*\ :ts=8 bk=0 * * BPD.asm: Stands for "Boot PAL, Dammit!" Written as an alternative to * all those other programs that attempt to set PAL mode, and * never get it right. * * See, in order for PAL mode to *truly* take effect, you have * to convince graphics.library that it's running PAL. To do * that, you have to get in before graphics configures itself * and set the PAL bit in the ECS agnus. And in order to do * *that*, you have to be part of the boot sequence. * * So this program does precisely that by creating and * installing a resident RomTag into the system that survives * reboots. * * Usage: BPD [ '?' | 'REMOVE' | 'NTSC' ] * * Thanks to Bryce Nesbitt for providing me with an example * of how to create resident RomTags. * * Leo L. Schwab, Silent Software, Inc. 9010.20 * NTSC hack added (inspired by Nico Francois) 9011.11 */ include 'exec/types.i' include 'exec/execbase.i' include 'exec/resident.i' include 'exec/memory.i' xref _LVOFindResident xref _LVOAllocMem xref _LVOCopyMem xref _LVOSumKickData xref _LVODisable xref _LVOEnable xref _LVOOpenLibrary xref _LVOCloseLibrary xref _LVOOutput xref _LVOWrite xref _vposr ; Custom chip register TAG_PRI EQU 100 ; Above graphics.library. **************** * And we're off! * SECTION BPD,CODE Hello: movea.l a0,a3 ; Save argument pointer movea.l 4.w,a6 ; ExecBase lea dosname(pc),a1 moveq #0,d0 jsr _LVOOpenLibrary(a6) moveq #20,d2 move.l d0,d6 beq openfailed lea Name(pc),a1 jsr _LVOFindResident(a6) * See if ECS Agnus is installed. We check for ID's 0x20 and 0x30. Anything * else is considered something we don't know how to deal with. * move.w _vposr,d1 ; Get ID bits andi.w #$3F00,d1 ; Mask off extraneous stuff. cmpi.w #$3000,d1 ; Is it NTSC ECS Agnus? beq.s 1$ cmpi.w #$2000,d1 ; Is it PAL ECS Agnus? bne notecs * Scan command line to see what the user wants to do. * 1$ move.b (a3)+,d1 cmpi.b #' ',d1 beq.s 1$ ; Skip past leading blanks. cmpi.b #'?',d1 ; Usage line beq usage cmpi.b #'r',d1 ; Remove beq remove cmpi.b #'R',d1 beq remove cmpi.b #'n',d1 ; NTSC beq.s 2$ cmpi.b #'N',d1 bne.s install * Exceedingly cheap hack to support PAL machines that want to boot into * NTSC mode (inspired by Nico Francois' NTSC-PAL programs). This will * cause the bootnode to stuff a 0 into the magic ECS Agnus register, * which should make the system come up in NTSC mode. * 2$ clr.w movearg * No meaningful command line arguments supplied, so we'll assume s/he wants * to install it. * install tst.l d0 bne installed ; Already installed * Allocate memory to survive reboot. * move.l #RESIDENT_SIZ,d0 move.l #MEMF_CHIP!MEMF_PUBLIC,d1 jsr _LVOAllocMem(a6) tst.l d0 beq nomem move.l d0,a2 ; Save pointer * Relocate pointers to destination. * lea RelTable(pc),a0 lea ResStart(pc),a1 sub.l a1,d0 ; Compute relocation difference move.l d0,d7 ; Save it for later 2$ move.l (a0)+,d0 ; Fetch address of thing to relocate beq.s 3$ ; NULL-terminated array move.l d0,a1 add.l d7,(a1) ; Add offset to thing bra.s 2$ 3$: * Set a few more things atomically. * jsr _LVODisable(a6) * Insert MemList into system KickMem list. (I would have used AddHead(), * but SysBase.KickMemPtr is not a struct List. Oh well... * lea MyMemList(pc),a0 ; Address of our memlist move.l KickMemPtr(a6),d0 move.l d0,(a0) ; Append current system entry to us add.l d7,a0 ; Add relocation offset move.l a0,KickMemPtr(a6) ; Add us to system * Insert into Resident module list. This is done so that running BPD twice * before rebooting will not cause it to be installed twice (that would be * bad, you see...). * lea MyResModule(pc),a0 ; Our ResModule array move.l ResModules(a6),d0 ; Already ResModules here? beq.s 4$ bset.l #31,d0 ; Yes, set special indirection flag move.l d0,4(a0) ; and store pointer. 4$: add.l d7,a0 ; Add relocation offset move.l a0,ResModules(a6) ; Insert us into Exec list * Insert into KickTagPtr list. * lea MyKickTagPtr(pc),a0 ; Our KickTagPtr array move.l KickTagPtr(a6),d0 ; Already KickTagPtrs here? beq.s 5$ bset.l #31,d0 ; Yep... move.l d0,4(a0) 5$: add.l d7,a0 ; Relocate... move.l a0,KickTagPtr(a6) ; Insert us into Exec list * Copy resident code and data into allocated memory. * lea ResStart(pc),a0 ; src movea.l a2,a1 ; dest move.l #RESIDENT_SIZ,d0 jsr _LVOCopyMem(a6) * Recompute KickCheckSum. * jsr _LVOSumKickData(a6) move.l d0,KickCheckSum(a6) * Return to reality. * jsr _LVOEnable(a6) lea BPD.msg(pc),a2 bsr climsg lea installed.msg(pc),a2 bsr climsg exit lea change.msg(pc),a2 bsr climsg eexit movea.l d6,a1 jsr _LVOCloseLibrary(a6) openfailed move.l d2,d0 ; D2 usually set to 0 by climsg rts errexit moveq #20,d2 bra.s eexit **************** * User wants to remove the goodie. * remove tst.l d0 beq.s nothere ; Nothing to remove * Remove ourselves from the system lists. First the KickMemPtr list. * lea KickMemPtr(a6),a1 1$ movea.l a1,a0 move.l (a0),d1 beq.s nothere ; Couldn't find MemList entry. movea.l d1,a1 cmp.l ML_ME+ME_ADDR(a1),d0 ; See if it's us. bne.s 1$ move.l (a1),(a0) ; Pull us from the list. * Now try to find us in the KickTagPtr list. * lea KickTagPtr(a6),a0 tablehop move.l (a0),d1 beq.s nothere ; End of tables; Couldn't find us. bclr.l #31,d1 movea.l d1,a1 tableloop move.l (a1)+,d1 bgt.s 2$ lea -4(a1),a0 ; Indirection, get pointer to it bra.s tablehop ; and loop to next table 2$ cmp.l d1,d0 ; Is it us? bne.s tableloop * We found ourselves. Now perform remove. (Since I know the format of * the table I installed, I can make assumptions about the data I'm zapping.) * move.l (a1),d1 ; Get pointer to next table. btst.b #7,(a0) ; Did we get here by indirection? bne.s 3$ bclr.l #31,d1 ; No, clear indirection bit. 3$ move.l d1,(a0) ; Patch to jumper over us. * Reset KickCheckSum. * jsr _LVOSumKickData(a6) move.l d0,KickCheckSum(a6) lea BPD.msg(pc),a2 bsr.s climsg lea removed.msg(pc),a2 bsr.s climsg bra.s exit **************** * Diagnostic messages. * installed lea BPD.msg(pc),a2 bsr.s climsg lea already.msg(pc),a2 bsr.s climsg bra.s errexit nomem lea nomem.msg(pc),a2 bsr.s climsg bra.s errexit notecs lea notecs.msg(pc),a2 bsr.s climsg bra.s errexit nothere lea BPD.msg(pc),a2 bsr.s climsg lea not.msg(pc),a2 bsr.s climsg lea installed.msg(pc),a2 bsr.s climsg bra errexit usage lea ID(pc),a2 bsr.s climsg lea usage.msg(pc),a2 bsr.s climsg bra exit **************** * Routine to print to CLI. * climsg exg d6,a6 ; Error string pointer in A2 jsr _LVOOutput(a6) move.l d0,d1 beq.s noout ; No output channel move.l a2,d2 ; Compute string length 1$ tst.b (a2)+ bne.s 1$ suba.l d2,a2 move.l a2,d3 subq.l #1,d3 jsr _LVOWrite(a6) ; Write string noout exg d6,a6 moveq #0,d2 rts **************** * Relocation table. Contains pointers to addresses to be moved. * RelTable dc.l RL0,RL1,RL2,RL3,RL4,RL5,RL6,RL7,RL8,0 * Diagnostic strings. * dosname dc.b 'dos.library',0 BPD.msg dc.b 'BPD ',0 already.msg dc.b 'already ' installed.msg dc.b 'installed.',10,0 not.msg dc.b 'not ',0 notecs.msg dc.b 'ECS Agnus not present.',10,0 nomem.msg dc.b 'No memory for resident RomTag.',10,0 removed.msg dc.b 'removed.',10,0 usage.msg dc.b 'This program may be freely distributed.',10,10 dc.b 'Usage: BPD [REMOVE | NTSC]',10,0 change.msg dc.b 'Change will take effect on next reboot.',10,0 ************************************************************************ * The resident stuff intended to survive reboot. * ResStart: cnop 0,2 * The Resident structure. * RomTag: ;STRUCTURE RT,0 dc.w RTC_MATCHWORD ; UWORD RT_MATCHWORD RL0: dc.l RomTag ; APTR RT_MATCHTAG RL1: dc.l ResEnd ; APTR RT_ENDSKIP dc.b RTF_COLDSTART ; UBYTE RT_FLAGS dc.b 1 ; UBYTE RT_VERSION dc.b NT_BOOTNODE ; UBYTE RT_TYPE dc.b TAG_PRI ; BYTE RT_PRI RL2: dc.l Name ; APTR RT_NAME RL3: dc.l ID ; APTR RT_IDSTRING RL4: dc.l PALTrick ; APTR RT_INIT * The MemList. * MyMemList: ; STRUCTURE ML,LN_SIZE ; STRUCTURE LN,0 dc.l 0 ; APTR LN_SUCC dc.l 0 ; APTR LN_PRED dc.b NT_MEMORY ; UBYTE LN_TYPE dc.b 0 ; BYTE LN_PRI RL5: dc.l Name ; APTR LN_NAME dc.w 1 ; UWORD ML_NUMENTRIES ; STRUCTURE ME,0 RL6: dc.l ResStart ; APTR ME_ADDR dc.l RESIDENT_SIZ ; ULONG ME_LENGTH * Array of pointers to RomTag structures describing things to be made * resident. If the entry in the array has bit 31 set (0x80000000), then * the pointer (sans high bit) is in fact a pointer to *another* array of * RomTag pointers. A NULL terminates the array. * (These also need relocation.) * RL7: MyKickTagPtr dc.l RomTag,0 RL8: MyResModule dc.l RomTag,0 * Name and ID strings. (I wonder if Xoper will show these?) * Name dc.b 'BPD.resident',0 ID dc.b 'BPD (Boot PAL, Dammit!) v1.1 by Leo L. Schwab ' dc.b '(11 Nov 1990)',13,10,0 **************** * Why we went to all this trouble. Kind of anti-climactic, isn't it? * (PAL Now Brown Cow) * PALTrick: btst.b #6,$BFE001 ; Check mouse button beq.s palexit ; If pressed, let user boot normally movearg EQU *+2 ; The immediate argument to the MOVE move.w #$0020,$DFF1DC ; Turn on PAL bit in ECS Agnus palexit: moveq #0,d0 rts ResEnd EQU * RESIDENT_SIZ EQU ResEnd-ResStart ; Size of preserved block. END