ProfitPress Mega CDROM2 Shareware Freeware (MSDOS)(1992)(Eng)

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Assembly Source File | 1992-06-06 | 54.7 KB | 1,626 lines

; ; ReSizeable RAMDisk device driver for XMS memory ; ; Copyright (c) 1992 Marko Kohtala ; ; Some documentation and license available in accompanying file ; SRDISK.DOC. If not, contact author by sending E-mail from ; ; Internet, Bitnet etc. to 'Marko.Kohtala@hut.fi' ; CompuServe to '>INTERNET:Marko.Kohtala@hut.fi' ; ; or by calling Airline QBBS, 24H, HST, V.32, V.42, MNP, ; +358-0-8725380, and leaving mail to me, Marko Kohtala. ; ; In general, this is FREEWARE. ; ; To compile with TASM: tasm /m2 srdisk.asm ; tlink /t srdisk.obj,srdisk.sys ; ; History: ; 1.00 Initial release ; 1.10 Added into IOCTL_msg media_change byte, that must be changed to ; -1 by srdisk if media changed. Changed header version to SRD 1.10. ; 1.20 Fixed name of program by adding the missing 'Re' to 'Sizeable'. ; Upgraded IOCTL_msg_s to version 1.20 by adding byte to tell usable ; memory types. ; Updated to work with DOS versions 2.x-5.x - not tested. ; 1.30 ; Major redesign of the reformatting system. Ioctl is no longer used. ; New data structures of version V_FORMAT 0 (beta format). ; Support for multiplex interrupt. ; Support for chaining of drivers for different memory to same disk. ; Support for DOS 4+ 32-bit sector addresses. ; [Allow forcing drive to some drive letter (even replace DOS drives).] ; Int 19 hooking is optional by defining HOOKINT19 to 0. ; Added if ... endif around all memory specific code to ease ; later adding of other memory support code. ; Fixed parameter reading to abort on every ctrl-character other ; than tab. DOS 5 could end line with LF if no parameters and CR if ; there were parameters. Now even NUL can end the line. ; 1.40 ; Moved the allocation conditionally out from this device driver. ; If C_NOALLOC in CAPABLE is set, the SRDISK.EXE is expected to do ; the allocation by itself. ; Changed multiplex interrupt interface to be more standardlike. ; Changed XMS handle to default 0 as indication there is no handle ; already allocated. ; Made the default BPB to contain a valid disk layout. The zero sectors ; in BPB made DR-DOS hang with divide error. ; Added check for DR-DOS 6 since it tells the init request header is ; not long enough to hold the drive letter, but the drive letter is ; there anyway. SRD_VERSION equ "1.41" ; FOUR LETTER VERSION STRING ; General capabilities in conf.c_flags C_APPENDED equ 1 ; Capable of having appended drivers C_MULTIPLE equ 2 ; Capable of driving many disks C_32BITSEC equ 4 ; Capable of handling over 32-bit sector addresses C_NOALLOC equ 8 ; Incapable of allocating memory by itself C_UNKNOWN equ 0xF0 ; If C_NOALLOC is not set, the malloc field in configuration structure points ; into the allocation function. If C_NOALLOC is set, then the malloc ; points into the data that SRDISK.EXE needs to be able to handle the memory ; by itself. ; What this driver can actually do ; Currently compiled for only C_32BITSEC, since no drivers for ; any other memory available and thus C_APPENDED is useless CAPABLE equ C_32BITSEC or C_NOALLOC ;CAPABLE equ C_32BITSEC or C_NOALLOC or C_APPENDED ; Boolean TRUE EQU 1 FALSE EQU 0 ; What memory this driver supports XMS_MEMORY equ TRUE ; Some important internal settings MULTIPLEXAH equ 72h ; Multiplex int 2F AH parameter V_FORMAT equ 0 ; config_s format version used here HOOKINT19 equ FALSE ; Hook int 19 if TRUE DEBUGGING equ FALSE DEBUGINIT equ FALSE ;******************* Derived definitions ******************** DR_ATTRIBUTES = 0800h ; Removable media if CAPABLE and C_32BITSEC DR_ATTRIBUTES = DR_ATTRIBUTES or 2 ; 32-bit addr endif if XMS_MEMORY .286c MEMSTR equ 'XMS ' ; Define 4 char memory type string else %out Memory defined by MEMORY not supported .err endif if DEBUGGING debug macro char,num push ax push dx IFDIFI <num>,<dx> IF TYPE num EQ 1 xor dh,dh mov dl,num ELSE mov dx,num ENDIF ENDIF mov al,char call debug_c pop dx pop ax endm else debug macro char endm endif ;DEBUGGING d_seg segment para public assume ds:d_seg, cs:d_seg org 0 device_start: ; The following is to be considered as both a device driver header and ; as a starting point for the configuration table. This driver will be ; identified by its segment address and this structure must be at offset ; 0. ; Device driver header drhdr_next dd -1 ; Pointer to next device (now last) drhdr_attr dw DR_ATTRIBUTES drhdr_strategy dw offset strategy ; Offset to strategy function drhdr_commands dw offset commands ; Offset to commands function drhdr_units db 1 ; Number of units ; The rest has four functions to be considered ; 1) usable as device driver name if this driver is changed ; into character device on init. ; 2) usable as a label to be returned in media check call ; 3) identifies this device driver as SRDISK driver by always having ; the letters SRD at offset dr_ID ; 4) identifies the memory used by the 4 char string at offset dr_memory dr_volume label byte dr_ID db 'SRD' ; SRDISK signature (3 char) dr_memory db MEMSTR ; Memory type identifier (4 char) dr_version db SRD_VERSION ; Device driver version (4 char) db 0 ; null to end volume label dr_v_format db V_FORMAT ; Configuration format version dr_conf dw offset conf ; Pointer to drive configuration ;************************************************************************** ; ; I/O ROUTINE TO THE RAM DISK ; ; This routine will read a group of sectors inside this part of ; the ram disk. If starting sector is not on this part of the disk, ; return without error with 0 sectors transferred. If not all sectors ; are on this part of the disk, transfer as many as can and report the ; number of sectors transferred. ; ; On entry ; bh - 0 then read, else write ; cx - number of sectors ; dx:ax - starting sector ; es:di - transfer buffer ; ; Preserve ; es, ds ; si, di ; ; Return ; - carry clear if no fatal error, transferred sector count in ax ; (if starting sector not in this part of disk, return ax = 0) ; - carry set and ax = 0 on fatal error ; ;************************************************************************** if XMS_MEMORY disk_IO proc far push ds push di push si push cs ; Make ds point to our data pop ds mov IO_startl,ax mov IO_starth,dx debug 'a',ax debug 'd',dx debug 'c',cx cmp ax,conf.c_sectorsl ; Starting sector on disk? sbb dx,conf.c_sectorsh jb disk_IO4 ; Yes debug 'O',ax xor ax,ax ; No, 0 sectors transferred clc ; No fatal error jmp disk_IOx ; Exit disk_IO4: mov dx,IO_starth add ax,cx ; Count ending sector adc dx,0 cmp dx,conf.c_sectorsh ; Ending sector on disk? jb disk_IO1 ; Jump if is jne disk_IO5 sub ax,conf.c_sectorsl jbe disk_IO1 ; Jump if is disk_IO5: sub cx,ax ; Count how many we CAN transfer debug 'T',cx disk_IO1: mov IO_sectors,cx ; Report # of transferred mov ax,cx ; Count number of bytes to move mul conf.c_BPB_bps mov si,offset XMS_alloc.XMS_cblk mov [si].XMS_sizel,ax ; Number of bytes to move mov [si].XMS_sizeh,dx mov ax,IO_starth ; Count starting byte mul conf.c_BPB_bps mov cx,ax mov ax,IO_startl mul conf.c_BPB_bps add dx,cx ; dx:ax is starting byte or bh,bh ; Input/output? mov bx,XMS_alloc.XMS_handle jnz disk_IO2 ; Jump if write ; -- Read mov [si].XMS_shandle,bx ; Source in XMS mov [si].XMS_soffl,ax mov [si].XMS_soffh,dx mov [si].XMS_dhandle,0 ; Destination in main memory mov [si].XMS_doffl,di mov [si].XMS_doffh,es jmp disk_IO3 disk_IO2: ; -- Write mov [si].XMS_shandle,0 ; Destination in main memory mov [si].XMS_soffl,di mov [si].XMS_soffh,es mov [si].XMS_dhandle,bx ; Source in XMS mov [si].XMS_doffl,ax mov [si].XMS_doffh,dx disk_IO3: mov ah,0Bh ; Move XMS block call dword ptr XMS_alloc.XMS_entry shr ax,1 cmc ; Carry set if err mov ax,IO_sectors ; Return # of sectors xferred jnc disk_IOx xor ax,ax disk_IOx: debug 'T',ax pop si ; Restore original si,di,ds pop di ; es was not changed pop ds ret_far: ret disk_IO endp ;************************************************************************** ; ; EXTERNAL MEMORY ALLOCATION ROUTINE ; ; Allocate requested amount of memory. If memory is available in chunks, ; the amount can be rounded up. If not enough memory available, allocate ; as much as possible or just report the amount that was previously ; allocated. It is expected that at least as much memory can be allocated ; as there previously was. Reallocation should not destroy memory ; contents - it is essential to be able to resize a disk without loosing ; the contents (a feature under development). ; ; On entry ; DWORD [sp+4] - Kbytes to allocate ; ; Preserve ; es, ds ; si, di ; ; Return dx:ax = Kbytes allocated ; ;************************************************************************** ife C_NOALLOC malloc proc C far arg kbytes:dword assume ds:nothing test word ptr kbytes+2,-1 ; Over 0FFFFh K is impossible jnz malloc_fail mov bx,word ptr kbytes ; New disk size mov dx,XMS_alloc.XMS_handle ; Handle to the memory mov ah,0Fh ; Reallocate call XMS_alloc.XMS_entry xor dx,dx ; Zero the high word of return or ax,ax jnz malloc_ok malloc_fail: mov ax,word ptr conf.c_size ; Fail, return current ret malloc_ok: mov ax,word ptr kbytes ; Ok, return requested ret assume ds:d_seg malloc endp endif ;************************************************************************** ; ; Warm Boot of Machine ; ; Release used XMS memory on warm boot. ; ; I guess this may be important if some virtual machine (VM) in some ; multitasking system has installed this driver and the VM is ended. ; Without this the other VMs would loose the space reserved for RAM disk ; in this VM. ;************************************************************************** if HOOKINT19 int_19_entry proc far assume ds:nothing pusha ; If XMS used, it must be 286 or above mov dx,XMS_alloc.XMS_handle or dx,dx jz int19_1 ; Jump if no XMS handle mov ah,0Ah call XMS_alloc.XMS_entry ; Free XMS memory mov XMS_alloc.XMS_handle,0 int19_1: xor ax,ax mov ds,ax mov ax,old_int19_off cli ; Disable interrupts mov ds:[19h*4],ax ; for the time to write mov ax,old_int19_seg ; old interrupt vector back mov ds:[19h*4+2],ax popa ; Enable interrupts jmp old_int19 assume ds:d_seg int_19_entry endp endif ;************************************************************************** ; ; Local data ; ; This data (as some from the Configuration tables too) is used by the ; two above routines that are needed resident in any case. ; ;************************************************************************** XMS_block struc XMS_sizel dw ? XMS_sizeh dw ? XMS_shandle dw ? XMS_soffl dw ? XMS_soffh dw ? XMS_dhandle dw ? XMS_doffl dw ? XMS_doffh dw ? XMS_block ends XMS_alloc_s struc ; Changing this structure needs changes in srdisk.exe XMS_handle dw 0 ; XMS handle to disk memory (0=no handle) XMS_entry dd ? ; XMS driver entry point XMS_cblk XMS_block <> ; XMS move command data structure XMS_alloc_s ends XMS_alloc XMS_alloc_s <> IO_sectors dw ? ; Temp storage for # of sec xferred IO_startl dw ? ; Temp storage for starting sector IO_starth dw ? ; Temp storage for starting sector if C_NOALLOC malloc EQU offset XMS_alloc endif else ; if XMS_MEMORY %out Memory defined by MEMORY not supported .err endif if HOOKINT19 old_int19 label dword ; Address of old INT 19 old_int19_off dw -1 old_int19_seg dw -1 endif ;************************************************************************** ; ; Debugging code ; ; This code prints out a character and a word in hex. This code can be ; used using "debug char,word" macro in the code to give some output of ; the actions device driver is doing. ; ; A color display is assumed with 80 characters on a row and 25 rows. ; ;************************************************************************** if DEBUGGING assume ds:nothing debug_c proc near push es push di mov ah,d_attr ; Load color attribute mov di,0B800h ; Load screen segment (assumes color) mov es,di mov di,d_loc ; Load line cmp di,26*160 ; Below screen? jb debug_c1 mov di,2*160 ; Yes, move to third line (for scroll off) mov d_loc,di add ah,10h ; Change color cmp ah,70h jb debug_c2 sub ah,60h debug_c2: mov d_attr,ah push es ; Wait if shift down mov ax,40h mov es,ax debug_c3: test byte ptr es:[17h],3 jnz debug_c3 pop es debug_c1: add di,d_col ; Advance to right column mov es:[di],ax ; Print error letter call debug_x ; Print high byte mov dh,dl call debug_x ; Print low byte add d_loc,160 ; Next line pop di pop es ret debug_c endp debug_x proc near ; Print a byte in hex mov al,dh shr al,1 shr al,1 shr al,1 shr al,1 call debug_x1 mov al,dh debug_x1: and al,0Fh ; Print a hex digit cmp al,10 jae debug_x2 add al,'0' jmp debug_x3 debug_x2: add al,'A'-10 debug_x3: inc di inc di mov es:[di],ax ret debug_x endp d_loc dw 2*160 d_col dw 150 d_attr db 40h assume ds:d_seg endif ; DEBUGGING ;************************************************************************** ; ; Configuration tables ; ; This structure holds all the formatting data used by the formatter. ; The formatter is passed a pointer to this data and it modifies it ; directly. For this arrangement to work THE BELOW TABLE MAY NOT BE ; MODIFIED WITHOUT PROPER CHANGES IN SRDISK.C. The table contains ; version number which is to be changed when a change is made to this ; structure. ; ; Only the first fields up to label appended_eor is resident and used in ; in every case. The rest is used only in the main driver in a chain of ; RAM disk drivers. ; ; !!! The formatter may use any initial values in this structure as ; default values i.e. set all needed values here !!! ; !!! A DR-DOS bug must be avoided by defining c_BPB_sectors and ; c_BPB_FATsectors so that they could be real !!! ;************************************************************************** READ_ACCESS equ 1 ; Bit masks for the RW_access WRITE_ACCESS equ 2 config_s struc c_drive db ? ; Drive letter c_flags db CAPABLE ; Misc capability flags c_disk_IO dd disk_IO ; disk_IO entry c_malloc dw malloc ; malloc entry offset (in DS/CS) c_next dw 0 ; Next driver in chain (segment) c_maxK dd 0FFFFh ; Maximum allowed size c_size dd 0 ; Current allocated size in Kbytes c_sectorsl dw 0 ; Sectors in this driver (low word) c_sectorsh dw 0 ; Sectors in this driver (high word) c_BPB_bps dw 128 ; Sector size c_BPB_spc db 4 ; Cluster size in sectors c_BPB_reserved dw 1 ; The boot sector is reserved c_BPB_FATs db 1 ; One FAT copy c_BPB_dir dw 64 ; 64 entries in root directory c_BPB_sectors dw 100 ; BPB number of sectors on disk c_BPB_media db 0FAh ; Media is RAM DISK c_BPB_FATsectors dw 1 ; Sectors per one FAT c_BPB_spt dw 8 ; Sectors per track (imaginary) c_BPB_heads dw 1 ; Number of heads (imaginary) c_BPB_hiddenl dw 0 ; # of hidden sectors (low word) (imag) c_BPB_hiddenh dw 0 ; # of hidden sectors (high word) c_BPB_tsectorsl dw 0 ; 32-bit # of sectors (low word) c_BPB_tsectorsh dw 0 ; 32-bit # of sectors (high word) c_tsize dd 0 ; Total size in Kbytes (all drivers) c_RW_access db 00b ; B0 = read, B1 = write (disabled now) c_media_change db 1 ; -1 if media changed, 1 if not c_open_files dw 0 ; Files currently open on drive c_next_drive dw 0 ; Segment of next SRDISK drive config_s ends conf config_s <> appended_eor equ offset conf.c_BPB_spc ; End of resident for appended driver ;************************************************************************** ; ; Other internal and resident data ; ; The order of this data is not significant as it will not be used outside ; ;************************************************************************** BPB equ byte ptr conf.c_BPB_bps pBPB dw offset BPB ; Pointer to BPB (for cmd_init) old_multiplex dd ? ; Multiplex hook if CAPABLE and C_APPENDED xaddr_off dw ? ; Temp data for cmd_io xaddr_seg dw ? xsecl dw ? xsech dw ? endif req_ptr dd ? ; Request structure pointer ; Pointers to commands command_tbl dw cmd_init ; 0 Init dw cmd_media ; 1 Media dw cmd_BPB ; 2 Build BPB dw cmd_unknown ; 3 IOCTL input dw cmd_input ; 4 Input dw cmd_unknown ; 5 nondest input (char) dw cmd_unknown ; 6 input status (char) dw cmd_unknown ; 7 input flush (char) dw cmd_output ; 8 Output dw cmd_output ; 9 Output with verify dw cmd_unknown ; 10 output status (char) dw cmd_unknown ; 11 output flush (char) dw cmd_unknown ; 12 IOCTL output dw cmd_open ; 13 Open device dw cmd_close ; 14 Close device dw cmd_removable ; 15 Removable media check HIGH_CMD EQU ($-offset command_tbl)/2 ;************************************************************************** ; ; Set request header address ; ; Called by DOS to set the request structure pointer ; ;************************************************************************** strategy proc far mov word ptr cs:req_ptr,bx mov word ptr cs:req_ptr+2,es ret strategy endp ;************************************************************************** ; ; Commands ; ; Called by DOS. Requested action defined in structure pointed by req_ptr. ; ;************************************************************************** commands proc far assume ds:nothing push ax push bx push cx push dx push si push di push ds push es cld lds si,cs:req_ptr ; We trust Microsoft that the unit is right at [req_ptr]+1 mov cx,[si+12h] ; Sectors/Cmd line/BPB pointer mov dx,[si+14h] ; Start sector/Device number mov bl,[si+2] ; Command cmp bl,HIGH_CMD ; Is command supported? ja cmd_unknown ; Jump if not xor bh,bh ; Count index to command_tbl shl bx,1 les di,dword ptr [si+0Eh] ; ES:DI = transfer address push cs pop ds ; DS to local data segment assume ds:d_seg jmp word ptr [command_tbl+bx] ; Do command cmd_unknown: assume ds:nothing mov al,3 jmp cmd_error cmd_IOerr: lds bx,req_ptr mov word ptr [bx+12h],0 ; Sector count zero cmd_error: mov ah,81h ; ERROR and DONE (err #, in al) jmp cmd_ret cmd_removable: ; Enough to return DONE without BUSY flag set cmd_ok: mov ax,100h ; DONE cmd_ret: debug 'Q',ax lds bx,req_ptr mov [bx+3],ax ; save status pop es pop ds pop di pop si pop dx pop cx pop bx pop ax retf ; Return far assume ds:d_seg commands endp ;************************************************************************** ; ; Media Check command ; ;************************************************************************** cmd_media proc near les bx,req_ptr mov ax,100h ; DONE status mov dh,conf.c_media_change ; Read the change return test conf.c_RW_access,READ_ACCESS jnz cmd_media1 mov ax,8102h ; "Device not ready" status mov dh,-1 ; "Changed" cmd_media1: debug 'C',ax mov es:[bx+0Eh],dh mov word ptr es:[bx+0Fh],offset dr_volume mov es:[bx+11h],cs jmp cmd_ret cmd_media endp ;************************************************************************** ; ; Build BPB command ; ;************************************************************************** cmd_BPB proc near les bx,req_ptr mov word ptr es:[bx+12h],offset BPB mov es:[bx+14h],cs mov conf.c_open_files,0 ; Reset open files to 0 debug 'B',<conf.c_RW_access> test conf.c_RW_access,READ_ACCESS jz cmd_BPB1 mov conf.c_media_change,1 ; Media not changed jmp cmd_ok cmd_BPB1: mov al,2 ; "Device not ready" jmp cmd_error cmd_BPB endp ;************************************************************************** ; ; Device Open command ; ;************************************************************************** cmd_open proc near debug 'O',-1 inc conf.c_open_files jmp cmd_ok cmd_open endp ;************************************************************************** ; ; Device Close command ; ;************************************************************************** cmd_close proc near cmp conf.c_open_files,0 jz cmd_close1 dec conf.c_open_files cmd_close1: jmp cmd_ok cmd_close endp ;************************************************************************** ; ; INPUT command ; ;************************************************************************** cmd_input proc near debug 'R',0 test conf.c_RW_access,READ_ACCESS jz cmd_input1 xor bh,bh jmp cmd_io cmd_input1: mov al,2 ; "Device not ready" jmp cmd_IOerr cmd_input endp ;************************************************************************** ; ; OUTPUT command ; ;************************************************************************** cmd_output proc near debug 'W',0 mov al,0 ; "Write protect violation" mov bh,1 test conf.c_RW_access,WRITE_ACCESS jnz cmd_io jmp cmd_output2 cmd_io: ; BH - read/write ; CX - sectors ; ES:DI - transfer address ; DS = CS mov ax,cx ; Count number of bytes to move mul conf.c_BPB_bps jc cmd_output4 ; Is it too much? (dx != 0) ; check transfer address and count that they do not ; exceed segment limit add ax,di ; (dx = 0 after the mul) jnc cmd_output5 cmd_output4: mov ax,di ; How many bytes CAN we move? xor ax,-1 xor dx,dx ; How many sectors? div conf.c_BPB_bps mov cx,ax cmd_output5: push es les si,req_ptr mov word ptr es:[si+12h],dx ; Xferred 0 sectors so far cmp byte ptr es:[si],1Ah ; Do we use 32-bit sec. address? jbe cmd_output3 debug '3',0 mov ax,es:[si+1Ah] ; Load 32-bit sec. address mov dx,es:[si+1Ch] jmp cmd_output8 cmd_output3: mov ax,es:[si+14h] ; Load 16-bit sec. address xor dx,dx cmd_output8: pop es if CAPABLE and C_APPENDED mov si,offset conf mov xaddr_off,di mov xaddr_seg,es mov xsecl,ax mov xsech,dx ; BH - read/write ; CX - sectors ; DS:SI - conf of current driver (main here) cmd_output7: push bx push cx call [si].c_disk_IO pop cx pop bx les di,cs:req_ptr ; Increment number of sectors add word ptr es:[di+12h],ax ; actually transferred jc cmd_output1 ; I/O error sub cx,ax ; All transferred? jbe cmd_output6 ; yes, so exit debug 'N',ax push ax mul [si].c_BPB_bps ; Increment transfer offset add cs:xaddr_off,ax ; which can not exceed 0FFFFh pop ax xor dx,dx add ax,cs:xsecl ; Count new starting sector adc dx,cs:xsech sub ax,conf.c_sectorsl ; Subtract passed sectors sbb dx,conf.c_sectorsh mov cs:xsecl,ax ; And store the result mov cs:xsech,dx mov es,cs:xaddr_seg ; Load these ready for disk_IO mov di,cs:xaddr_off mov si,[si].c_next ; Find next driver or si,si mov ds,si mov si,dr_conf jnz cmd_output7 ; there is no next driver - sectors not found! debug 'E',cx else ;if CAPABLE and C_APPENDED push cx call disk_IO pop cx les si,cs:req_ptr ; Return number of sectors mov word ptr es:[si+12h],ax ; actually transferred jc cmd_output1 ; I/O error cmp ax,cx je cmd_output6 endif cmd_output1: debug 'S',ax mov al,8 ; "Sector not found" cmd_output2: jmp cmd_IOerr cmd_output6: jmp cmd_ok cmd_output endp ;************************************************************************** ; ; MULTIPLEX server ; ;************************************************************************** multiplex proc far cmp ah,MULTIPLEXAH jne mplex_old cmp al,0 jz mplex_installed push cs ; Tell our segment pop es mplex_installed: mov al,-1 ; Tell we are installed iret mplex_old: jmp cs:old_multiplex multiplex endp ;************************************************************************** ;************************************************************************** ;************************************************************************** ;************************************************************************** ; ; INITIALIZATION TIME CODE ; ; This code and data is removed from the memory after driver is ; initialized. ;************************************************************************** end_of_resident EQU offset $ ; MARKS THE END OF RESIDENT PORTION OF DRIVER def_drive db 'C' ; Default drive, where to install main_config dd ? ; Pointer to main configuration table FLAG_1ST EQU 1 ; First SRDISK driver FLAG_FORCEDRIVE EQU 2 ; Force drive letter (in s_drive) FLAG_APPEND EQU 4 ; Append to other SRDISK driver FLAG_APPENDED EQU 8 ; Appended to other SRDISK driver FLAG_KNOWDRIVE EQU 10h ; Drive letter known FLAG_32BITS EQU 20h ; Capable of 32 bit sector addressing flags db 0 ;************************************************************************** ; ; prints macro ; ; This macro is used by initialization routines to display text. ; dx must point to the '$' terminated text about to be displayed. ;************************************************************************** prints macro mov ah,9 int 21h endm if DEBUGINIT print_x proc near ; Print a dword in hex print_lx: push ax mov ax,dx call print_sx mov ah,2 mov dl,':' int 21h pop ax print_sx: ; Print a word in hex push ax mov al,ah call print_cx pop ax print_cx: ; Print a byte in hex push ax shr al,1 shr al,1 shr al,1 shr al,1 call print_x1 pop ax print_x1: and al,0Fh ; Print a hex digit cmp al,10 jae print_x2 add al,'0' jmp print_x3 print_x2: add al,'A'-10 print_x3: mov ah,2 push dx mov dl,al int 21h pop dx ret print_x endp idebugc macro chr push ax mov al,chr call print_cx pop ax endm idebugs macro wrd push ax mov ax,wrd call print_sx pop ax endm idebugl macro high,low push ax push dx mov ax,low mov dx,high call print_lx mov ah,2 mov dl,' ' int 21h pop ax pop dx endm else idebugc macro chr endm idebugs macro wrd endm idebugl macro high,low endm endif ; DEBUGINIT ;************************************************************************** ; ; INIT command ; ; Init command does the following: ; - displays sign-on message ; - checks DOS version. This driver is built in a way that requires ; at least dos version 2.00. I'm not sure whether even that is enough. ; - determine which drive we are by default ; - read command line ; - abort on syntax errors ; - initialize memory to 0K disk ; - initialize multiplex interrupt ; - do hooks to other SRDISK drivers (specified in command line) ; - hook INT 19 bootstrap interrupt ; - fills in the request header ;************************************************************************** cmd_init proc near mov dx,offset s_sign_on ; "ReSizeable RAMdisk ver..." prints call init_dos jnc cmd_init4 jmp cmd_init_err cmd_init4: les si,req_ptr idebugl es,si idebugs <word ptr es:[si]> idebugs <word ptr es:[si+2]> idebugs <word ptr es:[si+16h]> mov al,'$' test flags,FLAG_KNOWDRIVE jz cmd_init1 mov al,es:[si+16h] ; Get drive number add al,'A' cmd_init1: mov def_drive,al mov s_drive,al test flags,FLAG_32BITS jnz cmd_init2 and conf.c_flags,NOT C_32BITSEC cmd_init2: call init_read_cmdline jc cmd_init_err call init_memory jc cmd_init_err call init_mplex jc cmd_init_err call init_hooks jc cmd_init_err if HOOKINT19 call set_int19 endif mov word ptr conf.c_disk_IO+2,cs mov al,s_drive mov conf.c_drive,al test flags,FLAG_APPENDED jz cmd_init7 mov s_appdrive,al ; Report append mov dx,offset s_appended prints mov bx,offset ret_far ; Strategy and commands short mov drhdr_strategy,bx mov drhdr_commands,bx mov drhdr_attr,8000h ; Plain character device mov drhdr_units,'$' ; Name for this driver '$SRD'MEMSTR lds bx,req_ptr mov byte ptr [bx+0Dh],1 ; One drive mov word ptr [bx+0Eh],appended_eor ; Ending address jmp cmd_init3 cmd_init_err: prints cmd_init_abort: call deinit ; Remove hooks xor ax,ax lds bx,req_ptr mov byte ptr [bx+0Dh],al ; Zero the number of drives mov [bx+0Eh],ax ; Ending address jmp cmd_init3 cmd_init7: ; Not appended to previously installed SRDISK driver mov al,s_drive cmp al,'$' ; Is the drive number known? jne cmd_init9 mov word ptr s_drive,2020h ; Don't tell drive cmd_init9: mov dx,offset s_installed ; Report install prints lds bx,req_ptr mov byte ptr [bx+0Dh],1 ; Save number of drives ; The following drive forcing code does not work! cmp byte ptr [bx],16h jbe cmd_init6 mov al,s_drive ; Force drive number cmp al,'$' ; Is the number known? je cmd_init6 sub al,'A' mov [bx+16h],al cmd_init6: mov word ptr [bx+0Eh],end_of_resident cmd_init3: mov [bx+10h],cs mov word ptr [bx+12h],offset pBPB mov [bx+14h],cs jmp cmd_ok cmd_init endp ;************************************************************************** ; ; CHECK DOS VERSION AND CAPABILITIES ; ;************************************************************************** init_dos proc near mov ax,4452h ; DR-DOS? stc int 21h jc idos_notc cmp ax,dx jne idos_notc cmp ah,10h jne idos_notc ; Not installed cmp al,67h ; DR-DOS version 6.0 ? jne idos_notc ; If not, treat it like MS-DOS or flags,FLAG_32BITS or FLAG_KNOWDRIVE jmp idos_x idos_notc: mov ah,30h int 21h ; Get DOS version number xchg ah,al idebugs ax cmp ax,200h jb idos1 cmp ax,700h jb idos2 idos1: mov dx,offset errs_eDOS ; Invalid DOS version stc ret idos2: cmp ax,31Fh ; DOS 3.31+ ? jb idos4 or flags,FLAG_32BITS idos4: les si,req_ptr cmp byte ptr es:[si],16h ; Device number supported? jbe idos_x ; No, make a guess or flags,FLAG_KNOWDRIVE idos_x: clc ret init_dos endp ;************************************************************************** ; ; READ COMMAND LINE ; ; Return carry set if error ;************************************************************************** init_read_cmdline proc near push ds les bx,req_ptr lds si,es:[bx+12h] ; Pointer to cmd line assume ds:nothing irc1: lodsb ; Skip over the driver name cmp al,9 ;tab je irc2 cmp al,' ' je irc2 ja irc1 jmp irc_eol irc2: irc_narg: call irc_skip_space cmp al,' ' ; Every ctrl character ends jb irc_eol cmp al,'/' jz irc_switch and al,11011111b ; Make lowercase to uppercase cmp al,'A' jb irc_syntax cmp al,'Z' ja irc_syntax cmp byte ptr [si],':' jne irc3 inc si ; Skip ':' irc3: mov byte ptr s_drive,al test flags,FLAG_FORCEDRIVE jnz irc_syntax or flags,FLAG_FORCEDRIVE jmp irc_narg irc_syntax: mov dx,offset errs_syntax stc pop ds ret irc_switch: lodsb and al,11011111b ; Make lowercase to uppercase cmp al,'A' jne irc_syntax or flags,FLAG_APPEND jmp irc_narg irc_eol: clc pop ds ret init_read_cmdline endp irc_skip_space proc near ircs1: lodsb cmp al,' ' je ircs1 cmp al,9 ;tab je ircs1 ret irc_skip_space endp assume ds:d_seg ;************************************************************************** ; ; Memory initialization ; ; Returns ; carry set if error ;************************************************************************** if XMS_MEMORY ; Get XMS driver API address and allocates 0K to get a memory handle ; for RAM disk init_memory proc near push es mov ax,4300h int 2Fh ; Get XMS installed status cmp al,80h jne init_XMS1 ; Jump if not installed mov ax,4310h int 2Fh ; Get XMS entry point jnc init_XMS2 ; Jump if no error init_XMS1: mov dx,offset errs_noXMS ; "No extended mem driver" jmp init_XMS4 init_XMS2: mov word ptr XMS_alloc.XMS_entry,bx mov word ptr XMS_alloc.XMS_entry+2,es xor dx,dx ; Allocate 0K to get a handle mov ah,9 call XMS_alloc.XMS_entry or ax,ax jz init_XMS3 ; Zero for failure mov XMS_alloc.XMS_handle,dx clc jmp init_XMS_ret init_XMS3: mov dx,offset errs_ealloc ; "Error in ext mem alloc" init_XMS4: stc init_XMS_ret: pop es ret init_memory endp else %out Memory defined by MEMORY not supported .err endif ;************************************************************************** ; ; Multiplex service initialization ; ; Queries multiplex interrupt to find out if SRDISK device drivers are ; already installed. If not install the multiplex server. ; ; Return carry set if error. ;************************************************************************** init_mplex proc near push ds push es mov ax,MULTIPLEXAH * 100h xor bx,bx xor cx,cx xor dx,dx push ds int 2Fh ; AL installed status pop ds cmp al,-1 ; Is something installed? je im_installed cmp al,0 ; Is it OK to install? je im_install im_used: ; Garbled return mov dx,offset errs_ml_used im_err: stc jmp imx im_installed: mov ax,MULTIPLEXAH * 100h + 1 push ds int 2Fh ; ES segmet of main SRDISK driver pop ds cmp word ptr es:dr_ID,'RS' ; Is it SRDISK structure? jne im_used ; No, multiplex used elsewhere cmp byte ptr es:dr_ID+2,'D' jne im_used ; No, multiplex used elsewhere mov dx,offset errs_ml_version cmp byte ptr es:dr_v_format,V_FORMAT ; Proper version? jne im_err ; No ; OK mov di,es:dr_conf mov word ptr main_config,di mov word ptr main_config+2,es jmp im_end im_install: mov word ptr main_config,offset conf mov word ptr main_config+2,ds or flags,FLAG_1ST mov ax,352Fh int 21h mov word ptr old_multiplex,bx mov word ptr old_multiplex+2,es mov dx,offset multiplex mov ax,252Fh int 21h im_end: clc imx: pop es pop ds ret init_mplex endp ;************************************************************************** ; ; INIT HOOKS to previous SRDISK drivers ; ; Append this driver into the list of installed SRDISK drivers ; Return carry set if error ;************************************************************************** init_hooks proc near test flags,FLAG_1ST ; If we are the first driver jnz ihxok ; no hooks are to be done les di,main_config ; es:di point to a drive config mov al,s_drive ; al is the drive to search cmp al,'$' ; Is drive letter unknown? je ih_nodrive ; Yes, do not check drive letter test flags,FLAG_APPEND ; If we append jz ih_find_drive test flags,FLAG_FORCEDRIVE ; but not specify drive jnz ih_find_drive ih_nodrive: mov al,-1 ; make sure drive not found ih_find_drive: ih1: cmp es:[di].c_drive,al ; Is it the same drive? je ih_append ih2: test word ptr es:[di].c_next_drive,-1 ; Is there next drive jz ih_newdrive ; No (valid segment is nonzero) mov es,es:[di].c_next_drive ; Yes, find the next drive mov di,es:dr_conf jmp ih1 ih_append_new: ; Append this driver into previously installed drive mov al,es:[di].c_drive ; Find the drive letter mov s_drive,al mov conf.c_drive,al ih_append: ; Append this driver into specified drive test es:[di].c_flags,C_APPENDED ; Append allowed? jz ih_appendfail ; No, fail test word ptr es:[di].c_next,-1 ; Is there next driver jz ih_a1 ; No, append here mov es,es:[di].c_next ; Yes, find the next drive mov di,es:dr_conf jmp ih_append ih_appendfail: mov al,def_drive mov s_drive,al mov dx,offset errs_noappend stc ret ihxok: clc ihx: ret ih_a1: mov es:[di].c_next,ds or flags,FLAG_APPENDED ; Remember to free extra memory if DEBUGGING mov ax,es:d_col ; Debug data display little left from sub ax,16 ; main data display mov d_col,ax endif ;DEBUGGING jmp ihxok ih_newdrive: test flags,FLAG_APPEND jnz ih_append_new ; This driver must be placed at the tail of list of ; SRDISK drivers mov es:[di].c_next_drive,ds jmp ihxok init_hooks endp ;************************************************************************** ; ; INT 19 hooking ; ; INT 19 is the bootstrap loader interrupt, which is invoked when user ; presses Ctrl-Alt-Del. We must hook it in order to release the ; extended memory allocated for RAM disk. ;************************************************************************** if HOOKINT19 set_int19 proc near push ax push dx push bx push es mov ax,3519h int 21h ; Get old int 19 handler mov old_int19_off,bx mov old_int19_seg,es mov dx,offset int_19_entry mov ax,2519h int 21h ; Set new int 19 handler pop es pop bx pop dx pop ax retn set_int19 endp endif ;************************************************************************** ; ; Deinitialization in case of aborted install ; ;************************************************************************** deinit proc near if HOOKINT19 mov ax,old_int19_seg or ax,old_int19_off jz di_noint19 push ds mov dx,old_int19_off mov ds,old_int19_seg mov ax,2519h int 21h ; Set old int 19 handler pop ds di_noint19: endif if XMS_MEMORY cmp XMS_alloc.XMS_handle,0 je di_nomem mov dx,XMS_alloc.XMS_handle mov ah,0Ah call XMS_alloc.XMS_entry ; Free XMS memory else %out Memory defined by MEMORY not supported .err endif di_nomem: mov ax,word ptr old_multiplex or ax,word ptr old_multiplex+2 jz no_mplex push ds mov dx,word ptr old_multiplex mov ds,word ptr old_multiplex+2 mov ax,252Fh int 21h ; Set old multiplex handler pop ds no_mplex: ret deinit endp ;************************************************************************** ; ; Initialization strings ; ;************************************************************************** errs_noXMS db 'RAMDisk: Extended Memory Manager not present.' db 0Dh, 0Ah, '$' errs_ealloc db 'RAMDisk: Error in extended memory allocation.' db 0Dh, 0Ah, '$' errs_eDOS db 'RAMDisk: Incorrect DOS version.' db 0Dh, 0Ah, '$' errs_ml_used db 'RAMDisk: Multiplex interrupt already in use.' db 0Dh, 0Ah, '$' errs_ml_version db 'RAMDisk: Driver of different version already ' db 'installed.' db 0Dh, 0Ah, '$' errs_noappend db 'RAMDisk: Can not append to previously installed driver.' db 0Dh, 0Ah, '$' errs_syntax db 'RAMDisk: Syntax error', 0Dh, 0Ah, 0Dh, 0Ah db 'Syntax: RDISK.SYS [d:] [/A]', 0Dh, 0Ah, 0Dh, 0Ah db ' d:', 9, 'Drive into which to append or tell the ' db 'drive letter', 0Dh, 0Ah db 9, 'of this device if DOS does not report it.' db 0Dh, 0Ah db ' /A', 9, 'Append this driver to previous SRDISK ' db 'driver.' db 0Dh, 0Ah, '$' s_sign_on db 0Dh, 0Ah, 'ReSizeable RAMDisk ' if XMS_MEMORY db '(XMS)' else %out Memory defined by MEMORY not supported .err endif db ' version ', SRD_VERSION, '. ' db 'Copyright (c) 1992 Marko Kohtala.' db 0Dh, 0Ah, '$' s_installed db 'Installed RAMDrive ' s_drive db 'C:', 0Dh, 0Ah, '$' s_appended db 'Appended to RAMDrive ' s_appdrive db 'C:', 0Dh, 0Ah, '$' ;************************************************************************** ; ; A note for binary debuggers ; ;************************************************************************** db 0Dh, 0Ah, "Copyright (c) 1992 Marko Kohtala. " db 0Dh, 0Ah, "Contact from Internet, Bitnet etc. to 'Marko.Kohtala@hut.fi', " db 0Dh, 0Ah, "CompuServe to '>INTERNET:Marko.Kohtala@hut.fi'" db 0Dh, 0Ah d_seg ends end