?? c0.asm
字號:
push si
push di
mov es, cs:DGROUP@@
xor ax, ax
mov si, ax
mov cx, lgth_CopyRight
ComputeChecksum label near
add al, es:[si]
adc ah, 0
inc si
loop ComputeChecksum
sub ax, CheckSum
jz @@SumOK
mov cx, lgth_NullCheck
mov dx, offset DGROUP: NullCheck
call ErrorDisplay
@@SumOK: pop di
pop si
ENDIF
ENDIF
ret
__checknull ENDP
; Exit to DOS
__terminate PROC DIST
PUBLIC __terminate
mov bp,sp
mov ah,4Ch
mov al,[bp+cPtrSize]
int 21h ; Exit to DOS
__terminate ENDP
STARTX ENDP
SUBTTL Vector save/restore & default Zero divide routines
PAGE
;[]------------------------------------------------------------[]
;| |
;| Interrupt Save/Restore routines and default divide by zero |
;| handler. |
;| |
;[]------------------------------------------------------------[]
ZeroDivision PROC FAR
mov cx, lgth_ZeroDivMSG
mov dx, offset DGROUP: ZeroDivMSG
jmp MsgExit3
ZeroDivision ENDP
;--------------------------------------------------------------------------
; savevectors()
;
; Save vectors for 0, 4, 5 & 6 interrupts. This is for extended
; signal()/raise() support as the signal functions can steal these
; vectors during runtime.
;--------------------------------------------------------------------------
SaveVectors PROC NEAR
push ds
; Save INT 0
mov ax, 3500h
int 021h
mov word ptr _Int0Vector@, bx
mov word ptr _Int0Vector@+2, es
; Save INT 4
mov ax, 3504h
int 021h
mov word ptr _Int4Vector@, bx
mov word ptr _Int4Vector@+2, es
; Save INT 5
mov ax, 3505h
int 021h
mov word ptr _Int5Vector@, bx
mov word ptr _Int5Vector@+2, es
; Save INT 6
mov ax, 3506h
int 021h
mov word ptr _Int6Vector@, bx
mov word ptr _Int6Vector@+2, es
;
; Install default divide by zero handler.
;
mov ax, 2500h
mov dx, cs
mov ds, dx
mov dx, offset ZeroDivision
int 21h
pop ds
ret
SaveVectors ENDP
;--------------------------------------------------------------------------
; _restorezero() puts back all the vectors that SaveVectors took.
;
;NOTE : TSRs must BE AWARE that signal() functions which take these
; vectors will be deactivated if the keep() function is executed.
; If a TSR wants to use the signal functions when it is active it
; will have to save/restore these vectors itself when activated and
; deactivated.
;--------------------------------------------------------------------------
__restorezero PROC DIST
PUBLIC __restorezero
IFDEF __HUGE__
push ds
mov ds, cs: DGROUP@@
ENDIF
push ds
mov ax, 2500h
lds dx, _Int0Vector@
int 21h
pop ds
push ds
mov ax, 2504h
lds dx, _Int4Vector@
int 21h
pop ds
push ds
mov ax, 2505h
lds dx, _Int5Vector@
int 21h
pop ds
IFNDEF __HUGE__
push ds
ENDIF
mov ax, 2506h
lds dx, _Int6Vector@
int 21h
pop ds
ret
ENDP
;------------------------------------------------------------------
; Loop through a startup/exit (SE) table,
; calling functions in order of priority.
; ES:SI is assumed to point to the beginning of the SE table
; ES:DI is assumed to point to the end of the SE table
; First 64 priorities are reserved by Borland
;------------------------------------------------------------------
PNEAR EQU 0
PFAR EQU 1
NOTUSED EQU 0ffh
SE STRUC
calltype db ? ; 0=near,1=far,ff=not used
priority db ? ; 0=highest,ff=lowest
addrlow dw ?
addrhigh dw ?
SE ENDS
Initialize proc near
@@Start: mov ax,100h ;start with lowest priority
mov dx,di ;set sentinel to end of table
mov bx,si ;bx = start of table
@@TopOfTable: cmp bx,di ;and the end of the table?
je @@EndOfTable ;yes, exit the loop
cmp es:[bx.calltype],NOTUSED;check the call type
je @@Next
mov cl, es:[bx.priority] ;move priority to CX
xor ch, ch
cmp cx,ax ;check the priority
jae @@Next ;too high? skip
mov ax,cx ;keep priority
mov dx,bx ;keep index in dx
@@Next: add bx,SIZE SE ;bx = next item in table
jmp @@TopOfTable
@@EndOfTable: cmp dx,di ;did we exhaust the table?
je @@Done ;yes, quit
mov bx,dx ;bx = highest priority item
cmp es:[bx.calltype],PNEAR ;is it near or far?
mov es:[bx.calltype],NOTUSED;wipe the call type
push es ;save es
je @@NearCall
@@FarCall: call DWORD PTR es:[bx.addrlow]
pop es ;restore es
jmp short @@Start
@@NearCall: call WORD PTR es:[bx.addrlow]
pop es ;restore es
jmp short @@Start
@@Done: ret
endp
Cleanup proc near
@@Start: mov ah,0 ;start with highest priority
mov dx,di ;set sentinel to end of table
mov bx,si ;bx = start of table
@@TopOfTable: cmp bx,di ;and the end of the table?
je @@EndOfTable ;yes, exit the loop
cmp es:[bx.calltype],NOTUSED;check the call type
je @@Next
cmp es:[bx.priority],ah ;check the priority
jb @@Next ;too low? skip
mov ah,es:[bx.priority] ;keep priority
mov dx,bx ;keep index in dx
@@Next: add bx,SIZE SE ;bx = next item in table
jmp @@TopOfTable
@@EndOfTable: cmp dx,di ;did we exhaust the table?
je @@Done ;yes, quit
mov bx,dx ;bx = highest priority item
cmp es:[bx.calltype],PNEAR ;is it near or far?
mov es:[bx.calltype],NOTUSED;wipe the call type
push es ;save es
je @@NearCall
@@FarCall: call DWORD PTR es:[bx.addrlow]
pop es ;restore es
jmp short @@Start
@@NearCall: call WORD PTR es:[bx.addrlow]
pop es ;restore es
jmp short @@Start
@@Done: ret
endp
;------------------------------------------------------------------
ErrorDisplay PROC NEAR
mov ah, 040h
mov bx, 2
int 021h
ret
ErrorDisplay ENDP
_abort PROC DIST
PUBLIC _abort
mov cx, lgth_abortMSG
mov dx, offset DGROUP: abortMSG
MsgExit3 label near
mov ds, cs: DGROUP@@
call ErrorDisplay
CallExit3 label near
mov ax, 3
push ax
call __exit ; _exit(3);
ENDP
; The DGROUP@ variable is used to reload DS with DGROUP
PubSym@ DGROUP@, <dw ?>, __PASCAL__
; __MMODEL is used to determine the memory model or the default
; pointer types at run time.
public __MMODEL
__MMODEL dw MMODEL
_TEXT ENDS
SUBTTL Start Up Data Area
PAGE
;[]------------------------------------------------------------[]
;| Start Up Data Area |
;| |
;| WARNING Do not move any variables in the data |
;| segment unless you're absolutely sure |
;| that it does not matter. |
;[]------------------------------------------------------------[]
_DATA SEGMENT
; Magic symbol used by the debug info to locate the data segment
public DATASEG@
DATASEG@ label byte
; The CopyRight string must NOT be moved or changed without
; changing the null pointer check logic
CopyRight db 4 dup(0)
db 'Borland C++ - Copyright 1991 Borland Intl.',0
lgth_CopyRight equ $ - CopyRight
IF LDATA EQ false
IFNDEF __TINY__
CheckSum equ 00D5Ch
NullCheck db 'Null pointer assignment', 13, 10
lgth_NullCheck equ $ - NullCheck
ENDIF
ENDIF
ZeroDivMSG db 'Divide error', 13, 10
lgth_ZeroDivMSG equ $ - ZeroDivMSG
abortMSG db 'Abnormal program termination', 13, 10
lgth_abortMSG equ $ - abortMSG
;
; Interrupt vector save areas
;
; Interrupt vectors 0,4,5 & 6 are saved at startup and then restored
; when the program terminates. The signal/raise functions might
; steal these vectors during execution.
;
; Note: These vectors save area must not be altered
; without changing the save/restore logic.
;
PubSym@ _Int0Vector <dd 0>, __CDECL__
PubSym@ _Int4Vector <dd 0>, __CDECL__
PubSym@ _Int5Vector <dd 0>, __CDECL__
PubSym@ _Int6Vector <dd 0>, __CDECL__
;
; Miscellaneous variables
;
PubSym@ _C0argc, <dw 0>, __CDECL__
dPtrPub@ _C0argv, 0, __CDECL__
dPtrPub@ _C0environ, 0, __CDECL__
PubSym@ _envLng, <dw 0>, __CDECL__
PubSym@ _envseg, <dw 0>, __CDECL__
PubSym@ _envSize, <dw 0>, __CDECL__
PubSym@ _psp, <dw 0>, __CDECL__
PubSym@ _version, <label word>, __CDECL__
PubSym@ _osversion, <label word>, __CDECL__
PubSym@ _osmajor, <db 0>, __CDECL__
PubSym@ _osminor, <db 0>, __CDECL__
PubSym@ errno, <dw 0>, __CDECL__
PubSym@ _StartTime, <dw 0,0>, __CDECL__
; Memory management variables
IF LDATA EQ false
PubSym@ __heapbase, <dw DGROUP:edata@>, __CDECL__
ENDIF
IFNDEF __HUGE__
PubSym@ __brklvl, <dw DGROUP:edata@>, __CDECL__
ENDIF
PubSym@ _heapbase, <dd 0>, __CDECL__
PubSym@ _brklvl, <dd 0>, __CDECL__
PubSym@ _heaptop, <dd 0>, __CDECL__
; If stack in DS and Large data model then override location of __emu
IFDEF _DSSTACK_
IF LDATA
public __emu
__emu db 044h DUP (0)
db 0CCh DUP (?)
ENDIF
ENDIF
_DATA ENDS
_CVTSEG SEGMENT
PubSym@ _RealCvtVector, <label word>, __CDECL__
ENDS
_SCNSEG SEGMENT
PubSym@ _ScanTodVector, <label word>, __CDECL__
ENDS
IFNDEF __HUGE__
_BSS SEGMENT
bdata@ label byte
ENDS
_BSSEND SEGMENT
edata@ label byte
ENDS
ENDIF
IFNDEF __TINY__
_STACK SEGMENT
db 128 dup(?) ;minimum stack size
ENDS
ENDIF ; __TINY__
END STARTX
?? 快捷鍵說明
復制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -