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FILE OPEN
Op-Code: PXENV_FILE_OPEN (00e0h)
Input: Far pointer to a t_PXENV_FILE_OPEN parameter structure
that has been initialised by the caller.
Output: PXENV_EXIT_SUCCESS or PXENV_EXIT_FAILURE must be
returned in AX. The status field in the parameter
structure must be set to one of the values represented
by the PXENV_STATUS_xxx constants.
Description: Opens a file specified by a URL for reading. Multiple
files may be opened and used concurrently.
typedef struct s_PXENV_FILE_OPEN {
PXENV_STATUS Status;
UINT16 FileHandle;
SEGOFF16 FileName;
UINT32 Reserved;
} t_PXENV_FILE_OPEN;
Set before calling API service:
FileName: URL of file to be opened. Null terminated.
Reserved: Must be zero.
Returned from API service:
FileHandle: Handle for use in subsequent PXE FILE API calls.
Status: See PXENV_STATUS_xxx constants.
FILE CLOSE
Op-Code: PXENV_FILE_CLOSE (00e1h)
Input: Far pointer to a t_PXENV_FILE_CLOSE parameter structure
that has been initialised by the caller.
Output: PXENV_EXIT_SUCCESS or PXENV_EXIT_FAILURE must be
returned in AX. The status field in the parameter
structure must be set to one of the values represented
by the PXENV_STATUS_xxx constants.
Description: Closes a previously opened file.
typedef struct s_PXENV_FILE_CLOSE {
PXENV_STATUS Status;
UINT16 FileHandle;
} t_PXENV_FILE_CLOSE;
Set before calling API service:
FileHandle: Handle obtained when file was opened.
Returned from API service:
Status: See PXENV_STATUS_xxx constants.
FILE SELECT
Op-Code: PXENV_FILE_SELECT (00e2h)
Input: Far pointer to a t_PXENV_FILE_SELECT parameter structure
that has been initialised by the caller.
Output: PXENV_EXIT_SUCCESS or PXENV_EXIT_FAILURE must be
returned in AX. The status field in the parameter
structure must be set to one of the values represented
by the PXENV_STATUS_xxx constants.
Description: Check a previously opened file's readiness for I/O.
typedef struct s_PXENV_FILE_SELECT {
PXENV_STATUS Status;
UINT16 FileHandle;
UINT16 Ready;
#define RDY_READ 0x0001
} t_PXENV_FILE_SELECT;
Set before calling API service:
FileHandle: Handle obtained when file was opened.
Returned from API service:
Ready: Indication of readiness. This can be zero, or more,
of the RDY_xxx constants. Multiple values are
arithmetically or-ed together.
Status: See PXENV_STATUS_xxx constants.
FILE READ
Op-Code: PXENV_FILE_READ (00e3h)
Input: Far pointer to a t_PXENV_FILE_READ parameter structure
that has been initialised by the caller.
Output: PXENV_EXIT_SUCCESS or PXENV_EXIT_FAILURE must be
returned in AX. The status field in the parameter
structure must be set to one of the values represented
by the PXENV_STATUS_xxx constants.
This API function is non-blocking. PXENV_EXIT_SUCCESS
and PXENV_STATUS_SUCCESS is returned if a data block
has been transferred into the caller's buffer.
PXENV_EXIT_FAILURE and PXENV_STATUS_FAILURE is
returned if no data is available to transfer.
Description: Read from a previously opened file.
typedef struct s_PXENV_FILE_READ {
PXENV_STATUS Status;
UINT16 FileHandle;
UINT16 BufferSize;
SEGOFF16 Buffer;
} t_PXENV_FILE_READ;
Set before calling API service:
FileHandle: Handle obtained when file was opened.
BufferSize: Maximum number of data bytes that can be copied into
Buffer.
Buffer: Segment:Offset address of data buffer.
Returned from API service:
BufferSize: Number of bytes written to the data buffer. End of
file if this is zero.
Status: See PXENV_STATUS_xxx constants.
GET FILE SIZE
Op-Code: PXENV_GET_FILE_SIZE (00e4h)
Input: Far pointer to a t_PXENV_GET_FILE_SIZE parameter
structure that has been initialised by the caller.
Output: PXENV_EXIT_SUCCESS or PXENV_EXIT_FAILURE must be
returned in AX. The status field in the parameter
structure must be set to one of the values represented
by the PXENV_STATUS_xxx constants.
Description: Determine size of a previously opened file.
typedef struct s_PXENV_GET_FILE_SIZE {
PXENV_STATUS Status;
UINT16 FileHandle;
UINT32 FileSize;
} t_PXENV_GET_FILE_SIZE;
Set before calling API service:
FileHandle: Handle obtained when file was opened.
Returned from API service:
FileSize: Size of the file in bytes.
Status: See PXENV_STATUS_xxx constants.
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