ECE344H1 Lecture Notes - Lecture 2: Instruction Register, Memory Address, Memory Controller
20 Dec 2018
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Reading: book chapter 1. 1-1. 4: overview of h/w. Os manages h/w, so lets provide an overview of h/w. Cpu executes instructions for a set of instructions. Program counter (pc): holds memory address of next instruction. Instruction register (ir): holds instruction currently being executed. Stack pointer (sp): holds address of memory for accessing stack. Processor status word (psw): control bits that affect program execution. Pc = ; while (halt_flag not set) { Pc = pc + 1; execute(ir); // decode & execute uses registers: memory. Unit of memory can be byte, word, block, page. Each word has a unique address by which it can be named. Nr. of bits that represent address is called the address width. Value = read(address), returns last value written. Devices are separate from cpu and connected to device-specific controllers. Communicate with cpu over a common bus. Device controllers provide a simple hardware interface to devices. Each device has a range of bus addresses.
