Instruction Set
The PDP-11 operates on bytes and words. Bytes are specified by a register number—identifying the register's low-order byte—or by a memory location. Words are specified by a register number or by the memory location of the low-order byte, which must be an even number. In most instructions that take operands, bit 15 is set to specify byte addressing, or clear to specify word addressing. In the lists in the following two sections, the assembly-language programmer appended B to the instruction symbol to specify a byte operation; for example, MOV became MOVB.
Read more about this topic: PDP-11 Architecture
Famous quotes containing the words instruction and/or set:
“And, fathers, do not provoke your children to anger, but bring them up in the discipline and instruction of the Lord.”
—Bible: New Testament, Ephesians 6:4.
“The apple tree has been celebrated by the Hebrews, Greeks, Romans, and Scandinavians. Some have thought that the first human pair were tempted by its fruit. Goddesses are fabled to have contended for it, dragons were set to watch it, and heroes were employed to pluck it.”
—Henry David Thoreau (1817–1862)