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1 csc250p1 Page 1 1/26 Tuesday, January 26, :17 PM 1 2 a ^15 2^14 2^13 2^12 2^11 2^10 2^9 2^8 2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 2^1+2^2+2^5+2^7+2^9+2^12 = 4,774

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6 csc250p1 Page 6 2/1 Monday, February 01, :35 PM FC = = -983 *3 = -2, /2 = -1474/2 = -737/2 = -368/2 = -184/2 = -92 /2 = /2 = -23 /2 = F47B 3 = = 1011 F47B -7*-8 = = = = 56 Pg 563 Floating point. Always follows IEEE standard. Single Precision = Float = 32 bits Double Precision= 64 bits Double Extended Precision = 80 bits High order bit is sign Single has 8 bits of exponent rest is Fraction (Mantissa) Double has 11 bits of exponent rest Double Extended has 16 bits of exponent rest...

7 csc250p1 Page 7 2/2 Tuesday, February 02, :56 PM Quiz What is FEDC hex as a twos complement decimal number? What is FEDC/2 in hex? F E D C ^2+2^5+2^8 = -292 FFFFFEDC F E D C F F 6 E /2 = FF6E ax is two bytes ah and al or 16 bits Eax is 32 bits (4 bytes) and the lower two bytes are in ax

8 csc250p1 Page Wednesday, February 03, :36 PM Sign bit 0-positive 1 negative 3E5 3*10^5 = 300, * 2^ Significand 4+127

9 csc250p1 Page 9 2/8 Monday, February 08, :29 PM *2^3 Sign = 0 Significand = Exponent = = h = / / / / / / / Sign = 0 Significand = Exponent = = = /3 2/3 1 1/ Sign = 1 Exponent = = 125 Significand = BEAA AAAAh - - C = = /7 BF77AAAA

10 csc250p1 Page 10 2/9 Tuesday, February 09, :18 PM 40B = *2^2 = /8 Report 1 due by midnight 2/25

11 csc250p1 Page 11 2/22 Monday, February 22, :24 PM Mov ebx,0 Cmp eax,0 Je zero Jg greater Less: mov edx,-1 Negloop: ; this loop adds up negative odd numbers until < eax add ebx,edx add edx,-2 cmp eax,edx jge Negloop Zero: mov safeplace,eax print str$(ebx) print " is the sum of the odd numbers between 0 and " print str$(safeplace) inkey exit Greater: mov edx,1 Posloop: add ebx,edx add edx,2 cmp eax,edx jle posloop jmp zero

12 csc250p1 Page 12 2/24 Wednesday, February 24, :58 PM ; multiplies numbers from user till 0 is entered multiplies PROC Mov product,1 ; initial value of product ; loop for input inputloop: ; get number from user Mov ebx,sval(input("enter a number: ")) Mov eax,product ; multiply a new number into the product ; figure out what should be in edx Cmp eax,0 Jl negativeproduct Mov edx,0 ; initialize overflow restofloop: Cmp ebx,0 ; if 0 then done Je done Imul ebx Mov product,eax Jmp inputloop negativeproduct: ; initializes edx when the product is <0 Mov edx,-1 Jmp restofloop Done: ; output result Print str$(product) Print " is the product of the numbers" ret Multiplies ENDPROC If = Cmp Jcond else ; then stuff ; ; end of then stuff Jmp endelse Else: ; else stuff ;. ; end of else stuff endelse:

13 csc250p1 Page 13 3/8 review Monday, March 08, :57 PM Project 2 due 3/ Review CSC 250 exam 1.docx A March Pts: Translate the SWORD A39c to binary and decimal. Show work. Binary: Decimal its negative ( ) = Pts: Give the binary bits for the REAL , what is the hex? Show work /2 = 117 R 0 117/2 = 58 R1 58/2 = 29 R0 29/2 = 14 R1 14/2 = 7 R0 7/2 = 3 R1 3/2 = 1 R1 1/2 = 0 R1 234 = *2 = 0.6 R0.6*2 =.2 R1.2*2 = 0.4 R0.4*2 = 0.8 R0.8*2 =.6 R = *2^ b C36A4CCCh 25 Pts: Write a MASM program that reads SDWORDS from the user until the product is > Store the product in a static variable. Starting with include \masm32\include\masm32rt.inc.data product SDWORD 1 ; holds the product of all user entries.code start: Mov eax, sval(input("enter number: ")) Xor edx,edx ; clear edx Imul product ; multiply user entry by product Mov product, eax ; store product away Cmp eax,1000 Jng start ; if not greater than 1000 keep looping Print str$(product) Print " is the product of the numbers you entered.",13,10 Inkey Exit End start

14 csc250p1 Page Pts: Write a MASM PROC that takes three SDWORD parameters and returns the largest of the three. Largest PROC first :SDWORD second :SDWORD third :SDWORD Mov eax,first ; assume the first is the largest Cmp eax,second Jge stillfirst ; if first is larger then do nothing else store second Mov eax,second stillfirst: Cmp eax,third ; if eax is bigger done otherwise put third in eax Jge notthird Mov eax,third notthird: Ret ; eax has the largest in it now Largest EndP Pasted from <file:///c:\users\public\ncc\class\spring10\csc250\csc%20250%20exam%201.docx>

15 csc250p1 Page 15 3/15 Monday, March 15, :45 PM 0 = sign bit 124 exponent 4/ exponent -3 8/25 r0 16/25 r0 7/25 r1 14/25 r0 3/25 r1 6/25 r0 12/25 r0 24/25 r0 23/25 r1 21/25 r1 17/25 r1 9/25 r1 18/25 r0 11/25 r1 22/25 r0 19/25 r1 13/25 r1 1/25 r1 2/25 r0 4/25 r e23d70a.data Counter SBYTE 0 Product SDWORD 1 Greater = 10 NumberToEnter = 10.code Start: mov al, counter cmp al, NumberToEnter jge done ; if the loop has run enough inc counter ; need count a loop mov eax,sval(input("enter number: ")) cmp eax,greater jng start ; if number is not greater than Greater loop again xor edx,edx ; clear any junk in edx imul Product mov Product,eax ; product is multiplied by user input

16 jmp start Done: print str$(product) print chr$(" is the product of the numbers > ") print str$(greater) print chr$(" that you entered ",13,10) inkey exit End start csc250p1 Page 16

17 csc250p1 Page 17 3/24 Wednesday, March 24, :13 PM Include \masm32\include\masm32rt.inc ; imports all the system stuff.data ; static data lives here N1 sdword 0 ; Integer n1 = 0 N2 sdword 1 ; integer n2 = 1 N3 real ; double n3 = code ; executable lines start here ; void Review(int p1, int p2, double p3) Review PROC USES eax p1:sdword, p2:sdword, p3:real8 LOCAL l: SDWORD ; int l; Finit ; puts the fpu into a clean state Fild p2 ; puts the integer p2 on the stack Fld p3 ; puts the real p3 on the stack Fcom ; compares p3 and p2 Fstsw ax ; puts the result of fcom into ax Sahf ; puts the flags in ah into a place where conditional jumps work Jna found ; if!(p3 > p2) done print cat$(str$(p2)," is less than ") ; output that p2 < p3 print cat$(real8$(p3),chr$(13,10)) Mov eax,p1 ; l = p1+p2 Add eax,p2 Mov l,eax Invoke Review,p2,l,p3 ; recurse with p2 and p1+p2 and p3 unchanged Ret ; just returns after it recurses found: ; base case print cat$(str$(p2)," is greater than ") ; outputs p2 > p3 print cat$(real8$(p3),chr$(13,10)) Ret ; finished recursing Review ENDP Begn: ; code actually starts here Invoke Review,N1,N2,N3 ; call the method inkey ; don't destroy window exit ; execution terminates End Begn ; end of program RangeSize PROC Uses esi ecx, array : PTR Real8, size : SDWORD LOCAL largest : Real8 LOCAL smallest : Real8 finit Mov esi,array fld [esi] Fst largest Fstp smallest Mov ecx,1 ; ecx will index the array

18 csc250p1 Page 18 forloop: Cmp ecx,size Jge finished Fld smallest Fld [esi+8*ecx] Fld largest Fcomp Fstsw ax Sahf Jb newlargest Fcompp Fstsw ax Sahf Jb newsmallest Inc ecx Jmp forloop newlargest: Fld [esi+8*ecx] Fstp largest Inc ecx Jmp forloop newsmallest: Fld [esi+8*ecx] Fstp smallest Inc ecx Jmp forloop Finished: Fld largest Fsub smallest Fstp eax Ret RangeSize EndP Divisible10 proc Uses esi ecx, array:ptr SWORD, size : SDWORD Local ten : SWORD Mov esi, array Mov ecx,0 Mov ten,10 forloop: Mov eax, 0 Mov ax,[esi+2*ecx] Idiv ten Mov ax,0 ; clear ax Cmp eax,0 Jne return0 Inc ecx Cmp ecx size Jge return1 Jmp forloop Return0: Mov eax,0 Ret Return1:

19 csc250p1 Page 19 Mov eax,1 Ret Divisible10 endp InOrder PROC b1 : Byte, b2 : Byte, b3 : Byte Mov eax,b1 Cmp eax,b2 Jg return0 Mov eax,b2 Cmp eax,b3 Jg return0 Mov eax,1 Ret Return0: Mov eax,0 Ret InOrder ENDP Proj 3 due 4/14

20 csc250p1 Page 20 4/12 Monday, April 12, :11 PM mov ax,sword ptr [esi+2*ecx] ; ax = array[ecx] mov sword ptr [esi + 2*ecx], ax ; array[ecx] = ax ; traverse array mov esi,array mov ecx,size lupe: dec ecx jl out ; do something with something ptr [esi+?*ecx] jmp lupe ; traverse array in order Mov esi,array Mov ecx,0 Lupe: Cmp ecx,size Jge out ; do something with something ptr [esi+?*ecx] Inc ecx jmp lupe Fldz ; puts 0 on floating pt stack. Xor eax,eax ; eax = 0 Mov ax,sword ptr [esi+2*ecx] Imul product Mov product,eax

21 alphastring PROC Uses esi, b1 : BYTE, b2 : BYTE, array : PTR BYTE Mov esi,array mov al,b1 Lupe: cmp al,b2 jg Out mov BYTE PTR [esi],al inc esi inc al Jmp Lupe Out: mov BYTE PTR [esi],0 ret alphastring ENDP csc250p1 Page 21