G ddr ddr2 ddr3 improving performance 2 move less data

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: he which the instrucGon operates must be fetched from memory and brought to the CPU   CPU < ­> Memory bandwidth can limit performance   Improving performance 1: hardware improvements to increase memory bandwidth (e.g., DDR → DDR2 → DDR3)   Improving performance 2: move less data into/out of the CPU   Put some “memory” in the CPU chip itself (this is “cache” memory) Memory 8 University of Washington Binary RepresentaJons   Base 2 number representaJon   Represent 35110 as 00000001010111112 or 1010111112   Electronic implementaJon   Easy to store with bi ­stable elements   Reliably transmiWed on noisy and inaccurate wires 0 1 0 3.3V 2.8V 0.5V 0.0V Memory 9 University of Washington Memory, Data, and Addressing           Preliminaries RepresenJng informaJon as bits and bytes Organizing and addressing data in memory ManipulaJng data in memory using C Boolean algebra and bit ­level manipulaJons Memory 10 University of Washington Encoding Byte Values   Binary 000000002  ­ ­ 111111112   Byte = 8 bits (binary digits)   Example: 001010112 = 32+8+2+1 = 4310   Example: 2610 = 16+8+2 = 001010102     Decimal 010  ­ ­ 25510 Hexadecimal 0016  ­ ­ FF16           Groups of 4 binary digits Byte = 2 hexadecimal (hex) or base 16 digits Base ­16 number representaGon Use characters ‘0’ to ‘9’ and ‘A’ to ‘F’ Write FA1D37B16 in C   as 0xFA1D37B or 0xfa1d37b Memory 0 1 2 3 4 5 6 7 8 9 A B C D E F 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 11 University of Washington What is memory, really?   How do we find data in memory? Memory 12 University of Washington Byte ­Oriented Memory OrganizaJon ••• !   Programs refer to addresses   Conceptually, a very large array of bytes, each with an address (index)   System provides an address space private to each “process”         Process = program being executed + its data + its “state” Pro...
View Full Document

This document was uploaded on 04/04/2014.

Ask a homework question - tutors are online