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; $NetBSD: milli_tiny.S,v 1.1 2014/02/24 07:23:43 skrll Exp $
; Copyright (c) 2003 ITOH Yasufumi.
; All rights reserved.
;
; Redistribution and use in source and binary forms, with or without
; modification, are permitted provided that the following conditions
; are met:
; 1. Redistributions of source code must retain the above copyright
; notice, this list of conditions and the following disclaimer.
; 2. Redistributions in binary forms are unlimited.
;
; THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS''
; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
; THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
; PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS
; BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
; CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
; SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
; INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
; CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
; ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
; THE POSSIBILITY OF SUCH DAMAGE.
; millicode library, optimized for size
.level 1.0
.code
.align 4
; $$divU unsigned division, return quotient
;
; inputs:
; %r26 dividend
; %r25 divisor
; %r31 return address
; outputs:
; %r29 quotient
; %r1, %r25, %r26 undefined
.export $$divU,millicode
$$divU:
.proc
.callinfo millicode,no_unwind
.entry
comb,<,n %r25,0,bigdivisor_divU ; special case (>=0x80000000)
bl sub_divU,%r29
subt,= %r0,%r25,%r1 ; trap divide by 0, negate
bv %r0(%r31) ; return millicode
.exit
addc %r26,%r26,%r29 ; fix quotient
bigdivisor_divU:
comclr,<< %r26,%r25,%r29 ; if dividend >= divisor
ldi 1,%r29 ; quotient is 1
bv,n %r0(%r31) ; return millicode
.procend
; Note this is not a normal subroutine
; r29: return address
sub_divU:
stwm %r19,64(%sp)
ldi 31,%r19
ds %r0,%r1,%r0
addc %r26,%r26,%r26
ds %r0,%r25,%r1
loop_sub_divU: ; addc/ds 31 times
addc %r26,%r26,%r26
addib,<> -1,%r19,loop_sub_divU
ds %r1,%r25,%r1
bv %r0(%r29)
ldwm -64(%sp),%r19
; $$remU unsigned division, return remainder
;
; inputs:
; %r26 dividend
; %r25 divisor
; %r31 return address
; outputs:
; %r29 remainder
; %r1, %r25, %r26 undefined
.export $$remU,millicode
$$remU:
.proc
.callinfo millicode,no_unwind
.entry
comb,<,n %r25,0,bigdivisor_remU ; special case (>=0x80000000)
bl sub_divU,%r29
subt,= %r0,%r25,%r1 ; trap divide by 0, negate
comclr,>= %r1,%r0,%r0
addl %r1,%r25,%r1 ; fix remainder
bv %r0(%r31) ; return millicode
.exit
copy %r1,%r29 ; the return value is remainder
bigdivisor_remU:
sub,>>= %r26,%r25,%r29 ; if dividend < divisor
copy %r26,%r29 ; the remainder is dividend
bv,n %r0(%r31) ; return millicode
.procend
; $$mulU unsigned multiplication
;
; inputs:
; %r26 multiplicand
; %r25 multiplier
; %r31 return address
; outputs:
; %r29 product
; %r1, %r25, %r26 undefined
.export $$mulU,millicode
.export $$mulI,millicode
$$mulU:
$$mulI: ; XXX actually wrong (not signed) but works for small positive numbers
.proc
.callinfo frame=0,no_calls,millicode
.entry
copy %r0,%r29
ldi 32,%r1 ; loop counter
add,nuv %r25,%r25,%r25 ; shift left, skip next if not C
loop_mul:
sh1add,tr %r29,%r26,%r29 ; shift left and add, skip next
sh1add %r29,%r0,%r29 ; shift left only
addib,<>,n -1,%r1,loop_mul ; check loop condition
add,nuv %r25,%r25,%r25 ; shift left, skip next if not C
.exit
bv,n %r0(%r31) ; return millicode
.procend
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