minix/lib/i86/em/em_dvu4.s
2009-11-09 10:26:00 +00:00

54 lines
682 B
ArmAsm

.define .dvu4
yl=6
yh=8
xl=10
xh=12
.text
.dvu4:
push si
push di
mov si,sp ! copy of sp
mov bx,yl(si)
mov ax,yh(si)
or ax,ax
jne 7f
xor dx,dx
mov cx,xl(si)
mov ax,xh(si)
div bx
xchg ax,cx
div bx
9:
! cx is high order result
! ax is low order result
mov dx,cx
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
jmp 9b
2:
sub dx,yl(si)
sbb bx,di
inc ax
loop 1b
jmp 9b