Topic       : The ATARI Compendium
Author      : Scott Sanders / JAY Software
Version     : 1.25 (20/6/2003)
Subject     : Documentation
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View Ref-FileRwabs()                                                                BIOS

Syntax

LONG Rwabs( mode, buf, count, recno, dev, lrecno )
WORD mode;
VOIDP buf;
WORD count,recno,dev;
LONG lrecno;

Function      Rwabs() reads and writes sectors to a mounted device.

Opcode        4 (0x04)

Availability  All TOS versions. Hard disk access requires the use of
              a hard disk driver (such as AHDI). The long sector offset
              version is only available as of AHDI 3.0. AHDI version
              numbers can be inquired through system variable pun_ptr (see
              discussion earlier in this chapter).

Parameters    mode is a bit mask which effects the operation to be
              performed as follows:

              Name            Bit  Meaning

              RW_READ or       0   0 = Read, 1 = Write
              RW_WRITE

              RW_NOMEDIACH     1   Do not read or modify the media change
                                   status.

              RW_NORETRIES     2   Disable retries

              RW_NOTRANSLATE   3   Do not translate logical sectors into
                                   physical sectors (recno specifies
                                   physical instead of logical sectors)

              The read or write operation is performed at address buf. buf
              must be count * bytes per logical sector in logical mode or
              count * 512 bytes in physical mode. count specifies how many
              sectors will be transferred.
              dev specifies the index of the mounted device.
              In logical mode, 'C:' is 2, 'D:' is 3, etc...
              In physical mode, devices 2-9 are the ACSI devices
              and 10-17 are SCSI devices. recno specifies the first sector
              to read from. If you need to specify a long offset, set
              recno to -1 and pass the long value in lrecno. When using
              a version of the AHDI below 3.0, the parameter lrecno should
              not be passed.

Binding       /* If running AHDI <3.0 omit first parameter */

              move.l   lrecno,-(sp)
              move.w   dev,-(sp)
              move.w   recno,-(sp)
              move.w   count,-(sp)
              pea      buf,-(sp)
              move.w   mode,-(sp)
              move.w   #$04,-(sp)
              trap     #13
              lea      18(sp),sp

Return Value  Rwabs() returns E_OK (0) if successful or a negative BIOS
              error code otherwise.

Comments      Some C compilers (Lattice C in particular) have a secondary
              binding called Lrwabs() used to pass the additional
              parameter. This function may invoke the critical error
              handler (etv_critic).