Source code of Windows XP (NT5)
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;****************************************************************************
;* *
;* PMDOS.ASM - *
;* *
;* Low level DOS routines needed by the Program Manager. *
;* *
;****************************************************************************
memS=1
?PLM=1
?WIN=1
include cmacros.inc
SelectDisk equ 0Eh
FCBFindFirstFile equ 11h
FCBFindNextFile equ 12h
FCBDeleteFile equ 13h
FCBRenameFile equ 17h
GetCurrentDisk equ 19h
SetDTAAddress equ 1Ah
GetFileSize equ 23h
GetDiskFreeSpace equ 36h
CreateDir equ 39h
RemoveDir equ 3Ah
ChangeCurrentDir equ 3Bh
CreateFile equ 3Ch
DeleteFile equ 41h
GetSetFileAttributes equ 43h
GetCurrentDir equ 47h
FindFirstFile equ 4Eh
FindNextFile equ 4Fh
RenameFile equ 56h
externFP DOS3CALL
externFP AnsiToOem
ifdef DBCS
externFP IsDBCSLeadByte
endif
;=============================================================================
createSeg _%SEGNAME, %SEGNAME, WORD, PUBLIC, CODE
sBegin %SEGNAME
assumes CS,%SEGNAME
assumes DS,DATA
cProc PathType, <FAR, PUBLIC>
parmD lpFile
localV szOEM, 128
cBegin
RegPtr lpszOEM, ss, bx
lea bx, szOEM
cCall AnsiToOem, <lpFile, lpszOEM>
lea dx, szOEM
mov ax, 4300h
call DOS3CALL
jnc id_noerror
xor ax, ax
jmp short id_exit
id_noerror:
and cx, 10h
jnz id_dir
mov ax, 1
jmp short id_exit
id_dir:
mov ax, 2
id_exit:
cEnd
;*--------------------------------------------------------------------------*
;* *
;* FileTime*() - *
;* *
;*--------------------------------------------------------------------------*
cProc FileTime, <FAR, PUBLIC>
parmW hFile
cBegin
mov ax, 5700h
mov bx, hFile
cCall DOS3CALL
jnc ft_ok
sub ax, ax
sub dx, dx
jmp short ft_ex
ft_ok:
mov ax, cx
ft_ex:
cEnd
;*--------------------------------------------------------------------------*
;* *
;* IsReadOnly() - *
;* *
;*--------------------------------------------------------------------------*
cProc IsReadOnly, <FAR, PUBLIC>
parmD lpFile
localV szOEM, 128
cBegin
RegPtr lpszOEM, ss, bx
lea bx, szOEM
cCall AnsiToOem,<lpFile,lpszOEM>
mov ax, 4300h ; get attributes...
lea dx, szOEM ; ...for given file...
call DOS3CALL
jc f_exit ; ax == 0 if error...
and ax, 1 ; test RO bit
jmp short t_exit ; true
f_exit:
xor ax, ax ; false
t_exit:
cEnd
;*--------------------------------------------------------------------------*
;* *
;* GetDOSErrorCode() - *
;* *
;*--------------------------------------------------------------------------*
cProc GetDOSErrorCode, <FAR, PUBLIC>, <SI,DI>
cBegin
mov ah,59h ; Get DOS extended error
sub bx,bx ; cause ray duncan says so
push ds ; function trashes registers
push bp ; so we gotta save 'em for cProc
call DOS3CALL
pop bp ; be nice to C
pop ds ; get DS
mov dl,bh ; class in byte 2
mov dh,ch ; locus in byte 3 (skip the rec. action)
cEnd
;*--------------------------------------------------------------------------*
;* *
;* GetCurrentDrive() - *
;* *
;*--------------------------------------------------------------------------*
cProc GetCurrentDrive, <FAR, PUBLIC>
cBegin
mov ah,GetCurrentDisk
call DOS3CALL
sub ah,ah ; Zero out AH
cEnd
;*--------------------------------------------------------------------------*
;* *
;* SetCurrentDrive() - *
;* *
;*--------------------------------------------------------------------------*
; Returns the number of drives in AX.
cProc SetCurrentDrive, <FAR, PUBLIC>
ParmW Drive
cBegin
mov dx,Drive
mov ah,SelectDisk
call DOS3CALL
sub ah,ah ; Zero out AH
cEnd
;*--------------------------------------------------------------------------*
;* *
;* GetCurrentDirectory() - *
;* *
;*--------------------------------------------------------------------------*
cProc GetCurrentDirectory, <FAR, PUBLIC>, <SI, DI>
parmW wDrive
ParmD lpDest
cBegin
push ds ; Preserve DS
mov ax,wDrive
or al,al
jnz GCDHaveDrive
call GetCurrentDrive
inc al ; Convert to logical drive number
GCDHaveDrive:
les di,lpDest ; ES:DI = lpDest
push es
pop ds ; DS:DI = lpDest
cld
mov dl,al ; DL = Logical Drive Number
add al,'@' ; Convert to ASCII drive letter
stosb
mov al,':'
stosb
mov al,'\' ; Start string with a backslash
stosb
mov byte ptr es:[di],0 ; Null terminate in case of error
mov si,di ; DS:SI = lpDest[1]
mov ah,GetCurrentDir
call DOS3CALL
jc GCDExit ; Skip if error
xor ax,ax ; Return FALSE if no error
GCDExit:
pop ds ; Restore DS
cEnd
;*--------------------------------------------------------------------------*
;* *
;* SetCurrentDirectory() - *
;* *
;*--------------------------------------------------------------------------*
cProc SetCurrentDirectory, <FAR, PUBLIC>, <DS, DI>
ParmD lpDirName
cBegin
lds di,lpDirName ; DS:DI = lpDirName
; Is there a drive designator?
ifdef DBCS
mov al, byte ptr [di] ; fetch a first byte of path
xor ah,ah
cCall IsDBCSLeadByte, <ax>
test ax,ax ; DBCS lead byte?
jnz SCDNoDrive ; jump if so
endif
cmp byte ptr [di+1],':'
jne SCDNoDrive ; Nope, continue
mov al,byte ptr [di] ; Yup, change to that drive
sub ah,ah
and al, 0DFH ;Make drive letter upper case
sub al,'A'
push ax
call SetCurrentDrive
mov al,byte ptr [di+2] ; string just a drive letter and colon?
cbw
or ax,ax
jz SCDExit ; Yup, just set the current drive and done
SCDNoDrive:
mov dx,di
mov ah,ChangeCurrentDir
call DOS3CALL
jc SCDExit ; Skip on error
xor ax,ax ; Return FALSE if successful
SCDExit:
cEnd
if 0
;*--------------------------------------------------------------------------*
;* *
;* IsRemovableDrive() - *
;* *
;*--------------------------------------------------------------------------*
cProc IsRemovableDrive, <FAR, PUBLIC>
ParmW wDrive
cBegin
mov ax,4408h ; IOCTL: Check If Block Device Is Removable
mov bx,wDrive
inc bx
call DOS3CALL
and ax,1 ; Only test bit 0
xor ax,1 ; Flip so 1 == Removable
cEnd
;*--------------------------------------------------------------------------*
;* *
;* IsRemoteDrive() - *
;* *
;*--------------------------------------------------------------------------*
cProc IsRemoteDrive, <FAR, PUBLIC>
ParmW wDrive
cBegin
mov ax,4409h ; IOCTL: Check If Block Device Is Remote
mov bx,wDrive
inc bx
call DOS3CALL
xor ax,ax
and dx,0001000000000000b ; Test bit 12
jz IRDRet
mov ax,1
IRDRet:
cEnd
endif
;*--------------------------------------------------------------------------*
;* *
;* DosDelete() - *
;* *
;*--------------------------------------------------------------------------*
%out assuming SS==DS
cProc DosDelete, <FAR, PUBLIC>
ParmD lpSource
localV szOEM, 128
cBegin
RegPtr lpszOEM,ss,bx ; convert path to OEM chars
lea bx, szOEM
cCall AnsiToOem, <lpSource, lpszOEM>
lea dx, szOEM
mov ah,DeleteFile ;
call DOS3CALL
jc DDExit
xor ax,ax ; Return 0 if successful
DDExit:
cEnd
;*--------------------------------------------------------------------------*
;* *
;* DosRename() - *
;* *
;*--------------------------------------------------------------------------*
cProc DosRename, <FAR, PUBLIC>, <DI>
ParmD lpSource
ParmD lpDest
localV szOEM1, 128
localV szOEM2, 128
cBegin
RegPtr lpszOEM1, ss, bx
lea bx, szOEM1
cCall AnsiToOem, <lpSource, lpszOEM1>
RegPtr lpszOEM2, ss, bx
lea bx, szOEM2
cCall AnsiToOem, <lpDest, lpszOEM2>
lea dx, szOEM1
lea di, szOEM2
push ss
pop es
mov ah,RenameFile
call DOS3CALL
jc DRExit
xor ax,ax ; Return 0 if successful
DRExit:
cEnd
; lmemmove() -
;
; Shamelessly heisted from the C5.1 runtime library, and modified to
; work in mixed model Windows programs!
;
;***
;memcpy.asm - contains memcpy and memmove routines
;
; Copyright (c) 1986-1988, Microsoft Corporation. All right reserved.
;
;Purpose:
; memmove() copies a source memory buffer to a destination memory buffer.
; This routine recognize overlapping buffers to avoid propogation.
;
; Algorithm:
;
; void * memmove(void * dst, void * src, size_t count)
; {
; void * ret = dst;
;
; if (dst <= src || dst >= (src + count)) {
; /*
; * Non-Overlapping Buffers
; * copy from lower addresses to higher addresses
; */
; while (count--)
; *dst++ = *src++;
; }
; else {
; /*
; * Overlapping Buffers
; * copy from higher addresses to lower addresses
; */
; dst += count - 1;
; src += count - 1;
;
; while (count--)
; *dst-- = *src--;
; }
;
; return(ret);
; }
;
;
;Entry:
; void *dst = pointer to destination buffer
; const void *src = pointer to source buffer
; size_t count = number of bytes to copy
;
;Exit:
; Returns a pointer to the destination buffer in DX:AX
;
;Uses:
; CX,DX,ES
;
;Exceptions:
;*******************************************************************************
cProc lmemmove,<FAR,PUBLIC>,<si,di>
parmD dst ; destination pointer
parmD src ; source pointer
parmW count ; number of bytes to copy
cBegin
push ds ; Preserve DS
lds si,src ; DS:SI = src
les di,dst ; ES:DI = dst
mov ax,di ; save dst in AX for return value
mov cx,count ; cx = number of bytes to move
jcxz done ; if cx = 0 Then nothing to copy
;
; Check for overlapping buffers:
; If segments are different, assume no overlap
; Do normal (Upwards) Copy
; Else If (dst <= src) Or (dst >= src + Count) Then
; Do normal (Upwards) Copy
; Else
; Do Downwards Copy to avoid propogation
;
mov ax,es ; compare the segments
cmp ax,word ptr (src+2)
jne CopyUp
cmp di,si ; src <= dst ?
jbe CopyUp
mov ax,si
add ax,cx
cmp di,ax ; dst >= (src + count) ?
jae CopyUp
;
; Copy Down to avoid propogation in overlapping buffers
;
mov ax,di ; AX = return value (offset part)
add si,cx
add di,cx
dec si ; DS:SI = src + count - 1
dec di ; ES:DI = dst + count - 1
std ; Set Direction Flag = Down
rep movsb
cld ; Set Direction Flag = Up
jmp short done
CopyUp:
mov ax,di ; AX = return value (offset part)
;
; There are 4 situations as far as word alignment of "src" and "dst":
; 1. src and dst are both even (best case)
; 2. src is even and dst is odd
; 3. src is odd and dst is even
; 4. src and dst are both odd (worst case)
;
; Case #4 is much faster if a single byte is copied before the
; REP MOVSW instruction. Cases #2 and #3 are effectively unaffected
; by such an operation. To maximum the speed of this operation,
; only DST is checked for alignment. For cases #2 and #4, the first
; byte will be copied before the REP MOVSW.
;
test al,1 ; fast check for dst being odd address
jz move
movsb ; move a byte to improve alignment
dec cx
;
; Now the bulk of the copy is done using REP MOVSW. This is much
; faster than a REP MOVSB if the src and dst addresses are both
; word aligned and the processor has a 16-bit bus. Depending on
; the initial alignment and the size of the region moved, there
; may be an extra byte left over to be moved. This is handled
; by the REP MOVSB, which moves either 0 or 1 bytes.
;
move:
shr cx,1 ; Shift CX for count of words
rep movsw ; CF set if one byte left over
adc cx,cx ; CX = 1 or 0, depending on Carry Flag
rep movsb ; possible final byte
;
; Return the "dst" address in AX/DX:AX
;
done:
pop ds ;restore ds
mov dx,es ;segment part of dest address
cEnd
sEnd %SEGNAME
end