Fibonacci sequence: Difference between revisions
→{{header|8086 Assembly}}
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JNZ LOOP ; jump if not zero
RET ; return from subroutine</lang>
=={{header|8086 Assembly}}==
Is it cheating to write it in C for 64-bit x86 then port it to 16-bit x86?
The max input is 25 before you start having 16-bit overflow.
<lang asm>fib:
; WRITTEN IN C WITH X86-64 CLANG 3.3 AND DOWNGRADED TO 16-BIT X86
; INPUT: DI = THE NUMBER YOU WISH TO CALC THE FIBONACCI NUMBER FOR.
; OUTPUTS TO AX
push BP
push BX
push AX
mov BX, DI ;COPY INPUT TO BX
xor AX, AX ;MOV AX,0
test BX, BX ;SET FLAGS ACCORDING TO BX
je LBB0_4 ;IF BX == 0 RETURN 0
cmp BX, 1 ;IF BX == 1 RETURN 1
jne LBB0_3
mov AX, 1 ;ELSE, SET AX = 1 AND RETURN
jmp LBB0_4
LBB0_3:
lea DI, WORD PTR [BX - 1] ;DI = BX - 1
call fib ;RETURN FIB(BX-1)
mov BP, AX ;STORE THIS IN BP
add BX, -2
mov DI, BX
call fib ;GET FIB(DI - 2)
add AX, BP ;RETURN FIB(DI - 1) + FIB(DI - 2)
LBB0_4:
add sp,2
pop BX
pop BP
ret</lang>
=={{header|8th}}==
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