DATA SEGMENT
    messtr       DB 0Dh, 0Ah, "Hello! Let`s solve piecewise function with your values", 0Dh, 0Ah, "$"
    funct        DB " { x-1, if x < 10", 0Dh, 0Ah, "Z= { (3x^2+4)/(x-2), if x = 10", 0Dh, 0Ah, " { (7x^2-56)/(2x-5), if x > 10", 0Dh, 0Ah, "$"
    xreadmes     DB "Input value of x (range -32767...32767,but correct result for -32767 ... 68) -> $"
    xinmes       DB 7,?, 7 DUP (" ")
    menuhold     DB 2,?, 2 DUP (" ")
    xvalue       DW ?
    out_msg      DB "Result: $"
    newline      DB 0Dh,0Ah,"$"
    err_msg      DB 0Dh, 0Ah, "Invalid input!", 0Dh, 0Ah, "$"
    range_err    DB "Number out of range!", 0Dh, 0Ah, "$"
    overflow_err DB "Calculation overflow occurred!", 0Dh, 0Ah, "$"
    reminder_msg DB " reminder $"
    end_msg      DB "Do you want to continue? (y/n): $"
    result       DW ?
    remainder    DW ?
    numerator    DW ?
    denominator  DW ?
    sign_flag    DB 0
    temp_reg     DW ?
DATA ENDS
STSEG SEGMENT PARA STACK "STACK"
          DB 64 DUP ( "STACK" )
STSEG ENDS
CODE SEGMENT
                         ASSUME CS:CODE, DS:DATA, SS:STSEG
    START:
                         MOV    AX, DATA
                         MOV    DS, AX
                         CALL   WELC_PROC
                         CALL   FUNC
                         CALL   PRINTING
                         CALL   END_PROGRAM
                         MOV    AH, 10
                         INT    21h
WELC_PROC PROC
                         MOV    DX, OFFSET messtr
                         MOV    AH, 9
                         INT    21h
                         MOV    DX, OFFSET funct
                         MOV    AH, 9
                         INT    21h
                         MOV    DX, OFFSET xreadmes
                         MOV    AH, 9
                         INT    21h
                         MOV    DX, OFFSET xinmes
                         MOV    AH, 10
                         INT    21h
                         CALL   CHECK_INPUT
                         MOV    SI, OFFSET xinmes
                         ADD    SI, 2
                         CALL   CONVERT
                         MOV    xvalue, BX
                         MOV    sign_flag, 0
                         RET
WELC_PROC ENDP
CHECK_INPUT PROC
                         MOV    SI, DX
                         MOV    CL, [SI+1]
                         MOV    BL, 0
                         ADD    SI, 2
                         MOV    AL, [SI]
                         CMP    AL, '-'
                         JNE    CHECK_DIGITS
                         MOV    sign_flag, 1
                         INC    SI
                         DEC    CX
                         JZ     INVALID_INPUT
    CHECK_DIGITS:
                         MOV    AL, [SI]
                         CMP    CX, 0
                         JZ     END_CHECK
    CHECK_LOOP:
                         MOV    AL, [SI]
                         CMP    AL, '0'
                         JB     INVALID_INPUT
                         CMP    AL, '9'
                         JA     INVALID_INPUT
                         INC    BL
                         INC    SI
                         DEC    CX
                         JNZ    CHECK_LOOP
                         CMP    BL, 0
                         JZ     INVALID_INPUT
                         JMP    END_CHECK
    INVALID_INPUT:
                         MOV    DX, OFFSET err_msg
                         MOV    AH, 9
                         INT    21h
                         JMP    END_ERROR
    END_ERROR:
                         JMP    START
    END_CHECK:
                         RET
CHECK_INPUT ENDP
CHECK_RANGE PROC
                         CMP    sign_flag, 0
                         JE     CHECK_NEGATIVE
                         NEG    AX
                         CMP    remainder, 0
                         JNE    CHECK_NEGATIVE
                         CMP    DX, 0
                         JNE    RANGE_ERROR
    CHECK_NEGATIVE:
                         CMP    AX, 32767
                         JA     RANGE_ERROR
                         CMP    sign_flag, 0
                         JNE    NEG_N
                         RET
    RANGE_ERROR:
                         MOV    DX, OFFSET newline
                         MOV    AH, 9
                         INT    21h
                         MOV    DX, OFFSET range_err
                         MOV    AH, 9
                         INT    21h
                         CALL   END_PROGRAM
    NEG_N:
                         NEG    AX
                         RET
CHECK_RANGE ENDP
CHECK_RANGE_RESULT PROC
                         MOV    AX, result
                         CMP    AX, -32768
                         JA     RANGE_ERROR_RES
                         CMP    AX, 32752
                         JG     RANGE_ERROR_RES
                         RET
    RANGE_ERROR_RES:
                         MOV    DX, OFFSET newline
                         MOV    AH, 9
                         INT    21h
                         MOV    DX, OFFSET range_err
                         MOV    AH, 9
                         INT    21h
                         JMP    START
CHECK_RANGE_RESULT ENDP
CONVERT PROC
                         XOR    AX, AX
                         XOR    BX, BX
                         PUSH   AX
                         PUSH   BX
                         PUSH   CX
                         PUSH   DX
                         MOV    BX, 0
                         CMP    sign_flag, 1
                         JNE    CONVERT_LOOP
                         INC    SI
                         DEC    CX
    CONVERT_LOOP:
                         MOV    AL, [SI]
                         CMP    AL, '0'
                         JB     CONVERT_END
                         CMP    AL, '9'
                         JA     CONVERT_END
                         SUB    AL, '0'
                         MOV    AH, 0
                         PUSH   AX
                         MOV    AX, BX
                         MOV    CX, 10
                         MUL    CX
                         CMP    DX, 0
                         JNE    OVERFLOW_ERROR
                         MOV    BX, AX
                         POP    AX
                         ADD    BX, AX
                         INC    SI
                         JMP    CONVERT_LOOP
    OVERFLOW_ERROR:
                         MOV    DX, OFFSET newline
                         MOV    AH, 9
                         INT    21h
                         MOV    DX, OFFSET range_err
                         MOV    AH, 9
                         INT    21h
                         JMP    START
    CONVERT_END:
                         CMP    sign_flag, 1
                         JNE    CONVERT_FINISH
                         NEG    BX
    CONVERT_FINISH:
                         MOV    AX, BX
                         CALL   CHECK_RANGE
                         POP    DX
                         POP    CX
                         POP    BX
                         MOV    BX, AX
                         POP    AX
                         RET
CONVERT ENDP
RET_PROC PROC
                         CALL   START
RET_PROC ENDP
FUNC PROC
                         XOR    AX, AX
                         MOV    AX, xvalue

                         CMP    AX, 10
                         JL     CASE_LESS_THAN_10
                         JE     CASE_EQUAL_10
                         JG     CASE_GREATER_THAN_10

    CASE_LESS_THAN_10:
    ; Calculate Z = x - 1
                         MOV    AX, xvalue
                         SUB    AX, 1
                         MOV    result, AX
                         MOV    remainder, 0
                         JMP    END_FUNC

    CASE_EQUAL_10:
    ; Calculate Z = (3x^2 + 4) / (x - 2)
    ; First calculate x^2
                         MOV    AX, xvalue
                         MUL    xvalue                        ; DX:AX = x^2

    ; Calculate 3x^2
                         MOV    BX, 3
                         MUL    BX                            ; DX:AX = 3x^2

    ; Add 4: AX = 3x^2 + 4
                         ADD    AX, 4

                         MOV    numerator, AX

    ; Calculate denominator: (x-2)
                         MOV    BX, xvalue
                         SUB    BX, 2
                         MOV    denominator, BX

    ; Perform division
                         MOV    AX, numerator
                         CWD                                  ; Convert word to double word for division
                         DIV    denominator
                         MOV    result, AX
                         MOV    remainder, DX
                         JMP    END_FUNC

    CASE_GREATER_THAN_10:
    ; Calculate Z = (7x^2 - 56) / (2x - 5)
                         MOV    AX, xvalue
                         MOV    temp_reg, AX                  ; Store x in temp_reg

                         MOV    AX, xvalue
                         MUL    xvalue                        ; DX:AX = x^2

                         CMP    DX, 0
                         JNE    CALC_OVERFLOW

                         CMP    AX, 4681                      ; 4681 = floor(32767 / 7)
                         JG     CALC_OVERFLOW
    ; Calculate 7x^2
                         MOV    BX, 7
                         MUL    BX                            ; DX:AX = 7x^2

    ; Check for overflow
                         CMP    DX, 0
                         JNE    CALC_OVERFLOW

    ; Subtract 56: AX = 7x^2 - 56
                         SUB    AX, 56
                         MOV    numerator, AX

    ; Calculate denominator: (2x-5)
                         MOV    AX, temp_reg                  ; Retrieve x from temp_reg
                         MOV    BX, 2
                         MUL    BX                            ; AX = 2x
                         SUB    AX, 5                         ; AX = 2x - 5
                         MOV    denominator, AX

    ; Check if denominator is 0
                         CMP    AX, 0
                         JE     RANGE_ERROR_FUNC

    ; Perform division - ensure signs are handled correctly
                         MOV    AX, numerator
                         MOV    BX, denominator

    ; Check if numerator is negative
                         CMP    AX, 0
                         JGE    CHECK_DENOM_SIGN

    ; Numerator is negative
                         NEG    AX
                         XOR    SI, SI                        ; SI=0 means positive result initially
                         INC    SI                            ; SI=1 means need to negate result
                         JMP    PERFORM_DIV

    CHECK_DENOM_SIGN:
                         XOR    SI, SI                        ; SI=0 means positive result

    ; Check if denominator is negative
                         CMP    BX, 0
                         JGE    PERFORM_DIV

    ; Denominator is negative
                         NEG    BX
                         INC    SI                            ; Toggle result sign

    PERFORM_DIV:
                         MOV    numerator, AX                 ; Update with absolute values
                         MOV    denominator, BX

    ; Perform division with absolute values
                         CWD                                  ; Convert word to double word for division
                         DIV    BX
                         MOV    result, AX
                         MOV    remainder, DX

    ; Apply sign if needed
                         CMP    SI, 0
                         JE     END_FUNC
                         NEG    result                        ; Negate result if signs were different
                         NEG    remainder                     ; Negate remainder too when result is negative

                         JMP    END_FUNC

    CALC_OVERFLOW:
                         MOV    DX, OFFSET newline
                         MOV    AH, 9
                         INT    21h
                         MOV    DX, OFFSET overflow_err
                         MOV    AH, 9
                         INT    21h
                         JMP    START

    END_FUNC:
                         RET

    RANGE_ERROR_FUNC:
                         MOV    DX, OFFSET newline
                         MOV    AH, 9
                         INT    21h
                         MOV    DX, OFFSET range_err
                         MOV    AH, 9
                         INT    21h
                         JMP    START
FUNC ENDP
PRINTING PROC
                         MOV    DX, OFFSET newline
                         MOV    AH, 9
                         INT    21h
                         MOV    DX, OFFSET out_msg
                         MOV    AH, 9
                         INT    21h
                         MOV    AX, remainder
                         CMP    AX, 0
                         JNE    PRINT_FRACTION
                         MOV    AX, result
                         CMP    AX, 0
                         JGE    PRINT_MAIN_NUMBER
                         MOV    DL, '-'
                         MOV    AH, 2
                         INT    21h
                         MOV    AX, result
                         NEG    AX
    PRINT_MAIN_NUMBER:
                         CALL   PRINT_NUM
                         JMP    END_PRINTING
    PRINT_FRACTION:
                         MOV    AX, numerator
                         CMP    AX, 0
                         JGE    PRINT_NUMERATOR
                         MOV    DL, '-'
                         MOV    AH, 2
                         INT    21h
                         MOV    AX, numerator
                         NEG    AX
    PRINT_NUMERATOR:
                         CALL   PRINT_NUM
                         MOV    DL, '/'
                         MOV    AH, 2
                         INT    21h
                         MOV    AX, denominator
                         CMP    AX, 0
                         JGE    PRINT_DENOMINATOR
                         MOV    DL, '-'
                         MOV    AH, 2
                         INT    21h
                         MOV    AX, denominator
                         NEG    AX
    PRINT_DENOMINATOR:
                         CALL   PRINT_NUM
                         MOV    DL, ' '
                         MOV    AH, 2
                         INT    21h
                         MOV    DL, '='
                         INT    21h
                         MOV    DL, ' '
                         INT    21h
                         MOV    AX, result
                         CMP    AX, 0
                         JGE    PRINT_RES_NUMBER
                         MOV    DL, '-'
                         MOV    AH, 2
                         INT    21h
                         MOV    AX, result
                         NEG    AX
    PRINT_RES_NUMBER:
                         CALL   PRINT_NUM
                         MOV    DX, OFFSET reminder_msg
                         MOV    AH, 9
                         INT    21h
                         MOV    AX, remainder
                         CMP    AX, 0
                         JL     NEG_REM
                         CALL   PRINT_NUM
                         JMP    END_PRINTING
    NEG_REM:
                         MOV    DL, '-'
                         MOV    AH, 2
                         INT    21h
                         MOV    AX, remainder
                         NEG    AX
                         CALL   PRINT_NUM
    END_PRINTING:
                         RET
PRINTING ENDP
PRINT_NUM PROC
                         PUSH   result
                         PUSH   CX
                         PUSH   DX
                         XOR    CX, CX
                         MOV    BX, 10
    CONVERT_TO_STR:
                         XOR    DX, DX
                         DIV    BX
                         ADD    DL, '0'
                         PUSH   DX
                         INC    CX
                         TEST   AX, AX
                         JNZ    CONVERT_TO_STR
    PRINT_LOOP:
                         POP    DX
                         MOV    AH, 2
                         INT    21h
                         LOOP   PRINT_LOOP
                         POP    DX
                         POP    CX
                         POP    result
                         RET
PRINT_NUM ENDP
END_PROGRAM PROC
                         MOV    DX, OFFSET newline
                         MOV    AH, 9
                         INT    21h
                         MOV    DX, OFFSET end_msg
                         MOV    AH, 9
                         INT    21h
                         MOV    DX, OFFSET menuhold
                         MOV    AH, 0Ah
                         INT    21h
                         MOV    AL, menuhold+2
                         CMP    AL, 'y'
                         JE     RETURN
                         CMP    AL, 'n'
                         JE     EXIT_PROGRAM
                         MOV    DX, OFFSET err_msg
                         MOV    AH, 9
                         INT    21h
                         JMP    END_PROGRAM
    EXIT_PROGRAM:
                         MOV    AH, 4Ch
                         INT    21h
    RETURN:
                         XOR    AX, AX
                         XOR    BX, BX
                         XOR    CX, CX
                         XOR    DX, DX
                         XOR    SI, SI
                         MOV    result, 0
                         MOV    remainder, 0
                         MOV    numerator, 0
                         MOV    denominator, 0
                         MOV    sign_flag, 0
                         CALL   RET_PROC
END_PROGRAM ENDP
CODE ENDS
END START