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/ Oakland CPM Archive / oakcpm.iso / cpm / pubpatch / pubpatch.aqm / PUBPATCH.ASM

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Assembly Source File | 1985-06-17 | 9.3 KB | 364 lines

.title 'pubpatch.asm 4-13-84 (c) 1984 Plu*Perfect Systems' .settim 16:19:00 .setdat 11/18/84 .setwid 90 .setlen 60 ;11/18/84 minor change to published DDJ version to produce ;relocatable object file, to be relocated using HXRLOAD .remark ~ -- PUBPATCH -- A CP/M 2.2 BDOS modification to support the PUBlic filetype. -------------------------------------------- Copyright (c) 1984 -- All rights reserved. Plu*Perfect Systems P. O. Box 1494 Idyllwild CA 92349 -------------------------------------------- Attribute bit 2 of a filename signifies a PUBlic file, accessible by its unambiguous filename from all user numbers. PUBlic files are not accessible via the usual ambiguous filenames (e.g. *.* or ABC.D?F), to prevent unintentional erasure and avoid directory clutter. Directory entries for PUBlic files are, however, accessible via ambiguous filenames by using the BDOS search-for-first, search-for-next functions with a '?' in the drive-byte of the fcb. Extended versions of SD and DISK7 displays PUBlic files. To erase a PUBlic file, use "ERA unambiguous-filename". Or use DISK7. Or change it to a private file and then erase with a wildcard erase command. The PUBLIC.COM utility is available to make files either PUBlic or private and to list the current PUBlic files. If another utility is used to set the PUBlic attribute bit, avoid creating multiple files with the same name on the same drive, unless all of them are private. (PUBLIC.COM checks for this situation and prevents a conflict.) The REName command removes all attributes, so RENaming a PUBlic file will make it private, R/W, DIR in its original user number. ~ .page .remark ~ --- TO INSTALL --- 1a. Determine the BIOSBASE address of your system in memory by subtracting 3 from the warm-boot address in memory: DDT L0 subtract 3 ==> BIOSBASE address 1b. Subtract 1600H to determine the CCPBASE_MEMORY address. 1c. Assemble PUBPATCH for these addresses. Either: use CDL's MACROIII assembler: MACROIII PUBPATCH A:DHK Or: convert the pseudo-opcodes to your assembler's pseudo-ops and assemble into a HEX file. e.g. .loc ==> org = ==> set =\ ==> ????, etc. 2. Create a system image for the SYSGEN operation. There are two ways to get the image: a. Either use SYSGEN to extract a system image from a disk in the usual manner -- SYSGEN source drive? A destination drive? <CR> SAVE pp ORIG.SYS. Use pp=50 pages or so to get the entire BIOS. b. Or generate a new system -- MOVCPM ss * where ss=64 for a 64K system, SAVE pp ORIG.SYS or whatever you are running. 3. Find the base address of the Command Processor in the image DDT ORIG.SYS Look for the command processor at 980H: You recognize it by two JMP instructions, followed by the command buffer (containing a Digital Research copyright notice, in the case of the original CCP): L980 D980 Call that address CCPBASE_IMAGE (normally 980H). (If you don't find it, you have a non-standard system, and your user's manual should have a memory map. See, e.g., the Compupro Disk 1 Controller manual, sec. 6.4). 4. Calculate the offset needed to cause the PUBPATCH.HEX file to load on top of the BDOS image. 'offset' will satisfy: CCPBASE_IMAGE = CCPBASE_MEMORY + offset 5. Create a new system image containing the patch: DDT ORIG.SYS IPUBPATCH.HEX Roffset G0 SAVE pp NEWSYS.SYS 6. Finally, put the new system on a FLOPPY disk for testing: SYSGEN NEWSYS.SYS <CR> destination_drive ------------------------------------------------ Code also corrects a CP/M 2.2 bug that caused Rename, Set Attribute, and Delete File functions to return 0 status on success instead of 0,1,2,3 per CP/M 2.2 Installation Guide. ------------------------------------------------ ~ .page .phex bdosbase = . ; Internal BDOS locations: ; FINDNXT = bdosbase+072Dh NXENTRY = bdosbase+0605h CKFILPOS = bdosbase+05F5h MOREFLS = bdosbase+057Fh FCB2HL = bdosbase+055Eh SAMEXT = bdosbase+0707h STFILPOS = bdosbase+05FEh SETSTAT = bdosbase+0301h SAVEFCB = bdosbase+0DD9h COUNTER = bdosbase+0DD8h FILEPOS = bdosbase+0DEAh STATUS = bdosbase+0345h FNDSTAT = bdosbase+0DD4h CHKWPRT = bdosbase+0554h CHKROFL = bdosbase+0544h FINDFST = bdosbase+0718h SETFILE = bdosbase+066bh DIRWRITE = bdosbase+05c6h CKFILPOS = bdosbase+05f5h DELFILE = bdosbase+0cd7h EXTMASK = bdosbase+0dc5h CLOSEFLG = bdosbase+0dd2h RDWRTFLG = bdosbase+0dd3h GETEMPTY = bdosbase+0924h OPENIT1 = bdosbase+085ah STRDATA = bdosbase+04bbh SETSTAT = bdosbase+0301h IOERR1 = bdosbase+0305h SETS2B7 = bdosbase+0578h ; .page .loc FINDNXT fnxt0: lxi h,0 shld pflag ;initialize PUBlic & wildcard flags mov c,h ;0 call NXENTRY call CKFILPOS jrz nomatch ;if done lhld SAVEFCB xchg ;de=user-fcb ldax d cpi 0E5h ;if Getempty fn wants first jrz fnxt1 ;..deleted file slot in directory push d call MOREFLS pop d jrnc nomatch ;if no more files ; fnxt1: call FCB2HL ;hl=directory fcb lda COUNTER mov b,a ;b=count mvi c,0 ;c=byte # ora a ;COUNTER=0 ==> Search fn jrz matched ;..so match every entry ; fnxt2: mov a,c ;get byte # cpi 13 jrz nxtbyte ;omit S1 byte ldax d ;get user-fcb char cpi '?' jrnz fnxt3 sta qflag ;flag wildcard jr nxtbyt ; fnxt3: mov a,m ;get directory-fcb char cpi 0E5h ;check for blank/deleted file mov a,c ;A = byte # jrz chkext ;if a deleted file, omit user # check ora a jrnz chkext ;or if not user # byte inx h ;else check for PUBlic file inx h bit 7,m ;..at attribute bit 2 dcx h dcx h jrz chkext ;if not PUBlic, match on user # ; ; the file is PUBlic ; -- but is BDOS looking for an empty directory slot? mov a,b ;if COUNTER=1, this is a Getempty request dcr a ; jrz fnxt0 ;..so go to next file sta pflag ;else flag the file PUBlic, jr nxtbyt ;..and omit matching user # ; chkext: cpi 12 ; (A=byte #) ldax d jrz tstext ;extent byte(#12) is special case sub m ;compare the characters ani 07fh ;..excluding attribute bits jr extdone tstext: push b ;check for same extent mov c,m call SAMEXT pop b extdone:jrnz fnxt0 ;if mismatch, get next file ; nxtbyt: inx d ;chars match, bump to next byte inx h inr c ;byte # ++ djnz fnxt2 ;count-- ; ; here if-- COUNTER > 1 and filenames match ; ;Test for PUBlic file and wild-card combination: ; ;flags initially = 0, but pflag = .+1 ; = COUNTER-1 if PUBlic qflag = .+2 ; = '?'(3Fh) if '?' in fcb+1... lxi h,.-. mov a,l ;if file is PUBlic ana h ;..and there's a wildcard ;(3Fh & 1...n) ==> NZ jrnz fnxt0 ;..get next directory entry ; ; here if-- ; (a) non-PUBlic filenames match, ; or (b) find-all-files (searchfirst/searchnext functions ; with drive byte = '?') ; or (c) delete unambiguous PUBlic-filename. ; matched:jmp PATCH1 ; nomatch:call STFILPOS mov a,l ;l=0ffh jmp SETSTAT ; .page ; the ERASE FILE routine -- in a new location ; ; Routine is split, with remainder stuffed ; into free bytes at end of BDOS. ; ERAFILE:call CHKWPRT ;write-protect aborts mvi c,12 call FINDFST eraf1: call CKFILPOS ;check for 'E5' case rz call CHKROFL ;read-only file aborts call FCB2HL jmp PATCH2 LAST1 = . ;must be <= bdosbase+07BEh ; ; ;Remainder of ERASE routine goes at end of BDOS ; .loc bdosbase+0deeh ;there are 18 spare bytes PATCH2: eraf2: mvi m,0E5h ;install erase mark mvi c,0 call SETFILE ;clear file's space in bitmap call DIRWRITE ;write directory sector eraf3: call FINDNXT ;look for next entry jmp eraf1 LAST2 = . ;must be <= bdosbase+0E00h ; .page ;rewrite last part of bdos GETNEXT routine to gain space ; .LOC bdosbase+0971h ; gnxt0: jrz gnxt1 ;( overlaying jz gtnext1) mov b,a ;extent byte lda EXTMASK ana b lxi h,CLOSEFLG ana m jrz gnxt2 ;must read next extent gnxt3: call OPENIT1 ;open current extent gnxt4: call STRDATA ;update rec#, extent#,... xra a jsetst: jmp SETSTAT ; ; have overflowed normal extent, check s2 byte gnxt1: inx h ;shorter code, replacing inx h ;lxi b,2 & dad b inr m ;bump s2 byte mov a,m ani 0fh jrz gnxt5 ;error if too many extents gnxt2: mvi c,15 ;open the next extent call FINDFST call CKFILPOS jrnz gnxt3 lda RDWRTFLG ;no extant extent inr a ;..if reading, can't open one jrz gnxt5 call GETEMPTY ;writing, so get next free entry call CKFILPOS jrnz gnxt4 ;and if no error, save the data gnxt5: call IOERR1 ;set error & jmp SETS2B7 ;..don't close file ; ; ; use space (14 bytes) for fragment from FINDNXT routine: ; PATCH1: lda FILEPOS ani 03h sta STATUS ;save its directory buffer index lxi h,FNDSTAT ; .remark ~ The original CP/M 2.2 code removed below is erroneous, and causes BDOS Erasefile, Renamefile, Setattribute functions to return A=0 on success rather than the directory index (0,1,2 or 3) specified in the Interface Guide. ;; mov a,m ;; ral ;; rnc ;; xra a ~ ; mov m,a ;also save it for use ret ;..by Erase,Rename,Set Attribute fns ; LAST3 = . ;must be <= bdosbase+09BCh ; ; ;patch ERAFILE reference to its new location ; .loc (DELFILE+3) CALL ERAFILE ; .end