User:Kublai/Kublai'snotes


 * $$(x+y)^n=\sum_{k=0}^n{n \choose k}x^ky^{n-k}\quad\quad\quad(1)$$

=Computer Studies=

Common skill

 * 1) arithmematic shift left, right = muplite 2, div 2
 * 2) * muplite 8 = shift left, shift left, shift left
 * 3) * muplite 10 = shift left, shift left, shift left, add, add
 * 4) logical shift, routate(cyclic shift), rotate with carry..
 * AND, OR, NOT (for testing) + conditational JUMP instruction
 * 1) Overflow proglem
 * 2) ADC/ADC and SUB/SBB to perform double width registers(carray will be used)
 * MOV, ADD, SUB,
 * MUL, DIV (annoying, digits of value will be changed, alway work with implicit operands, haven't been seen in ALCS PAST paper)
 * 1) hexadecimal arithmetics

Past paper
LEA, indexing instruction
 * 1) 1995 Paper I Q14 (easy) (80x86)
 * 1) 1996 Paper I Q 14 (general version, lots of addressing mode)

CPU
PC, IR, ACC, MAR, MDR, PSW, SR, XR, etc. Machine instruction decoding/encoding 1995 Paper 1 Q14 (80x86 syntax) 1996 Paper 1 Q14 (general syntax) 1997 paper 1 Q14 (general syntax) 1998 Paper 1 Q14 (general syntax) 1999 Paper 1 Q12 (general syntax) 2000 Paper 1 Q11 (*) link with 6.1-6.4 2001 Paper 1 Q13 (general syntax) 2002 Paper 1 Q13 (*) link with 6.1-6.4 2003 Paper 1 Q14 (general syntax) 2004 Paper 1 Q12 (general syntax) strongly recommend 2000 and 2002 for final check up point. Multiplexer
 * CPU structure
 * fetch-decode-execute cycle
 * data bus, address bus, control bus
 * Memory Unit
 * Machine languages
 * addressing modes
 * direct addressing
 * indirect addressing
 * immediate
 * index addressing (offset)
 * relative addressing
 * Past paper
 * Single common bus (only one register can send/receive data)
 * MUX
 * two types of instructions
 * jump, branch (edit the content of PC, from IR to PC)
 * add, sub, muptile, div

cool stuff

 * 1) The assembly process : assembler
 * 2) use of symbol table
 * 3) use of library routines
 * 4) directives(non excutable statements)
 * 5) *examples : var, label, macro, begin, end
 * 6) two passes ammemblers
 * 7) linker and loader

The fundamental Flip-flop

 * RS cross-coupled NOR gates Flip-flop

Basic concept

 * gate
 * NOR
 * NAND
 * trigger (set)
 * postive trigger :send postive signal to set
 * negative trigger : send negative signal to set
 * enable (clock)
 * postive enable :send postive signal to enable the clock
 * negative enable :send negative signal to enable the clock
 * not allow

Steps to slove Flip-flop problems

 * find the fundamental step
 * draw truth table
 * e.g.

examples
2003 section A 4
 * 1) find Q and bar(Q)
 * 2) find trigger type (negative or positive)
 * 3) find enable mode (negative or positive)
 * 4) determine the type of the flip-flop

K-MAP
encirclings can only encompass 2^n fields, where n is an integer ? 0 (1, 2, 3, 4...).

review terms

 * pos(' ',str); {pay attention on the target and source}
 * val;
 * str;
 * copy(str,1,length(str)+999);
 * the copy length can bigger then the actual length of str

find max
max := 1;{max is a index not a value} for i := 2 to total do  if data[i] > data[max] then max := i;
 * set first be the max then check whether other bigger than it

bubble sort
for i := 1 to max-1 do  for j := 1 to max-1 do     if data[j] > data[j+1] then swap(data[j],data[j+1]);

=Physics=

properties of light

 * reversible(stright line ray in, foucs out ====> focus in, stright line ray out)
 * if a object can be formed a image with a convex lens, there are another distance for forming another image.(e.g. MC1992 # 16, notes p3/3)

point light source

 * 1) calculate the image position with the equation
 * 2) all light from the source to the mirror must then shine through the image

name of mirror / lens

 * 1) converging lens = convex lens
 * 2) diverging lens = concave lens


 * 1) converging mirror = concave mirror
 * 2) diverging mirror = convex mirror

how to draw a ray graph

 * consider whether it will be converged or diverged
 * real image ===> invert
 * virtual image ===> upright
 * the bigger height of image is, the longer distance from the lens


 * parallel lines ====> focus plane
 * stright line =====> focus point


 * 1) light rays passing through the optical centre of a lens do not bend.
 * 2) when light rays pass through the focus of a convex lens, the refracted light ray is parallel to the principle axis.