EX1 1.3.17

.MODEL SMALL
.STACK 100h
.DATA
fibo0   DD ?
fibo1   DD ?
fibo2   DD ?
i       DW ?
index   DW ?
res     DD ?
.CODE
.386
;extern unsigned long int find_largest_fibo(unsigned long int n, unsigned int *index)
;                                                       [BP+4]          [BP+8]
PUBLIC _find_largest_fibo
_find_largest_fibo PROC NEAR
    PUSH BP
    MOV BP,SP

    ;FIBO0=FIBO1=FIBO2=1
    MOV EAX,1
    MOV fibo0, EAX
    MOV fibo1, EAX
    MOV fibo2, EAX

    ;i=0
    XOR AX,AX
    MOV i,AX

    ;EBX=n=[bp+4]
    MOV EBX, DWORD PTR [BP+4]

    ;for(i=0;n>=fibo2;i++)
    JMP checkn
myLoop:
    ;fibo2=fibo1+fibo0
    MOV EAX, fibo0
    ADD EAX, fibo1
    MOV fibo2, EAX
    ;fibo0=fibo1
    MOV EAX, fibo1
    MOV fibo0, EAX
    ;fibo1=fibo2
    MOV EAX, fibo2
    MOV fibo1, EAX
    INC i
checkn:
    CMP EBX, fibo2
    JAE myLoop

    MOV DI, WORD PTR[BP+8]
    MOV AX, i
    MOV [DI], AX

    PUSH fibo0
    POP AX
    POP DX

    POP BP
    RET
    _find_largest_fibo ENDP

;extern unsigned long int compute_fibo_code(unsigned long int n);
;                                                   [BP+4]
PUBLIC _compute_fibo_code
_compute_fibo_code PROC NEAR
    PUSH BP
    MOV BP, SP

    MOV EBX, DWORD PTR [BP+4]

    JMP check
whileLoop:

    PUSH OFFSET index
    PUSH EBX
    CALL _find_largest_fibo
    ADD SP, 6
    PUSH DX
    PUSH AX
    POP EAX

    ;n-=eax
    SUB EBX, EAX

    ;adding bit indexed "i" to result
    XOR EAX,EAX
    INC EAX
    MOV CX, index
    SHL EAX, CL
    ADD res, EAX

check:
    CMP EBX,0
    JA whileLoop

    PUSH res
    POP AX
    POP DX

    POP BP
    RET
    _compute_fibo_code ENDP
    END