Human brains work (mostly) in parallel. Multitasking gives the appearance of parallel processing. Brains and some computers actually do it.
Here is a summary of the basic MIPS programming model. Click on the hyper-links for more details.
Machine Instructions: Machine instructions are thirty-two bits wide. Bit patterns specify the operation, the operands, and the destination for the result. Basic operations are arithmetic, logic, memory access, and control branches.
Machine Cycle: The machine cycle is illustrated at right. Execution proceeds sequentially one instruction at a time. The control point indicates the instruction about to execute. ALU operations never directly access memory.
Thirty-two 32-bit wide general purpose registers,
which have various
$0 is hard-wired to 32 zero-bits.
Memory: Thirty-two bit address space, but only the lower half (most of it anyway) is for user programs. User memory is further divided (by software convention) into text, data, and stack segments.