MZ is back!HEADmain

1 files changed, 131 insertions, 0 deletions

diff --git a/v4.0/src/DOS/DINFO.ASM b/v4.0/src/DOS/DINFO.ASM
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+++ b/v4.0/src/DOS/DINFO.ASM
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+;       SCCSID = @(#)dinfo.asm  1.1 85/04/10
+;       SCCSID = @(#)dinfo.asm  1.1 85/04/10
+TITLE   DISK_INFO - Internal Get Disk Info
+NAME    DISK_INFO
+; Low level routine for returning disk drive information from a local
+;   or NET device
+;
+; DISK_INFO
+;
+;   Modification history:
+;
+;       Created: ARR 30 March 1983
+;
+
+;
+; get the appropriate segment definitions
+;
+.xlist
+include dosseg.asm
+
+CODE    SEGMENT BYTE PUBLIC  'CODE'
+        ASSUME  SS:DOSGROUP,CS:DOSGROUP
+
+.xcref
+INCLUDE DOSSYM.INC
+INCLUDE DEVSYM.INC
+.cref
+.list
+
+Installed = TRUE
+
+        i_need  THISCDS,DWORD
+        i_need  CURBUF,DWORD
+        i_need  EXTERR_LOCUS,BYTE
+if debug
+        I_need  BugLev,WORD
+        I_need  BugTyp,WORD
+include bugtyp.asm
+endif
+
+Break   <DISK_INFO -- Get Disk Drive Information>
+
+; Inputs:
+;       [THISCDS] Points to the Macro List Structure of interest
+;               (It MAY NOT be NUL, error not detected)
+; Function:
+;       Get Interesting Drive Information
+; Returns:
+;       DX = Number of free allocation units
+;       BX = Total Number of allocation units on disk
+;       CX = Sector size
+;       AL = Sectors per allocation unit
+;       AH = FAT ID BYTE
+;       Carry set if error (currently user FAILed to I 24)
+; Segs except ES preserved, others destroyed
+
+        procedure   DISK_INFO,NEAR
+        DOSAssume   CS,<DS>,"Disk_Info"
+        ASSUME  ES:NOTHING
+
+        Invoke  TestNet
+        JNC     LOCAL_INFO
+IF NOT Installed
+        transfer NET_DISK_INFO
+ELSE
+        MOV     AX,(multNET SHL 8) OR 12
+        INT     2FH
+        return
+ENDIF
+
+LOCAL_INFO:
+        MOV     [EXTERR_LOCUS],errLOC_Disk
+        EnterCrit   critDisk
+        invoke  FATREAD_CDS             ; perform media check.
+        JC      CRIT_LEAVE
+        MOV     BX,2
+        invoke  UNPACK                  ; Get first FAT sector into CURBUF
+        JC      CRIT_LEAVE
+        LDS     SI,[CURBUF]
+ASSUME  DS:NOTHING
+        MOV     AH,[SI].bufinsiz        ; get FAT ID BYTE
+        context DS
+        MOV     CX,ES:[BP.dpb_max_cluster]
+;
+; Examine the current free count.  If it indicates that we have an invalid
+; count, do the expensive calculation.
+;
+        MOV     DX,ES:[BP.dpb_free_cnt] ; get free count
+        CMP     DX,-1                   ; is it valid?
+        JZ      DoScan
+;
+; Check to see if it is in a reasonalbe range.  If so, trust it and return.
+; Otherwise, we need to blast out an internal error message and then recompute
+; the count.
+;
+        CMP     DX,CX                   ; is it in a reasonable range?
+        JB      GotVal                  ; yes, trust it.
+        fmt     TypInt,LevLog,<"Internal error: MaxClus <= FreeClus\n">
+DoScan:
+        XOR     DX,DX
+        DEC     CX
+SCANFREE:
+        invoke  UNPACK
+        JC      Crit_Leave
+        JNZ     NOTFREECLUS
+        INC     DX                      ; A free one
+NOTFREECLUS:
+        INC     BX                      ; Next cluster
+        LOOP    SCANFREE
+        DEC     BX                      ; BX was next cluster.  Convert to
+ReturnVals:
+        DEC     BX                      ; count
+        MOV     AL,ES:[BP.dpb_cluster_mask]
+        INC     AL                      ; Sectors/cluster
+        MOV     CX,ES:[BP.dpb_sector_size]  ; Bytes/sector
+        MOV     ES:[BP.dpb_free_cnt],DX
+        CLC
+CRIT_LEAVE:
+        LeaveCrit   critDisk
+        return
+;
+; We have correctly computed everything previously.  Load up registers for
+; return.
+;
+GotVal: MOV     BX,CX                   ; get cluster count
+        JMP     ReturnVals
+
+EndProc DISK_INFO
+
+CODE    ENDS
+    END