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; SCCSID = @(#)buffer.asm 1.1 85/04/09
BREAK <Disk I/O Buffer Header>
;----+----+----+----+----+----+----+----+----+----+----+----+----+----+----;
; C A V E A T P R O G R A M M E R ;
; ;
; Field definition for I/O buffer information
BUFFINFO STRUC
buf_next DW ? ; Pointer to next buffer in list
buf_prev DW ? ; Pointer to prev buffer in list
buf_ID DB ? ; Drive of buffer (bit 7 = 0)
; SFT table index (bit 7 = 1)
; = FFH if buffer free
buf_flags DB ? ; Bit 7 = 1 if Remote file buffer
; = 0 if Local device buffer
; Bit 6 = 1 if buffer dirty
; Bit 5 = Reserved
; Bit 4 = Search bit (bit 7 = 1)
; Bit 3 = 1 if buffer is DATA
; Bit 2 = 1 if buffer is DIR
; Bit 1 = 1 if buffer is FAT
; Bit 0 = Reserved
buf_sector DD ? ; Sector number of buffer (bit 7 = 0)
; The next two items are often refed as a word (bit 7 = 0)
buf_wrtcnt DB ? ; For FAT sectors, # times sector written out
buf_wrtcntinc DW ? ; " " " , # sectors between each write
buf_DPB DD ? ; Pointer to drive parameters
buf_fill DW ? ; How full buffer is (bit 7 = 1)
buf_reserved DB ? ; make DWORD boundary for 386
BUFFINFO ENDS
buf_offset EQU DWORD PTR buf_sector
;For bit 7 = 1, this is the byte
;offset of the start of the buffer in
;the file pointed to by buf_ID. Thus
;the buffer starts at location
;buf_offset in the file and contains
;buf_fill bytes.
BUFINSIZ EQU SIZE BUFFINFO
; Size of structure in bytes
buf_Free EQU 0FFh ; buf_id of free buffer
;Flag byte masks
buf_isnet EQU 10000000B
buf_dirty EQU 01000000B
;***
buf_visit EQU 00100000B
;***
buf_snbuf EQU 00010000B
buf_isDATA EQU 00001000B
buf_isDIR EQU 00000100B
buf_isFAT EQU 00000010B
buf_type_0 EQU 11110001B ; AND sets type to "none"
buf_NetID EQU BUFINSIZ
;
; Buffer Hash Entry Structure
BUFFER_HASH_ENTRY STRUC ; DOS 4.00
EMS_PAGE_NUM DW -1 ; logical page number for EMS handle
BUFFER_BUCKET DD ? ; pointer to buffers
DIRTY_COUNT DB 0 ; number of dirty buffers
BUFFER_RESERVED DB 0 ; reserved
BUFFER_HASH_ENTRY ENDS
MaxBuffinBucket EQU 15 ; Max number of buffers per bucket
MaxBucketinPage EQU 2 ; Max number of buckets per 16kb page
; ;
; C A V E A T P R O G R A M M E R ;
;----+----+----+----+----+----+----+----+----+----+----+----+----+----+----;
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