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GNU Info (nasm.info)Section B.4.195B.4.195. `OUTSB', `OUTSW', `OUTSD': Output String to I/O Port ------------------------------------------------------------- OUTSB ; 6E [186] OUTSW ; o16 6F [186] OUTSD ; o32 6F [386] `OUTSB' loads a byte from `[DS:SI]' or `[DS:ESI]' and writes it to the I/O port specified in `DX'. It then increments or decrements (depending on the direction flag: increments if the flag is clear, decrements if it is set) `SI' or `ESI'. The register used is `SI' if the address size is 16 bits, and `ESI' if it is 32 bits. If you need to use an address size not equal to the current `BITS' setting, you can use an explicit `a16' or `a32' prefix. The segment register used to load from `[SI]' or `[ESI]' can be overridden by using a segment register name as a prefix (for example, `es outsb'). `OUTSW' and `OUTSD' work in the same way, but they output a word or a doubleword instead of a byte, and increment or decrement the addressing registers by 2 or 4 instead of 1. The `REP' prefix may be used to repeat the instruction `CX' (or `ECX' - again, the address size chooses which) times. automatically generated by info2www version 1.2.2.9 |