX) .ENTRY POINT, @GATET(LIX) .SEL,@EXCEP); -IF EXCEP=OK THEN 1* Set present bit. *1GATET(LIX) .RIGHTS=GATET(LIX) .RIGHTS OR B0H;END 1* inserting pointer *1;END 1* stepping through all descriptors *1;END LOAD_DESCRP;/*******************************************************/1* Transfer remaining descriptors to new LDT *1TRANSFER REMAINDERS: PROCEDURE;1* Handles descriptors for which there was noLODTXT record (e.g. stacks and gates). *1DECLARE NEW LDT SEL SELECTOR,NEW-LDT-SEL W WORD AT (@NEW LDT SEL),SEG=RIGHTS - BYTE; --1* Step thru DESCRP entries, skipping LDT alias */DO LIX = 2 TO MODULE_HEADER.DESCR_COUNT-l;IF (SEGDT(LIX) .RIGHTS AND 0FH) = 4THEN 1* call~gate *1 DO;1* Construct selector for slot in new LDT *1NEW LDT SEL W = (SHL(LIXj3) OR 07H);I*-Transfer descriptor to new LDT */CALL LOAD LDT GATE (TASK SLOT, NEW LDT SEL,GATET(LIX) .RIGHTS,- --BUILD$PTR(GATET(LIX) .SEL,GATET(LIX) .ENTRY POINT) ,GATET(LIX) .WORD COUNT, @EXCEP);IF EXCEPTION THEN CALL REPORT (@EXCEP);END 1* call gate */;ELSE IF (SEGDT(LIX) .RIGHTS AND 10H) 0THEN 1* unallocated data or code segment *1 DO;IF (SEGDT(LIX) .RIGHTS AND 06H) = 06H1* expand-down data segment? */THEN SEG RIGHTS=DATA WD;ELSE SEG-RIGHTS=DATA-W;/* Allocate a segment *1CALL ALLOCATE (DCS SEL, SEG RIGHTS,SEGDT(LIX) .LIMIT+l, @EXCEP);IF EXCEPTION THEN CALL REPORT (@EXCEP);/* Put actual access rights in descriptor *1CALL CHANGE AR (DCS SEL, ,SEGDT (LI X) • RIGHTS, @EXCEP);IF EXCEPTION THEN CALL REPORT (@EXCEP);1* Construct selector for slot in new LDT *1Figure 11-6. ,Binding Loader (Cont'd.)11-21 121960-001