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Text File | 1990-02-02 | 19.1 KB | 917 lines

page ,132 title crt0dat - DOS and Windows shared startup and termination ;*** ;crt0dat.asm - DOS and Windows shared startup and termination ; ; Copyright (c) 1985-1990, Microsoft Corporation. All rights reserved. ; ;Purpose: ; Shared startup and termination. ; ; NOTE: This source is included in crt0.asm for assembly purposes ; when building .COM startup. This is so the .COM startup resides ; in a single special object that can be supplied to the user. ; ;******************************************************************************* _NFILE_ = 20 ; Maximum number of file handles ?DF = 1 ;; tell cmacros.inc we want to define our own segments .xlist include version.inc include cmacros.inc include msdos.inc .list ifdef FARSTACK ife sizeD error <You cannot have a far stack in Small or Medium memory models.> endif endif ifdef _COM_ if sizeC or sizeD error <Must use Small memory model for .COM files.> endif endif ;_COM_ createSeg _TEXT, code, word, public, CODE, <> createSeg CDATA, cdata, word, common, DATA, DGROUP createSeg _DATA, data, word, public, DATA, DGROUP createSeg DBDATA, dbdata, word, common, DATA, DGROUP createSeg XIQC, xiqcseg, word, common, DATA, DGROUP ; QC initializer -Zr (DOS only) createSeg XIFB, xifbseg, word, public, DATA, DGROUP createSeg XIF, xifseg, word, public, DATA, DGROUP ; far init's createSeg XIFE, xifeseg, word, public, DATA, DGROUP createSeg XIB, xibseg, word, public, DATA, DGROUP createSeg XI, xiseg, word, public, DATA, DGROUP ; init's createSeg XIE, xieseg, word, public, DATA, DGROUP createSeg XOB, xobseg, word, public, BSS, DGROUP createSeg XO, xoseg, word, public, BSS, DGROUP ; onexit table createSeg XOE, xoeseg, word, public, BSS, DGROUP createSeg XPB, xpbseg, word, public, DATA, DGROUP createSeg XP, xpseg, word, public, DATA, DGROUP ; preterm's createSeg XPE, xpeseg, word, public, DATA, DGROUP createSeg XCB, xcbseg, word, public, DATA, DGROUP createSeg XC, xcseg, word, public, DATA, DGROUP ; term's createSeg XCE, xceseg, word, public, DATA, DGROUP createSeg XCFB, xcfbseg, word, public, DATA, DGROUP createSeg XCF, xcfseg, word, public, DATA, DGROUP ; far term's createSeg XCFE, xcfeseg, word, public, DATA, DGROUP ifdef _COM_ createSeg EMULATOR_DATA, EmData, para, public, FAR_DATA, DGROUP createSeg EMULATOR_TEXT, EmCode, para, public, CODE, DGROUP endif ;_COM_ defGrp DGROUP ; define DGROUP codeOFFSET equ offset _TEXT: dataOFFSET equ offset DGROUP: page sBegin xifbseg xifbegin label byte sEnd xifbseg sBegin xifeseg xifend label byte sEnd xifeseg sBegin xibseg xibegin label byte sEnd xibseg sBegin xieseg xiend label byte sEnd xieseg sBegin xobseg xontab label byte ; start of onexit table sEnd xobseg sBegin xoeseg xonend label byte sEnd xoeseg sBegin xpbseg xpbegin label byte ; end of onexit table sEnd xpbseg sBegin xpeseg xpend label byte sEnd xpeseg sBegin xcbseg xcbegin label byte sEnd xcbseg sBegin xceseg xcend label byte sEnd xceseg sBegin xcfbseg xcfbegin label byte sEnd xifbseg sBegin xcfeseg xcfend label byte sEnd xcfeseg sBegin cdata ; floating point setup segment assumes ds,data dw 0 ; force segment to be at least 0's labelD <PUBLIC,_fpinit> ; public for signal fpmath dd 1 dup (?) ; linking trick for fp fpdata dd 1 dup (?) fpsignal dd 1 dup (?) ; fp signal message sEnd sBegin dbdata ;* assumes ds,data ;* Used to do the running under externW __aDBswpflg ;* a debugger screen swapping externW __aDBexit ;* sEnd dbdata ;* extrn __aDBdoswp:ABS ;* sBegin xiqcseg globalW __qczrinit, 0 ;* QC -Zr initializer call address sEnd xiqcseg ifdef _COM_ sBegin EmData labelB _EmDataLabel sEnd EmData sBegin EmCode globalW _EmDataSeg,0 sEnd EmCode else ;not _COM EMULATOR_DATA segment para public 'FAR_DATA' EMULATOR_DATA ends EMULATOR_TEXT segment para public 'CODE' public __EmDataSeg __EmDataSeg dw EMULATOR_DATA EMULATOR_TEXT ends endif ;not _COM_ sBegin data assumes ds,data ; special C environment string labelB <PUBLIC,_acfinfo> cfile db '_C_FILE_INFO=' cfilex db 0 cfileln = cfilex-cfile globalD _aintdiv,0 ; divide error interrupt vector save globalT _fac,0 ; floating accumulator globalW errno,0 ; initial error code globalW _umaskval,0 ; initial umask value ;=============== following must be in this order globalW _pspadr,0 ; psp:0 (far * to PSP segment) globalW _psp,0 ; psp:0 (paragraph #) ;=============== above must be in this order ;=============== following must be in this order labelW <PUBLIC,_osversion> labelB <PUBLIC,_dosvermajor> globalB _osmajor,0 labelB <PUBLIC,_dosverminor> globalB _osminor,0 ;=============== above must be in this order globalB _osmode,0 ; 0 = real mode labelW <PUBLIC,_oserr> globalW _doserrno,0 ; initial DOS error code globalW _nfile,_NFILE_ ; maximum number of file handles labelB <PUBLIC,_osfile> db 3 dup (FOPEN+FTEXT) ; stdin, stdout, stderr db 2 dup (FOPEN) ; stdaux, stdprn db _NFILE_-5 dup (0) ; the other 15 handles globalW __argc,0 globalDP __argv,0 globalDP environ,0 ; environment pointer labelD <PUBLIC,_pgmptr> ; pointer to program name dw dataOFFSET dos2nam ifdef _COM_ dw 0 ; No relocations in tiny model elseifdef _QC2 dw 0 ; No DGROUP references allowed elseifdef _WINDOWS dw 0 ; No DGROUP references allowed else ;DEFAULT dw DGROUP endif dos2nam db 0 ; dummy argv[0] for DOS 2.X ; signal related common data globalW _child,0 ; flag used to handle signals from child process ;Overlay related data globalB _ovlflag,0 ;Overlay flag (0 = no overlays) globalB _intno,0 ;Overlay interrupt value (e.g., 3F) globalD _ovlvec,0 ;Address of original overlay handler sEnd data page externNP _fptrap externP _cintDIV externP _nullcheck ifdef FARSTACK endif sBegin code assumes cs,code if sizeC global proc far endif page ;*** ;_cinit - C initialization ; ;Purpose: ; This routine performs the shared DOS and Windows initialization. ; The following order of initialization must be preserved - ; ; 1. Integer divide interrupt vector setup ; 2. Floating point initialization ; 3. Copy ;C_FILE_INFO into _osfile ; 4. Check for devices for file handles 0 - 4 ; 5. General C initializer routines ; ;Entry: ; ;Exit: ; ;Uses: ; ;Exceptions: ; ;******************************************************************************* cProc _cinit,<PUBLIC>,<> cBegin <nogen> ; no local frame to set up in standard libs assumes ds,data ifndef FARSTACK assumes ss,data endif ; ; Initialize the DGROUP portion of _pgmptr. We must do this at ; runtime since there are no load-time fixups in .COM files. ; ifdef _COM_ mov word ptr [_pgmptr+2],ds ; init seg portion of _pgmptr endif ;_COM_ ; *** Increase File Handle Count *** ; ; (1) This code only works on DOS Version 3.3 and later. ; (2) This code is intentially commented out; the user must enable ; this code to access more than 20 files. ; ; mov ah,67h ; system call number ; mov bx,_NFILE_ ; number of file handles to allow ; callos ; issue the system call ; ;check for error here, if desired (if carry set, AX equals error code) ; ; *** End Increase File Handle Count *** ; 1. Integer divide interrupt vector setup mov ax,DOS_getvector shl 8 + 0 callos ; save divide error interrupt mov word ptr [_aintdiv],bx mov word ptr [_aintdiv+2],es push cs pop ds assumes ds,nothing mov ax,DOS_setvector shl 8 + 0 mov dx,codeOFFSET _cintDIV callos ; set divide error interrupt push ss pop ds assumes ds,data ; 2. Floating point initialization if memS cmp word ptr [fpmath], 0 ; Note: make sure offset __fpmath != 0 je nofloat_i mov word ptr [fpmath+2], cs ; fix up these far addresses mov word ptr [fpsignal+2], cs ; in the small model math libs ifdef _COM_ mov [_EmDataSeg], cs mov ax, offset DGROUP:_EmDataLabel sub ax, offset EMULATOR_DATA:_EmDataLabel mov cl, 4 shr ax, cl add [_EmDataSeg], ax endif ;_COM_ else ;not memS mov cx,word ptr [fpmath+2] jcxz nofloat_i endif ;not memS mov es,[_psp] ; psp segment mov si,es:[DOS_ENVP] ; environment segment ifdef FARSTACK mov ax, word ptr [fpdata] mov dx, word ptr [fpdata+2] else lds ax,[fpdata] ; get task data area assumes ds,nothing mov dx,ds ; into dx:ax endif xor bx,bx ; (si) = environment segment call [fpmath] ; fpmath(0) - init ifdef FARSTACK mov ax, DGROUP mov ds, ax endif jnc fpok ifndef FARSTACK push ss ; restore ds from ss pop ds endif jmp _fptrap ; issue "Floating point not loaded" ; error and abort fpok: ifdef FARSTACK mov ax, word ptr [fpsignal] mov dx, word ptr [fpsignal+2] else lds ax,[fpsignal] ; get signal address assumes ds,nothing mov dx,ds endif mov bx,3 call [fpmath] ; fpmath(3) - set signal address ifdef FARSTACK mov ax, DGROUP mov ds, ax ; restore DS=DGROUP else push ss pop ds assumes ds,data endif nofloat_i: ; 3. Copy _C_FILE_INFO= into _osfile ; fix up files inherited from parent using _C_FILE_INFO= mov es,[_psp] ; es = PSP mov cx,word ptr es:[DOS_envp] ; es = user's environment jcxz nocfi ; no environment !!! mov es,cx xor di,di ; start at 0 cfilp: cmp byte ptr es:[di],0 ; check for end of environment je nocfi ; yes - not found mov cx,cfileln mov si,dataOFFSET cfile repe cmpsb ; compare for '_C_FILE_INFO=' je gotcfi ; yes - now do something with it mov cx,07FFFh ; environment max = 32K xor ax,ax repne scasb ; search for end of current string jne nocfi ; no 00 !!! - assume end of env. jmp cfilp ; keep searching ; found _C_FILE_INFO= and transfer info into _osfile gotcfi: push es push ds pop es ; es = DGROUP pop ds ; ds = env. segment assumes ds,nothing assumes es,data mov si,di ; si = startup of _osfile info mov di,dataOFFSET _osfile ; di = _osfile block mov cl, 4 osfile_lp: lodsb sub al, 'A' jb donecfi shl al, cl xchg dx, ax lodsb sub al, 'A' jb donecfi or al, dl stosb jmp short osfile_lp donecfi: ifdef FARSTACK push es else push ss endif pop ds ; ds = DGROUP assumes ds,data nocfi: ; 4. Check for devices for file handles 0 - 4 ; ; Clear the FDEV bit (which might be inherited from C_FILE_INFO) ; and then call DOS to see if it really is a device or not ; mov bx,4 devloop: and _osfile[bx],not FDEV ; clear FDEV bit on principal mov ax,DOS_ioctl shl 8 + 0 ; issue ioctl(0) to get dev info callos jc notdev test dl,80h ; is it a device ? jz notdev ; no or _osfile[bx],FDEV ; yes - set FDEV bit notdev: dec bx jns devloop ; 5. General C initializer routines mov si,dataOFFSET xifbegin mov di,dataOFFSET xifend if sizeC call initterm ; call the far initializers else call farinitterm ; call the far initializers endif mov si,dataOFFSET xibegin mov di,dataOFFSET xiend call initterm ; call the initializers ret cEnd <nogen> ; standard C libs page ;*** ;exit(status), _exit(status), _cexit(void), _c_exit(void) - C termination ; ;Purpose: ; ; Entry points: ; ; exit(code): Performs all the C termination functions ; and terminates the process with the return code ; supplied by the user. ; ; _exit(code): Performs a quick exit routine that does not ; do certain 'high-level' exit processing. The _exit ; routine terminates the process with the return code ; supplied by the user. ; ; _cexit(): Performs the same C lib termination processing ; as exit(code) but returns control to the caller ; when done (i.e., does NOT terminate the process). ; ; _c_exit(): Performs the same C lib termination processing ; as _exit(code) but returns control to the caller ; when done (i.e., does NOT terminate the process). ; ; Termination actions: ; ; exit(), _cexit (): ; ; 1. call user's terminator routines ; 2. call C runtime preterminators ; ; _exit(), _c_exit(): ; ; 3. call C runtime terminators ; 4. perform _nullcheck() for null pointer assignment ; 5. terminate floating point ; 6. reset divide by zero interrupt vector ; 7. restore int 3F handler ; 8. return to DOS or caller ; ; Notes: ; ; The termination sequence is complicated due to the multiple entry ; points sharing the common code body while having different entry/exit ; sequences. ; ;Entry: ; exit(), _exit() ; int status - exit status (0-255) ; ; _cexit(), _c_exit() ; <no input> ; ;Exit: ; exit(), _exit() ; <EXIT to DOS> ; ; _cexit(), _c_exit() ; Return to caller ; ;Uses: ; ;Exceptions: ; ;******************************************************************************* ; ;--- exit(): Full exit and term process --- ; public _exit _exit: cProc dummy1,<>,<> parmw status ; termination code cBegin xor cx,cx ; exit(): cl = 0, ch = 0 jmp short common1 ; join common code cEnd <nogen> ; ;--- _exit(): Quickie exit and term process --- ; public __exit __exit: cProc dummy2,<>,<> parmw status ; termination code cBegin mov cx,1 ; _exit(): cl = 1, ch = 0 jmp short common1 ; join common code cEnd <nogen> if sizeC global endp endif ; ;--- _cexit(): Full exit and return to caller --- ; cProc _cexit,<PUBLIC>,<SI,DI> cBegin mov cx,(1 SHL 8) ; _cexit(): ch = 1, cl = 0 jmp short common1 ; join common code cEnd <nogen> ; ;--- _c_exit(): Quickie exit and return to caller --- ; cProc _c_exit,<PUBLIC>,<SI,DI> cBegin mov cx,(1 SHL 8)+1 ; _c_exit(): ch = 1, cl = 1 ;fall through ; ;--- Common entry point --- ; cx = entry value: ; cl = full vs quick exit path ; 0 = exit() code ; 1 = _exit() code ; ch = term process vs return to caller ; 0 = term process ; 1 = return to caller ; common1: ; all code paths join here assumes ds,data ifndef FARSTACK assumes ss,data endif ; ; If _exit()/_c_exit(), jump over the initial termination processing ; cx = entry code ; push cx ; save entry code on top of stack or cl,cl ; cl != 0 means _exit()/_c_exit() jnz short common2 ; if _exit()/_c_exit(), jump down ;fall thru ; continue (exit, _cexit) ; 1. call user terminators ; - onexit processing mov si,dataOFFSET xontab ; beginning of onexit table mov di,dataOFFSET xonend ; end of onexit table call initterm ; 2. call C runtime preterminators ; - flushall ; - rmtmp mov si,dataOFFSET xpbegin ; beginning of pre-terminators mov di,dataOFFSET xpend ; end of pre-terminators call initterm ;* ;* Tell the debugger we are going to exit ;* ; *** NOTE: Currently, this appears to be called for both ; exit() and _cexit(). Is this what we want? ; cmp __aDBswpflg,__aDBdoswp ;* Are we under a debugger? jne @F ;* No -- skip forward cCall __aDBexit ;* Yes -- tell it we are exiting @@: ; ;--- Common entry point --- ; common2: ; __exit() enters here ; 3. perform C terminators mov si,dataOFFSET xcbegin mov di,dataOFFSET xcend call initterm ; call the terminators mov si,dataOFFSET xcfbegin mov di,dataOFFSET xcfend if sizeC call initterm ; call the far terminators else call farinitterm ; call the far terminators endif ; 4. perform _nullcheck() for null pointer assignment ifndef _COM_ ; DS:0 is the PSP in .COM files! call _nullcheck ; check data in NULL data segment at DS:0 ; this must be far call in large code models ; since user can stub it out or ax,ax ; zero if no null ptr assignment detected jz afternullchk pop ax ; get entry code or ah,ah ; ah != 0 means _cexit()/_c_exit() push ax ; put it back for later jnz short afternullchk ; jump if no status value (_cexit/_c_exit) cmp status,0 ; zero if no other error has occurred jnz short afternullchk mov status,255 ; nonzero status to indicate an ; null-pointer-assignment error afternullchk: endif ;_COM_ ; 5. terminate floating point ; 6. reset divide by zero interrupt vector ; 7. restore int 3F handler call _ctermsub ; fast cleanup ; 8. return to the DOS or caller pop ax ; get entry code off top of stack or ah,ah ; ah = 0 means term process jnz returning ; skip down if not term'ing ; 8a. return to the DOS exiting: mov ax,status ; get return value callos terminate ; exit with al = return code ;*** PROCESS IS TERMINATED *** ; 8b. Return to caller. returning: cEnd <nolocals> page ;*** ;_ctermsub - more C termination code ; ;Purpose: ; This routine ; (1) performs floating-point termination ; (2) resets the divide by zero interrupt vector ; (3) restore int 3F handler ; ;Entry: ; ;Exit: ; ;Uses: ; AX,BX,CX,DX. ; ;Exceptions: ; ;******************************************************************************* labelNP <PUBLIC,_ctermsub> ; 4. terminate floating point mov cx,word ptr [fpmath+2] ; test for floating point jcxz nofloat_t ; no mov bx,2 ; yes - cleanup call [fpmath] nofloat_t: ; 5. reset divide by zero interrupt vector push ds lds dx,[_aintdiv] ; ds:dx = restore vector mov ax,DOS_setvector shl 8 + 0 callos ; set divide error interrupt pop ds ; 6. restore overlay interrupt vector cmp byte ptr [_ovlflag],0 ; Overlays in use ?? jz done_ovlvec ; if 0, don't restore overlay vector push ds ; save ds mov al,byte ptr [_intno] ; overlay interrupt number lds dx,dword ptr [_ovlvec] ; original ovl interrupt vector callos setvector ; restore the overlay vector pop ds ; restore ds done_ovlvec: ret page ;*** ;initterm - do a set of initializers or terminators ; ;Purpose: ; The initializors and terminators may be written in C ; so we are assuming C conventions (DS=SS, CLD, SI and DI preserved) ; We go through them in reverse order for onexit. ; ;Entry: ; SI = start of procedure list ; DI = end of procedure list ; ;Exit: ; ;Uses: ; ;Exceptions: ; ;******************************************************************************* initterm: cmp si,di ; are we done? jae itdone ; yes - no more if sizeC sub di,4 mov ax,[di] or ax,[di+2] jz initterm ; skip null procedures call dword ptr [di] else dec di dec di mov cx,[di] jcxz initterm ; skip null procedures call cx endif jmp initterm ; keep looping itdone: ret page ife sizeC ; S/C models only ;*** ;farinitterm - do a set of far initializers or terminators ; ;Purpose: ; The initializors and terminators may be written in C ; so we are assuming C conventions (DS=SS, CLD, SI and DI preserved) ; We go through them in reverse order for onexit. ; ;Entry: ; SI = start of procedure list ; DI = end of procedure list ; ;Exit: ; ;Uses: ; ;Exceptions: ; ;******************************************************************************* farinitterm: cmp si,di ; are we done? jae faritdone ; yes - no more sub di,4 mov ax,[di] or ax,[di+2] jz farinitterm ; skip null procedures call dword ptr [di] jmp farinitterm ; keep looping faritdone: ret endif ;sizeC sEnd end