CnC_Red_Alert/WWFLAT32/FILE/DEVICES.ASM

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;
; Command & Conquer Red Alert(tm)
; Copyright 2025 Electronic Arts Inc.
;
; This program is free software: you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation, either version 3 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program. If not, see <http://www.gnu.org/licenses/>.
;
; $Header: g:/library/wwlib32/system/rcs/devices.asm 1.2 1994/04/28 12:41:41 jeff_wilson Exp $
;***************************************************************************
;** C O N F I D E N T I A L --- W E S T W O O D A S S O C I A T E S **
;***************************************************************************
;* *
;* Project Name : LIBRARY *
;* *
;* File Name : DEVICES.ASM *
;* *
;* Programmer : Christopher Yates *
;* *
;* Last Update : 12 December, 1990 [CY] *
;* *
;*-------------------------------------------------------------------------*
;* Functions: *
;* *
; VOID Get_Devices(VOID); *
; WORD Is_Device_Real(WORD drive); *
;* *
;* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - *
;----------------------------------------------------------------------------
IDEAL
P386
MODEL USE32 FLAT
GLOBAL Get_Devices :NEAR
GLOBAL Is_Device_Real :NEAR
GLOBAL MaxDevice :BYTE
GLOBAL DefaultDrive :BYTE
; ----------------------------------------------------------------
;
; Here are prototypes for the routines defined within this module:
;
; VOID Get_Devices(VOID);
; WORD Is_Device_Real(WORD drive);
;
; ----------------------------------------------------------------
CODESEG
;***********************************************************
;
; GET_DEVICES
;
; VOID Get_Devices(VOID);
;
; This routine establishes the default disk drive and the maximum drive
; available in the current system.
;
;*
DOS equ 21h
PROC Get_Devices C near
USES eax,ebx,edx
sub eax,eax
mov ah,25 ; get current drive service
int DOS ; drive returned in al
mov [DefaultDrive],al ; save it
mov dl,al
mov ah,14 ; set current as current drive
int DOS
dec al ; al = max drives, make it n - 1
xor ah,ah ; clear high byte
mov edx,eax ; use dx to go backward to find out
sub ebx,ebx
??back_loop:
mov bl,dl ; find out about the drive in dl
inc bl
mov eax,0440Eh ; get the physical drive associated
int DOS ; with this letter
jnc short ??later ; if c clear, no error
cmp al,0Fh ; was it invalid? (0Fh = invalid)
jne short ??later ; yes, so LATER
dec edx
jmp ??back_loop ; try, try again
??later:
mov eax,edx ; restore ax
mov [MaxDevice],al ; save the max drive #
ret
ENDP Get_Devices
;***************************************************************
;***************************************************************
;
; IS_DEVICE_REAL
;
; WORD Is_Device_Real(WORD drive);
;
; This routine will tell whether or not a device is a true
; phisical one. Send it the drive # to check.
;
;*
PROC Is_Device_Real C near
USES ebx,edx
ARG drive:WORD
sub edx,edx
mov dx,[drive]
??next_drive:
push ebx
mov bl,dl ; find out about the drive in dl
inc bl
mov eax,0440Eh ; get the physical drive associated
int DOS ; with this letter
pop ebx
jnc short ??it_is_real ; jump if no error
cmp al,01 ; 1 = invalid command,
; 0F = invalid device
je short ??real ; 1? it is ok (RAM device)
jmp short ??invalid ; 0Fh, it was not a device
??it_is_real:
cmp al,0 ; was it a fixed device?
je short ??real ; yes, it's ok
dec al ; make it a drive #
cmp al,dl ; is it a valid drive?
je short ??real
??invalid: ; The device is invalid.
mov eax,0
jmp short ??out
??real: ; Return true, for valid device.
mov eax,1
??out:
ret
ENDP Is_Device_Real
;***************************************************************
END