asked on

CALL getC

I use call getc to read in a character from the keyboard in a label called reads1, which test if the character is lowecase or uppercase. a label isUPPER & isLOWER display messages.

I have in my lecture notes JE (Jump if equal) - a code for testing equality. How does this check if the characters read from the keyboard is uppercase or lowecase?

.MODEL      SMALL
.STACK      100h

.DATA

bdos      EQU 21H
cr      EQU 0DH
lf      EQU 0AH

enter1      DB      'Enter a character $'
UPPER DB      ' The character is uppercase $'
LOWER DB      ' The character is lowercase $'
NUMERIC DB      ' The character is numeric $'
NEITHER DB       ' The character is not lowercase, uppercase or numeric $'

.CODE

INCLUDE ioproc.asm

start:
      MOV AX,@data
      MOV DS,AX
      CALL newline

reads1:
      MOV DX,OFFSET(enter1)
      MOV AH,09H
      INT bdos
      CALL newline

      CALL getc
      CMP AL,cr
      JE isUPPER
      ;CMP AL,cr
      ;JE isLOWER

      MOV DX,OFFSET(NEITHER)
      MOV AH,09H
      INT bdos
      CALL newline
      JMP reads1

isUPPER:
      MOV DX,OFFSET(UPPER)
      MOV AH,09H
      INT bdos
      CALL newline
      JMP reads1

isLOWER:
      MOV DX,OFFSET(LOWER)
      MOV AH,09H
      INT bdos
      CALL newline
      JMP reads1

isNUMERIC:
      MOV DX,OFFSET(NUMERIC)
      MOV AH,09H
      INT bdos
      CALL newline
      JMP reads1

isNEITHER:
      MOV DX,OFFSET(NEITHER)
      MOV AH,09H
      INT bdos
      CALL newline
      JMP reads1

finish:
      CALL newline
      MOV AX,4C00H
      INT bdos
      END start

manish_regmi

hi,
You can check if character is greater than 64 and smaller than 91, it is upper case and if
it is greater than 96 and smaller than 126.

/* check if the character in al is in upper case */
cmp al, 64
ja chk2 /* if above */
; not in upper case

chk2:

cmp al, 91
jb upper /* if below */

upper:
;print upper /* It is in upper case */

similarly do for lower case,
cmp al, 96
ja chk2 /* if above */
; not in upper case

chk2:

cmp al, 126
jb upper /* if below */

upper:
;print lower /* it is in lower case */

joghurt

As a note, in most compilers you can use characters constants to make the source more human-readable.

/* check if the character in al is in upper case */
cmp al, 'A'
jge chk2 /* if greater or equal */
; not in upper case

chk2:

cmp al, 'Z'
jl upper /* if less */

upper:
;print upper /* It is in upper case */

similarly do for lower case,
cmp al, 'a'
jge chk2 /* if greater or equal */
; not in upper case

chk2:

cmp al, 'z'
jl upper /* if less */

upper:
;print lower /* it is in lower case */

gbilios

ASKER

For the reply. i added the code and tested it. I get a the same result if i read in a lowercase or uppercase. Have i got it right?

reads1:
      MOV DX,OFFSET(enter1)
      MOV AH,09H
      INT bdos
      CALL newline

      CALL getc
      CMP AL,cr
      CMP AL,64
      JA isLOWER

      ;CMP AL,91
      ;JB isUPPER
      ;CMP AL,cr
      ;JE isLOWER

      MOV DX,OFFSET(NEITHER)
      MOV AH,09H
      INT bdos
      CALL newline
      JMP reads1

isUPPER:
      MOV DX,OFFSET(UPPER)
      MOV AH,09H
      INT bdos
      CALL newline
      JMP reads1

isLOWER:
      MOV DX,OFFSET(LOWER)
      MOV AH,09H
      INT bdos
      CALL newline
      JMP reads1

manish_regmi

hi,
Do it this way.
reads1:
MOV DX,OFFSET(enter1)
MOV AH,09H
INT bdos
CALL newline

CALL getc
; CMP AL,cr
CMP AL,64
JA isUPPER
cmp al, 96
ja isLOWER

;CMP AL,91
;JB isUPPER
;CMP AL,cr
;JE isLOWER

MOV DX,OFFSET(NEITHER)
MOV AH,09H
INT bdos
CALL newline
JMP reads1

isUPPER:
cmp al, 91
ja goend
MOV DX,OFFSET(UPPER)
MOV AH,09H
INT bdos
CALL newline
JMP reads1

isLOWER:
cmp al, 126
ja goend
MOV DX,OFFSET(LOWER)
MOV AH,09H
INT bdos
CALL newline
JMP reads1
goend:
end

regards manish

gbilios

ASKER

If i wanted to test if the character was a numeric type, then would I use the following:

CALL getc
CMP AL,cr

CMP AL,9
JB isNUMERIC

manish_regmi

no,
check for the ascii value
0= 48,

cmp al, 47
ja chk2

chk2:
cmp al, 58
ja end
print it is numeric.

in short numeric value is fro 48 to 57.

regards manish

gbilios

ASKER

Not sure why the isNumeric is overriden. i tested it on its own and works but not with the code below.

reads1:
      MOV DX,OFFSET(enter1)
      MOV AH,09H
      INT bdos
      CALL newline

      CALL getc
      CMP AL,cr

      CMP AL,96
      JA isLOWER

      CMP AL,126
      JB isUPPER

      CMP AL,58
      JB isNumeric
;else
      MOV DX,OFFSET(NEITHER)
      MOV AH,09H
      INT bdos
      CALL newline
      JMP reads1

ASKER CERTIFIED SOLUTION

manish_regmi

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial