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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <mach.h>
include <config.h>
include <fio.h>
include "ki.h"
# KZRDMT -- Asynchronous read from a magtape file.
procedure kzrdmt (chan, obuf, max_bytes, offset)
int chan #I magtape channel
char obuf[ARB] #O buffer to receive data
int max_bytes #I max bytes to read
long offset #I file offset
pointer bd
int server, status
int ki_send(), ki_receive()
include "kichan.com"
include "kii.com"
begin
server = k_node[chan]
if (server == NULL) {
call zzrdmt (k_oschan[chan], obuf, max_bytes, offset)
return
}
# Ignore zero reads and requests on a node closed by an error.
if (max_bytes <= 0) {
k_status[chan] = 0
return
}
# Send the request to initiate the read.
p_arg[1] = k_oschan[chan]
p_arg[2] = max_bytes
p_arg[3] = offset
if (ki_send (server, KI_ZFIOMT, MT_RD) == ERR) {
status = ERR
} else {
bd = k_bufp[chan]
# Wait for the ZAWT packet.
if (ki_receive (server, KI_ZFIOMT, MT_WT) == ERR)
status = ERR
else {
status = p_arg[1]
call amovi (p_arg[2], Memi[bd], LEN_MTDEVPOS)
}
# Read the data block (if any) directly into caller's buffer.
if (status > 0) {
call ks_aread (server, obuf, status)
call ks_await (server, status)
}
}
k_status[chan] = status
end
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