I have to create a small program which carries out the formula and gives the right answer using assembler language with EMU8086 microprocessor emulator. I coded it, there were some errors, I succeed to fix them but the answer which it gives is not correct. I spent a lot of time trying to solve this problem, but unfortunately, unsuccessfully. I need help.
Formula:
y = |x+b| if c = a*x
y = a^2 - 3*b if c < a*x
y = ] (2*c-a) / (c+a*x) [ if c > a*x
][ - means bring out only whole number not remnant.
Set variables:
a=3
b=4
c=6
array x[] = 2,3,1,4,5
array y[] is the answers
So this is the basic point. Here it counts multiplication of a*x and compares the result with variable c. Depending on result it should switch to different calculations.
cikl: ; cycle starts
XOR dx,dx
MOV bx,a ; bx=a
MOV al,x[si]
XOR ah,ah
MUL bx;
JC kl1; overflow
CMP ax,0 ; compare ax with 0
JB f2 ; if a*x < 0 jump to f2
JA f3 ; if a*x > 0 jump to f3
So it should give me this result like this:
x=2 y=6
x=3 y=-3 (overflow error should be here)
x=1 y=1
x=4 y=8
x=5 y=9
But currently it prints this: screenshot
Code:
; task: | x+b | if c= a*x
; a^2 - 3*b if c< a*x
; ] ( 2c-a ) / ( c+ax ) [ if c> a*x
; a=DW b=DB c=DB x=DB y=DW
;
stekas SEGMENT STACK
DB 256 DUP(0)
stekas ENDS
duom SEGMENT
a DW 3;
b DB 4;
c DB 6;
x DB 2,3,1,4,5
kiek = ($-x);
y DW kiek dub(0AAh)
isvb DB 'x=',6 dup (?), ' y=',6 dup (?), 0Dh, 0Ah, '$'
perp DB 'Perpildymas', 0Dh, 0Ah, '$'
daln DB 'Dalyba is nulio', 0Dh, 0Ah, '$'
netb DB 'Netelpa i baita', 0Dh, 0Ah, '$'
spausk DB 'Skaiciavimas baigtas, spausk bet kuri klavisa,', 0Dh, 0Ah, '$'
duom ENDS
prog SEGMENT
assume ss:stekas, ds:duom, cs:prog
pr:
MOV ax, duom ;move data to ax
MOV ds,ax
XOR si,si ; si=0
XOR di,di ; di = 0;
MOV cx,kiek ; cx = kiek
JCXZ pab ; if kiek = 0 jump to the end
cikl: ; cycle starts
XOR dx,dx
MOV bx,a ; bx=a
MOV al,x[si]
XOR ah,ah
MUL bx;
JC kl1; overflow
CMP ax,0 ; compare ax with 0
JB f2 ; if a*x < 0 jump to f2
JA f3 ; if a*x > 0 jump to f3
; part of task: | x+b | if c= a*x
f1:
MOV al, b
MOV dl, x[si]
ADD al, x[si]
JC kl1
JMP re
; a^2 - 3*b if c< a*x
f2:
MOV ax, a
XOR ah, ah
MOV bl, al
MUL bl
JC kl1; overflow
MOV dx, ax
XOR ax, ax
XOR bl, bl
MOV bl, 3
MOV al, b
XOR ah, ah
MUL bl
JC kl1; overflow
SUB dx, ax
XOR ax, ax
MOV ax, dx
JMP re
; ] ( 2c-a ) / ( c+ax ) [ if c> a*x
f3:
MOV al, c
XOR ah, ah
MOV dl, 2
MUL dl
JC kl1; overflow
XOR dl, dl
MOV dx, a
SUB ax, dx
CMP ax, 0
JE kl2; number can be only positive
XOR dl, dl
MOV bx, ax
XOR ax, ax
MOV dx, a ; dx=a
MOV al, x[si]
XOR ah, ah
MUL dx;
JC kl1;overflow
XOR dx, dx
MOV dl, c
ADD ax, dx
JC kl1;overflow
MOV dx, ax
MOV ax, bx
MOV bx, dx
XOR dx, dx
DIV bx
JC kl1
XOR ah, ah
re:
CMP ax, 0 ;does result fit
JE ger
JMP kl3
ger:
MOV y[di], ax
INC si
;INC si
;INC di
INC di
LOOP cikl
pab:
;bring out results to screen
;============================
XOR si, si
XOR di, di
MOV cx, kiek
JCXZ is_pab
is_cikl:
MOV al, x[si] ; number x is in ax reg.
XOR ah,ah
PUSH ax
MOV bx, offset isvb+2
PUSH bx
CALL binasc
MOV ax, y[di]
;XOR ah, ah ; number y is in ax reg.
PUSH ax
MOV bx, offset isvb+11
PUSH bx
CALL binasc
MOV dx, offset isvb
MOV ah, 9h
INT 21h
;============================
INC si
;INC si
iNC di
;INC di
LOOP is_cikl
is_pab:
;===== PAUSE ===================
;===== press any key ===
LEA dx, spausk
MOV ah, 9
INT 21h
MOV ah, 0
INT 16h
;============================
MOV ah, 4Ch ; program ends, come back to OS
INT 21h
;============================
kl1: LEA dx, perp
MOV ah, 9
INT 21h
XOR al, al
JMP ger
kl2: LEA dx, daln
MOV ah, 9
INT 21h
XOR al, al
JMP ger
kl3: LEA dx, netb
MOV ah, 9
INT 21h
XOR al, al
JMP ger
; convert number to decimal and save
; ASCII kode. Parametrai perduodami per steka
; in ASCII code. Parameters pass through stack
; Fist parameter ([bp+6])- converted number
; Second parameter ([bp+4])- place for result
binasc PROC NEAR
PUSH bp
MOV bp, sp
; saving used registers
PUSHA
; Filling line with spaces
MOV cx, 6
MOV bx, [bp+4]
tarp: MOV byte ptr[bx], ' '
INC bx
LOOP tarp
; number is prepared for DIV is 10
MOV ax, [bp+6]
MOV si, 10
val: XOR dx, dx
DIV si
; remnant to ASCII code
ADD dx, '0' ; can be--> ADD dx, 30h
; write number to the end of the line
DEC bx
MOV [bx], dl
; count number of converted symbols
INC cx
; do we need to DIV more ?
CMP ax, 0
JNZ val
POPA
POP bp
RET
binasc ENDP
prog ENDS
END pr
