add directory study
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study/sabre/os/files/Disk/cdromfaq.txt
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study/sabre/os/files/Disk/cdromfaq.txt
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From marcj@nando.net Wed Mar 1 17:51:03 1995
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From: marcj@nando.net (MarcJ)
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Newsgroups: comp.os.msdos.programmer
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||||
Subject: CD-ROM FAQ
|
||||
Date: 19 Feb 1995 23:18:50 -0500
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Organization: NandO -- The News & Observer online service
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NNTP-Posting-Host: parsifal.nando.net
|
||||
|
||||
In recognition of a number of questions I've seen recently asking
|
||||
questions on programming CD-ROMs...
|
||||
|
||||
CD-ROM programming FAQ Version 1.00
|
||||
|
||||
Copyright (C) 1995 by Marcus W. Johnson. All rights reserved. This
|
||||
article is not in the public domain, but it may be redistributed so
|
||||
long as this notice, the acknowledgments, and the information on
|
||||
obtaining the latest copy of this list are retained and no fee is
|
||||
charged. The code fragments may be used freely; credit would be
|
||||
polite.
|
||||
|
||||
------- Table of Contents --------------------------------------------
|
||||
|
||||
Section 0 - Availability
|
||||
0.01. How can I get the latest copy of this FAQ?
|
||||
Section 1 - MSCDEX Status
|
||||
1.01. How do I know if MSCDEX is installed?
|
||||
1.02. How do I determine the MSCDEX version?
|
||||
Section 2 - CD-ROM Existence
|
||||
2.01. How many CD-ROMs are present?
|
||||
2.02. Which drives are CD-ROMs?
|
||||
2.03. How do I get the name of the CD-ROM device driver?
|
||||
Section 3 - Drive Interface
|
||||
3.01. How do I open the door?
|
||||
3.02. How do I close the door?
|
||||
3.03. How do I unlock the door?
|
||||
3.04. How do I lock the door?
|
||||
3.05. How do I reset the drive?
|
||||
3.06. How do I get drive status?
|
||||
Section 4 - Drive Capacity
|
||||
4.01. What sector size is supported?
|
||||
4.02. How many sectors are on the disk?
|
||||
4.03. How much data is on the disk?
|
||||
Section 5 - Volume Table of Contents
|
||||
5.01. How do I get the abstract file name?
|
||||
5.02. How do I get the bibliography file name?
|
||||
5.03. How do I get the copyright file name?
|
||||
5.04. How do I read the Volume Table of Contents (VTOC)?
|
||||
Section 6 - Audio
|
||||
6.01. How do I find out how many tracks are on a CD?
|
||||
6.02. What are Red Book and HSG formats?
|
||||
6.03. How can I determine where a particular track starts?
|
||||
6.04. How do I play audio?
|
||||
6.05. How do I pause audio playback?
|
||||
6.06. How do I resume audio playback?
|
||||
|
||||
======================================================================
|
||||
Section 0 - Administration
|
||||
----------------------------------------------------------------------
|
||||
0.01. How can I get the latest copy of this FAQ?
|
||||
|
||||
The FAQ is published monthly in comp.os.msdos.programming and
|
||||
alt.msdos.programmer.
|
||||
----------------------------------------------------------------------
|
||||
0.02. Where did this information come from?
|
||||
|
||||
Ralf Brown's interrupt list
|
||||
"MS-DOS Extensions", by Ray Duncan, Microsoft Press
|
||||
My personal research for "PC-Programmer's Guide to Low-Level
|
||||
Functions and Interrupts", Sams
|
||||
The mention of particular books or programs must not be construed
|
||||
to reflect unfavorably on any that are not mentioned.
|
||||
----------------------------------------------------------------------
|
||||
0.03. How accurate is this information?
|
||||
|
||||
I have personally tested the code fragments in this FAQ, and
|
||||
they appear to work as advertised, but there is no warranty on
|
||||
the code or on the techniques described in this article.
|
||||
As testing may not have been perfect, and machines and
|
||||
configurations vary, it is possible that the fragments will not
|
||||
work for you.
|
||||
Please send corrections to marcj@nando.net.
|
||||
======================================================================
|
||||
Section 1 - MSCDEX Status
|
||||
======================================================================
|
||||
1.01. How do I know if MSCDEX is installed?
|
||||
|
||||
Call the MSCDEX installation check function. Here's code that
|
||||
performs the check:
|
||||
|
||||
mov AX,0DADAH
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||||
push AX
|
||||
mov AX,01100H
|
||||
int 2FH
|
||||
pop BX
|
||||
cmp BX,0ADADH
|
||||
jne not_installed
|
||||
cmp AL,0FFH
|
||||
jne not_installed
|
||||
;
|
||||
; MSCDEX is installed
|
||||
;
|
||||
----------------------------------------------------------------------
|
||||
1.02. How do I determine the MSCDEX version?
|
||||
|
||||
Call the MSCDEX version check function. Here's code that gets
|
||||
the version:
|
||||
|
||||
mov AX,150CH
|
||||
int 2FH
|
||||
;
|
||||
; BH holds the major version
|
||||
; BL holds the minor version
|
||||
; Prior to MSCDEX version 2.0, the version returned is 0.0 (BX =
|
||||
; 0)
|
||||
;
|
||||
======================================================================
|
||||
Section 2 - CD-ROM Existence
|
||||
======================================================================
|
||||
2.01. How many CD-ROMs are present?
|
||||
|
||||
Ask MSCDEX. Here's code that gives the count of CD-ROMs
|
||||
installed and the drive letter of the first one:
|
||||
|
||||
mov AX,1500H
|
||||
xor BX,BX
|
||||
int 2FH
|
||||
;
|
||||
; BX will hold the number of CD-ROMs
|
||||
; CL will hold the first CD-ROM's drive; 0 = A:, 1 = B:, and so
|
||||
; on
|
||||
;
|
||||
|
||||
A problem with this method, BTW, is that it conflicts with DOS
|
||||
4.0's GRAPHICS.COM.
|
||||
----------------------------------------------------------------------
|
||||
2.02. Which drives are CD-ROMs?
|
||||
|
||||
There are two ways to find out. Both ways require MSCDEX version
|
||||
2 (see question 1.02, How do I determine the MSCDEX version?).
|
||||
The first way gives a list of all CD-ROM drives; the second
|
||||
verifies whether a specific drive is a CD-ROM.
|
||||
|
||||
Method 1: (get list of CD-ROMs)
|
||||
This method requires a block of memory; the size, in bytes, must
|
||||
be at least the number of drives returned by function 1500H (see
|
||||
question 2.01, How many CD-ROMs are present?).
|
||||
|
||||
mov AX,150DH
|
||||
les BX,LetterArray
|
||||
int 2FH
|
||||
;
|
||||
; each byte in LetterArray will contain a drive value (0 = A:, 1
|
||||
; = B:, etc.)
|
||||
;
|
||||
|
||||
Method 2: (is a specified drive a CD-ROM?)
|
||||
|
||||
mov AX,150BH
|
||||
mov CX,Drive ; 0 = A:, 1 = B:, and so on
|
||||
int 2FH
|
||||
or AX,AX
|
||||
jz not_cd_rom
|
||||
cmp BX,0ADADH
|
||||
jne not_cd_rom
|
||||
;
|
||||
; the drive is a CD-ROM
|
||||
;
|
||||
----------------------------------------------------------------------
|
||||
2.03. How do I get the name of the CD-ROM device driver?
|
||||
|
||||
First, you need to know how many CD-ROMs you have (see question
|
||||
2.01, How many CD-ROMs are present?). You need a block of memory
|
||||
whose size, in bytes, is 5 times the number of CD-ROMs present.
|
||||
This code will fill that array:
|
||||
|
||||
mov AX,1501H
|
||||
les BX,DriverArray
|
||||
int 2FH
|
||||
|
||||
Each 5-byte element in the array consists of the drive's subunit
|
||||
number (a CD-ROM device driver may support several drives as
|
||||
subunits), followed by the address of the drive's device driver.
|
||||
The filename is 10 bytes into the device driver. The filename is
|
||||
at most 8 bytes long, and if less than 8 bytes, is terminated by
|
||||
a space (20H).
|
||||
======================================================================
|
||||
Section 3 - Drive Interface
|
||||
======================================================================
|
||||
3.01. How do I open the door?
|
||||
|
||||
First, you need the name of the device driver (see question 2.03,
|
||||
How do I get the name of the CD-ROM device driver?). Open the
|
||||
file for read/write and obtain the file handle (DOS function 3DH
|
||||
will suffice).
|
||||
|
||||
Once you have the file handle, you need a one byte block of
|
||||
memory. Call DOS IOCTL function 4403H, as shown here:
|
||||
|
||||
mov BX,FileHandle
|
||||
mov Command,0
|
||||
lds DX,Command
|
||||
mov CX,1
|
||||
mov AX,4403H
|
||||
int 21H
|
||||
jc error
|
||||
cmp AX,1
|
||||
jne write_error
|
||||
;
|
||||
; door should be open
|
||||
;
|
||||
|
||||
On error (carry set), AX will hold an error code: 0001H (invalid
|
||||
function), 0005H (access denied), 0006H (invalid handle), or
|
||||
000DH (invalid data).
|
||||
----------------------------------------------------------------------
|
||||
3.02. How do I close the door?
|
||||
|
||||
First, you need the name of the device driver (see question 2.03,
|
||||
How do I get the name of the CD-ROM device driver?). Open the
|
||||
file for read/write and obtain the file handle (DOS function 3DH
|
||||
will suffice).
|
||||
|
||||
Once you have the file handle, you need a one byte block of
|
||||
memory. Call DOS IOCTL function 4403H, as shown here:
|
||||
|
||||
mov BX,FileHandle
|
||||
mov Command,5
|
||||
lds DX,Command
|
||||
mov CX,1
|
||||
mov AX,4403H
|
||||
int 21H
|
||||
jc error
|
||||
cmp AX,1
|
||||
jne write_error
|
||||
;
|
||||
; door should be closed
|
||||
;
|
||||
|
||||
On error (carry set), AX will hold an error code: 0001H (invalid
|
||||
function), 0005H (access denied), 0006H (invalid handle), or
|
||||
000DH (invalid data).
|
||||
|
||||
The drive should be reset after closing the door before
|
||||
accessing the drive (see question 3.05, How do I reset the
|
||||
drive?).
|
||||
----------------------------------------------------------------------
|
||||
3.03. How do I unlock the door?
|
||||
|
||||
First, you need the name of the device driver (see question 2.03,
|
||||
How do I get the name of the CD-ROM device driver?). Open the
|
||||
file for read/write and obtain the file handle (DOS function 3DH
|
||||
will suffice).
|
||||
|
||||
Once you have the file handle, you need a two-byte block of
|
||||
memory. Call DOS IOCTL function 4403H, as shown here:
|
||||
|
||||
mov BX,FileHandle
|
||||
mov Command,1
|
||||
mov Command+1,0
|
||||
lds DX,Command
|
||||
mov CX,2
|
||||
mov AX,4403H
|
||||
int 21H
|
||||
jc error
|
||||
cmp AX,2
|
||||
jne write_error
|
||||
;
|
||||
; door should be unlocked
|
||||
;
|
||||
|
||||
On error (carry set), AX will hold an error code: 0001H (invalid
|
||||
function), 0005H (access denied), 0006H (invalid handle), or
|
||||
000DH (invalid data).
|
||||
|
||||
The drive should be reset after unlocking the door before
|
||||
accessing the drive (see question 3.05, How do I reset the
|
||||
drive?).
|
||||
----------------------------------------------------------------------
|
||||
3.04. How do I lock the door?
|
||||
|
||||
First, you need the name of the device driver (see question 2.03,
|
||||
How do I get the name of the CD-ROM device driver?). Open the
|
||||
file for read/write and obtain the file handle (DOS function 3DH
|
||||
will suffice).
|
||||
|
||||
Once you have the file handle, you need a two-byte block of
|
||||
memory. Call DOS IOCTL function 4403H, as shown here:
|
||||
|
||||
mov BX,FileHandle
|
||||
mov Command,1
|
||||
mov Command+1,1
|
||||
lds DX,Command
|
||||
mov CX,2
|
||||
mov AX,4403H
|
||||
int 21H
|
||||
jc error
|
||||
cmp AX,2
|
||||
jne write_error
|
||||
;
|
||||
; door should be locked
|
||||
;
|
||||
|
||||
On error (carry set), AX will hold an error code: 0001H (invalid
|
||||
function), 0005H (access denied), 0006H (invalid handle), or
|
||||
000DH (invalid data).
|
||||
|
||||
The drive should be reset after locking the door before
|
||||
accessing the drive (see question 3.05, How do I reset the
|
||||
drive?).
|
||||
----------------------------------------------------------------------
|
||||
3.05. How do I reset the drive?
|
||||
|
||||
First, you need the name of the device driver (see question 2.03,
|
||||
How do I get the name of the CD-ROM device driver?). Open the
|
||||
file for read/write and obtain the file handle (DOS function 3DH
|
||||
will suffice).
|
||||
|
||||
Once you have the file handle, you need a one-byte block of
|
||||
memory. Call DOS IOCTL function 4403H, as shown here:
|
||||
|
||||
mov BX,FileHandle
|
||||
mov Command,2
|
||||
lds DX,Command
|
||||
mov CX,1
|
||||
mov AX,4403H
|
||||
int 21H
|
||||
jc error
|
||||
cmp AX,1
|
||||
jne write_error
|
||||
;
|
||||
; drive should be reset
|
||||
;
|
||||
|
||||
On error (carry set), AX will hold an error code: 0001H (invalid
|
||||
function), 0005H (access denied), 0006H (invalid handle), or
|
||||
000DH (invalid data).
|
||||
----------------------------------------------------------------------
|
||||
3.06. How do I get drive status?
|
||||
|
||||
First, you need the name of the device driver (see question 2.03,
|
||||
How do I get the name of the CD-ROM device driver?). Open the
|
||||
file for read/write and obtain the file handle (DOS function 3DH
|
||||
will suffice).
|
||||
|
||||
Once you have the file handle, you need a five-byte block of
|
||||
memory. Call DOS IOCTL function 4402H, as shown here:
|
||||
|
||||
mov BX,FileHandle
|
||||
mov Command,6
|
||||
lds DX,Command
|
||||
mov CX,5
|
||||
mov AX,4402H
|
||||
int 21H
|
||||
jc error
|
||||
cmp AX,5
|
||||
jne read_error
|
||||
;
|
||||
; The word at offset 1 of the five-byte block of memory contains
|
||||
; status
|
||||
; bit 10 is set if audio is playing
|
||||
; bit 9 is set if Red Book and HSG addressing are both
|
||||
; supported
|
||||
; bit 8 is set if audio channel control is supported
|
||||
; bit 7 is set if prefetch requests are supported
|
||||
; bit 5 is set if interleaving is supported
|
||||
; bit 4 is set if audio/video track playback is supported
|
||||
; bit 3 is set if the CD-ROM is writable
|
||||
; bit 2 is set if raw and cooked read is supported
|
||||
; bit 1 is set if the door is unlocked
|
||||
; bit 0 is set if the door is open
|
||||
;
|
||||
|
||||
On error (carry set), AX will hold an error code: 0001H (invalid
|
||||
function), 0005H (access denied), 0006H (invalid handle), or
|
||||
000DH (invalid data).
|
||||
|
||||
The drive should be reset after checking drive status before
|
||||
accessing the drive (see question 3.05, How do I reset the
|
||||
drive?).
|
||||
======================================================================
|
||||
Section 4 - Drive Capacity
|
||||
======================================================================
|
||||
4.01. What sector size is supported?
|
||||
|
||||
First, you need the name of the device driver (see question 2.03,
|
||||
How do I get the name of the CD-ROM device driver?). Open the
|
||||
file for read/write and obtain the file handle (DOS function 3DH
|
||||
will suffice).
|
||||
|
||||
Once you have the file handle, you need a four-byte block of
|
||||
memory. Call DOS IOCTL function 4402H, as shown here:
|
||||
|
||||
mov BX,FileHandle
|
||||
mov Command,7
|
||||
lds DX,Command
|
||||
mov CX,4
|
||||
mov AX,4402H
|
||||
int 21H
|
||||
jc error
|
||||
cmp AX,4
|
||||
jne read_error
|
||||
;
|
||||
; The byte at offset 1 of the four-byte block of memory contains
|
||||
; raw/cooked status (0 = cooked, 1 = raw)
|
||||
; The word at offset 2 of the four-byte block of memory contains
|
||||
; the sector size
|
||||
|
||||
On error (carry set), AX will hold an error code: 0001H (invalid
|
||||
function), 0005H (access denied), 0006H (invalid handle), or
|
||||
000DH (invalid data).
|
||||
|
||||
The drive should be reset after getting the sector size before
|
||||
accessing the drive (see question 3.05, How do I reset the
|
||||
drive?).
|
||||
----------------------------------------------------------------------
|
||||
4.02. How many sectors are on the disk?
|
||||
|
||||
First, you need the name of the device driver (see question 2.03,
|
||||
How do I get the name of the CD-ROM device driver?). Open the
|
||||
file for read/write and obtain the file handle (DOS function 3DH
|
||||
will suffice).
|
||||
|
||||
Once you have the file handle, you need a five-byte block of
|
||||
memory. Call DOS IOCTL function 4402H, as shown here:
|
||||
|
||||
mov BX,FileHandle
|
||||
mov Command,8
|
||||
lds DX,Command
|
||||
mov CX,5
|
||||
mov AX,4402H
|
||||
int 21H
|
||||
jc error
|
||||
cmp AX,5
|
||||
jne read_error
|
||||
;
|
||||
; The dword at offset 1 of the five-byte block of memory
|
||||
; contains the number of sectors
|
||||
|
||||
On error (carry set), AX will hold an error code: 0001H (invalid
|
||||
function), 0005H (access denied), 0006H (invalid handle), or
|
||||
000DH (invalid data).
|
||||
|
||||
The drive should be reset after getting the number of sectors
|
||||
before accessing the drive (see question 3.05, How do I reset
|
||||
the drive?).
|
||||
----------------------------------------------------------------------
|
||||
4.03. How much data is on the disk?
|
||||
|
||||
See question 4.01, What sector size is supported?, and question
|
||||
4.02, How many sectors are on the disk?. Take the product of the
|
||||
two values returned. The conventional DOS functions don't work
|
||||
reliably.
|
||||
======================================================================
|
||||
Section 5 - Volume Table of Contents
|
||||
======================================================================
|
||||
5.01. How do I get the abstract file name?
|
||||
|
||||
You need a 38-byte block of memory to hold the abstract file
|
||||
name. This code will fill that block:
|
||||
|
||||
les BX,Buffer
|
||||
mov CX,Drive ; must be in format 0 = A:, 1 = B:, etc.
|
||||
mov AX,1503H
|
||||
int 2FH
|
||||
jc error
|
||||
;
|
||||
; buffer is filled with the abstract file name.
|
||||
;
|
||||
|
||||
The file name is nul-terminated.
|
||||
|
||||
The drive should be reset after getting the abstract file name
|
||||
before accessing the drive (see question 3.05, How do I reset
|
||||
the drive?).
|
||||
----------------------------------------------------------------------
|
||||
5.02. How do I get the bibliography file name?
|
||||
|
||||
You need a 38-byte block of memory to hold the bibliography file
|
||||
name. This code will fill that block:
|
||||
|
||||
les BX,Buffer
|
||||
mov CX,Drive ; must be in format 0 = A:, 1 = B:, etc.
|
||||
mov AX,1504H
|
||||
int 2FH
|
||||
jc error
|
||||
;
|
||||
; buffer is filled with the bibliography file name.
|
||||
;
|
||||
|
||||
The file name is nul-terminated.
|
||||
|
||||
The drive should be reset after getting the bibliography file
|
||||
name before accessing the drive (see question 3.05, How do I
|
||||
reset the drive?).
|
||||
----------------------------------------------------------------------
|
||||
5.03. How do I get the copyright file name?
|
||||
|
||||
You need a 38-byte block of memory to hold the copyright file
|
||||
name. This code will fill that block:
|
||||
|
||||
les BX,Buffer
|
||||
mov CX,Drive ; must be in format 0 = A:, 1 = B:, etc.
|
||||
mov AX,1502H
|
||||
int 2FH
|
||||
jc error
|
||||
;
|
||||
; buffer is filled with the copyright file name.
|
||||
;
|
||||
|
||||
The file name is nul-terminated.
|
||||
|
||||
The drive should be reset after getting the copyright file name
|
||||
before accessing the drive (see question 3.05, How do I reset
|
||||
the drive?).
|
||||
----------------------------------------------------------------------
|
||||
5.04. How do I read the Volume Table of Contents (VTOC)?
|
||||
|
||||
The VTOC is read in 2048-byte blocks. This code fills a VTOC
|
||||
block:
|
||||
|
||||
les BX,Buffer
|
||||
mov CX,Drive ; must be in format 0 = A:, 1 = B:, etc.
|
||||
mov DX,BlockNumber ; 0 for the first block
|
||||
mov AX,1505H
|
||||
int 2FH
|
||||
jc error
|
||||
;
|
||||
; block is filled
|
||||
;
|
||||
; AX contains the descriptor type for this block:
|
||||
; 0001H = standard volume descriptor
|
||||
; 00FFH = volume descriptor terminator
|
||||
;
|
||||
|
||||
On error, AX will hold an error value: 000FH (invalid drive) or
|
||||
0015H (drive not ready).
|
||||
======================================================================
|
||||
Section 6 - Audio
|
||||
======================================================================
|
||||
6.01. How do I find out how many tracks are on a CD?
|
||||
|
||||
First, you need the name of the device driver (see question
|
||||
2.03, How do I get the name of the CD-ROM device driver?). Open
|
||||
the file for read/write and obtain the file handle (DOS function
|
||||
3DH will suffice).
|
||||
|
||||
Once you have the file handle, you need a seven-byte block of
|
||||
memory. Call DOS IOCTL function 4402H, as shown here:
|
||||
|
||||
mov BX,FileHandle
|
||||
mov Command,0AH
|
||||
lds DX,Command
|
||||
mov CX,7
|
||||
mov AX,4402H
|
||||
int 21H
|
||||
jc error
|
||||
cmp AX,7
|
||||
jne read_error
|
||||
;
|
||||
; The byte at offset 1 of the seven-byte block of memory is the
|
||||
; number of the first track
|
||||
; The byte at offset 2 of the seven-byte block of memory is the
|
||||
; number of the last track
|
||||
; The dword at offset 4 of the seven-byte block of memory is the
|
||||
; start address of the first track in Red Book format
|
||||
|
||||
On error (carry set), AX will hold an error code: 0001H (invalid
|
||||
function), 0005H (access denied), 0006H (invalid handle), or
|
||||
000DH (invalid data).
|
||||
----------------------------------------------------------------------
|
||||
6.02. What are Red Book and HSG formats?
|
||||
|
||||
Both are ways of encoding frame information. An audio frame is
|
||||
1/75 second of audio. HSG encodes frame information into a
|
||||
double word: minute multiplied by 4500, plus second multiplied
|
||||
by 75, plus frame, minus 150. Red Book encodes frame information
|
||||
into a four-byte data structure:
|
||||
Byte 0: frame number
|
||||
Byte 1: second
|
||||
Byte 2: minute
|
||||
Byte 3: unused
|
||||
----------------------------------------------------------------------
|
||||
6.03. How can I determine where a particular track starts?
|
||||
|
||||
First, you need the name of the device driver (see question
|
||||
2.03, How do I get the name of the CD-ROM device driver?). Open
|
||||
the file for read/write and obtain the file handle (DOS function
|
||||
3DH will suffice).
|
||||
|
||||
Once you have the file handle, you need an eight-byte block of
|
||||
memory. Call DOS IOCTL function 4402H, as shown here:
|
||||
|
||||
mov BX,FileHandle
|
||||
mov Command,0BH
|
||||
mov Command+1,TrackNumber
|
||||
lds DX,Command
|
||||
mov CX,8
|
||||
mov AX,4402H
|
||||
int 21H
|
||||
jc error
|
||||
cmp AX,8
|
||||
jne read_error
|
||||
;
|
||||
; The dword at offset 2 of the eight-byte block of memory is the
|
||||
; start address of the specified track in Red Book format
|
||||
; The word at offset 6 of the eight-byte block of memory is the
|
||||
; track control information. Bits 15-12 are used:
|
||||
; 0xxx: Two audio channels, no pre-emphasis, digital copy not
|
||||
; permitted
|
||||
; 1xxx: Two audio channels, with pre-emphasis, digital copy not
|
||||
; permitted
|
||||
; 2xxx: Two audio channels, no pre-emphasis, digital copy
|
||||
; permitted
|
||||
; 3xxx: Two audio channels, with pre-emphasis, digital copy
|
||||
; permitted
|
||||
; 4xxx: Data track, digital copy not permitted
|
||||
; 6xxx: Data track, digital copy permitted
|
||||
; 8xxx: Four audio channels, no pre-emphasis, digital copy not
|
||||
; permitted
|
||||
; 9xxx: Four audio channels, with pre-emphasis, digital copy not
|
||||
; permitted
|
||||
; Axxx: Four audio channels, no pre-emphasis, digital copy
|
||||
; permitted
|
||||
; Bxxx: Four audio channels, with pre-emphasis, digital copy
|
||||
; permitted
|
||||
|
||||
On error (carry set), AX will hold an error code: 0001H (invalid
|
||||
function), 0005H (access denied), 0006H (invalid handle), or
|
||||
000DH (invalid data).
|
||||
----------------------------------------------------------------------
|
||||
6.04. How do I play audio?
|
||||
|
||||
For starters, you need MSCDEX Version 2.1 or greater (see
|
||||
question 1.02, How do I determine the MSCDEX version?).
|
||||
|
||||
You also need the subunit number for the drive containing the
|
||||
audio CD (see question 2.03, How do I get the name of the CD-ROM
|
||||
device driver?)
|
||||
|
||||
You also need to know what frame you want to start with (see
|
||||
question 6.03, How can I determine where a particular track
|
||||
starts?), and how many frames you want to play.
|
||||
|
||||
Now, you need a 22-byte block of memory. Write 22 (16H) to the
|
||||
first byte. Write the subunit number to the second byte. Write
|
||||
84H to the third byte. Write 0 to the byte at offset 0DH (this
|
||||
sets up HSG addressing). Convert the starting frame number to
|
||||
HSG format and write the 4-byte result to the dword at offset
|
||||
0EH. Finally, write the frame count to the dword at offset 12H.
|
||||
|
||||
To play the CD as instructed, execute this code:
|
||||
|
||||
les BX,Buffer
|
||||
mov CX,Drive ; must be in format 0 = A:, 1 = B:, etc.
|
||||
mov AX,1510H
|
||||
int 2FH
|
||||
;
|
||||
; status is in the word at offset 3 of the buffer. Look for bit
|
||||
; 8 set (done), and watch out for bit 15 set (error).
|
||||
;
|
||||
----------------------------------------------------------------------
|
||||
6.05. How do I pause audio playback?
|
||||
|
||||
For starters, you need MSCDEX Version 2.1 or greater (see
|
||||
question 1.02, How do I determine the MSCDEX version?).
|
||||
|
||||
You also need the subunit number for the drive containing the
|
||||
audio CD (see question 2.03, How do I get the name of the CD-ROM
|
||||
device driver?)
|
||||
|
||||
Now, you need a 13-byte block of memory. Write 13 (0DH) to the
|
||||
first byte. Write the subunit number to the second byte. Write
|
||||
85H to the third byte.
|
||||
|
||||
To pause the CD, execute this code:
|
||||
|
||||
les BX,Buffer
|
||||
mov CX,Drive ; must be in format 0 = A:, 1 = B:, etc.
|
||||
mov AX,1510H
|
||||
int 2FH
|
||||
;
|
||||
; status is in the word at offset 3 of the buffer. Look for bit
|
||||
; 8 set (done), and watch out for bit 15 set (error).
|
||||
;
|
||||
----------------------------------------------------------------------
|
||||
6.06. How do I resume audio playback?
|
||||
|
||||
For starters, you need MSCDEX Version 2.1 or greater (see
|
||||
question 1.02, How do I determine the MSCDEX version?).
|
||||
|
||||
You also need the subunit number for the drive containing the
|
||||
audio CD (see question 2.03, How do I get the name of the CD-ROM
|
||||
device driver?)
|
||||
|
||||
Now, you need a 13-byte block of memory. Write 13 (0DH) to the
|
||||
first byte. Write the subunit number to the second byte. Write
|
||||
88H to the third byte.
|
||||
|
||||
To resume, execute this code:
|
||||
|
||||
les BX,Buffer
|
||||
mov CX,Drive ; must be in format 0 = A:, 1 = B:, etc.
|
||||
mov AX,1510H
|
||||
int 2FH
|
||||
;
|
||||
; status is in the word at offset 3 of the buffer. Look for bit
|
||||
; 8 set (done), and watch out for bit 15 set (error).
|
||||
;
|
||||
|
||||
|
||||
|
||||
|
||||
Reference in New Issue
Block a user