Description

Semester: V

Experiment No. 9: Floating point operations

9a) Floating point addition

Input: 2 floating point numbers
Output: Sum of floating point numbers

Program

ASSUME CS:CODESEG, DS:DATASEG ; ————————————————————–
DATASEG SEGMENT ; start of data segment
ORG 00H ; directive to assign an offset address for a variable
X DD 20.4375
ORG 10H
Y DD 20.4375
ORG 20H
SUM DD ?
DATASEG ENDS ; end of data segment
; ————————————————————–
CODESEG SEGMENT ; start of code segment
start: MOV AX,DATASEG ; load the data segment address
MOV DS,AX ; assign value to DS
FINIT ; initialize 8087 stack
FLD X ; load X into ST(0)
FLD
Y ; load Y into ST(0)
FADD
ST(0),ST(1) ; ST(0) = X+Y
FST
SUM ; store ST(0) in sum
MOV AH,4CH ; setup function-4C of the int21
INT 21H ; call BIOS int21 to return to DOS
CODESEG ENDS ; end of code segment
END START

9b) Floating point subtraction

Input: 2 floating point numbers
Output: difference of floating point numbers

Program

ASSUME CS:CODESEG, DS:DATASEG ; ————————————————————–
DATASEG SEGMENT ; start of data segment
ORG 00H ; directive to assign an offset address for a variable
X DD 20.4375
ORG 10H
Y DD 0.125
ORG 20H
SUM DD ?
DATASEG ENDS ; end of data segment

; ————————————————————–

CODESEG
SEGMENT ; start of code segment
start: MOV AX,DATASEG ; load the data segment address
MOV
DS,AX ; assign value to DS
FINIT ; initialize 8087 stack
FLD Y ; load X into ST(0)
FLD
X ; load Y into ST(0)
FSUB
ST(0),ST(1) ; ST(0) = X+Y
FST
SUM ; store ST(0) in sum
MOV AH,4CH ; setup function-4C of the int21
INT 21H ; call BIOS int21 to return to DOS

CODESEG ENDS ; end of code segment
END START