AMD Typewriter x86 사용자 설명서

22007E/0—November 1999

MOV     ECX, EAX 

;save quotient

IMUL    EDI, EAX 

;quotient * divisor hi-word 
; (low only)

MUL     DWORD PTR [ESP+20];quotient * divisor lo-word
ADD     EDX, EDI 

;EDX:EAX = quotient * divisor

SUB     EBX, EAX 

;dividend_lo – (quot.*divisor)_lo

MOV     EAX, ECX 

;get quotient

MOV     ECX, [ESP+16] 

;dividend_hi

SBB     ECX, EDX 

;subtract divisor * quot. from dividend

SBB     EAX, 0 

;adjust quotient if remainder negative

XOR     EDX, EDX 

;clear hi-word of quot(EAX<=FFFFFFFFh)

POP     EDI 

;restore EDI as per calling convention

POP     EBX 

;restore EBX as per calling convention

RET 

;done, return to caller

_ulldiv ENDP

;_ullrem divides two unsigned 64-bit integers, and returns
;

the remainder.

;
;INPUT: 

[ESP+8]:[ESP+4]   dividend

; 

[ESP+16]:[ESP+12] divisor

;
;OUTPUT: 

EDX:EAX     remainder of division

;
;DESTROYS:  EAX,ECX,EDX,EFlags

_ullrem PROC
PUSH    EBX 

;save EBX as per calling convention

MOV     ECX, [ESP+20]  ;divisor_hi
MOV     EBX, [ESP+16]  ;divisor_lo
MOV     EDX, [ESP+12]  ;dividend_hi
MOV     EAX, [ESP+8]  ;dividend_lo
TEST    ECX, ECX 

;divisor > 2^32–1?

JNZ     $r_big_divisor ;yes, divisor > 32^32–1
CMP     EDX, EBX 

;only one division needed? (ECX = 0)

JAE     $r_two_divs 

;need two divisions

DIV     EBX 

;EAX = quotient_lo

MOV     EAX, EDX 

;EAX = remainder_lo

MOV     EDX, ECX 

;EDX = remainder_hi = 0

POP     EBX 

;restore EBX as per calling convention

RET 

;done, return to caller