From 2d04cacc5322951f187bb17e017c12920ac8ebe2 Mon Sep 17 00:00:00 2001
From: Mark Zbikowski
Date: Thu, 25 Apr 2024 21:24:10 +0100
Subject: MZ is back!

---
 v4.0/src/DOS/DINFO.ASM | 131 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 131 insertions(+)
 create mode 100644 v4.0/src/DOS/DINFO.ASM

(limited to 'v4.0/src/DOS/DINFO.ASM')

diff --git a/v4.0/src/DOS/DINFO.ASM b/v4.0/src/DOS/DINFO.ASM
new file mode 100644
index 0000000..10738b1
--- /dev/null
+++ b/v4.0/src/DOS/DINFO.ASM
@@ -0,0 +1,131 @@
+;	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
-- 
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