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_umulsi3.s
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1992-06-15
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781b
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38 lines
; unsigned long integer multiplication routine
;
; written by Kai-Uwe Bloem (I5110401@dbstu1.bitnet).
;
;
; Revision 1.1, kub 03-90
; first version, replaces the appropriate routine from fixnum.s.
; This one is short and fast for the common case of both longs <= 0x0000ffff,
; but the case of a zero lowword is no longer recognized.
; (besides it's easier to read this source 8-)
text
even
xdef __CXM33
__CXM33:
movem.l d2-d3,-(sp)
move.l d1,d2
move.l d1,d3
swap d2
move.l d0,d1
swap d0
ext.l d0 ; u.h <> 0 ?
beq.s 1$
mulu.w d3,d0 ; r = v.l * u.h
1$ tst.w d2 ; v.h <> 0 ?
beq.s 2$
mulu.w d1,d2 ; r += v.h * u.l
add.w d2,d0
2$ swap d0
clr.w d0
mulu.w d3,d1 ; r += v.l * u.l
add.l d1,d0
movem.l (sp)+,d2-d3
rts
end