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File name MBoot.asm_Sep78.pdf

MBoot.asm 2-Sep-78 17:21:64 Page 1 ALTO MESA BOOT LOADER - MBoot.asm LOADED ALMOST ANYWHERE AND EXECUTED R. Johnsson - 20 Feb 76 Last edited March 20, 1978 6:40 PM . TITL BOOT .TXTM B .ENT MBOOT .ENT SwatFlag .SREL MBOOT: BOOT SwatFlag: BREAK .NREL .GET "Mesa-NovaDefs.asm" ;ACO is pointer to argument list BOOT: MOV 0 2 LOA 3 0,2 POINTER TO BOOTMAP RECORD LOA 0 0,3 SN1 STA 0 DCB1+snl STA 0 DCB2+snl LOA 0 1,3 STA 0 OCB1+sn2 STA 0 DCB2+sn2 LOA 0 5,3 first page STA 0 DCB2+pagenumber NEG 0 0 -1 COM 0 0 STA 0 OCB1+pagenumber LOA 0 C6 ADO 3 0 STA 0 PGPTR LOA 0 1,2 STA 0 OCB1+diskaddress LOA 0 2,2 initial State STA 0 currentState BLTLOOP; LOA 0 C3 ADD 0 2 LOA 0 0,2 MOV 0 0 SNR JMP DOlT LOA 1 1,2 LOA 3 2,2 BLT do some BLTs JMP BLTLOOP C3: 3 DOlT: DIR ; NO MORE INTERRUPTS SUB 0 0 ;CLEAR SOME LOCATIONS LOA 2 PAGEl ; POINTER TO PAGE 1 LOCATIONS STA 0 OISP,2 ; DISPLAY OFF STA 0 IWW,2 ;WAKEUPS WAITING ; JSR .+1 ;RELOCATE CURSOR POINTERS ;CURFIX: LOA 1 POCURSORM1 ADD 3 1 STA 1 POCURSORM1 LOA 1 PMCURSORMl ADO 3 1 STA 1 PMCURSORMl LOA 0 PCURSORMl LOA 1 PMCURSORM1 LOA 3 CN16 BLT ;SAVE OLD CURSOR LOA 0 PMCURSORMl LOA 1 CURENO LOA 3 CN16 MBoot. asm 2-Sep-78 17:21:54 Page 2 BLT ;INSERT MESA CURSOR NOW FIXUP THE ADDRESSES IN THE DISK BLOCKS JSR .+1 F: MOV 3 1 ADDR OF FIXUP TO ACl LOA 2 DCB2 OFFSET OF FIRST DCB IS IN SECOND LOA 3 DCBl AND VICE VERSA ADD 1 2 ADD 1 3 THE FIXUPS STA 2 DCBl STA 3 DCBl NOW FIX THE HEADER AND LABEL ADDRESSES LOA 0 3 2 ADD 1 0 STA 0 3 2 LOA 0 4 2 ADD 1 0 STA 0 4 2 LOA 0 3 3 ADD 1 0 STA 0 3 3 LOA 0 4 3 ADD 1 0 STA 0 4 3 START THE DISK