;=============================================================================
;                               crypt01.asm
; This program takes ciphertext from crypt.txt and then calculates the
; frequencies of the letters and outputs on screen.
;                               Algorithm
; C1: Open file
; C2: Find next word
; C3: Read symbols in word and put number into buffer
; C4: Show the buffer
; C5: Show total number of characters
;(C)I don't take any responsibility for the use of this program
;                           Zedr0n -- connection closed
;=============================================================================
;=============================================================================
; .Com declaration
;=============================================================================
.MODEL TINY
;=============================================================================
; Data definition/declaration
;=============================================================================
.DATA
;-----------------------------------------------------------------------------
; Equals
;-----------------------------------------------------------------------------
SPACE EQU 20H                   ;
;-----------------------------------------------------------------------------
; Constants
;-----------------------------------------------------------------------------
CRLF    DB      0DH,0AH,'$'
A_STR   DB      "A - ",'$'
FILENAME: DB	"CIPHER.TXT",0 
TOTAL DB 	"Total number of chars - ",'$'
  
;-----------------------------------------------------------------------------
; File variables
;-----------------------------------------------------------------------------
BUFFER DB 26 DUP(?)
HFILE  DW ?
TOT    DB ?
;-----------------------------------------------------------------------------
; Stack variables
;-----------------------------------------------------------------------------


.CODE
.386
ORG 100H
;=============================================================================
; Code segment
;=============================================================================
CUR_BYT1 EQU [BP-1]
START:
        ENTER 1,0              ; Allocate space for filename
        DEC DI                  ; DI is assumed to be 0
C1:
        MOV AH,3DH              ;
        XOR AL,AL               ; Set the read only mode
        XOR CL,CL               ;
        LEA DX, FILENAME
        INT 21H
        OR AX,AX                ;
        JZ EXIT
        MOV HFILE,AX
        CALL CLEAR
C2:                             ;

        CALL FINDWORD   ;
C3:                             ;
        CALL GETSYM            ;
        MOV AH,3FH              ;
        MOV BX,HFILE            ;
        MOV CX,1                ;
        LEA DX,CUR_BYT1
        INT 21H                 ;
        MOV AH,BYTE PTR CUR_BYT1;
        CMP AH,'@'              ;
        JZ  C4                  ;
	JMP C2
C4:				;
	CALL CALC_TOTAL		;
	MOV TOT,AL
	MOV BX,-1
C41:
    inc bx
    cmp bx,26
    jz C5
    cmp BUFFER[bx],0
    jz C41

    mov ah,09h
    mov dx,offset CRLF
    int 21h

    push bx
        add bl,41h
        mov A_str[0],bl
    pop bx

    mov dx,offset A_str
    int 21h

    mov al,BUFFER[bx]
    xor ah,ah
	CALL HEXDEC
    jmp C41
C5:				;
	MOV AH,09H
	MOV DX,OFFSET CRLF	;
	INT 21H			;
	MOV DX,OFFSET TOTAL	;
	INT 21H
	MOV AL,TOT
	CALL HEXDEC
EXIT:	
        LEAVE
        RET
;===============================================================================
;                                    Procedures
;===============================================================================
;-----------------------------------------------------------------------------
;                                   FindWord
; Find the next word in the file
;                                   Algorithm
;
; F1: Read the byte.
; F2: Check if it is space, or end of line, if it isn't then it was the
;           beginning of the new word
; F3: Decrease pointer
;-----------------------------------------------------------------------------
FindWord proc
cur_byte      equ   [bp-1]
    enter 1,0
    pusha
F1:
    mov ah,3Fh
    mov bx,HFILE
    mov cx,1
    lea dx,cur_byte
    int 21h
F2:
    mov ah,cur_byte
    cmp ah,SPACE
    jz F1
    cmp ah,0Dh
    jz F1
    cmp ah,0Ah
    jz F1
F3:
    mov ah,42h
    mov al,1
    xor cx,cx
    xor dx,dx
    int 21h

    mov dx,ax
    mov ah,42h
    xor al,al
    xor cx,cx
    dec dx

    int 21h
    popa
    leave
    ret
FindWord endp
;-----------------------------------------------------------------------------
;                                   GetSym
; G1: Read char
; G2: Is it space, or new line? If not read another!
;-----------------------------------------------------------------------------
GETSYM PROC                     ;
CUR_BYT EQU     [BP-1]          ;
        ENTER 1,0               ;
        PUSHA

G1:                             ;
        MOV AH,3FH              ;
        MOV CX,1
        MOV BX,HFILE            ;
        LEA DX,CUR_BYT          ;
        INT 21H
        MOVZX BX,BYTE PTR CUR_BYT
G2:                             ;
        CMP BX,SPACE            ;
        JZ G3
        CMP BX,0DH              ;
        JZ G3                   ;
        CMP BX,0AH              ;
        JZ G3
        AND BX,5FH              ;
	CMP BX,'A'		;
	JL G1		;
	CMP BX,'Z'		;
	JG G1
        SUB BX,'A'              ;
        INC BUFFER[BX]
        JMP G1
G3:
        POPA
        LEAVE
        RET
GETSYM ENDP
;-----------------------------------------------------------------------------
;                                    CLEAR
; Clear the buffer
;                                  Algorithm
; L1:
; L2:
;-----------------------------------------------------------------------------
CLEAR PROC                      ;
        PUSHA
        MOV BX,26               ;
L1:
        MOV BUFFER[BX-1],00     ;
        DEC BX                  ;
        JNZ L1                  ;
                        ;
        POPA
        RET
CLEAR ENDP
;--------------------------------------------------------------------------------------------------------------------------------------------
;                                                                   HEXDEC
; Convert the hexadecimal value in al to ascii and output it. Show a colon also...
; H1: Get the number of 10's
; H2: Show the digit
; H3: Is it seconds? If not go H7
; H4: Show colon!
; H5: exits
;--------------------------------------------------------------------------------------------------------------------------------------------
HEXDEC proc
    mov dl,30h
H1:
    push dx
H2:
    cmp al,10
    JL H3          ;jl H3. Otherwise 2 nop's are inserted
    sub al,10
    inc dx          ; shorter than inc dl, but in this case does just the same
    jmp H2
H3:
    mov ah,02h
    push ax
    int 21h

    pop ax
    pop dx

    add dl,al
    int 21h
H4:
    ret
HEXDEC endp
;-----------------------------------------------------------------------------
; 				    CALC_TOTAL
; Calculate total number of chars
;-----------------------------------------------------------------------------
CALC_TOTAL PROC			;
	MOV BX,26		;
	XOR AL,AL
T1:
	ADD AL,BUFFER[BX-1]
	DEC BX			;
	JNZ T1
	RET
			;
CALC_TOTAL ENDP

END START