/
file.asm
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/
file.asm
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;===================================================================================================
; File Handling
;
; Written By: Oded Cnaan (oded.8bit@gmail.com)
; Site: http://odedc.net
; Licence: GPLv3 (see LICENSE file)
; Package: UtilLib
;
; Description:
; Set of procedures for reading, writing and manipulating files
; This library allows managing a single file at a time, using the glabl variables _fHandle and _fErr
;===================================================================================================
LOCALS @@
DATASEG
SEEK_SET equ 0
SEEK_CUR equ 1
SEEK_END equ 2
CODESEG
; These vars are defined in CODESEG
_fHandle dw 0 ; Handler
_fErr db 0 ; DOS error code
;------------------------------------------------------------------
; Open a file
;
; push address of file name
; push segment of file name
; call Fopen
;
; Output:
; _fHandle, _fErr
;------------------------------------------------------------------
PROC fopen
store_sp_bp
pusha
push ds
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => seg
; bp+6 => addr
; saved registers
mov dx, [WORD bp+6] ; address
push [WORD bp+4] ; seg
pop ds
mov ax,3D02h
int 21h
mov bl,0
jnc @@fopen0
mov bl,al
sub ax,ax
@@fopen0:
mov [cs:_fHandle],ax
mov [cs:_fErr],bl
pop ds
popa
restore_sp_bp
ret 4
ENDP fopen
;------------------------------------------------------------------
; Creates a file
;
; push segment of file name
; push address of file name
; call Fnew
;
; Output:
; _fHandle, _fErr
;------------------------------------------------------------------
PROC fnew
store_sp_bp
pusha
push ds
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => seg
; bp+6 => addr
; saved registers
mov dx, [WORD bp+6] ; address
push [WORD bp+4] ; seg
pop ds
mov ah,3ch
mov cx,0 ; attr
int 21h
mov bl,0
jnc @@fnew0
mov bl,al
sub ax,ax
@@fnew0:
mov [cs:_fHandle],ax
mov [cs:_fErr],bl
pop ds
popa
restore_sp_bp
ret 4
ENDP fnew
;------------------------------------------------------------------
; Close a file
;
; call Fclose
;
; Output:
; _fHandle, _fErr
;------------------------------------------------------------------
PROC fclose
store_sp_bp
pusha
mov bx,[cs:_fHandle]
mov ah,3eh
int 21h
mov bl,0
jnc @@fclose0
mov bl,al
sub ax,ax
@@fclose0:
mov [cs:_fErr],bl
mov [cs:_fHandle],ax
popa
restore_sp_bp
ret
ENDP fclose
;------------------------------------------------------------------
; Reads from a file
;
; push length
; push address of buffer
; push seg of buffer
; call Fread
;
; Output:
; _fHandle, _fErr
; ax - number of bytes read
;------------------------------------------------------------------
PROC fread
store_sp_bp
pusha
push ds
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => seg
; bp+6 => addr
; bp+8 => length
; saved registers
mov dx, [WORD bp+6] ; address
push [WORD bp+4] ; seg
pop ds
mov cx, [WORD bp+8] ; length
mov bx,[cs:_fHandle]
mov ax,3F00h
int 21h
mov bl,0
jnc @@fread0
mov bl,al
sub ax,ax
@@fread0:
mov [cs:_fErr],bl
pop ds
popa
restore_sp_bp
ret 6
ENDP fread
;------------------------------------------------------------------
; Write to a file
;
; push length
; push segment of buffer
; push address of buffer
; call Fwrite
;
; Output:
; _fHandle, _fErr
; ax - number of bytes written
;------------------------------------------------------------------
PROC fwrite
store_sp_bp
pusha
push ds
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => seg
; bp+6 => addr
; bp+8 => length
; saved registers
mov dx, [WORD bp+6] ; address
push [WORD bp+4] ; seg
pop ds
mov cx, [WORD bp+8] ; length
mov bx,[cs:_fHandle]
mov ah,40h
int 21h
mov bl,0
jnc @@fwrite0
mov bl,al
sub ax,ax
@@fwrite0:
mov [cs:_fErr],bl
pop ds
popa
restore_sp_bp
ret 6
ENDP fwrite
;------------------------------------------------------------------
; Write a byte to a file
;
; push value (byte)
; call Fwrite
;
; Output:
; _fHandle, _fErr
; ax - number of bytes written
;------------------------------------------------------------------
PROC fwriteByte
store_sp_bp
pusha
push ds
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => value
; saved registers
mov dx, bp ; value offset
add dx, 4 ; this is the bp+4 offset
push ss ; on ss segment
pop ds ; value seg
mov cx, 1 ; length
mov bx,[cs:_fHandle]
mov ah,40h
int 21h
mov bl,0
jnc @@fwrite0
mov bl,al
sub ax,ax
@@fwrite0:
mov [cs:_fErr],bl
pop ds
popa
restore_sp_bp
ret 2
ENDP fwriteByte
;------------------------------------------------------------------
; Delete a file
;
; push segment of file name
; push address of file name
; call Fdelete
;
; Output:
; _fHandle, _fErr
;------------------------------------------------------------------
PROC fdelete
store_sp_bp
pusha
push ds
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => seg
; bp+6 => addr
; saved registers
mov dx, [WORD bp+6] ; address
push [WORD bp+4] ; seg
pop ds
mov ah,41h
int 21h
mov bl,0
jnc @@fdel0
mov bl,al
@@fdel0:
mov [cs:_fErr],bl
pop ds
popa
restore_sp_bp
ret 4
ENDP fdelete
;------------------------------------------------------------------
; Change attribute of a file
;
; push attribute
; push segment of file name
; push address of file name
; call FchangeAttr
;
; Output:
; _fHandle, _fErr
;------------------------------------------------------------------
PROC fchangeAttr
store_sp_bp
pusha
push ds
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => seg
; bp+6 => addr
; bp+8 => attr
; saved registers
mov dx, [WORD bp+6] ; address
push [WORD bp+4] ; seg
pop ds
mov cx, [WORD bp+8] ; attr
mov ax,4301h ;4300 pre attr read => cx ... uprav push/pop
int 21h ; 7 6 5 4 3 2 1 0
mov bl,0 ;cx = attr: 0 0 A 0 0 S H R
jnc @@fattr0
mov bl,al
@@fattr0:
mov [cs:_fErr],bl
pop ds
popa
restore_sp_bp
ret 6
ENDP fchangeAttr
;------------------------------------------------------------------------
; Seek in file
;
; Input:
; whence - SEEK_SET, SEEK_CUR, SEEK_END
; offset_high - high order of offset
; offset_low - low order of offset
;
;------------------------------------------------------------------------
PROC fseek
store_sp_bp
pusha
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => offset low
; bp+6 => offset high
; bp+8 => whence
; saved registers
;{
whence equ [word bp+8]
offsetHi equ [word bp+6]
offsetLow equ [word bp+4]
;}
cmp [cs:_fHandle], 0
je @@end ; file not open
mov ax, whence
cmp whence, SEEK_END
je @@s_end
mov cx, offsetHi
mov dx, offsetLow
jmp @@do_seek
@@s_end:
xor cx, cx
xor dx, dx
@@do_seek:
mov bx, [cs:_fHandle]
mov ah, 42h
int 21h
@@end:
popa
restore_sp_bp
ret 6
ENDP fseek
;------------------------------------------------------------------------
; Gets the size of a file
;
; Input:
; push file path address
; push file path segment
; call ffilesize
;
; Output:
; DS:AX - file size, -1 on error
;
; fsize( path, seg )
;------------------------------------------------------------------------
PROC fsize
store_sp_bp
push bx cx
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => file path seg
; bp+6 => file path address
; saved registers
;{
pathSegment_ equ [word bp+4]
pathAddress_ equ [word bp+6]
;}
push pathAddress_
push pathSegment_
call fopen
cmp [cs:_fErr], 0
jne @@error ; cannot open file
; seek to end
mov ah, 42h
mov al, 2 ; end of file plus offset (SEEK_END)
mov bx, [cs:_fHandle]
xor cx, cx
xor dx, dx
int 21h ; will set dx:ax
jnc @@close ; no error
jmp @@error ; error
@@close:
call fclose
jmp @@end
@@error:
call fclose
mov ax,0ffffh
mov dx,0ffffh
@@end:
pop cx bx
restore_sp_bp
ret 4
ENDP fsize
;------------------------------------------------------------------------
; Create folder
;
; Input:
; push folder path address
; push folder path segment
; call mkdir
;
; Output:
; CF = 0 if successful
; = 1 if error
; AX = error code
;
; mkdir( path, seg )
;------------------------------------------------------------------------
PROC mkdir
store_sp_bp
push ds
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => folder path seg
; bp+6 => folder path address
; saved registers
;{
pathSegment_ equ [word bp+4]
pathAddress_ equ [word bp+6]
;}
mov ah, 39h
push pathSegment_
pop ds
mov dx, pathAddress_
int 21h
@@end:
pop ds
restore_sp_bp
ret 4
ENDP mkdir
;------------------------------------------------------------------------
; Delete folder
;
; Input:
; push folder path address
; push folder path segment
; call rmdir
;
; Output:
; CF = 0 if successful
; = 1 if error
; AX = error code
;
; rmdir( path, seg )
;------------------------------------------------------------------------
PROC rmdir
store_sp_bp
push ds
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => folder path seg
; bp+6 => folder path address
; saved registers
;{
pathSegment_ equ [word bp+4]
pathAddress_ equ [word bp+6]
;}
mov ah, 3Ah
push pathSegment_
pop ds
mov dx, pathAddress_
int 21h
@@end:
pop ds
restore_sp_bp
ret 4
ENDP rmdir
;------------------------------------------------------------------------
; Delete folder
;
; Input:
; push folder path address
; push folder path segment
; call rmdir
;
; Output:
; CF = 0 if successful
; = 1 if error
; AX = error code
;
; chdir( path, seg )
;------------------------------------------------------------------------
PROC chdir
store_sp_bp
push ds
; now the stack is
; bp+0 => old base pointer
; bp+2 => return address
; bp+4 => folder path seg
; bp+6 => folder path address
; saved registers
;{
pathSegment_ equ [word bp+4]
pathAddress_ equ [word bp+6]
;}
mov ah, 3Bh
push pathSegment_
pop ds
mov dx, pathAddress_
int 21h
@@end:
pop ds
restore_sp_bp
ret 4
ENDP chdir
;////////////////////////////////////////////////////////////////////////////
; FUNCTION LIKE MACROS
;////////////////////////////////////////////////////////////////////////////
;----------------------------------------------------------------------
; Open a file
;
; utm_fopen (pathOffset, pathSegment)
;----------------------------------------------------------------------
MACRO utm_fopen pathOffset, pathSegment
push pathOffset
push pathSegment
call fopen
ENDM
;----------------------------------------------------------------------
; Creates a new file
;
; utm_fnew (pathOffset, pathSegment)
;----------------------------------------------------------------------
MACRO utm_fnew pathOffset, pathSegment
push pathOffset
push pathSegment
call fnew
ENDM
;----------------------------------------------------------------------
; Gets file size
;
; utm_fsize (pathOffset, pathSegment)
;----------------------------------------------------------------------
MACRO utm_fsize pathOffset, pathSegment
push pathOffset
push pathSegment
call fsize
ENDM
;----------------------------------------------------------------------
; Close a file
;
; utm_fclose
;----------------------------------------------------------------------
MACRO utm_fclose
call fclose
ENDM
;----------------------------------------------------------------------
; Write to a file
;
; utm_fwrite (length, bufOffset, bufSegment)
;----------------------------------------------------------------------
MACRO utm_fwrite length, bufOffset, bufSegment
push length
push bufOffset
push bufSegment
call fwrite
ENDM
;----------------------------------------------------------------------
; Read from a file
;
; utm_fread (length, bufOffset, bufSegment)
;----------------------------------------------------------------------
MACRO utm_fread length, bufOffset, bufSegment
push length
push bufOffset
push bufSegment
call fread
ENDM
;----------------------------------------------------------------------
; Deletes a file
;
; utm_fdelete (pathOffset, pathSegment)
;----------------------------------------------------------------------
MACRO utm_fdelete pathOffset, pathSegment
push pathOffset
push pathSegment
call fdelete
ENDM
;----------------------------------------------------------------------
; Change attribute of a file
;
; utm_fdelete (pathOffset, pathSegment)
;----------------------------------------------------------------------
MACRO utm_fchangeAttr attrib, pathOffset, pathSegment
push attrib
push pathOffset
push pathSegment
call fchangeAttr
ENDM
;----------------------------------------------------------------------
; Write a single byte to file
;
; utm_fwriteByte (valueB)
;----------------------------------------------------------------------
MACRO utm_fwriteByte valueB
push valueB
call fwriteByte
ENDM
;----------------------------------------------------------------------
; Seek file
;
; grm_fseek (whence, offset_high, offset_low)
;----------------------------------------------------------------------
MACRO grm_fseek whence, offset_high, offset_low
push whence
push offset_high
push offset_low
call fseek
ENDM
;----------------------------------------------------------------------
; Create folder
;
; utm_mkdir (pathOffset, pathSegment)
;----------------------------------------------------------------------
MACRO utm_mkdir pathOffset, pathSegment
push pathOffset
push pathSegment
call mkdir
ENDM
;----------------------------------------------------------------------
; Remove folder
;
; utm_rmdir (pathOffset, pathSegment)
;----------------------------------------------------------------------
MACRO utm_rmdir pathOffset, pathSegment
push pathOffset
push pathSegment
call rmdir
ENDM
;----------------------------------------------------------------------
; Change folder
;
; utm_chdir (pathOffset, pathSegment)
;----------------------------------------------------------------------
MACRO utm_chdir pathOffset, pathSegment
push pathOffset
push pathSegment
call chdir
ENDM