TITLE Reading characters, strings, and integers  (input.asm)

; Testing Following Procedures in the assembly32.lib Library:
; ReadChar:     Read a single character from standard input
; ReadString:   Read a null-terminated string from standard input
; ReadHex:      Read hexadecimal integer from standard input
; ReadInt:      Read signed decimal integer from standard input

.686
.MODEL flat, stdcall
.STACK

INCLUDE Irvine32.inc

.data

charvar     BYTE    0           ; Character variable
string      BYTE    21 DUP(0)   ; Extra byte for null char
bytecount   DWORD   0           ; Count of bytes read in string
hexvar      DWORD   0           ; Unsigned integer variable
intvar      SDWORD  0           ; Signed integer variable

prompt1     BYTE    "Enter a character (char will not appear): ",0
prompt2     BYTE    "Enter a string (max 20 chars): ",0
prompt3     BYTE    "Enter a hexadecimal number (max 8 digits): ",0
prompt4     BYTE    "Enter a decimal number with optional sign: ",0


.code
main PROC
    call Clrscr

; Display prompt1
    lea  edx, prompt1
    call WriteString
; Read a character (without echo) from standard input
    call ReadChar           ; character is returned in AL
    mov  charvar, al        ; save character in charvar
    call Crlf               ; Write end-of-line after reading character

; Display prompt2
    lea  edx, prompt2
    call WriteString
; Read a null-terminated string from standard input
    lea  edx, string        ; edx = address of storage area for string
    mov  ecx, SIZEOF string ; ecx = max characters to be stored
    call ReadString         ; read string from standard input
    mov  bytecount, eax     ; eax = actual number of chars read

; Display prompt3
    lea  edx, prompt3
    call WriteString
; Read a hexadecimal string and convert it to a number
    call ReadHex            ; number is returned in EAX register
    mov  hexvar, eax        ; save number in hexvar

; Display prompt4
    lea  edx, prompt4
    call WriteString
; Read a signed decimal string and convert it to a number
    call ReadInt            ; number is returned in EAX register
    mov  intvar, eax        ; save number in intvar

    exit
main ENDP
END main