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/ Apple II Magazines (PO) / Nibble Volume 09, No. 12 (1988-12)(MicroSPARC)(Side A).zip / Nibble Volume 09, No. 12 (1988-12)(MicroSPARC)(Side A).po / MERGESORT.OBJ.S < prev next >

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Text File | 1996-12-24 | 11KB | 491 lines

* * MERGESORT.S * BY CHESTER H. PAGE * (C) 1988 MICROSPARC, INC. * CONCORD, MA 01742 * TEXT EQU $0 KEEP EQU $0 dual names for dual use of NODE EQU $2 pointers, for readability PTR EQU $2 of source remarks HOLD EQU $4 NEXTA EQU $6 Pointers to next NEXTB EQU $8 lists to be merged START EQU $A FINISH EQU $CE S1 EQU $1A S2 EQU $1E LETTER EQU $D6 $40 for testing for caps MARK EQU $D7 Holds delimiter N EQU $EB INDEX EQU $ED LINE EQU $EF FLAG EQU $F9 TEMP EQU $F9 TXTLOAD EQU $1600 Start of text area HEADLIST EQU $8E00 SLIST EQU $9200 Stringlist, node list COUNT EQU $9200 COUT EQU $FDED ORG $1200 JMP TXTEND JMP LOAD JMP MAKELIST JMP PRESHOW TXTEND LDA #2 prepare parmlist for STA $300 PRODOS GET.EOF LDA #1 STA $301 JSR $BF00 call PRODOS MLI to get DB $D1 length of file DW $300 address of parmlist LDA $302 build pointer to storage STA TEXT position of EOF CLC LDA $303 ADC #<TXTLOAD STA TEXT+1 LDY #0 TYA STA (TEXT),Y load a 00 at EOF RTS LOAD LDA #$40 Initialize, and load text STA LETTER LDY #0 clear node area STY NODE for convenience LDA #<HEADLIST in analysis and STA NODE+1 debugging L0 LDA #0 STA (NODE),Y INY BNE L0 INC NODE+1 LDA NODE+1 CMP #$9A BNE L0 LDA #>SLIST initialize START pointer STA START LDA #<SLIST STA START+1 LDY #3 STA (START),Y DEY LDA #>SLIST CLC ADC #4 STA (START),Y LDY #0 STY TEXT LDA #<TXTLOAD initialize text pointer STA TEXT+1 LDA #>SLIST CLC ADC #4 STA NODE LDA #<SLIST STA NODE+1 LDA (TEXT),Y STA MARK save first text character L1 INY LDA (TEXT),Y BEQ L2 end of file CMP MARK BNE L1 DEY TYA LDY #0 STA (TEXT),Y mark replaced by length STA TEMP of following string LDA TEXT STA (NODE),Y mark-address as node value INY LDA TEXT+1 STA (NODE),Y SEC LDA TEMP advance text pointer ADC TEXT STA TEXT LDA TEXT+1 ADC #0 STA TEXT+1 CLC INY LDA NODE advance node, enter link ADC #4 STA (NODE),Y STA TEMP INY LDA NODE+1 ADC #0 CMP #$9A BCC L3 STA $1A RTS L3 STA (NODE),Y STA NODE+1 LDA TEMP STA NODE LDY #0 BEQ L1 L2 LDY #0 enter terminating dummy, TYA a string greater than STA (TEXT),Y can occur in the list INY LDX #6 LDA #$FF DUMMY STA (TEXT),Y INY INY DEX BNE DUMMY LDY #2 LDX #5 LDA #$D D1 STA (TEXT),Y INY INY DEX BNE D1 LDY #0 LDA TEXT STA (NODE),Y INY LDA TEXT+1 STA (NODE),Y INY LDA NODE link dummy to itself STA FINISH at address called STA (NODE),Y FINISH INY LDA NODE+1 STA FINISH+1 STA (NODE),Y SEC LDA FINISH SBC #>SLIST STA COUNT LDA FINISH+1 SBC #<SLIST STA COUNT+1 LSR COUNT+1 ROR COUNT LSR COUNT+1 ROR COUNT RTS OFFSET LDA INDEX offset into HEADLIST STA PTR LDA INDEX+1 STA PTR+1 ASL PTR ROL PTR+1 twice the index LDA PTR ADC #>HEADLIST STA PTR LDA PTR+1 ADC #<HEADLIST STA PTR+1 RTS FETCH JSR OFFSET fetch node address at LDY #0 indexed location LDA (PTR),Y STA HOLD INY LDA (PTR),Y STA HOLD+1 RTS STORE JSR OFFSET store node address at LDY #0 indexed location LDA HOLD STA (PTR),Y INY LDA HOLD+1 STA (PTR),Y RTS MAKELIST LDA COUNT build list of nodes STA N in their linked order LDA COUNT+1 STA N+1 LDA #0 STA INDEX STA INDEX+1 LDY #2 init pointers LDA (START),Y STA HOLD INY LDA (START),Y STA HOLD+1 LDA #>HEADLIST STA NODE LDA #<HEADLIST STA NODE+1 pointers set M1 JSR STORE INY LDA (HOLD),Y STA NEXTA INY LDA (HOLD),Y STA NEXTA+1 LDA FINISH+1 STA (HOLD),Y DEY LDA FINISH STA (HOLD),Y DEC N BNE M2 LDA N+1 BEQ SORT DEC N+1 M2 LDA NEXTA STA HOLD LDA NEXTA+1 STA HOLD+1 INC INDEX BNE M1 INC INDEX+1 JMP M1 SORT LDA COUNT get NEXTA, NEXTB from STA N HEADLIST LDA COUNT+1 STA N+1 SO1 LDA #0 STA INDEX STA INDEX+1 SO2 JSR FETCH LDA HOLD STA NEXTA LDA HOLD+1 STA NEXTA+1 INC INDEX BNE SO3 INC INDEX+1 SO3 JSR FETCH LDA HOLD STA NEXTB LDA HOLD+1 STA NEXTB+1 JSR MERGE LDY #2 LDA (START),Y STA HOLD INY LDA (START),Y STA HOLD+1 LDA INDEX temp storage of index STA KEEP LDA INDEX+1 STA KEEP+1 LSR INDEX+1 halve the index ROR INDEX JSR STORE LDA KEEP restore index STA INDEX LDA KEEP+1 STA INDEX+1 INC INDEX BNE SO4 INC INDEX+1 SO4 SEC LDA N SBC INDEX STA KEEP LDA N+1 SBC INDEX+1 BNE SO2 LDA KEEP CMP #1 BCC SO5 BNE SO2 JSR FETCH LDA INDEX STA KEEP LDA INDEX+1 STA KEEP+1 LSR INDEX+1 ROR INDEX JSR STORE LDA KEEP STA INDEX LDA KEEP+1 STA INDEX+1 SO5 INC N BNE SO6 INC N+1 SO6 LSR N+1 ROR N LDA N+1 BNE SO7 LDA N CMP #1 BNE SO7 RTS SO7 JMP SO1 MERGE LDA START STA NODE LDA START+1 STA NODE+1 JSR VALUES JSR UPDATE ME1 JSR VALUES JSR UPDATE LDA NODE CMP FINISH BNE ME1 LDA NODE+1 CMP FINISH+1 BNE ME1 RTS VALUES LDY #0 get string addresses LDA (NEXTA),Y STA S1 LDA (NEXTB),Y STA S2 INY LDA (NEXTA),Y STA S1+1 LDA (NEXTB),Y STA S2+1 RTS UPDATE JSR COMPARE LDA FLAG BEQ U1 *LINK TO S2, POINT TO S2, ADVANCE NEXTB TO ITS LINK LDY #2 LDA NEXTB STA (NODE),Y INY LDA NEXTB+1 STA (NODE),Y LDA NEXTB STA NODE LDA NEXTB+1 STA NODE+1 LDY #2 LDA (NODE),Y STA NEXTB INY LDA (NODE),Y STA NEXTB+1 RTS *as above, but for S1 and NEXTA U1 LDY #2 LDA NEXTA STA (NODE),Y INY LDA NEXTA+1 STA (NODE),Y LDA NEXTA STA NODE LDA NEXTA+1 STA NODE+1 LDY #2 LDA (NODE),Y STA NEXTA INY LDA (NODE),Y STA NEXTA+1 RTS COMPARE LDY #0 STY FLAG assume S1<=S2 LDA LINE find n-th CR CMP #1 BEQ CLOOP TAX C1 DEX BEQ C2 C5 INY LDA (S1),Y CMP #$D BNE C5 BEQ C1 C2 CLC TYA ADC S1 advance starting address STA S1 to line beginning LDA S1+1 ADC #0 STA S1+1 LDA LINE find n-th CR TAX LDY #0 C3 DEX BEQ C4 C6 INY LDA (S2),Y CMP #$D BNE C6 BEQ C3 C4 CLC TYA ADC S2 advance starting address STA S2 to line beginning LDA S2+1 ADC #0 STA S2+1 LDY #0 CLOOP INY character comparison loop LDA (S1),Y CMP #$D BEQ CL1 BIT LETTER BEQ CL2 AND #$DF capitalize for comparison CL2 STA HOLD LDA (S2),Y CMP #$D BEQ CL3 BIT LETTER BEQ CL4 AND #$DF CL4 CMP HOLD compare characters BEQ CLOOP BCS CL1 CL3 LDA #1 STA FLAG S2<S1 CL1 RTS PRESHOW LDA START STA NEXTA LDA START+1 STA NEXTA+1 FIND.S LDY #2 find next string LDA (NEXTA),Y STA NODE INY LDA (NEXTA),Y STA NODE+1 STA NEXTA+1 LDA NODE STA NEXTA LDY #0 LDA (NODE),Y STA HOLD INY LDA (NODE),Y STA HOLD+1 LDY #0 LDA (HOLD),Y BEQ P1 TAX LDA FLAG non-zero when saving BEQ PRINT to disk LDA MARK JSR COUT PRINT INY LDA (HOLD),Y ORA #$80 for benefit of screen JSR COUT BIT $C000 BPL P2 LDA $C000 CMP #$9B BEQ DONE P2 DEX BNE PRINT JMP FIND.S P1 LDA FLAG check for disk save BEQ DONE LDA MARK restore closing mark JSR COUT DONE BIT $C010 RTS LST NOA,NOV