logic instruction การใช้

For instance, a modern CPU typically has two or three functional units dedicated to processing integer data and logic instructions, known as FPUs, or multimedia data, SIMD . MAJC instead used a single multi-purpose functional unit which could process any sort of data.
The same ALU that is used to execute arithmetic and logic instructions is also used to calculate effective addresses . ( There is a separate adder for adding a shifted segment register to the offset address, but the offset EA itself is always calculated entirely in the main ALU . ) Furthermore, the loose coupling of the EU and BIU ( bus unit ) inserts communication overhead between the units, and the four clock period bus transfer cycle is not particularly streamlined . ( Contrast the two clock period bus cycle of the 6502 CPU and the 80286's three clock period bus cycle with pipelining down to two cycles for most transfers . ) Most 8088 instructions that can operate on either registers or memory, including common ALU and data-movement operations, are at least four times slower for memory operands than for only register operands.