17 Status Polling Assembly Code Step 4: Read transmit holding register empty Step 5: If empty, write a byte to transmit data xmit: inb (%dx), %al# get thre andb $0x20, %al# look at thre jz loop2# if tx hr empty movb somewhere, %al# get data to send movw $0x2f8, %dx# i/o data addr outb %al, (%dx)# send it jmp loop2# and loop
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