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Text File | 1996-12-21 | 12.2 KB | 910 lines

/************************************************************************** * * lOADER FOR 6502 RELOCATABLE BINARY FORMAT * * tHE LOADER SUPPORTS 16 BIT O65 VERSION 1 FILES WITHOUT UNDEFINED * REFERENCES. aLSO IT DOESN'T LIKE PAGEWISE RELOCATION AND 65816 * CODE, BECAUSE THERE ARE DIFFERENT/ADDITIONAL RELOCATION ENTRIES. * * tHE SUPPORT ROUTINES, THAT HAVE TO BE CHANGED ARE AT THE END OF THE * FILE. tHE STUFF IN THIS FILE IS IN ABSOLUTE FORMAT (WELL, YOU HAVE TO * BOOTSTRAP FROM SOMETHING :-) * tHE SUPPORT ROUTINES FOR THE FILE HANDLING ARE FOR THE OPERATING SYSTEM * os/a65, AS OF VERSION 1.3.10B. tHE FIRST PART OF THE FILE (WRAPPED IN * "#IFDEF c64") SHOWS HOW TO USE IT WITH A c64, FOR EXAMPLE. * * tHE SUBROUTINE 'LOADER' IS CALLED WITH A FILE DESCRIPTOR, THAT HAS A * MEANING FOR THE SUPPORT ROUTINES, IN THE x REGISTER. * tHE FILE MUST ALREADY BE OPEN. aLSO BINIT MUST HAVE BEEN CALLED BEFORE. * tHE LOADER DOESN'T CLOSE THE FILE. * * sUPPORT ROUTINES ARE: * BINITA = HI BYTE START ADDRESS MEMORY TO HANDLE, *X = HI BYTE LENGTH OF MEMORY TO HANDLE * BALLOCA/Y = LENGTH OF BLOCK -> X = MEMORY DESCRIPTOR * BFREE X = MEMORY BLOCK DESCRIPTOR TO FREE * GETBADRX = MEMORY DESCRIPTOR -> A/Y ADDRESS OF MEMORY BLOCK * * ZALLOCA = LENGTH OF NEEDED ZEROPAGE BLOCK. RETURNS A=ADDRESS * ZFREEA = ADDRESS OF BLOCK TO FREE * * FGETCX = FILE DESCRIPTOR, RETURNS READ BYTE (C=0) OR ERROR (C=1) * tHE ERROR IS PASSED THROUGH; FGETC BLOCKS IF NO DATA * AVAILABLE * FGETBX = FILEDESCRIPTOR, A/Y = ADDRESS OF BLOCK DESCRIPTOR, * I.E. A WORD START ADDRESS AND A WORD LENGTH OF BLOCK. * RETURNS (C=0) OR ERROR IN ACCU (C=1). * **************************************************************************/ /************************************************************************** * tHIS PART IS A BINDING FOR A c64 * TO SHOW HOW IT WORKS */ #DEFINEc64 #IFDEF c64 SYSMEM=$033C SYSZP=$57 .WORD $0801 *=$801 .WORD NEXTL .WORD 10 .BYT $9E, "2080",0 NEXTL.WORD 0 .DSB 2080-*, 0 C64LOAD.( LDA #>prgend+255 LDX #>$a000-prgend JSR BINIT; INIT MEMORY HANDLING LDA #7 LDX #<FNAME LDY #>FNAME JSR $FFBD; SETFNPAR LDA #2 LDX #11 LDY #0 JSR $FFBA; SETFPAR JSR $FFC0; OPEN BCS END LDX #2 JSR $FFC6; CHKIN BCS END JSR LOADER; DON'T CARE ABOUT X, CHKIN DID IT PHP PHA JSR $FFCC; CLRCH LDA #2 JSR $FFC3; CLOSE PLA PLP ENDRTS FNAME;.ASC "EXAMPLE",0 .BYT $45, $58, $41, $4D, $50, $4C, $45, 0 .) FGETC.( JSR $FFCF PHP PHA BCC CARRY LDA #"c" JSR $FFD2 PLA PHA CARRY JSR HEXOUT LDA #$20 JSR $FFD2 PLA PLP RTS .) HEXOUT.( PHA LSR LSR LSR LSR JSR NIBOUT PLA NIBOUTAND #$0F CLC ADC #$30 CMP #$3A BCC OK ADC #$41-$3A-1 OKJMP $FFD2 .) ZALLOC.( CMP #$80; SAVE FROM $90 UPWARD = os, BELOW IS ONLY BASIC BCS END LDA #$10 ENDRTS .) ZFREE.( CLC RTS .) #ENDIF /************************************************************************** * hERE IS THE REAL LOADER CODE */ #INCLUDE "FILE.DEF" #DEFINEe_nomem<-40 #DEFINEe_fversion<-41 LOADER .( P1=SYSZP P2=SYSZP+2 -SYSZP+=4 TMP=SYSMEM FILE=SYSMEM+1 -SYSMEM+=2 HEADER=SYSMEM -SYSMEM+=hdr_len TEXTB=SYSMEM; MEMORY BLOCK id TEXTA=SYSMEM+1; ADDRESS OF BLOCK TEXTL=SYSMEM+3; ADDRESS OF BLOCK TEXTD=SYSMEM+5; DIFFERENCE TO ASSEMBLE ADDRESS -SYSMEM+=7 DATAB=SYSMEM DATAA=SYSMEM+1 DATAL=SYSMEM+3 DATAD=SYSMEM+5 -SYSMEM+=7 BSSB=SYSMEM BSSA=SYSMEM+1 BSSD=SYSMEM+3 -SYSMEM+=5 ZEROA=SYSMEM ZEROD=SYSMEM+1 -SYSMEM+=3 STX FILE JSR FGETC BCS END STA TMP JSR FGETC BCS END TAY LDA TMP CPY #0 BNE RT CMP #1 BEQ LOAD RT LDA #e_fversion; OK, BUT NOT THIS VERSION ENDSEC RTS LOAD.( LDA #<HEADER STA P1 LDA #>HEADER STA P1+1 LDA #<hdr_len STA P1+2 LDA #>hdr_len STA P1+3 LDX FILE LDA #<P1 LDY #>P1 JSR FGETB BCS END ; HEADER LOADED, CHECK MAGIC AND VERSION LDA HEADER+hdr_magic CMP #$6F BNE END LDA HEADER+hdr_magic+1 CMP #"6" BNE END LDA HEADER+hdr_magic+2 CMP #"5" BNE END LDA HEADER+hdr_version CMP #0 BNE END LDA HEADER+hdr_mode+1 AND #%11110000 BNE END ; NOW ALLOCATE BUFFERS LDA HEADER+hdr_tlen LDY HEADER+hdr_tlen+1 STA TEXTL STY TEXTL+1 JSR BALLOC STX TEXTB BCS NO_TEXT2 JSR GETBADR STA TEXTA STY TEXTA+1 SEC SBC HEADER+hdr_tbase STA TEXTD TYA SBC HEADER+hdr_tbase+1 STA TEXTD+1 LDA HEADER+hdr_dlen LDY HEADER+hdr_dlen+1 STA DATAL STY DATAL+1 JSR BALLOC STX DATAB BCS NO_DATA2 NO_TEXT2 BCS NO_TEXT1 JSR GETBADR STA DATAA STY DATAA+1 SEC SBC HEADER+hdr_dbase STA DATAD TYA SBC HEADER+hdr_dbase+1 STA DATAD+1 LDA HEADER+hdr_blen LDY HEADER+hdr_blen+1 JSR BALLOC STX BSSB BCS NO_BSS NO_TEXT1 BCS NO_TEXT NO_DATA2 BCS NO_DATA JSR GETBADR STA BSSA STY BSSA+1 SEC SBC HEADER+hdr_bbase STA BSSD TYA SBC HEADER+hdr_bbase+1 STA BSSD+1 LDA HEADER+hdr_zlen JSR ZALLOC BCS NO_ZERO STA ZEROA SEC SBC HEADER+hdr_zbase STA ZEROD LDA #0 STA ZEROD+1 JMP DO_LOAD &NO_FILE LDA ZEROA JSR ZFREE NO_ZERO LDX BSSB JSR BFREE NO_BSSLDX DATAB JSR BFREE NO_DATALDX TEXTB JSR BFREE NO_TEXTRTS DO_LOAD; LOAD OPTIONS (I.E. IGNORE THEM NOW) JSR FGETC BCS NO_FILE CMP #0 BEQ LOAD_TEXT TAY DEY OPTLJSR FGETC BCS NO_FILE DEY BNE OPTL BEQ DO_LOAD LOAD_TEXT; LOAD TEXT SEGMENT LDX FILE LDA #<TEXTA LDY #>TEXTA JSR FGETB BCS NO_FILE LDX FILE LDA #<DATAA LDY #>DATAA JSR FGETB BCS NO_FILE ; CHECK NUMBER OF UNDEFINED REFERENCES LDX FILE JSR FGETC &NO_FILE2 BCS NO_FILE CMP #0 BNE NO_FILE; WE HAVE SOME -> NOT HANDLED LDX FILE JSR FGETC BCS NO_FILE CMP #0 BNE NO_FILE ; OK, TEXT SEGMENTS LOADED, NOW RELOCATE LDA TEXTA SEC SBC #1 STA P1 LDA TEXTA+1 SBC #0 STA P1+1 JSR TREL LDA DATAA SEC SBC #1 STA P1 LDA DATAA+1 SBC #0 STA P1+1 JSR TREL LDA TEXTA; RETURN START OF TEXT SEGMENT LDY TEXTA+1 CLC RTS .) TREL.( LDX FILE JSR FGETC NO_FILE1 BCS NO_FILE2 CMP #0 BEQ RELOC_RTS CMP #255 BNE T1 LDA #254 CLC ADC P1 STA P1 BCC TREL INC P1+1 JMP TREL T1CLC ADC P1 STA P1 BCC T1A INC P1+1 T1A; P1 IS THE RELOCATION ADDRESS LDX FILE JSR FGETC BCS NO_FILE1 TAY AND #a_mask STA TMP TYA AND #a_fmask JSR GETRELDIFF LDY TMP CPY #a_adr BNE T2 LDY #0 CLC ADC (P1),Y STA (P1),Y INY TXA ADC (P1),Y STA (P1),Y JMP TREL T2 CPY #a_low BNE T3 LDY #0 CLC ADC (P1),Y STA (P1),Y JMP TREL T3 CPY #a_high BNE TREL STA P2 STX P2+1 LDX FILE JSR FGETC CLC ADC P2; JUST GET THE CARRY BIT LDY #0 LDA P2+1; RELOCATE HIGH BYTE ADC (P1),Y STA (P1),Y JMP TREL RELOC_RTS CLC RTS .) GETRELDIFF .(; COMPARING WITH seg_undef WOULD GIVE A WAY ; TO GET LABEL VALUE HERE FOR UNDEFINED REFS CMP #seg_text BNE NOTEXT LDA TEXTD LDX TEXTD+1 RTS NOTEXTCMP #seg_data BNE NODATA LDA DATAD LDX DATAD+1 RTS NODATACMP #seg_bss BNE NOBSS LDA BSSD LDX BSSD+1 RTS NOBSSCMP #seg_zero BNE NOZERO LDA ZEROD LDX ZEROD+1 NOZERORTS .) .) /************************************************************************** * hERE COME THE SUPPORT ROUTINES * * FIRST IS A SIMPLE AND BASIC IMPLEMENTATION OF FGETB, JUST USING FGETC */ FGETB.( P=SYSZP -SYSZP+=2 FILE=SYSMEM L=SYSMEM+1 -SYSMEM+=3 STX FILE; X=FILE, A=ZP-ADR OF ADDRESS, Y=ZP-ADR OF LEN STA P STY P+1 LDY #3 LDA (P),Y STA L+1 DEY LDA (P),Y STA L DEY LDA (P),Y PHA DEY LDA (P),Y STA P PLA STA P+1 LOOPLDX FILE JSR FGETC; THIS IS A SIMPLE IMPLEMENTATION BCS END LDY #0 STA (P),Y INC P BNE L0 INC P+1 L0 LDA L BNE L1 DEC L+1 L1DEC L LDA L ORA L+1 BNE LOOP CLC END RTS .) /************************************************************************** * SUPPORT FOR MEMORY ALLOCATION * * tHESE ROUTINES ARE TAKEN FROM A PRELIMINARY slip IMPLEMENTATION, AS OF * os/a65 VERSION 1.3.10B */ #DEFINEmaxslot8 /**********************************************************************/ /* nEW MEMORY MANAGEMENT FOR ip BUFFERS */ /* EXPORTS */ /* BINIT */ /* BALLOC, BFREE, BTRUNC, BSPLIT, BREALLOC */ /*GETBADR, GETBLEN */ #DEFINEminbuf8 #DEFINEminmask%11111000 .( SLOTLADR =SYSMEM SLOTHADR =SYSMEM+maxslot SLOTLLEN =SYSMEM+maxslot*2 SLOTHLEN =SYSMEM+maxslot*3 -SYSMEM+=maxslot*4 FLIST =SYSMEM SLOT=SYSMEM+2 -SYSMEM+=3 P=SYSZP P2=SYSZP+2 P3=SYSZP+4 P4=SYSZP+6 -SYSZP+=8 /* INIT MEMORY MANAGEMENT */ &BINIT.( STA P+1; HI BYTE STARTADRESS BUFFER STX P2+1; HI BYTE LENGTH OF BUFFER LDA #0 TAY L0STA SLOTLADR,Y STA SLOTHADR,Y INY CPY #maxslot BCC L0 STA P TAY STA (P),Y INY STA (P),Y INY STA (P),Y INY LDA P2+1 STA (P),Y LDA P STA FLIST LDA P+1 STA FLIST+1 CLC RTS .) /* A/Y = SIZE OF BUFFER TO BE ALLOCATED -> X BUFFER-id */ &BALLOC.( /* WALK ALONG FREELIST, AND TAKE FIRST MATCHING BUFFER LENGTH IS MADE A MULTIPLE OF 8 (FOR FREELIST CONNECTORS */ PHA JSR GETBSLOT PLA BCC GOTSLOT LDA #e_nomem RTS GOTSLOT STX SLOT ADC #minbuf-1 AND #minmask STA SLOTLLEN,X TYA ADC #0 STA SLOTHLEN,X LDA #0 STA P2 STA P2+1 LDA FLIST STA P LDA FLIST+1 STA P+1 L0 LDY #2 LDA (P),Y SEC SBC SLOTLLEN,X STA P3 INY LDA (P),Y SBC SLOTHLEN,X STA P3+1 BCS FOUND LDA P STA P2 LDA P+1 STA P2+1 LDY #1 LDA (P2),Y STA P+1 DEY LDA (P2),Y STA P ORA P+1 BNE L0 OOPSLDA #e_nomem SEC RTS FOUND /* OK, WE FOUND A FREE BUFFER: P POINTS TO THE BUFFER, P2 TO THE PREVIOUS ONE. P3 IS THE LENGTH OF THE FREE BUFFER MINUS THE NEEDED SIZE. iF THE BUFFER IS LONGER THAN NEEDED, CREATE A NEW FREE BUFFER, THEN LINK NEW BUFFER TO FREELIST */ LDA P/* SAVE BUFFER ADDRESS */ STA SLOTLADR,X LDA P+1 STA SLOTHADR,X LDA P3 /* CHECK LENGTH */ ORA P3+1 BEQ NOCREATE LDA P/* GET ADDRESS OF NEW FREE BUFFER */ CLC ADC SLOTLLEN,X STA P4 LDA P+1 ADC SLOTHLEN,X STA P4+1 LDY #0/* COPY NEXT POINTER */ LDA (P),Y STA (P4),Y INY LDA (P),Y STA (P4),Y INY/* SET NEW LENGTH */ LDA SLOTLLEN,X STA (P),Y LDA P3 STA (P4),Y INY LDA SLOTHLEN,X STA (P),Y LDA P3+1 STA (P4),Y LDA P4 STA P LDA P4+1 STA P+1 NOCREATE LDA P2 ORA P2+1 BEQ FREESTART LDY #0 LDA P STA (P2),Y INY LDA P+1 STA (P2),Y CLC BCC GETA FREESTART LDA P STA FLIST LDA P+1 STA FLIST+1 CLC GETA LDA SLOTLADR,X LDY SLOTHADR,X RTS .) /* FREE BUFFER (id=XR) */ &BFREE.( LDA SLOTHADR,X STA P3+1 LDA SLOTLADR,X STA P3 ORA P3+1 BEQ END2 LDY #2 LDA SLOTLLEN,X STA (P3),Y INY LDA SLOTHLEN,X STA (P3),Y LDA #0 STA SLOTHADR,X STA SLOTLADR,X LDA FLIST ORA FLIST+1 BNE OK/* NO FREE BUFFER SO FAR? */ LDA P3 STA FLIST LDA P3+1 STA FLIST+1 LDY #0 TYA STA (P3),Y INY STA (P3),Y END2CLC RTS OK LDA #0 STA P2 STA P2+1 LDA FLIST STA P LDA FLIST+1 STA P+1 /* WE HAVE TO FIND THE PLACE WHERE TO PUT THE BUFFER IN THE ORDERED FREE LIST. tHEN WE HAVE TO CHECK IF WE CAN MERGE FREE BUFFERS */ LOOP LDA P3+1 CMP P+1 BCC FOUND BNE NEXT LDA P3 CMP P BCC FOUND NEXT LDA P STA P2 LDA P+1 STA P2+1 LDY #0 LDA (P2),Y STA P INY LDA (P2),Y STA P+1 ORA P BNE LOOP BEQ FOUND END CLC RTS FOUND/* P2 IS THE BUFFER BEFORE THE ONE TO BE FREED, P THE ONE BEHIND. P3 IS THE BUFFER TO BE INSERTED */ LDA P2 ORA P2+1 BNE FOK ; INSERT BEFORE THE FIRST FREE BUFFER SO FAR LDY #0 LDA FLIST STA (P3),Y INY LDA FLIST+1 STA (P3),Y LDA P3 STA FLIST LDY P3+1 STY FLIST+1 JSR BMERGE CLC RTS FOK; INSERT TO LIST LDY #1 LDA P+1;LDA (P2),Y STA (P3),Y DEY LDA P;LDA (P2),Y STA (P3),Y LDA P3 STA (P2),Y INY LDA P3+1 STA (P2),Y LDA P3 LDY P3+1 JSR BMERGE LDA P2 LDY P2+1 JSR BMERGE CLC RTS .) /* GET ADRESS OF BUFFER */ &GETBADR .( LDA SLOTLADR,X LDY SLOTHADR,X CLC RTS .) /* GET LENGTH OF BUFFER */ &GETBLEN .( LDA SLOTLLEN,X LDY SLOTHLEN,X CLC RTS .) /* GET FREE BUFFER-id SLOT */ GETBSLOT .( LDX #0 L0 CLC LDA SLOTLADR,X ORA SLOTHADR,X BEQ FOUND INX CPX #maxslot BCC L0 FOUND RTS .) /* CHECK IF TWO BUFFERS (I.E. A/Y PLUS FOLLOWING) CAN BE MERGED */ BMERGE.( STA P STY P+1 LDY #2 CLC LDA (P),Y ADC P STA P3 INY LDA (P),Y ADC P+1 STA P3+1 LDY #0 LDA (P),Y CMP P3 BNE NOMERGE INY LDA (P),Y CMP P3+1 BNE NOMERGE MERGE LDY #2 CLC LDA (P3),Y ADC (P),Y STA (P),Y INY LDA (P3),Y ADC (P),Y STA (P),Y LDY #0 LDA (P3),Y STA (P),Y INY LDA (P3),Y STA (P),Y NOMERGE CLC RTS .) .) prgend