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Assembly Source File | 1991-06-23 | 40.9 KB | 1,436 lines

; Nifty James' Famous Expanded Memory Disk Drive ; (C) Copyright 1987 by Mike Blaszczak. All Rights Reserved ; Version 1.01 of 24 May 1987 ; Version 1.10 of 25 May 1987 ; Version 1.15 of 31 May 1987 ; Version 1.20 of 16 Oct 1987 ; Version 1.30 of 05 Dec 1989 ; Version 1.40 of 23 Jun 1991 ; Shareware $15 Please register! ; Assemble with ; MASM NJRAMD; ; (Use MASM /DV286 NJRAMD; to assemble 286 version.) ; LINK NJRAMD; ; EXE2BIN NJRAMD.EXE NJRAMD.SYS ; DEL NJRAMD.EXE ; --> DEVICE DRIVER FORMAT FILE <-- ; --> REMEMBER TO USE EXE2BIN <-- ; --------------------------------------------------------------------------- ; ASCII Characters bell equ 7 ; bell character tab equ 9 ; tab character lf equ 10 ; linefeed cr equ 13 ; carriage return space equ 32 ; space eos equ '$' ; end of DOS string ; --------------------------------------------------------------------------- EMM equ 067h ; the E/EMS memory manager ; --------------------------------------------------------------------------- ; I/O Ports Speak equ 061h ; speaker port SpeakMask equ 011111110b ; mask for speaker set bit SpeakToggle equ 000000010b ; toggle bit for the speaker ; --------------------------------------------------------------------------- ; DOS Calls ; These are DOS functions used by the driver. DisplayOut equ 002h ; call to print a single character PrintString equ 009h ; call to print a '$' string GetDOSVersion equ 030h ; call to get the DOS version # ; --------------------------------------------------------------------------- ; E/EMM Routines ; These are the E/EMM functions that we use. (These are specific functions ; of the EMM interrupt.) E_PageBase equ 041h ; determine the Page Fram Base Addr E_Counts equ 042h ; determine free/total mem E_Open equ 043h ; open, allocate, obtain handle ID E_MapPage equ 044h ; map a logical page into window E_Version equ 046h ; get the E/EMM version number E_Save equ 047h ; save mapping context E_Restore equ 048h ; restore mapping context ; --------------------------------------------------------------------------- ; Driver Equates ; This is the media descriptor byte. Since our RAM drive is not 2 sided, ; does not have 8 sectors per track, and is not removable, we use 0F8h. ; At least, that's what the IBM DTR manual says. MediaD equ 0F8h ; These are equates used by the driver. They are all status and ; error flags, as defined in the DOS Technical Reference Manual. ; FEDCBA9876543210 <- BIT NUMBERS errorflag equ 01000000000000000b ; error bit flag busystat equ 00000001000000000b ; busy status bit flag donestat equ 00000000100000000b ; done status bit flag err_writeprot equ 0 ; write protect violation err_badunit equ 1 ; unknown unit number err_notready equ 2 ; device not ready err_unknown equ 3 ; unknown command err_CRC equ 4 ; error CRC command err_reqlen equ 5 ; bad request length err_seek equ 6 ; seek failure err_badmedia equ 7 ; bad media err_badsector equ 8 ; sector not found err_badwrite equ 10 ; write fault err_badread equ 11 ; read fault err_general equ 12 ; general failure ; --------------------------------------------------------------------------- ; Structure Definitions ; The structures defined here are used to find information in the ; various request header formats. Of course, being structures, they ; don't take up space... they are used to define offsets for the ; addressing of the request header. rq equ es:[bx] ; base address used in routines ; -- Request Header (General Format) rhead struc rlen db ? ; length of the structure unitn db ? ; unit number command db ? ; command code status dw ? ; status code (returned by us) db 8 dup(?); reserved bytes rhead ends ; -- Request Header (INIT Command) inithead struc db (type rhead) dup (?) units db ? ; number of units ndadro dw ? ; ending address offset ndadrs dw ? ; ending address segment bpboff dw ? ; BPB offset pointer bpbseg dw ? ; BPB segment pointer taglet db ? ; drive tag letter inithead ends ; -- Request Header (Media Check) mediahead struc db (type rhead) dup (?) media db ? ; our meida descriptor byte change db ? ; changed media flag mediahead ends ; -- Request Header (Build BPB) bbpbhead struc db (type rhead) dup (?) db ? ; media descriptor byte baoff dw ? ; transferr buffer address offset baseg dw ? ; transferr buffer address segment dw ? ; BIOS parameter block pointer dw ? ; BIOS parameter block pointer bbpbhead ends ; -- Request Header (Read and Write) rwhead struc db (type rhead) dup (?) db ? ; media descriptor byte tbaoff dw ? ; transferr buffer address offset tbaseg dw ? ; transferr buffer address segment count dw ? ; sector count strtsec dw ? ; starting sector number rwhead ends ; With these headers defined as they are, access to the request header ; and command info fields is greatly simplified. By setting ES:BX to ; point to the request header, the information can be easily referenced ; by using constructs such as ; mov rq.count,ax ; or ; mov al,rq.command ; Note that any part of the program can easily reference any particular ; command's structure, since the line ; db (type rhead) dup (?) ; makes all the command-specific structures "equivalent". ; Check to see if this is the 286 version ifdef V286 .286 if1 %OUT Enhanced processor version endif ifdef PCL if1 %OUT for the PC's Limited 286/386 endif endif else if1 %OUT Standard Version endif endif ; This macro is used during debugging. It prints a single character ; via the BIOS screen interface, and leaves the registers unchanged. ifdef DEBUG if1 %OUT DEBUG Version endif PrintChar macro Char ifdef PCL push ax mov al,Char out 095h,al ; put it digit 3 of smartvu pop ax else push ax ; save the regs push bx push dx mov ah,15 int 010h ; get the current page mov al,Char mov ah,14 ; print the character int 010h xor dx,dx mov ah,0 ; also to printer mov al,Char int 017h pop dx pop bx ;restore the regs pop ax endif endm else PrintChar macro Char ; if not debugging, blow it off endm endif ; --------------------------------------------------------------------------- ; Public declarations for SYMDEB ; These are public declarations included to allow SYMDEB to know where ; various lables and addresses are. They are only needed for debugging, ; and serve no other useful purpose. PUBLIC NextPlace PUBLIC Attrib, JumpTable, TopCommand, RBPoint, RBPointOff, RBPointSeg, SaveSS PUBLIC SaveSP, SaveAX, EMMHandle, EMMBase, StackTop, STRATPROC, Strategy PUBLIC INTPROC, Interrupt, NoSaveM, FreakOut, IOCTLInput, ReadNoWait PUBLIC InputStatus, InputFlush, badcommand, BigLog, NoRestore, MC, MediaCheck PUBLIC BBPB, BuildBPB, BPBArray, OurBoot, OurBPB, SecSize, SecPerCluster PUBLIC RDirLen, DiskSize, SecPerFAT, BootCode, TAddr, TAddrOff, TAddrSeg PUBLIC TDone, TCount, TSector, RSEC, Read, ReadLoop, ReadDone PUBLIC ReadFinish, ReadError, WSEC, Write, WriteLoop, WriteDone, WriteFinish PUBLIC WriteError, CLIPPER, RangeError, InRange, SPEAKERCLICK, MakeClick PUBLIC NoClick, SpeakerFlag, LastTime, GS, GetSector, CantGet, LastResident PUBLIC EMMPresent, GenFailHook, EMMPresent2, MemForMe, EatingWhite, GotOption PUBLIC NoBump, NotSilence, PagesLoop, LastDigit, NotPages, NotUseAll PUBLIC Unrecognized, EndOfLine, GoodSize, GotPages, BigBust, ReTry PUBLIC GoodCombo, NoKludge, WipeOut, WipeOut2, FindFree, CalcEMMFree PUBLIC CalcDiskFree, ClickOkay, MsgOkay, InitFail, GenFail, HowMuch PUBLIC RqdPages, MajorVersion, OurVolume, Banner, EMMIDString, General PUBLIC NoEMMThere, EMMError, Init, NoMem, TooBig, BadOption, NoClicking PUBLIC Installed, DriveName, InstalledB, Installed2, UsedSpace, Bin2Dec PUBLIC Bin2DecLoop, Bin2DecDigit, WorkAreaL, WorkAreaH ; --------------------------------------------------------------------------- driver segment para public assume cs:driver,ds:driver,es:driver,ss:driver org 0 ; drivers begin at zero firstplace equ this byte ; this is the first byte ; --------------------------------------------------------------------------- ; Device Header ; This area contains the header information. It is used by DOS when loading ; the device driver, and it contains information used to describe the ; driver to the DOS environment. NextPlace dw -1,-1 ; pointer to next driver Attrib dw 00010000000000000b ; attribute word ;FEDCBA9876543210 ; device is non-ibm and block mode ; doesn't support IOCTL, is not ; a network device dw offset Strategy ; the strategy entry dw offset Interrupt ; the interrupt entry db 1,'NJ_DISK' ; Nifty James' Disk! ; --------------------------------------------------------------------------- JumpTable label word ; This area is a "Jump Table" that is used to dispatch the code. ; Only the functions marked with a "*" in their comment field ; are actually implemented. (Since this is a block device, only ; some of the areas are actually used.) dw offset Init ; 0 * initialize dw offset MediaCheck ; 1 * media check dw offset BuildBPB ; 2 * build BIOS parameter block dw offset IOCTLInput ; 3 I/O Control (Input) dw offset Read ; 4 * read from device dw offset ReadNoWait ; 5 read from device (nondest, ; no wait, char only) dw offset InputStatus ; 6 input status dw offset InputFlush ; 7 flush pending input dw offset Write ; 8 * Write data dw offset Write ; 9 * Write data with Verify ; ; dw offset OutputStat ; 10 Output status ; dw offset OutputFlush ; 11 flush pending output ; dw offset IOCTLOutput ; 12 I/O Control (Output) ; dw offset DeviceOpen ; 13 Open Device ; dw offset DeviceClose ; 14 Close Device ; dw offset Removeable ; 15 Removable media check ; ; (The commands above 9 are all not implemented -- we don't ; make entries for them to optimize for space (and speed). ; The equate TopCommand must be set to the last used ; command code.) TopCommand equ 9 ; highest valid command RBPoint label dword ; Pointer to request buffer RBPointOff dw 0 ; offset part RBPointSeg dw 0 ; segment part SaveSS dw 0 ; save place for the SS register SaveSP dw 0 ; save place for the SP register SaveAX dw 0 ; save place for the accumulator EMMHandle dw 0 ; our handle, as assigned by the EMM EMMBase dw 0 ; base of the EMM physical window ; --------------------------------------------------------------------------- ; TDATA ; This is a "temporary" data area that is used to hold the data used ; by the transfer routines. TAddr label dword TAddrOff dw 0 ; the transferr (read to, write from) TAddrSeg dw 0 ; address TDone dw 0 ; count of sectors done TCount dw 0 ; number of sectors to do TSector dw 0 ; the sector to be transfer ; --------------------------------------------------------------------------- ; The local stack even ; make the stack a word-aligned area dw 64 dup (0DEADh) StackTop: ; --------------------------------------------------------------------------- ; Strategy Entry Point For the Device Driver ; This routine simply stores the pointer to the request header ; so that request header has it. That's all it does. Really. STRATPROC proc far Strategy: mov cs:RBPointOff,bx mov cs:RBPointSeg,es ; just store the pointer ret ; and get outta here! ; (isn't it ironic that the shortest routine is called "Strategy"?) STRATPROC endp ; --------------------------------------------------------------------------- ; Interrupt Entry Point For the Device Driver ; This routine executes the command contained in the passed request header. ; DOS has called STRATEGY, and that routine stored a pointer to the request ; header for our use. We will construct our own stack area because the ; EMM uses a great deal of stack space. INTPROC proc far Interrupt: PrintChar 'D' mov CS:SaveSS,ss ; save the SS register mov CS:SaveSP,sp ; save the SP register mov CS:SaveAX,ax cli mov ax,offset StackTop ; initialize our stack mov sp,ax mov ax,cs mov ss,ax sti ifdef V286 pusha else push bx ; save the other regs push cx push dx push bp push si push di endif pushf ; and the flags cld ; set the string direction up push es push ds mov ds,ax ; setup the data segment register mov ax,0FFFFh ; wipe out any memory of previous mov LastTime,ax ; page mappings ; Note that during calls we use DS to point to our local data ; and ES to point to the request header. les bx,RBPoint ; get the request buffer mov al,rq.command ; get the command cbw ; be sure that the command is in our range cmp al,TopCommand ; fifteen is the highest for us jg badcommand ; too high! bad command ; it's a good command - be on the lookout for an unorthodox ; initialization call or al,al ; is it function zero? je NoSaveM ; yes, don't save the map context push ax ; no, save the AX register mov ah,E_Save ; save the mapping context mov dx,EMMHandle ; under our handle int EMM ; ask the manager to do it or ah,ah ; if there was an error, jnz FreakOut ; freak out! pop ax ; if not, get the AX back NoSaveM: shl ax,1 ; (one word offset = 2 bytes) mov si,ax ; fake a "short call" by setting the return address to the exit routine mov ax,offset BigLog push ax xor ax,ax ; clear our status jmp cs:JumpTable[si] ; and hop to it! jmp short BigLog ; --------------------------------------------------------------------------- ; We come here if we run into an EMM error. We'll set the "General ; Failure" flag, and return to MS-DOS FreakOut: mov rq.status,(errorflag+err_general) ; general failure ; and error settings jmp short BigLog ; --------------------------------------------------------------------------- ; Ran into an unsupported command - set the flag in the status word. IOCTLInput: ReadNoWait: ; those table entries are invalid commands InputStatus: InputFlush: pop ax ; (forget about the short call) badcommand: mov ax,(err_unknown+errorflag) ; an unknown command err ; --------------------------------------------------------------------------- ; This is the mass exit; everone splits through this point! When we ; arrive here, the AX reg will contain the word to be put into the ; status word. We'll do that: BigLog: PrintChar 'X' les bx,cs:RBPoint ; point to the request block push ax mov al,rq.command ; was it an init? and al,al ; yes! don't restore pop ax je NoRestore push ax mov ah,E_Restore ; restore the EMS mov dx,EMMHandle ; mapping context int EMM or ah,ah ; if there was an error pop ax jnz FreakOut NoRestore: or ax,donestat ; set the done status mov rq.status,ax ; Now, we just undo the registers. pop ds ; the seg regs pop es popf ; the flags ifdef V286 popa else pop di pop si ; and the data regs pop bp pop dx pop cx pop bx endif PrintChar 'd' cli mov ax,CS:SaveAX mov sp,CS:SaveSP ; restore the calling stack mov ss,CS:SaveSS sti ret INTPROC endp ; --------------------------------------------------------------------------- ; MEDIA CHECK ; This command checks to see if the media has been removed and replaced. ; Since a RAM drive is non-removable media, this command will always ; return a "false". MC proc near PrintChar 'M' MediaCheck: mov rq.change,1 ; media has not been changed PrintChar 'm' ret ; return to leave MC endp ; --------------------------------------------------------------------------- ; BUILD BIOS PARAMETER BLOCK ; This command simply "builds" a BPB by telling DOS where it is located. BBPB proc near BuildBPB: PrintChar 'P' mov rq.bpboff,offset OurBPB ; the offset mov rq.bpbseg,cs ; in our CS PrintChar 'p' ret BPBArray dw offset OurBPB OurBoot: db 0,0,0 db 'NiftyEMS' ; whodat? OurBPB: SecSize dw 512 ; standard DOS sector size SecPerCluster db 1 ; sectors per allocation unit dw 1 ; number of reserved sectors db 1 ; number of copies of the FAT RDirLen dw 32 ; number of root directory entries DiskSize dw 1024 ; number of sectors on the disk db MediaD ; (media descriptor) SecPerFAT dw 1 ; number of sectors per FAT dw 8 ; sectors per track dw 1 ; number of heads dw 0 ; number of hidden sectors BootCode: OurBootLen equ this byte - OurBoot BBPB endp ; --------------------------------------------------------------------------- ; READ ; This command reads the specified number of sectors starting at the ; given sector. It returns the number of sectors actually read. Errors ; are returned if the sector is out of range, or if the number of sectors ; is past the end of the disk. (The error checking is done in the ; CLIPPER procedure.) This procedure doesn't do much itself. It's ; body is mostly a string move instruction. The starting address ; and ending address are set up by the CLIPPER procedure. RSEC proc near Read: ifdef PCL mov al,'N' out 097h,al mov al,'J' out 096h,al ; display "NJ-R" on Smart-Vu mov al,'-' out 095h,al mov al,'R' out 094h,al endif PrintChar 'R' call CLIPPER ; do the clipping, if need be ReadLoop: mov ax,TCount ; are we done transferring yet? cmp TDone,ax je ReadDone ; yes! quit the loop mov ax,TSector ; no ... do some more! call GetSector jc ReadError PrintChar 'y' mov si,di ; setup the get from address les di,TAddr ; get the store to address mov cx,256 ; number of words to move mov ds,EMMBase rep movsw ; move it! mov ax,cs ; get addressing back mov ds,ax add TAddrOff,512 ; increment transferr address inc TDone inc TSector jmp short ReadLoop ReadDone: xor ax,ax ; clear error flags ReadFinish: les bx,[RBPoint] ; point to request header mov dx,TDone ; store actual transferred mov rq.Count,dx jmp MakeClick ; finish clicking ReadError: mov ax,(err_badread+errorflag) ; there was an error! jmp short ReadFinish RSEC endp ; --------------------------------------------------------------------------- ; WRITE ; This command writes the specified number of sectors starting at the ; given sector. It returns the number of sectors actually written. ; Errors are returned if the sector is out of range, or if the number ; of sectors is past the end of the disk. (The error checking is done ; in the CLIPPER procedure.) The procedure does very little itself; ; it's body consists mostly of a string move instruction. The ; source, destination, and other counts are set up by the CLIPPER ; procedure. WSEC proc near Write: ifdef PCL mov al,'N' out 097h,al mov al,'J' out 096h,al ; display "NJ-W" on Smart-Vu mov al,'-' out 095h,al mov al,'W' out 094h,al endif PrintChar 'W' call CLIPPER ; do the clipping, if need be WriteLoop: mov ax,TCount ; are we done transferring yet? cmp TDone,ax je WriteDone ; yep, we are, quit the loop mov ax,TSector ; no ... do some more! call GetSector jc WriteError PrintChar 'k' mov es,EMMBase lds si,cs:TAddr ; get the store to address mov cx,256 ; number of words to move rep movsw ; move it! mov ax,cs ; reset addressing back mov ds,ax add TAddrOff,512 ; increment transferr address inc TDone ; count of sectors inc TSector ; and current sector number jmp short WriteLoop WriteDone: xor ax,ax ; clear error flags WriteFinish: les bx,[RBPoint] ; point to request header mov dx,TDone ; store actual transferred mov rq.Count,dx jmp MakeClick ; finish clicking WriteError: mov ax,(err_badwrite+errorflag) ; there was an error! jmp short WriteFinish WSEC endp ; --------------------------------------------------------------------------- ; Clipper ; This local procedure checks the parameters passed to the READ and ; WRITE commands to be sure that they are valid. If they are indeed ; valid, it will call the speaker click procedure to take care of ; the "audible" options. It also saves the context of the EMM, and ; sets up the EMM to work with our process. CLIPPER proc near mov cx,rq.strtsec ; get the starting sector number mov TSector,cx cmp cx,DiskSize ; is it larger than the drive? jg RangeError ; yes! there's an error mov ax,rq.count mov TCount,ax ; save it for later add cx,ax ; add in the number of sec to read cmp cx,DiskSize ; is it larger than life? jle InRange ; no... it's okay RangeError: pop ax ; forget our our return address mov ax,err_badsector; that's a bad sector! or ax,errorflag ; (and that's an error in my book) mov rq.count,0 ; no sectors were read, you know ret ; return back to the dispatcher InRange: mov ax,rq.tbaoff ; get the transfer base addr mov TAddrOff,ax mov ax,rq.tbaseg mov TAddrSeg,ax xor ax,ax ; zero transferred count mov TDone,ax ; just flow through to MakeClick CLIPPER endp ; --------------------------------------------------------------------------- ; This is a local procedure that clicks the speaker transparently. It ; is executed at the end of the CLIPPER procedure, which is excuted ; at the very beginning of the "READ" and "WRITE" functions. It is ; also JMP'd to at the end of the READ and WRITE routines, and the RET ; at the end of this procedure will return to the caller of the READ ; and WRITE functions. (Saves 2 bytes and a bunch of clocks, hey.) SPEAKERCLICK proc near MakeClick: pushf cmp SpeakerFlag,0 ; should we? je NoClick ; no, forget it happened push ax ; yes, save the accumulator in al,Speak and al,SpeakMask ; mask out the bit we don't need xor al,SpeakToggle ; toggle the control bit out Speak,al ; and re-output it pop ax ; retrieve the accumulator NoClick: popf ret ; return to the caller SpeakerFlag db 1 ; one if we should be ticking ; (the default is ticking) SPEAKERCLICK endp ; --------------------------------------------------------------------------- ; GetSector ; This routine calls the EMM to map the page with the requested sector ; into the physical window. On entry, AX contains the requested sector. ; On exit, the EMS is setup so that the requested sector is in the window. ; [EMMBASE]:DI will point to it. This routine is rather funky; it does ; the mapping using the slippery shift functions, instead of using DIV ; or a lookup table. *SUPER FAST*! GS proc near GetSector: PrintChar 'G' cmp ax,DiskSize ; check the range! jg CantGet push ax ; save a copy of the number ifdef V286 shr ax,5 else mov cl,5 shr ax,cl ; divide the sector by 32 ; so that AX=EMM Page endif cmp ax,LastTime ; is it the same thing je Optimized ; we got last time? mov LastTime,ax ; remember it for later mov bx,ax ; nah, we'll have to get this one mov ah,E_MapPage mov al,0 ; map it into zero mov dx,EMMHandle int EMM or ah,ah ; was there an error? jne CantGet Optimized: pop ax ; retrieve the remainder and ax,01Fh ; mask out high bits of offset ifdef V286 shl ax,9 else mov cl,9 shl ax,cl ; find the offset of the sector endif mov di,ax clc PrintChar 'g' jmp short MakeClick ; tick-tock on the way out CantGet: pop ax ; forget the remainder, since there was err stc ; set the error flag, if error ret ; An ingenious optimization, if I must say so myself. This variable holds ; the last EMS logical page that was fetched by this routine. This way, ; the program never gets the same page twice in a row. It's reset to ; 0FFFFh by the Interrupt routine so that we won't forget to get a page ; when one hasn't been attained. (0FFFFh is a unique code that will never ; correspond to an actual page.) Since DOS often does more than one ; sequential read or write in a single call to the driver, this small ; feature can save quite a bit of time. LastTime dw 0FFFFh GS endp ; --------------------------------------------------------------------------- ; This label marks the last byte of the device driver that actually ; remains resident. This driver takes less than 800 bytes, guaranteed. LastResident: ; --------------------------------------------------------------------------- ; INITIALIZE ; This command sets up the internal data used by NJRAMD. The procedure ; sets the EMM to get the number of pages that the user requests. (The ; information following the specification in the CONFIG.SYS file is ; parsed to find the user parameters. See the NJFRAMD.DOC file to find ; the format of the CONFIG information.) The procedure requests memory ; from the EMM Init: PrintChar 'I' mov dx,offset Banner mov ah,PrintString ; show our copyright! int 21h mov ah,GetDOSVersion ; get the DOS version int 21h mov MajorVersion,al xor ax,ax ; point to the 0000 segment mov es,ax mov bx,(EMM*4)+2 ; find the EMM interrupt mov ax,es:[bx] mov es,ax ; point to the EMM device mov di,10 ; header mov si,offset EMMIDString ; point to the EMM identifier mov cx,8 repz cmpsb ; compare a bunch of bytes jz EMMPresent mov dx,offset NoEMMThere ; point to our error jmp InitFail ; the EMM isn't there!! EMMPresent: ; the Extended Memory Manager is present. It's okay! ; get the EMM Page base, and save it for future reference. mov ah,E_PageBase ; get the page base int EMM or ah,ah je EMMPresent2 ; general failure? GenFailHook: jmp GenFail ; (RELATIVE JMP OUT OF RANGE EMMPresent2: mov EMMBase,bx ; save it for later mov ah,E_Counts ; get count of available int EMM ; memory or ah,ah jne GenFailHook ; general failure? ; (RELATIVE JMP OUT OF RANGE) cmp bx,0 ; is there any left for me? jne MemForMe mov dx,offset NoMem ; print error jmp InitFail MemForMe: mov HowMuch,bx ; remember how much is left ; We will now attempt to parse the line of the CONFIG.SYS ; file to see if any of our options are on it. les bx,[RBPoint] ; get pointer to header les si,es:[bx+18] ; get pointer to commands EatingWhite: mov al,es:[si] ; get the next byte inc si cmp al,cr ; is it a carriage return? je EndOfLine cmp al,'-' ; is it an option marker? je GotOption ; yeah! go process it! cmp al,'/' jne EatingWhite ; no... go back for more ; We are now pointing at the text of an option. We will ; get the option into the al to see exactly what it is, and we ; will then act accordningly. GotOption: mov al,es:[si] ; get the option inc si ; and increment the pointer cmp al,'a' ; bump it to upper case? jl NoBump ; no need to cmp al,'z' jg NoBump ; no need to sub al,('a' - 'A') ; make it lower case NoBump: cmp al,'S' ; is it a silence option? jne NotSilence ; no... mov SpeakerFlag,0 ; yes, it is. Reset the option! jmp EatingWhite ; and eat up until end of ; this option NotSilence: cmp al,'P' ; is it the pages option? jne NotPages ; We will handle the pages option by reading the command line until ; a non-numeric character. The resulting number will be the number ; of pages that the user requested. xor dx,dx ; zero the result PagesLoop: mov al,es:[si] ; get the character inc si cmp al,'0' ; is it a number? jl LastDigit ; nope! cmp al,'9' ; is it a number? jg LastDigit ; note! push ax ; save the digit temporarily mov ax,10 mul dx ; multiply it out pop dx ; pop the digit into dx and dx,0Fh ; make a decimal digit of it add dx,ax ; add it into the sum jmp short PagesLoop LastDigit: mov RqdPages,dx ; save requested number of pages and dx,dx ; is the requested page number zero? je BadPages ; yeah! can't have that cmp al,cr ; was that last char a CR? je EndOfLine ; yes! end of the parse jne EatingWhite ; no, go back for more parsing BadPages: mov dx,offset TooSmall BadPages2: jmp InitFail NotPages: cmp al,'A' ; is it use all memory? jne NotUseAll mov ax,HowMuch mov RqdPages,ax ; request them all jmp EatingWhite NotUseAll: Unrecognized: mov dx,offset BadOption ; don't install jmp short BadPages2 EndOfLine: ; The parsing is done! We will now check to see if the ; requested size is bigger than the available memory. mov ax,RqdPages ; is the reqested amount cmp HowMuch,ax ; greater than available? jge GoodSize ; no, size is good mov dx,offset TooBig ; yes, that's an error jmp InitFail GoodSize: ; Now, we'll try to allocate that many pages. If the user ; didn't specify a number of pages, the default is 32 pages, ; which is 512k of storage. mov bx,ax mov ah,E_Open ; open a new handle of (BX) pages int EMM or ah,ah je GotPages ; (RELATIVE JMP OUT OF RANGE) jmp GenFail GotPages: mov EMMHandle,dx ; save the handle for later ; We will now setup the information in the BPB to reflect the ; status of the RAM drive. First, we'll store the DiskSize. mov ax,RqdPages ; get number of pages ifdef V286 shl ax,5 else mov cl,5 ; thirty-two 512-byte sectors shl ax,cl ; in a 16384-byte page endif mov DiskSize,ax ; store it in BPB ; Now, we'll figure out how many entries there will be in the ; root directory. We will allow 1 root directory entry for ; each 2k of storage that the disk has. We won't allow moer ; than 512 root dir entries, though. ifdef V286 shr ax,2 else shr ax,1 ; figure out length of shr ax,1 ; root directory endif cmp ax,512 ; 1 entry per 2k of storage jl BigBust ; up to 512 mov ax,512 BigBust: add ax,31 ; make sure it's a multiple and ax,not 31 ; of 32 (round it) mov RDirLen,ax ; Since we use a 12-bit FAT, we must have 4087 clusters or less. ; We will start with a 1024-byte cluster, and double the cluster ; size until we have enough FAT space. The maximum amount of ; memory on a single EMS card is 2 megabytes. A user must ; configure about 3.75 megabytes of memory as a RAM drive to ; cause the program to use 2048-byte clusters... otherwise, the ; drive will have 1024-byte clusters. mov cx,2 ; Two clusters per sector ; for starters. ReTry: mov ax,DiskSize ; get the disk size xor dx,dx div cx ; AX = (DiskSize/SPC) cmp ax,4087 ; is it less than 4087? jl GoodCombo ; yeah! shl cx,1 ; no. double the SPC and jnc ReTry ; try it again GoodCombo: mov SecPerCluster,cl ; save SPC number ; AX still is set to the number of clusters on the disk. Very ; useful number, you know. We will find now the amount of FAT ; space that is needed. mov bx,ax ; ax = clustsers add ax,ax ; ax = 2*(clusters) add ax,bx ; ax = 3*(clusetrs) shr ax,1 ; ax = 1.5*(clusters) xor dx,dx ; (FAT Length) mov cx,512 ; AX = ---------------- div cx ; (BytesPerSector) or dx,dx ; is there a remainder? je NoKludge inc ax ; yes, add another sector NoKludge: mov SecPerFAT,ax ; store it in the BPB ; The BPB is now set up properly. We will now "format" the ; RAM disk. First, we will have to set all the RAM area to ; zero. (Even on extremely large "drives", this doesn't take ; very long. Especially if you have an IBM PS/2 System 80 -- ; and then, all the chicks will dig ya!) mov cx,RqdPages ; get number of pages in disk WipeOut: mov bx,cx ; ask for this page dec bx mov dx,EMMHandle ; into physical page zero mov ah,E_MapPage mov al,0 int EMM or ah,ah je WipeOut2 ; if there was an error, get out jmp GenFail ; (RELATIVE JMP OUT OF RANGE) WipeOut2: mov es,EMMBase ; get addressing to it xor ax,ax ; store a zero mov di,ax ; zero the destination push cx mov cx,8192 ; *words* in a page rep stosw pop cx loop WipeOut ; if more, go back ; Now that everything is zeroed, we will copy the pseudo-boot ; sector that we have. DOS uses some of this information while ; reading and writing the disk, so we set it up there. xor ax,ax ; get the 0 sector call GetSector mov es,EMMBase mov si,offset OurBoot mov cx,OurBootLen rep movsb ; move it in there ; The boot sector has been written in. We will now set up ; the FAT. This task is rather simplified, since we only ; have one copy of the FAT. mov ax,1 call GetSector ; get sector 1 mov byte ptr es:[di],MediaD mov word ptr es:[di+1],0FFFFh ; Now, we will figure out where the first directory sector is. ; *WARNING* - This code assumes that there is only one copy of ; the FAT, and that there is one reserved sector. If ya change ; the drive to have 2 copies of the FAT, or modify it to have ; reserved sectors (for whatever reason you'd wanna do that), ; you'll have to change this code fragment! mov ax,SecPerFAT inc ax ; AX = first dir sector call GetSector mov si,offset OurVolume mov cx,OurVolumeLen ; move words rep movsw ; Phew! Now the whole thing is done! We will show the user ; what has been done. First, we will figure out what device ; tag that we have. We will tell the user about it. DOS versions ; earlier than 3.00 don't let us know what our device tag is, ; so we can't tell the user. les bx,[RBPoint] ; point to the header, again mov al,rq.taglet ; get the tag letter add al,'A' ; change it to a capital drive letter. mov DriveName,al mov bx,offset LastResident ; calculate used size xor ax,ax mov si,offset UsedSpace call Bin2Dec ; store it in the messgae mov ah,E_Counts ; find amount of space left int EMM ; in the EMS memory or ah,ah je FindFree jmp GenFail FindFree: xor ax,ax ; zero high side (the EMM call put ; the # of free pages in BX.) mov cx,14 ; multiply the # of pages by 16k CalcEMMFree: rcl bx,1 ; shift it low side rcl ax,1 ; and carry though to high side loop CalcEMMFree mov si,offset Installed2 call Bin2Dec ; put it into the message! mov ax,DiskSize ; get sectors of disk space sub ax,SecPerFAT ; subtract space used by the FAT mov bx,ax ; put that subtotal in bx mov ax,RDirLen ; get the entries in the root dir ifdef V286 shr ax,4 else mov cl,4 shr ax,cl ; divide by # of entries per sec endif sub bx,ax ; subtract some more dec bx ; and adjust down mov cx,9 ; multiply the answer by 512 xor ax,ax ; zero the high side CalcDiskFree: rcl bx,1 ; shift low side up rcl ax,1 ; shift high side over, with carry loop CalcDiskFree mov si,offset Installed call Bin2Dec ; store it in the message mov al,SpeakerFlag ; is there clicking? or al,al jne ClickOkay mov ah,PrintString mov dx,offset NoClicking ; tell the user that it's int 21h ; been diasbled. ClickOkay: mov al,MajorVersion cmp al,3 ; is it version three? je MsgOkay mov al,eos ; its version two mov DriveName,al MsgOkay: mov dx,offset Installed ;print part one of mov ah,PrintString ; installed! message int 21h mov dx,offset InstalledB ;print part two int 21h les bx,[RBPoint] ; get that pesky pointer mov ax,offset LastResident ; show DOS where we end mov rq.ndadro,ax ; offset mov ax,cs ; show DOS were we end mov rq.ndadrs,ax ; segment mov rq.bpbseg,ax ; show DOS the BPB array mov rq.units,1 ; we installed one unit mov ax,offset BPBArray ; BPB array offset mov rq.bpboff,ax xor ax,ax ; no return value ret ; --------------------------------------------------------------------------- ; Init failure ; We will come here if there is a failure during the initialization ; of the driver. We print a message letting the user know why we can't ; install, and we then zero ourselves out so that DOS doesn't waste any ; memory on us. InitFail: push dx ; save the specific error mov dx,offset General mov ah,PrintString int 21h pop dx ; now print specific error mov ah,PrintString int 21h les bx,[RBPoint] ; point to the request header mov ax,cs mov rq.ndadrs,ax ; ending address is zero xor ax,ax ; because no memory is taken mov rq.ndadro,ax ; since we failed mov rq.units,al ; no units, either PrintChar 'i' ret ; --------------------------------------------------------------------------- ; General Failure ; There was an EMM Failure during the installation. If such is the case, ; we will terminate with an error message, and then go to the regular ; fail routine. GenFail: mov dx,offset EMMError jmp short InitFail ; --------------------------------------------------------------------------- ; Transient Data Area ; The TDA contains the variables used by the Initialization segment of ; the device driver. It doesn't stay resident. HowMuch dw ? ; amount of free EMS, in pages RqdPages dw 32 ; amount of pages requested ; (512k is the default) MajorVersion db 3 ; the DOS major version number OurVolume db 'Niftys_Disk' ; 11-byte volume name db 000001000b ; volume label attribute db 10 dup (0) ; reserved space dw 953 ;FEDCBA9876543210b ;YYYYYYYMMMMDDDDD dw 00000111101011111b ; DATE = Oct 31, 1987 db 6 dup (0) ; more reserved space OurVolumeLen equ 16 ; --------------------------------------------------------------------------- ; Messages ; These are messages that are used by the initialization section of the ; driver. Banner db cr,lf,"Nifty James Famous E/EMS RAMdisk Drive",cr,lf db 'Copyright 1987 by Mike Blaszczak',cr,lf db 'Version 1.40ASP of 23 June, 1991',cr,lf ifdef V286 ifdef PCL db "(PC's Limited Version)",cr,lf else db '(Enhanced Processor Version)',cr,lf endif endif db lf,eos EMMIDString db 'EMMXXXX0' General db 'Device not installed.',cr,lf,eos NoEMMThere db 'The EMM is not installed.',cr,lf,lf,eos EMMError db 'EMM failure during installation.',cr,lf,lf,eos NoMem db 'No free EMM Memory.',cr,lf,lf,eos TooBig db 'Requested size too big to fit.',cr,lf,lf,eos TooSmall db "Can't have zero disk size.",cr,lf,lf,eos BadOption db 'Unrecognized option encountered.',cr,lf,lf,eos NoClicking db 'Clicking suppressed.',cr,lf,eos ; "Installed" marks the beginning of the information that is printed ; if the device is successfully installed. The beginning of each ; line has eight spaces, which are filled with the information by the ; BIN2DEC procedure. There is then one more space, so that the end ; of the number doesn't bump the first word... thus, a total of nine ; spaces begin the Installed, Installed2, and UsedSpace labels. Installed db ' bytes available on RAM drive ' DriveName db '_:.',eos InstalledB db cr,lf Installed2 db ' bytes left in EMS storage.',cr,lf UsedSpace db ' bytes of standard DOS memory were' db ' taken.',cr,lf,lf db eos ; --------------------------------------------------------------------------- ; Init Subroutines ; The following area contains subroutines used by the INIT procedure of ; the device driver. They aren't kept in memory after the device has been ; installed. ; --------------------------------------------------------------------------- ; BIN2DEC ; This routine converts a binary number, in AX:BX, to decimal notation. ; It will convert up to 8 digits, and will supress leading zeros. The ; routine should be called with DS:SI set to point to the area to store ; the converted number. Bin2Dec proc near push es ; save the registers push ds push di push si mov WorkAreaL,bx mov WorkAreaH,ax ; put the number on our scratchpad mov ax,ds ; point to the answer with ES:DI mov es,ax mov di,si add di,7 mov si,offset WorkAreaL ; point at scratchpad Bin2DecLoop: push si xor bx,bx ; done flag mov cx,2 ; 2 words in our number mov dx,bx ; clear remainder add si,2 ; point to the high end Bin2DecDigit: push cx ; save word count mov ax,[si] ; get the digit mov cx,10 div cx ; convert it mov [si],ax ; store it back or bx,ax ; set the done flag appropriately sub si,2 ; point to next lower pop cx loop Bin2DecDigit or dl,'0' ; make it into a decimal digit mov [di],dl ; and store it dec di ; adjust pointer pop si ; get the pointer back and bx,bx ; is the result zero? jne Bin2DecLoop ; nope! Do more! pop si ; retrieve the used registers pop di pop ds pop es ret WorkAreaL dw 0 ; low end of the work area WorkAreaH dw 0 ; high side of the work area Bin2Dec endp driver ends end ; That's a wrap. ; Special thanks to Bob Brody and Dr File Finder~~~~~~~~~~~~.