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Assembly Source File | 1991-06-23 | 38.6 KB | 1,331 lines

; DEBUG EQU TRUE V286 EQU TRUE ; No XMS on 8088 PC's! ; 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 ; Modified Terje Mathisen 20 March 90 ; Version 1.02 of XMS-compatible NJRAMDX 14 Sep 1990 ; Version 1.40 of 23 Jun 1991 by Mike Blaszczak ; Shareware $15 Please contribute! ; Assemble with ; TASM NJRAMDX ; (Comment out V286 EQU TRU for 8088 version.) ; TLINK /t NJRAMDX, NJRAMDX.SYS ; --> DEVICE DRIVER FORMAT FILE <-- ; --------------------------------------------------------------------------- ; ASCII Characters bell equ 7 ; bell character tab equ 9 ; tab character lf equ 10 ; linefeed cr equ 13 ; carriage return space equ 32 ; space eos equ '$' ; end of DOS string ; --------------------------------------------------------------------------- ; 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 # ; --------------------------------------------------------------------------- ; XMS Routines ; These are the XMS functions that we use. (These are specific functions ; of the XMS call.) X_Counts equ 08h ; determine free/total mem X_Alloc equ 09h ; open, allocate, obtain handle ID X_Version equ 00h ; get the XMS version number X_Move equ 0Bh ; move an XMS block ; --------------------------------------------------------------------------- ; 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". ; XMS Extended Memory Move structure ExtendedMemoryMove STRUC NrOfBytes dw 0,0 SourceHandle dw 0 SourceOffset dw 0,0 DestHandle dw 0 DestOffset dw 0,0 ExtendedMemoryMove ENDS ; 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. IF 1 PUBLIC NextPlace PUBLIC Attrib, JumpTable, TopCommand, RBPoint, RBPointOff, RBPointSeg, SaveSS PUBLIC SaveSP, StackTop, STRATPROC, Strategy PUBLIC INTPROC, Interrupt, FreakOut, IOCTLInput, ReadNoWait PUBLIC InputStatus, InputFlush, badcommand, BigLog, MC, MediaCheck PUBLIC BBPB, BuildBPB, BPBArray, OurBoot, OurBPB, SecSize, SecPerCluster PUBLIC RDirLen, DiskSize, SecPerFAT, BootCode PUBLIC RSEC, Read PUBLIC WSEC, Write PUBLIC TestValues, RangeError, SPEAKERCLICK, MakeClick PUBLIC SpeakerFlag, LastResident PUBLIC EatingWhite, GotOption PUBLIC NoBump, NotSilence, PagesLoop, LastDigit, NotPages, NotUseAll PUBLIC Unrecognized, EndOfLine, BigBust, ReTry PUBLIC GoodCombo, WipeOut PUBLIC CalcDiskFree, ClickOkay, MsgOkay, InitFail, GenFail, HowMuch PUBLIC RqdPages, MajorVersion, OurVolume, Banner, General PUBLIC NoEMMThere, EMMError, Init, NoMem, TooBig, BadOption, NoClicking PUBLIC Installed, DriveName, InstalledB, Installed2, UsedSpace, Bin2Dec PUBLIC Bin2DecLoop, Bin2DecDigit, WorkAreaL, WorkAreaH ENDIF ; --------------------------------------------------------------------------- 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,'NJTMDSK' ; Nifty James/TM' Disk! ; --------------------------------------------------------------------------- ALIGN 2 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 R_EMM ExtendedMemoryMove <> ; EMM block for read requests W_EMM ExtendedMemoryMove <> ; EMM block for write EMM_Vector dd ? ; --------------------------------------------------------------------------- ; The local stack even ; make the stack a word-aligned area dw 128 dup ('TM') ; HIMEM.SYS may need 256 byte stack! 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 ; XMS driver uses a great deal of stack space. (Up to 256 bytes!) INTPROC proc far Interrupt: PrintChar 'D' push ax ; TMA mov [CS:SaveSS],ss ; save the SS register mov [CS:SaveSP],sp ; save the SP register mov ax, cs ;TMA mod cli mov ss, ax mov sp, offset StackTop ; initialize our stack 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 ; 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 ; word for jump table ; be sure that the command is in our range cmp al,TopCommand ; fifteen is the highest for us ja badcommand ; too high! # UNSIGNED! TMA shl ax,1 ; (one word offset = 2 bytes) mov si,ax ; fake a "short call" by setting the return address to the exit routine ifdef V286 push offset BigLog else mov ax,offset BigLog push ax endif mov ax,donestat ; assume OK jmp JumpTable[si] ; and hop to it! ; --------------------------------------------------------------------------- ; We come here if we run into an XMS error. We'll set the "General ; Failure" flag, and return to MS-DOS FreakOut: mov ax,(errorflag+err_general+donestat) ; general failure ; and error settings jmp short BigLog ; --------------------------------------------------------------------------- ; Ran into an unsupported command - set the flag in the status word. BadInit: ; A second INIT call is a NO-NO IOCTLInput: ReadNoWait: ; those table entries are invalid commands InputStatus: InputFlush: pop ax ; (forget about the short call) badcommand: mov ax,(err_unknown+errorflag+donestat) ; 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' 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 ss,[CS:SaveSS] mov sp,[CS:SaveSP] ; restore the calling stack sti pop ax ; TMA 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 'TerjeXMS' ; 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 sectors TMA 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 ; --------------------------------------------------------------------------- ; 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 ; TestValues procedure.) This procedure doesn't do much itself. It's ; body is mostly an XMS move call. 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' mov si, offset W_EMM call TestValues mov [si.DestOffset+1],ax mov [si.SourceOffset],cx mov [si.SourceOffset+2],dx jmp Do_XMS_Transfer WSEC 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 ; TestValues procedure.) This procedure doesn't do much itself. It's ; body is mostly a call for an XMS move instruction. 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' mov si, offset R_EMM call TestValues ; AX = Sec# Shl 1, DX:CX = TBA mov [si.SourceOffset+1],ax mov [si.DestOffset],cx mov [si.DestOffset+2],dx Do_XMS_Transfer: ; Common code for Read & Write mov ah, X_Move call [EMM_Vector] or ax,ax jz XMS_Transfer_Error mov ax,donestat ; OK! ReadClick label byte jmp MakeClick ; finish clicking XMS_Transfer_Error: mov ax,(err_general+errorflag+donestat) mov [rq.Count],0 ; Tell DOS nothing done! WriteClick label byte jmp MakeClick ; finish clicking RSEC endp RangeError: pop ax ; forget our return address mov ax,err_badsector + errorflag + donestat ; TMA mov [rq.count],0 ; no sectors were read, you know ret ; return back to the dispatcher TestValues proc near mov ax,[rq.strtsec] mov dx,ax mov cx,[rq.count] add dx,cx jc RangeError cmp dx,DiskSize ja RangeError shl ax,1 ; 512 byte/sector = 256 Shl 1 shl cx,1 ; NrOfSectors Shl 9 mov [si.NrOfBytes+1],cx mov cx,[rq.tbaoff] mov dx,[rq.tbaseg] TestValues endp ; --------------------------------------------------------------------------- ; This is a local procedure that clicks the speaker transparently. It ; is executed at the end of the TestValues 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.) ; From here modified by TMA: Uses self-modifying code to decrease the size ; If no clicks, the init call will modify the PUSHF to a RETN, and save ; the rest of the proc from staying resident. The JMPs from READ & WRITE ; to this proc will also be patched into RETNs. This way, we don't have to ; test the SpeakerFlag at each call. SPEAKERCLICK proc near MakeClick: pushf 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 jmp $+2 ; For fast PC's out Speak,al ; and re-output it pop ax ; retrieve the accumulator popf NearRet label byte ; TMA Use this to get RETN opcode ret ; return to the caller SPEAKERCLICK endp ; --------------------------------------------------------------------------- ; This label marks the last byte of the device driver that actually ; remains resident. This driver takes less than 800 bytes, guaranteed. LastResident dw $ ; Current End Of Program SpeakerFlag db 1 ; one if we should be ticking JUMPS ; Non-critical code ; --------------------------------------------------------------------------- ; INITIALIZE ; This command sets up the internal data used by NJRAMD. The procedure ; sets the XMS to get the number of kB 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 XMS driver 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 mov ax,4300h int 2Fh ; Is an XMS driver loaded? cmp al,80h mov dx,offset NoEMMThere ; point to our error jne InitFail ; No XMS driver! PrintChar '1' ; the XMS is present. It's okay! Get EMM_Vector to call mov ax,4310h int 2Fh mov word ptr [EMM_Vector],bx mov word ptr [EMM_Vector+2],es mov ah,X_Counts ; get count of available call [EMM_Vector] ; memory ; QEMM 5.1 or bl,bl ; jl GenFail ; general failure? PrintChar '2' cmp ax,16 ; At least 16 kB? mov dx,offset NoMem ; print error jb InitFail PrintChar '3' mov [HowMuch],ax ; 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: lods byte ptr es:[si] ; get the next byte cmp al,cr ; is it a carriage return? je EndOfLine cmp al,'0' jb NotPages cmp al,'9' ja 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 kB that the user requested. xor dx,dx ; zero the result sub al,'0' mov dl,al PagesLoop: lods byte ptr [es:si]; get the character cmp al,'0' ; is it a number? jb LastDigit ; nope! cmp al,'9' ; is it a number? ja 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 cmp dx,16 ; is the requested # of KB < 16 jb 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,'-' ; 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: lods byte ptr es:[si] ; get the option 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,'A' ; is it use all memory? jne NotUseAll mov ax,[HowMuch] mov [RqdPages],ax ; request them all (KB) jmp EatingWhite NotUseAll: Unrecognized: mov dx,offset BadOption ; don't install jmp InitFail EndOfLine: ; The parsing is done! We will now check to see if the ; requested size is bigger than the available memory. PrintChar 'e' mov ax,[RqdPages] ; is the reqested amount cmp ax,[HowMuch] ; greater than available? mov dx,offset TooBig ; error msg ja InitFail ; yes, abort ; Now, we'll try to allocate that many kB. If the user ; didn't specify a number of kB, the default is 512 PrintChar '4' mov dx,ax mov ah,X_Alloc ; open a new handle of (DX) kB call [EMM_Vector] or ax,ax jz GenFail PrintChar '5' mov [R_EMM.SourceHandle],dx ; save the handle for later mov [W_EMM.DestHandle],dx ; 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 shl ax,1 ; 2 sectors in one KB ; add ax,7 ; and ax, NOT 7 ; Should be divisible by 8! 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 more ; 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 jb 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 up) 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. 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? jb GoodCombo ; yeah! shl cx,1 ; no. double the SPC and jnc ReTry ; try it again jmp GenFail ; 64kB cluster is an error! GoodCombo: mov [SecPerCluster],cl ; save SPC number PrintChar '6' ; 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) inc ax ; In case of odd # of clusters TMA shr ax,1 ; ax = 1.5*(clusters) add ax,511 ; To round up TMA xor dx,dx ; (FAT Length) mov cx,512 ; AX = ---------------- div cx ; (BytesPerSector) 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.) mov di, OFFSET InitBuffer ; Make a block of ZERO's push cs pop es mov cx, 512 xor ax,ax rep stosw mov cx,[DiskSize] ; get number of sectors on disk shr cx,1 ; CX = # of KB mov si, OFFSET W_EMM; Use W_EMM for all writing ; mov [si.DestOffset+1],0 ; Init to 0 mov [si.NrOfBytes],1024 mov [si.SourceOffset], OFFSET InitBuffer mov [si.SourceOffset+2], CS WipeOut: mov ah, X_Move call [EMM_Vector] or ax,ax jz GenFail add [si.DestOffset+1],4 ; 4 * 256 = 1024 = 1 kB loop WipeOut ; if more, go back PrintChar '7' ; 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. mov [si.DestOffset+1],0 ; Init to 0 mov [si.NrOfBytes], (OurBootLen + 1) AND 0FFFEh mov [si.SourceOffset], OFFSET OurBoot mov ah,X_Move call [EMM_Vector] or ax,ax jz GenFail PrintChar '8' ; 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 byte ptr [InitBuffer],MediaD mov word ptr [InitBuffer+1],0FFFFh mov [si.DestOffset+1],2 ; 2 * 256 = 1 sector mov [si.NrOfBytes], 4 mov [si.SourceOffset], OFFSET InitBuffer mov ah,X_Move call [EMM_Vector] or ax,ax jz GenFail PrintChar '9' ; 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 shl ax,1 ; * 2 for 256 byte blocks mov [si.DestOffset+1],ax mov [si.NrOfBytes], (OurVolumeLen + 1) AND 0FFFEh mov [si.SourceOffset], OFFSET OurVolume mov ah,X_Move call [EMM_Vector] or ax,ax jz GenFail ; Initialize W_EMM.NrOfBytes back to Zero mov [si.NrOfBytes],0 PrintChar '!' ; 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. ; TMA: First, check if not clicking, if so disable that part: cmp SpeakerFlag, 0 ; is there clicking? jne UsingClick mov al, [NearRet] mov byte ptr [MakeClick], al ; RETN opcode TMA mov [ReadClick], al mov [WriteClick], al mov [LastResident], offset MakeClick + 1 ; Reduce RAM TMA UsingClick: 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,[LastResident] ; calculate used size xor ax,ax mov si,offset UsedSpace call Bin2Dec ; store it in the messgae mov ah,X_Counts ; find amount of space left call [EMM_Vector] or bl,bl jl GenFail PrintChar '"' mov cl,6 ; AX:BX = (Space left SHL 16) SHR 6 = KB xor bx,bx ; Zero low word @@1: shr ax,1 rcr bx,1 loop @@1 mov si,offset Installed2 call Bin2Dec ; put it into the message! mov bx,[DiskSize] ; get sectors of disk space sub bx,[SecPerFAT] ; subtract space used by the FAT 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 for boot sector mov cx,9 ; multiply the answer by 512 xor ax,ax ; zero the high side CalcDiskFree: shl 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 cmp [SpeakerFlag], 0 ; is there clicking? jne ClickOkay mov ah,PrintString mov dx,offset NoClicking ; tell the user that it's int 21h ; been disabled. ClickOkay: cmp [MajorVersion],3 ; is it version three+? jae MsgOkay mov [DriveName],eos ; TMA Ver 2.x, so no drive letter 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, [LastResident] ; show DOS where we end TMA mov [rq.ndadro],ax ; offset ; show DOS were we end mov [rq.ndadrs],cs ; segment mov [rq.bpbseg],cs ; show DOS the BPB array mov [rq.units],1 ; we installed one unit mov [rq.bpboff],OFFSET BPBArray ; BPB array offset mov [JumpTable], OFFSET BadInit ; In case second INIT call 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 512 ; amount of pages requested ; (512k is the default) MajorVersion db 3 ; the DOS major version number MTIME MACRO h,m,s dw (h SHL 11) + (m SHL 5) + (s SHR 1) ENDM MDATE MACRO y,m,d dw ((y-80) SHL 9) + (m SHL 5) + d ENDM OurVolume db 'Terjes_Disk' ; 11-byte volume name db 000001000b ; volume label attribute db 10 dup (0) ; reserved space ;FEDCBA9876543210b ; File Time & Date MTIME 23 08 40 ; 23:08:40 MDATE 90 09 30 ; 90-09-30 db 6 dup (0) ; more reserved space OurVolumeLen equ $ - OFFSET OurVolume ; --------------------------------------------------------------------------- ; Messages ; These are messages that are used by the initialization section of the ; driver. Banner label byte db cr,lf db 'NJ/TMa Ram Disk (C) 1987 by Mike Blaszczak',cr,lf ifdef V286 ifdef PCL db "PC's Limited " else db '286 ' endif endif db 'XMS Version 1.02 (C) Terje Mathisen ',??time,' ',??date,cr,lf db cr,lf,eos General db 'Device not installed.',cr,lf,eos NoEMMThere db 'The XMS driver is not installed.',cr,lf,lf,eos EMMError db 'XMS failure during installation.',cr,lf,lf,eos NoMem db 'No free XMS Memory.',cr,lf,lf,eos TooBig db 'Requested size too big to fit.',cr,lf,lf,eos TooSmall db "Can't have disk size < 16kB.",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 XMS 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 InitBuffer label byte ; Use 1kB from here for init driver ends end ; That's a wrap. ; Special thanks to Bob Brody and Dr File Finder