Assembly language recursive program example

Assembly language recursive program computes N!

DSEG SEGMENT
    N DW 5             ;compute N!
    RESULT DW ?  
DSEG ENDS

SSEG SEGMENT
    DW 128 DUP(0)
    TOS LABEL WORD
SSEG ENDS

CSEG SEGMENT
MAIN PROC FAR
    ASSUME CS:CSEG,DS:DSEG,SS:SSEG
START1:
    MOV AX,SSEG
    MOV SS,AX
    MOV SP,OFFSET TOS 



    MOV AX,DSEG
    MOV DS,AX

    MOV BX,N
    PUSH BX
    CALL FACT
    POP RESULT
    MOV AH,4CH
    INT 21H
MAIN ENDP

FACT PROC NEAR
    PUSH AX
    PUSH BP
    MOV BP,SP
    MOV AX,[BP+6]
    CMP AX,0     
    JNE FACT1
    INC AX
    JMP EXIT

FACT1:
    DEC AX
    PUSH AX
    CALL FACT   ;递归调用
    POP AX
    MUL WORD PTR [BP+6]

EXIT:
    MOV [BP+6],AX
    POP BP
    POP AX
    RET

FACT ENDP

CSEG ENDS
   END MAIN