// DATE 040222 // NOHALT * *** RUN MAINT. * // LOAD $MAINT,F1 // RUN // COPY FROM-READER,TO-F1,RETAIN-R,LIBRARY-S,NAME-$URCH MACRO $URCH .* .* 5703-XM1 SEARCH THE NULL DIRECTORY .* TEXT TITLE 'SURCHN - SEARCH THE NULL DIRECTORY' *********************************************************************** * 5703-XM1 COPYRIGHT IBM CORP. 1970 * * REFER TO INSTRUCTIONS ON COPY RIGHT NOTICE, 120-2083 * * * *********************************************************************** *STATUS * * VERSION 1 MODIFICATION 0 * * * *FUNCTION * * * SURCHN WILL SEARCH THE NULL DIRECTORY FOR AN ENTRY OF AT LEAST * * N SECTORS WHERE N IS THE NUMBER OF SECTORS REQUIRED. IF THE * * SPACE IS FOUND THE STARTING ADDRESS IS PLACED IN SMNDEA. IF IT * * IS NOT FOUND SMNDEA IS SET TO ZERO, AND SMNULT CONTAINS THE * * TOTAL OF ALL NULL SECTORS IN THE LIBRARY. * * * *ENTRY POINTS * * SURCHN - ENTRY TO SEARCH FOR NULL SPACE. THE CALLING * * SEQUENCE IS AS FOLLOWS: * * B SURCHN * * * *INPUT * * * THE INPUT TO SURCHN IS VIA TSMLES. SMNSCT MUST CONTAIN THE * * NUMBER OF SECTORS REQUIRED. SMNDBA MUST CONTAIN THE ADDRESS OF * * THE NULL DIRECTORY IN CORE. * * * *OUTPUT * * * SMNDEA WILL CONTAIN THE RELATIVE DISK ADDRESS OF THE NULL AREA * * SMNDEA WILL BE ZERO IF THE SPACE IS NOT FOUND. * * * IF THE SPACE REQUIRED IS NOT FOUND SMNULT WILL CONTAIN THE * * TOTAL OF NULL SECTORS IN THE LIBRARY. * * * *EXTERNAL REFERENCES * * $CAERR - LOCATION OF SYSTEM ERROR CODE INDICATOR * * SMNDBA - LOCATION OF NULL DIRECTORY BUFFER ADDRESS * * SMNULT - LOCATION OF NULL TOTAL COUNT * * SMNSCT - LOCATION OF REQUIRED SECTOR COUNT * * SMNDEA - LOCATION OF THE NULL DIRCTY ENTRY ADDRESS. * * * *EXITS, NORMAL * * NORMAL RETURN IS TO THE FIRST INSTRUCTION FOLLOWING THE BRANCH * * TO SURCHN. * * * *EXITS, ERROR * * N/A * * * *TABLES/WORKAREAS * * NONE * * * *ATTRIBUTES * * RELOCATABLE * * REUSEABLE * * * *CHARACTER CODE DEPENDENCY * * THE OPERATION OF THIS MODULE DOES NOT DEPEND ON A PARTICULAR * * INTERNAL REPRESENTATION OF THE EXTERNAL CHARACTER SET. * * * *NOTES * * ERROR PROCEDURES * * N/A * * * * REGISTER USAGE * * @BR AND @XR ARE SAVED AND RESTORED ON EXIT. @BR IS USED AS A * * BASE REGISTER AND @XR IS USED TO POINT TO THE NULL DIRECTORY. * * * * SAVED/RESTORED AREAS * * NONE * * * * MODIFICATION CONSIDERATIONS * * NONE * * * * REQUIRED MODULES * * @SYSEQ - SYSTEM SOFTWARE EQUATES. * * @DIREQ - LIBRARY DIRECTORY EQUATES * * @FXDEQ - SYSTEM NUCLEUS EQUATES * * * * OTHER * * NONE * *********************************************************************** EJECT *********************************************************************** * SURCHN WILL SEARCH THE NULL DIRECTORY FOR THE NUMBER OF SECTORS * * SPECIFIED IN SMNSCT. THE ADDR OF THE SPACE FOUND WILL BE PLACED * * IN SMNDEA. IF NO SPACE IS FOUND SMNDEA IS SET TO ZERO. * *********************************************************************** SURCHN EQU * ENTRY TO SURCHN SURE01 EQU 1 VALUE TO TEST COUNTERS USING SUR000,@BR SPECIFY BASE REGISTER ST SUR900+@OP1,@BR SAVE BASE OF CALLER SUR000 LA SUR000,@BR ESTABLISH BASE ADDR ST SUR910+@OP1(,@BR),@XR SAVE INDEX ST SUR920+@OP1(,@BR),@ARR SET RETURN ADDR MVI $CAERR,@@E300 LIBRARY SPACE NOT AVAILABLE * L SMNDBA,@XR GET ADDR TO NULL DIRCTY MVC SMNULT(SURE02),SURC00(,@BR) CLEAR TOTAL FIELD * MVC SURCNT(SURE01,@BR),##DNHC(,@XR) ENTRY COUNT FROM HEADER LA ##DNE1(,@XR),@XR BUMP POINTER TO FIRST ENTRY SUR010 CLI SURC00(,@BR),*-* SURCNT EQU SUR010+@Q JE SUR0G2 NO ENTRIES * * SEARCH ENTRIES FOR ONE WITH ENOUGH SPACE * CLC ##DNEF(##LNEF,@XR),SMNSCT LOOK FOR LARGE ENOUGH COUNT JNL SUR0A2 ENTRY GREATER OR EQUAL * * ENTRY IS LESS THAN SPECIFIED COUNT. ADD ENTRY COUNT TO * SMNULT AND TOTAL AVAILABLE SPACE. * ALC SMNULT,##DNEF(##LNEF,@XR) ADD COUNT TO NULL TOTAL LA ##LNE(,@XR),@XR BUMP TO NEXT ENTRY SLC SURCNT(SURE01,@BR),SURC01(,@BR) DECR WORKING COUNT B SUR010(,@BR) GO LOOK AT NEXT ENTRY * * LARGE ENOUGH SPACE HAS BEEN FOUND. TAKE THE REQUIRED * NUMBER OF SECTORS AND MODIFY OR DELETE THE ENTRY. SAVE * DIRECTORY ENTRY ADDR. * SUR0A2 MVC SMNDEA,##DNEA(@DADDR,@XR) SAVE DADDR OF SPACE FOUND * * TEST IF ENTRY IS OF EQUAL SIZE OF REQUIRED SPACE. * JNE SUR0A3 ENTRY NOT THE SAKE SIZE JUMPS * * ENTRY IS OF EQUAL SIZE SO DELETE IT FROM THE DIRECTORY. * * MOVE EACH ENTRY OF DIRECTORY UP ONE POSITION * SUR020 MVC ##DNER(,@XR),##DNER+##LNE(##LNE,@XR) MOVE ENTRY SLC SURCNT(SURE01,@BR),SURC01(,@BR) DECR ENTRY COUNT JE SUR024 ZERO COUNT JUMP * LA ##LNE(,@XR),@XR BUMP POINTER TO NEXT *TRY B SUR020(,@BR) BACK TO MOVE NEXT ENTRY SPACE SUR024 L SMNDBA,@XR RESTORE POINTER TO START OF BUF SLC ##DNHC(SURE02,@XR),SURC01(,@BR) DECR HEADER COUNT * * RETURN ACTION * SUR900 LA *-*,@BR RESTORE BASE SUR910 LA *-*,@XR RESTORE INDEX SUR920 B *-* RETURN ADDR * * NO ENTRY FOUND. CLEAR SMNDEA AND RETURN * SUR0G2 MVC SMNDEA(@CADDR),SURC00(,@BR) CLEAR DADDR POINTER B SUR900(,@BR) * * REDUCE ENTRY BY REQUIRED SECTORS. MODIFY THE RELATIVE * ADDRESS OF ENTRY TO NEW STARTING LOCATION OF THE NULL * AREA WHICH IS THE REQUIRED SPACE+1. * SUR0A3 SLC ##DNEF(##LNEF,@XR),SMNSCT DECR ENTRY BY REQUIRED COUNT MVC SURSWK(1,@BR),##DNEA-1(,@XR) GET CYL COUNT MVI ##DNEA-1(,@XR),@ZERO CLEAR CYL IN ENTRY ALC ##DNEA(SURE02,@XR),SMNSCT BUMP SECTOR BY SPACE USED SUR034 SLC ##DNEA(SURE02,@XR),SURC48(,@BR) DECR BY 1 CYL VALUE JL SUR033 JUMP LEIS THAN A SECTOR ALC SURSWK(1,@BR),SURC01(,@BR) BUMP CYL COUNT B SUR034(,@BR) BACK FOR NEXT CYL SUR033 ALC ##DNEA(SURE02,@XR),SURC48(,@BR) RESTORE REMAINDER SUR03C MVI ##DNEA-1(,@XR),*-* PLUG CYLINDER BACK INTO DADDR SURSWK EQU SUR03C+@Q ADDR OF CYL IN INSTR B SUR900(,@BR) GO TO RETURN * * CONSTANTS AND WORK AREA * SURE02 EQU 2 VALUE FOR MOVES SURC00 DC IL2'0' ZERO FOR COUNT TEST SURC01 DC IL1'1' VALUE TO INCR COUNTS SURC48 DC IL2'48' CYL VALUE *** END OF SURCHN *** MEND // CEND // END * // READER CONSOLE