Addressing Modes
Most instructions allocate six bits to specify an operand. Three bits select one of eight addressing modes, and three bits select one of the eight general registers. The use of three-bit groups made octal notation natural.
In the following sections, each item includes an example of how the operand would be written in assembly language for a hypothetical single-operand instruction with symbol OPR. Rn means one of the registers, written R0 through R7. (Rn) signifies the contents of that register.
Read more about this topic: PDP-11 Architecture
Famous quotes containing the words addressing and/or modes:
“He took up his pen, which seemed to parch like a martyr in his hand. He began to write, nevertheless, addressing the nine-and-ninety lies of the moment he hoped with for a night of saloperie at the side of the twisted strumpet, Fiction, who lasciviously rolled her eyes at him, hiked up her skirt, and beckoned him on.”
—Alexander Theroux (b. 1940)
“There are two modes of transport in Los Angeles: car and ambulance. Visitors who wish to remain inconspicuous are advised to choose the latter”
—Fran Lebowitz (b. 1951)