minix/lib/i86/em/em_rmu4.s

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ArmAsm
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2005-04-21 16:53:53 +02:00
.define .rmu4
.text
yl=6
yh=8
xl=10
xh=12
.rmu4:
push si
push di
mov si,sp ! copy of sp
mov bx,yl(si)
mov ax,yh(si)
or ax,ax
jne 7f
1:
xor dx,dx
mov cx,xl(si)
mov ax,xh(si)
2:
div bx
xchg ax,cx
div bx
xor bx,bx
9:
! bx is high order result
! dx is low order result
mov ax,dx
mov dx,bx
pop di
pop si
ret 8 ! result in ax/dx
7:
mov di,ax
xor bx,bx
mov ax,xl(si)
mov dx,xh(si)
mov cx,#16
1:
shl ax,#1
rcl dx,#1
rcl bx,#1
cmp di,bx
ja 3f
jb 2f
cmp yl(si),dx
jbe 2f
3:
loop 1b
! dx=result(low), bx=result(high)
jmp 9b
2:
sub dx,yl(si)
sbb bx,di
inc ax
loop 1b
1:
! dx=result(low), bx=result(high)
jmp 9b