;=============================================================================
;                               crypt03.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
LOCALS @@
;=============================================================================
; Data definition/declaration
;=============================================================================
.DATA
;-----------------------------------------------------------------------------
; Equals
;-----------------------------------------------------------------------------
SPACE EQU 20H                   ;
;-----------------------------------------------------------------------------
; Constants
;-----------------------------------------------------------------------------
CRLF    DB      0DH,0AH,'$'
A_STR   DB      "A   ",'$'
FILENAME: DB    "CIPHER.TXT",0
HEADER DB "     F : I    2    3    -    3    2    E",'$'
OFF_2 DW OFFSET FIRST,OFFSET SECOND,OFFSET THIRD,OFFSET OTHER,OFFSET THIRDL
      DW OFFSET SECONDL,OFFSET LAST
;-----------------------------------------------------------------------------
; File variables
;-----------------------------------------------------------------------------
BUFFER DB 26 DUP(?)
HFILE  DW ?
TOT    DB ?                     ;
FIRST  DB 26 DUP(?)             ;
SECOND DB 26 DUP(?)             ;
THIRD  DB 26 DUP(?)             ;
OTHER  DB 26 DUP(?)             ;
THIRDL DB 26 DUP(?)             ;
SECONDL  DB 26 DUP(?)           ;
LAST   DB 26 DUP(?)


;-----------------------------------------------------------------------------
; Stack variables
;-----------------------------------------------------------------------------


.CODE
.386
ORG 100H
;=============================================================================
; Code segment
;=============================================================================
CUR_BYT1 EQU [BP-1]
START:
        ENTER 1,0              ; Allocate space for filename
        CALL SHOW_HEADER
        MOV DI,-1               ; 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
C5:                             ;
        CALL SHOW_LETTER
	PUSH BX
	MOV AH,02H		;
	MOV DL,20H		;
	INT 21H			;
	MOV DL,':'		;
 	INT 21H			;
	MOV DL,20H		;
	INT 21H
        CALL SHOW_FREQ
	POP BX
        CMP BX,25               ;
        JL  C5
C6:                             ;
        MOV AH,09H
        MOV DX,OFFSET CRLF      ;
        INT 21H                 ;
	MOV AH,02H		;
	MOV DL,20H		;
	INT 21H			;
	INT 21H			;
	INT 21H
	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
	XOR SI,SI
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]
        CALL CALC_FREQ
	INC SI
        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     ;
	MOV FIRST[BX-1],00	;
	MOV SECOND[BX-1],00	;
	MOV THIRD[BX-1],00
	MOV OTHER[BX-1],00	;
	MOV THIRDL[BX-1],00	;
	MOV SECONDL[BX-1],00	;
	MOV LAST[BX-1],00
        DEC BX                  ;
        JNZ L1                  ;
                        ;
        POPA
        RET
CLEAR ENDP
;-------------------------------------------------------------------------------
;                                   HEXDEC
; Convert the hexadecimal value in al to ascii and output it. 
; 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  
    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
;-----------------------------------------------------------------------------
;                               Show_Letter
; Show the letter and number of appearences
;                               Algorithm
; S1: Check if it appears at all.
; S2: Jump line
; S3: Update the string to show
; S4: Show the string
; S5: Convert and show the number of appearences
;
;-----------------------------------------------------------------------------
SHOW_LETTER PROC                ;
@@S1:				;
	INC BX

        CMP BUFFER[BX],0        ;
        JZ @@S1  
	PUSH BX
@@S2:
        MOV AH,09H              ;
        MOV DX,OFFSET CRLF      ;
        INT 21H
@@S3:
        PUSH BX
        ADD BL,'A'
        MOV A_STR[0],BL
        POP BX                  ;
@@S4:
        MOV DX,OFFSET A_STR     ;
        INT 21H
@@S5:
        MOV AL,BUFFER[BX]
        XOR AH,AH               ;
        CALL HEXDEC
@@EXIT:				;
	POP BX
        RET
SHOW_LETTER ENDP
;-----------------------------------------------------------------------------
;                                 Show_Freq
; Show the letter position frequencies
;                                 Algorithm
; S1: Check if empty
; S2: Show value
; S3:
;
;
;-----------------------------------------------------------------------------
SHOW_FREQ PROC			;
	MOV DI,BX
	PUSH BX
	MOV BX,-1
@@S1:				;
 	INC BX	
	PUSH BX
	SHL BX,1
        MOV BX,OFF_2[BX]
@@S2:
	MOVZX AX,[BX][DI]
        CALL HEXDEC		;
	MOV AH,02H		;
	MOV DL,20H		;
	INT 21H			;
	INT 21H			;
	INT 21H
        POP BX			;
	CMP BX,6		;
	JL @@S1
@@EXIT:				;
	POP BX
        RET			;
SHOW_FREQ ENDP
;-----------------------------------------------------------------------------
;                               Calc_freq
; Calculate the letter position
; Â× - index in the buffer
; SI - index of the letter
;                               Algorithm
; C1: Check if it is first,second or third letter
; C2: Save the current file pointer position
; C3: Check if these are last letters
; C4: Increment other[letter]
; C5: 
;
;-----------------------------------------------------------------------------
CALC_FREQ PROC                  ;
@@CUR_BYTE EQU [BP-1]
@@TEMP EQU [BP-3]
@@SHORT EQU [BP-4]
	ENTER 4,0		;
	MOV @@SHORT,0
@@C1:
	PUSH SI
        PUSH BX
	MOV BX,SI
        CMP BX,3               ;
        JGE @@C2
        SHL BX,1		;
        JMP OFF_1[BX]
REACT_1:                        ;
	POP BX			;
	INC @@SHORT  
        INC FIRST[BX]           ;
	PUSH BX
        JMP @@C2  
REACT_2:	
        POP BX			;
        INC @@SHORT  
        INC SECOND[BX]          ;
	PUSH BX
        JMP @@C2                ;
REACT_3:			;
	POP BX			;
	INC @@SHORT  
        INC THIRD[BX]           ;
	PUSH BX
        JMP @@C2  
@@C2:
        MOV SI,-1          ;
	MOV AH,42H
	MOV BX,HFILE
	MOV AL,1H		;
	XOR CX,CX		;
	XOR DX,DX		;
	INT 21H			;
	MOV @@TEMP,AX
@@C3: 				;
	INC SI
	MOV AH,3FH		;
 	MOV BX,HFILE		;
	MOV CX,1		;
	LEA DX,@@CUR_BYTE	;
	INT 21H			;
	MOV AH,CUR_BYTE		;
	MOV BX,SI
	CMP AH,20H		;
	JZ JUMP     
	CMP SI,2		;
 	JL @@C3			;
	JMP @@C4
JUMP:				;
	SHL BX,1
	JMP OFF_3[BX]
REAC_1:				;
	POP BX
	INC LAST[BX]		;
	JMP @@C5  
REAC_2:				;
	POP BX			;
	INC SECONDL[BX]		;
	JMP @@C5  
REAC_3:
	POP BX			;
	INC THIRDL[BX] 
	JMP @@C5  
@@C4:				;
;MOV DX,@@TEMP
;MOV AH,42H		;
;MOV BX,HFILE		;
;XOR CX,CX		;
;XOR AL,AL
;INT 21H			;
	POP BX
	MOV AH,@@SHORT
	CMP AH,1      	 
	JZ @@C5  
	INC OTHER[BX]
;JMP @@EXIT
@@C5:				;
	MOV DX,@@TEMP
	MOV AH,42H		;
	MOV BX,HFILE		;
	XOR CX,CX		;
	XOR AL,AL
	INT 21H
@@EXIT:				;
	POP SI
	LEAVE
        RET
OFF_1 DW OFFSET REACT_1,OFFSET REACT_2,OFFSET REACT_3
OFF_3 DW OFFSET REAC_1,OFFSET REAC_2,OFFSET REAC_3

CALC_FREQ ENDP
;-----------------------------------------------------------------------------
;                               Show_header
; Show header
;
;-----------------------------------------------------------------------------
SHOW_HEADER PROC                ;
        MOV AH,09H              ;
        MOV DX,OFFSET HEADER    ;
        INT 21H
	MOV DX,OFFSET CRLF	;
	INT 21H
        RET
SHOW_HEADER ENDP
END START