**CIGAL Reference Manual, Chapter 2 (Commands): PORTIO**
===== PORTIO -- Read or write to one of the PC's I/O ports =====
**usage: portio flag port write_data             (FLAG == 1,3,5)**\\
**or: portio flag port read_data              (FLAG == 0,2)**\\
**or: portio flag port write_data read_data   (FLAG == 4)**

PORTIO reads or writes the value specified by DATA to or from the I/O port
specified by PORT.  Reading or writing is controlled by FLAG, as:

     FLAG = 0     Read 1 byte from PORT, put into READ_DATA
            1     Write 1 byte from WRITE_DATA to PORT
            2     Read 1 word (16 bits) from PORT, put into READ_DATA
            3     Write 1 word (16 bits) from WRITE_DATA to PORT
            4     Write 1 byte from WRITE_DATA to PORT,
                     then read 1 byte from PORT+1 and put it into READ_DATA
            5     Write low byte of WRITE_DATA to PORT,
                     then write high byte to PORT+1

WARNING: Reading or writing I/O ports can be dangerous; proceed with caution.

**See Also:**\\
[[jvs:cigal|CIGAL Home]], 
[[jvs:cigal:manual|CIGAL Manual]], 
[[jvs:cigal:manual:chapter2|Commands List]], 
[[jvs:cigal:manual:help|Manual Help]]