xref: /src/sys/arch/m68k/060sp/dist/ilsp.s

#
# $NetBSD: ilsp.s,v 1.3 2022/05/28 21:14:56 andvar Exp $
#

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP
# M68000 Hi-Performance Microprocessor Division
# M68060 Software Package Production Release
#
# M68060 Software Package Copyright (C) 1993, 1994, 1995, 1996 Motorola Inc.
# All rights reserved.
#
# THE SOFTWARE is provided on an "AS IS" basis and without warranty.
# To the maximum extent permitted by applicable law,
# MOTOROLA DISCLAIMS ALL WARRANTIES WHETHER EXPRESS OR IMPLIED,
# INCLUDING IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
# FOR A PARTICULAR PURPOSE and any warranty against infringement with
# regard to the SOFTWARE (INCLUDING ANY MODIFIED VERSIONS THEREOF)
# and any accompanying written materials.
#
# To the maximum extent permitted by applicable law,
# IN NO EVENT SHALL MOTOROLA BE LIABLE FOR ANY DAMAGES WHATSOEVER
# (INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS,
# BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR OTHER PECUNIARY LOSS)
# ARISING OF THE USE OR INABILITY TO USE THE SOFTWARE.
#
# Motorola assumes no responsibility for the maintenance and support
# of the SOFTWARE.
#
# You are hereby granted a copyright license to use, modify, and distribute the
# SOFTWARE so long as this entire notice is retained without alteration
# in any modified and/or redistributed versions, and that such modified
# versions are clearly identified as such.
# No licenses are granted by implication, estoppel or otherwise under any
# patents or trademarks of Motorola, Inc.
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

#
# litop.s:
# 	This file is appended to the top of the 060FPLSP package
# and contains the entry points into the package. The user, in
# effect, branches to one of the branch table entries located here.
#

	bra.l	_060LSP__idivs64_
	short	0x0000
	bra.l	_060LSP__idivu64_
	short	0x0000

	bra.l	_060LSP__imuls64_
	short	0x0000
	bra.l	_060LSP__imulu64_
	short	0x0000

	bra.l	_060LSP__cmp2_Ab_
	short	0x0000
	bra.l	_060LSP__cmp2_Aw_
	short	0x0000
	bra.l	_060LSP__cmp2_Al_
	short	0x0000
	bra.l	_060LSP__cmp2_Db_
	short	0x0000
	bra.l	_060LSP__cmp2_Dw_
	short	0x0000
	bra.l	_060LSP__cmp2_Dl_
	short	0x0000

# leave room for future possible aditions.
	align	0x200

#########################################################################
# XDEF ****************************************************************	#
#	_060LSP__idivu64_(): Emulate 64-bit unsigned div instruction.	#
#	_060LSP__idivs64_(): Emulate 64-bit signed div instruction.	#
#									#
#	This is the library version which is accessed as a subroutine	#
# 	and therefore does not work exactly like the 680X0 div{s,u}.l	#
#	64-bit divide instruction.					#
#									#
# XREF ****************************************************************	#
#	None.								#
#									#
# INPUT ***************************************************************	#
#	0x4(sp)  = divisor						#
#	0x8(sp)  = hi(dividend)						#
#	0xc(sp)  = lo(dividend)						#
#	0x10(sp) = pointer to location to place quotient/remainder	#
# 									#
# OUTPUT **************************************************************	#
#	0x10(sp) = points to location of remainder/quotient.		#
#		   remainder is in first longword, quotient is in 2nd.	#
#									#
# ALGORITHM ***********************************************************	#
#	If the operands are signed, make them unsigned and save the 	#
# sign info for later. Separate out special cases like divide-by-zero	#
# or 32-bit divides if possible. Else, use a special math algorithm	#
# to calculate the result.						#
#	Restore sign info if signed instruction. Set the condition 	#
# codes before performing the final "rts". If the divisor was equal to	#
# zero, then perform a divide-by-zero using a 16-bit implemented	#
# divide instruction. This way, the operating system can record that	#
# the event occurred even though it may not point to the correct place.	#
#									#
#########################################################################

set	POSNEG,		-1
set	NDIVISOR,	-2
set	NDIVIDEND,	-3
set	DDSECOND,	-4
set	DDNORMAL,	-8
set	DDQUOTIENT,	-12
set	DIV64_CC,	-16

##########
# divs.l #
##########
	global		_060LSP__idivs64_
_060LSP__idivs64_:
# PROLOGUE BEGIN ########################################################
	link.w		%a6,&-16
	movm.l		&0x3f00,-(%sp)		# save d2-d7
#	fmovm.l		&0x0,-(%sp)		# save no fpregs
# PROLOGUE END ##########################################################

	mov.w		%cc,DIV64_CC(%a6)
	st		POSNEG(%a6)		# signed operation
	bra.b		ldiv64_cont

##########
# divu.l #
##########
	global		_060LSP__idivu64_
_060LSP__idivu64_:
# PROLOGUE BEGIN ########################################################
	link.w		%a6,&-16
	movm.l		&0x3f00,-(%sp)		# save d2-d7
#	fmovm.l		&0x0,-(%sp)		# save no fpregs
# PROLOGUE END ##########################################################

	mov.w		%cc,DIV64_CC(%a6)
	sf		POSNEG(%a6)		# unsigned operation

ldiv64_cont:
	mov.l		0x8(%a6),%d7		# fetch divisor

	beq.w		ldiv64eq0		# divisor is = 0!!!

	mov.l		0xc(%a6), %d5 		# get dividend hi
	mov.l		0x10(%a6), %d6 		# get dividend lo

# separate signed and unsigned divide
	tst.b		POSNEG(%a6)		# signed or unsigned?
	beq.b		ldspecialcases		# use positive divide

# save the sign of the divisor
# make divisor unsigned if it's negative
	tst.l		%d7			# chk sign of divisor
	slt		NDIVISOR(%a6)		# save sign of divisor
	bpl.b		ldsgndividend
	neg.l		%d7			# complement negative divisor

# save the sign of the dividend
# make dividend unsigned if it's negative
ldsgndividend:
	tst.l		%d5			# chk sign of hi(dividend)
	slt		NDIVIDEND(%a6)		# save sign of dividend
	bpl.b		ldspecialcases

	mov.w		&0x0, %cc		# clear 'X' cc bit
	negx.l		%d6			# complement signed dividend
	negx.l		%d5

# extract some special cases:
# 	- is (dividend == 0) ?
#	- is (hi(dividend) == 0 && (divisor <= lo(dividend))) ? (32-bit div)
ldspecialcases:
	tst.l		%d5			# is (hi(dividend) == 0)
	bne.b		ldnormaldivide		# no, so try it the long way

	tst.l		%d6			# is (lo(dividend) == 0), too
	beq.w		lddone			# yes, so (dividend == 0)

	cmp.l	 	%d7,%d6			# is (divisor <= lo(dividend))
	bls.b		ld32bitdivide		# yes, so use 32 bit divide

	exg		%d5,%d6			# q = 0, r = dividend
	bra.w		ldivfinish		# can't divide, we're done.

ld32bitdivide:
	tdivu.l		%d7, %d5:%d6		# it's only a 32/32 bit div!

	bra.b		ldivfinish

ldnormaldivide:
# last special case:
# 	- is hi(dividend) >= divisor ? if yes, then overflow
	cmp.l		%d7,%d5
	bls.b		lddovf			# answer won't fit in 32 bits

# perform the divide algorithm:
	bsr.l		ldclassical		# do int divide

# separate into signed and unsigned finishes.
ldivfinish:
	tst.b		POSNEG(%a6)		# do divs, divu separately
	beq.b		lddone			# divu has no processing!!!

# it was a divs.l, so ccode setting is a little more complicated...
	tst.b		NDIVIDEND(%a6)		# remainder has same sign
	beq.b		ldcc			# as dividend.
	neg.l		%d5			# sgn(rem) = sgn(dividend)
ldcc:
	mov.b		NDIVISOR(%a6), %d0
	eor.b		%d0, NDIVIDEND(%a6)	# chk if quotient is negative
	beq.b		ldqpos			# branch to quot positive

# 0x80000000 is the largest number representable as a 32-bit negative
# number. the negative of 0x80000000 is 0x80000000.
	cmpi.l		%d6, &0x80000000	# will (-quot) fit in 32 bits?
	bhi.b		lddovf

	neg.l		%d6			# make (-quot) 2's comp

	bra.b		lddone

ldqpos:
	btst		&0x1f, %d6		# will (+quot) fit in 32 bits?
	bne.b		lddovf

lddone:
# if the register numbers are the same, only the quotient gets saved.
# so, if we always save the quotient second, we save ourselves a cmp&beq
	andi.w		&0x10,DIV64_CC(%a6)
	mov.w		DIV64_CC(%a6),%cc
	tst.l		%d6			# may set 'N' ccode bit

# here, the result is in d1 and d0. the current strategy is to save
# the values at the location pointed to by a0.
# use movm here to not disturb the condition codes.
ldexit:
	movm.l		&0x0060,([0x14,%a6])	# save result

# EPILOGUE BEGIN ########################################################
#	fmovm.l		(%sp)+,&0x0		# restore no fpregs
	movm.l		(%sp)+,&0x00fc		# restore d2-d7
	unlk		%a6
# EPILOGUE END ##########################################################

	rts

# the result should be the unchanged dividend
lddovf:
	mov.l		0xc(%a6), %d5 		# get dividend hi
	mov.l		0x10(%a6), %d6 		# get dividend lo

	andi.w		&0x1c,DIV64_CC(%a6)
	ori.w		&0x02,DIV64_CC(%a6)	# set 'V' ccode bit
	mov.w		DIV64_CC(%a6),%cc

	bra.b		ldexit

ldiv64eq0:
	mov.l		0xc(%a6),([0x14,%a6])
	mov.l		0x10(%a6),([0x14,%a6],0x4)

	mov.w		DIV64_CC(%a6),%cc

# EPILOGUE BEGIN ########################################################
#	fmovm.l		(%sp)+,&0x0		# restore no fpregs
	movm.l		(%sp)+,&0x00fc		# restore d2-d7
	unlk		%a6
# EPILOGUE END ##########################################################

	divu.w		&0x0,%d0		# force a divbyzero exception
	rts

###########################################################################
#########################################################################
# This routine uses the 'classical' Algorithm D from Donald Knuth's	#
# Art of Computer Programming, vol II, Seminumerical Algorithms.	#
# For this implementation b=2**16, and the target is U1U2U3U4/V1V2,	#
# where U,V are words of the quadword dividend and longword divisor,	#
# and U1, V1 are the most significant words.				#
# 									#
# The most sig. longword of the 64 bit dividend must be in %d5, least 	#
# in %d6. The divisor must be in the variable ddivisor, and the		#
# signed/unsigned flag ddusign must be set (0=unsigned,1=signed).	#
# The quotient is returned in %d6, remainder in %d5, unless the		#
# v (overflow) bit is set in the saved %ccr. If overflow, the dividend	#
# is unchanged.								#
#########################################################################
ldclassical:
# if the divisor msw is 0, use simpler algorithm then the full blown
# one at ddknuth:

	cmpi.l		%d7, &0xffff
	bhi.b		lddknuth		# go use D. Knuth algorithm

# Since the divisor is only a word (and larger than the mslw of the dividend),
# a simpler algorithm may be used :
# In the general case, four quotient words would be created by
# dividing the divisor word into each dividend word. In this case,
# the first two quotient words must be zero, or overflow would occur.
# Since we already checked this case above, we can treat the most significant
# longword of the dividend as (0) remainder (see Knuth) and merely complete
# the last two divisions to get a quotient longword and word remainder:

	clr.l		%d1
	swap		%d5			# same as r*b if previous step rqd
	swap		%d6			# get u3 to lsw position
	mov.w		%d6, %d5		# rb + u3

	divu.w		%d7, %d5

	mov.w		%d5, %d1		# first quotient word
	swap		%d6			# get u4
	mov.w		%d6, %d5		# rb + u4

	divu.w		%d7, %d5

	swap		%d1
	mov.w		%d5, %d1		# 2nd quotient 'digit'
	clr.w		%d5
	swap		%d5			# now remainder
	mov.l		%d1, %d6		# and quotient

	rts

lddknuth:
# In this algorithm, the divisor is treated as a 2 digit (word) number
# which is divided into a 3 digit (word) dividend to get one quotient
# digit (word). After subtraction, the dividend is shifted and the
# process repeated. Before beginning, the divisor and quotient are
# 'normalized' so that the process of estimating the quotient digit
# will yield verifiably correct results..

	clr.l		DDNORMAL(%a6)		# count of shifts for normalization
	clr.b		DDSECOND(%a6)		# clear flag for quotient digits
	clr.l		%d1			# %d1 will hold trial quotient
lddnchk:
	btst		&31, %d7		# must we normalize? first word of
	bne.b		lddnormalized		# divisor (V1) must be >= 65536/2
	addq.l		&0x1, DDNORMAL(%a6)	# count normalization shifts
	lsl.l		&0x1, %d7		# shift the divisor
	lsl.l		&0x1, %d6		# shift u4,u3 with overflow to u2
	roxl.l		&0x1, %d5		# shift u1,u2
	bra.w		lddnchk
lddnormalized:

# Now calculate an estimate of the quotient words (msw first, then lsw).
# The comments use subscripts for the first quotient digit determination.
	mov.l		%d7, %d3		# divisor
	mov.l		%d5, %d2		# dividend mslw
	swap		%d2
	swap		%d3
	cmp.w	 	%d2, %d3		# V1 = U1 ?
	bne.b		lddqcalc1
	mov.w		&0xffff, %d1		# use max trial quotient word
	bra.b		lddadj0
lddqcalc1:
	mov.l		%d5, %d1

	divu.w		%d3, %d1		# use quotient of mslw/msw

	andi.l		&0x0000ffff, %d1	# zero any remainder
lddadj0:

# now test the trial quotient and adjust. This step plus the
# normalization assures (according to Knuth) that the trial
# quotient will be at worst 1 too large.
	mov.l		%d6, -(%sp)
	clr.w		%d6			# word u3 left
	swap		%d6			# in lsw position
lddadj1: mov.l		%d7, %d3
	mov.l		%d1, %d2
	mulu.w		%d7, %d2		# V2q
	swap		%d3
	mulu.w		%d1, %d3		# V1q
	mov.l		%d5, %d4		# U1U2
	sub.l		%d3, %d4		# U1U2 - V1q

	swap		%d4

	mov.w		%d4,%d0
	mov.w		%d6,%d4			# insert lower word (U3)

	tst.w		%d0			# is upper word set?
	bne.w		lddadjd1

#	add.l		%d6, %d4		# (U1U2 - V1q) + U3

	cmp.l	 	%d2, %d4
	bls.b		lddadjd1		# is V2q > (U1U2-V1q) + U3 ?
	subq.l		&0x1, %d1		# yes, decrement and recheck
	bra.b		lddadj1
lddadjd1:
# now test the word by multiplying it by the divisor (V1V2) and comparing
# the 3 digit (word) result with the current dividend words
	mov.l		%d5, -(%sp)		# save %d5 (%d6 already saved)
	mov.l		%d1, %d6
	swap		%d6			# shift answer to ms 3 words
	mov.l		%d7, %d5
	bsr.l		ldmm2
	mov.l		%d5, %d2		# now %d2,%d3 are trial*divisor
	mov.l		%d6, %d3
	mov.l		(%sp)+, %d5		# restore dividend
	mov.l		(%sp)+, %d6
	sub.l		%d3, %d6
	subx.l		%d2, %d5		# subtract double precision
	bcc		ldd2nd			# no carry, do next quotient digit
	subq.l		&0x1, %d1		# q is one too large
# need to add back divisor longword to current ms 3 digits of dividend
# - according to Knuth, this is done only 2 out of 65536 times for random
# divisor, dividend selection.
	clr.l		%d2
	mov.l		%d7, %d3
	swap		%d3
	clr.w		%d3			# %d3 now ls word of divisor
	add.l		%d3, %d6		# aligned with 3rd word of dividend
	addx.l		%d2, %d5
	mov.l		%d7, %d3
	clr.w		%d3			# %d3 now ms word of divisor
	swap		%d3			# aligned with 2nd word of dividend
	add.l		%d3, %d5
ldd2nd:
	tst.b		DDSECOND(%a6)	# both q words done?
	bne.b		lddremain
# first quotient digit now correct. store digit and shift the
# (subtracted) dividend
	mov.w		%d1, DDQUOTIENT(%a6)
	clr.l		%d1
	swap		%d5
	swap		%d6
	mov.w		%d6, %d5
	clr.w		%d6
	st		DDSECOND(%a6)		# second digit
	bra.w		lddnormalized
lddremain:
# add 2nd word to quotient, get the remainder.
	mov.w 		%d1, DDQUOTIENT+2(%a6)
# shift down one word/digit to renormalize remainder.
	mov.w		%d5, %d6
	swap		%d6
	swap		%d5
	mov.l		DDNORMAL(%a6), %d7	# get norm shift count
	beq.b		lddrn
	subq.l		&0x1, %d7		# set for loop count
lddnlp:
	lsr.l		&0x1, %d5		# shift into %d6
	roxr.l		&0x1, %d6
	dbf		%d7, lddnlp
lddrn:
	mov.l		%d6, %d5		# remainder
	mov.l		DDQUOTIENT(%a6), %d6 	# quotient

	rts
ldmm2:
# factors for the 32X32->64 multiplication are in %d5 and %d6.
# returns 64 bit result in %d5 (hi) %d6(lo).
# destroys %d2,%d3,%d4.

# multiply hi,lo words of each factor to get 4 intermediate products
	mov.l		%d6, %d2
	mov.l		%d6, %d3
	mov.l		%d5, %d4
	swap		%d3
	swap		%d4
	mulu.w		%d5, %d6		# %d6 <- lsw*lsw
	mulu.w		%d3, %d5		# %d5 <- msw-dest*lsw-source
	mulu.w		%d4, %d2		# %d2 <- msw-source*lsw-dest
	mulu.w		%d4, %d3		# %d3 <- msw*msw
# now use swap and addx to consolidate to two longwords
	clr.l		%d4
	swap		%d6
	add.w		%d5, %d6		# add msw of l*l to lsw of m*l product
	addx.w		%d4, %d3		# add any carry to m*m product
	add.w		%d2, %d6		# add in lsw of other m*l product
	addx.w		%d4, %d3		# add any carry to m*m product
	swap		%d6			# %d6 is low 32 bits of final product
	clr.w		%d5
	clr.w		%d2			# lsw of two mixed products used,
	swap		%d5			# now use msws of longwords
	swap		%d2
	add.l		%d2, %d5
	add.l		%d3, %d5	# %d5 now ms 32 bits of final product
	rts

#########################################################################
# XDEF ****************************************************************	#
#	_060LSP__imulu64_(): Emulate 64-bit unsigned mul instruction	#
#	_060LSP__imuls64_(): Emulate 64-bit signed mul instruction.	#
#									#
#	This is the library version which is accessed as a subroutine	#
#	and therefore does not work exactly like the 680X0 mul{s,u}.l	#
#	64-bit multiply instruction.					#
#									#
# XREF ****************************************************************	#
#	None								#
#									#
# INPUT ***************************************************************	#
#	0x4(sp) = multiplier						#
#	0x8(sp) = multiplicand						#
#	0xc(sp) = pointer to location to place 64-bit result		#
# 									#
# OUTPUT **************************************************************	#
#	0xc(sp) = points to location of 64-bit result			#
#									#
# ALGORITHM ***********************************************************	#
#	Perform the multiply in pieces using 16x16->32 unsigned		#
# multiplies and "add" instructions.					#
#	Set the condition codes as appropriate before performing an	#
# "rts".								#
#									#
#########################################################################

set MUL64_CC, -4

	global		_060LSP__imulu64_
_060LSP__imulu64_:

# PROLOGUE BEGIN ########################################################
	link.w		%a6,&-4
	movm.l		&0x3800,-(%sp)		# save d2-d4
#	fmovm.l		&0x0,-(%sp)		# save no fpregs
# PROLOGUE END ##########################################################

	mov.w		%cc,MUL64_CC(%a6)	# save incoming ccodes

	mov.l		0x8(%a6),%d0		# store multiplier in d0
	beq.w		mulu64_zero		# handle zero separately

	mov.l		0xc(%a6),%d1		# get multiplicand in d1
	beq.w		mulu64_zero		# handle zero separately

#########################################################################
#	63			   32				0	#
# 	----------------------------					#
# 	| hi(mplier) * hi(mplicand)|					#
# 	----------------------------					#
#		     -----------------------------			#
#		     | hi(mplier) * lo(mplicand) |			#
#		     -----------------------------			#
#		     -----------------------------			#
#		     | lo(mplier) * hi(mplicand) |			#
#		     -----------------------------			#
#	  |			   -----------------------------	#
#	--|--			   | lo(mplier) * lo(mplicand) |	#
#	  |			   -----------------------------	#
#	========================================================	#
#	--------------------------------------------------------	#
#	|	hi(result)	   |	    lo(result)         |	#
#	--------------------------------------------------------	#
#########################################################################
mulu64_alg:
# load temp registers with operands
	mov.l		%d0,%d2			# mr in d2
	mov.l		%d0,%d3			# mr in d3
	mov.l		%d1,%d4			# md in d4
	swap		%d3			# hi(mr) in lo d3
	swap		%d4			# hi(md) in lo d4

# complete necessary multiplies:
	mulu.w		%d1,%d0			# [1] lo(mr) * lo(md)
	mulu.w		%d3,%d1			# [2] hi(mr) * lo(md)
	mulu.w		%d4,%d2			# [3] lo(mr) * hi(md)
	mulu.w		%d4,%d3			# [4] hi(mr) * hi(md)

# add lo portions of [2],[3] to hi portion of [1].
# add carries produced from these adds to [4].
# lo([1]) is the final lo 16 bits of the result.
	clr.l		%d4			# load d4 w/ zero value
	swap		%d0			# hi([1]) <==> lo([1])
	add.w		%d1,%d0			# hi([1]) + lo([2])
	addx.l		%d4,%d3			#    [4]  + carry
	add.w		%d2,%d0			# hi([1]) + lo([3])
	addx.l		%d4,%d3			#    [4]  + carry
	swap		%d0			# lo([1]) <==> hi([1])

# lo portions of [2],[3] have been added in to final result.
# now, clear lo, put hi in lo reg, and add to [4]
	clr.w		%d1			# clear lo([2])
	clr.w		%d2			# clear hi([3])
	swap		%d1			# hi([2]) in lo d1
	swap		%d2			# hi([3]) in lo d2
	add.l		%d2,%d1			#    [4]  + hi([2])
	add.l		%d3,%d1			#    [4]  + hi([3])

# now, grab the condition codes. only one that can be set is 'N'.
# 'N' CAN be set if the operation is unsigned if bit 63 is set.
	mov.w		MUL64_CC(%a6),%d4
	andi.b		&0x10,%d4		# keep old 'X' bit
	tst.l		%d1			# may set 'N' bit
	bpl.b		mulu64_ddone
	ori.b		&0x8,%d4		# set 'N' bit
mulu64_ddone:
	mov.w		%d4,%cc

# here, the result is in d1 and d0. the current strategy is to save
# the values at the location pointed to by a0.
# use movm here to not disturb the condition codes.
mulu64_end:
	exg		%d1,%d0
	movm.l		&0x0003,([0x10,%a6])		# save result

# EPILOGUE BEGIN ########################################################
#	fmovm.l		(%sp)+,&0x0		# restore no fpregs
	movm.l		(%sp)+,&0x001c		# restore d2-d4
	unlk		%a6
# EPILOGUE END ##########################################################

	rts

# one or both of the operands is zero so the result is also zero.
# save the zero result to the register file and set the 'Z' ccode bit.
mulu64_zero:
	clr.l		%d0
	clr.l		%d1

	mov.w		MUL64_CC(%a6),%d4
	andi.b		&0x10,%d4
	ori.b		&0x4,%d4
	mov.w		%d4,%cc			# set 'Z' ccode bit

	bra.b		mulu64_end

##########
# muls.l #
##########
	global		_060LSP__imuls64_
_060LSP__imuls64_:

# PROLOGUE BEGIN ########################################################
	link.w		%a6,&-4
	movm.l		&0x3c00,-(%sp)		# save d2-d5
#	fmovm.l		&0x0,-(%sp)		# save no fpregs
# PROLOGUE END ##########################################################

	mov.w		%cc,MUL64_CC(%a6)	# save incoming ccodes

	mov.l		0x8(%a6),%d0		# store multiplier in d0
	beq.b		mulu64_zero		# handle zero separately

	mov.l		0xc(%a6),%d1		# get multiplicand in d1
	beq.b		mulu64_zero		# handle zero separately

	clr.b		%d5			# clear sign tag
	tst.l		%d0			# is multiplier negative?
	bge.b		muls64_chk_md_sgn	# no
	neg.l		%d0			# make multiplier positive

	ori.b		&0x1,%d5		# save multiplier sgn

# the result sign is the exclusive or of the operand sign bits.
muls64_chk_md_sgn:
	tst.l		%d1			# is multiplicand negative?
	bge.b		muls64_alg		# no
	neg.l		%d1			# make multiplicand positive

	eori.b		&0x1,%d5		# calculate correct sign

#########################################################################
#	63			   32				0	#
# 	----------------------------					#
# 	| hi(mplier) * hi(mplicand)|					#
# 	----------------------------					#
#		     -----------------------------			#
#		     | hi(mplier) * lo(mplicand) |			#
#		     -----------------------------			#
#		     -----------------------------			#
#		     | lo(mplier) * hi(mplicand) |			#
#		     -----------------------------			#
#	  |			   -----------------------------	#
#	--|--			   | lo(mplier) * lo(mplicand) |	#
#	  |			   -----------------------------	#
#	========================================================	#
#	--------------------------------------------------------	#
#	|	hi(result)	   |	    lo(result)         |	#
#	--------------------------------------------------------	#
#########################################################################
muls64_alg:
# load temp registers with operands
	mov.l		%d0,%d2			# mr in d2
	mov.l		%d0,%d3			# mr in d3
	mov.l		%d1,%d4			# md in d4
	swap		%d3			# hi(mr) in lo d3
	swap		%d4			# hi(md) in lo d4

# complete necessary multiplies:
	mulu.w		%d1,%d0			# [1] lo(mr) * lo(md)
	mulu.w		%d3,%d1			# [2] hi(mr) * lo(md)
	mulu.w		%d4,%d2			# [3] lo(mr) * hi(md)
	mulu.w		%d4,%d3			# [4] hi(mr) * hi(md)

# add lo portions of [2],[3] to hi portion of [1].
# add carries produced from these adds to [4].
# lo([1]) is the final lo 16 bits of the result.
	clr.l		%d4			# load d4 w/ zero value
	swap		%d0			# hi([1]) <==> lo([1])
	add.w		%d1,%d0			# hi([1]) + lo([2])
	addx.l		%d4,%d3			#    [4]  + carry
	add.w		%d2,%d0			# hi([1]) + lo([3])
	addx.l		%d4,%d3			#    [4]  + carry
	swap		%d0			# lo([1]) <==> hi([1])

# lo portions of [2],[3] have been added in to final result.
# now, clear lo, put hi in lo reg, and add to [4]
	clr.w		%d1			# clear lo([2])
	clr.w		%d2			# clear hi([3])
	swap		%d1			# hi([2]) in lo d1
	swap		%d2			# hi([3]) in lo d2
	add.l		%d2,%d1			#    [4]  + hi([2])
	add.l		%d3,%d1			#    [4]  + hi([3])

	tst.b		%d5			# should result be signed?
	beq.b		muls64_done		# no

# result should be a signed negative number.
# compute 2's complement of the unsigned number:
#   -negate all bits and add 1
muls64_neg:
	not.l		%d0			# negate lo(result) bits
	not.l		%d1			# negate hi(result) bits
	addq.l		&1,%d0			# add 1 to lo(result)
	addx.l		%d4,%d1			# add carry to hi(result)

muls64_done:
	mov.w		MUL64_CC(%a6),%d4
	andi.b		&0x10,%d4		# keep old 'X' bit
	tst.l		%d1			# may set 'N' bit
	bpl.b		muls64_ddone
	ori.b		&0x8,%d4		# set 'N' bit
muls64_ddone:
	mov.w		%d4,%cc

# here, the result is in d1 and d0. the current strategy is to save
# the values at the location pointed to by a0.
# use movm here to not disturb the condition codes.
muls64_end:
	exg		%d1,%d0
	movm.l		&0x0003,([0x10,%a6])	# save result at (a0)

# EPILOGUE BEGIN ########################################################
#	fmovm.l		(%sp)+,&0x0		# restore no fpregs
	movm.l		(%sp)+,&0x003c		# restore d2-d5
	unlk		%a6
# EPILOGUE END ##########################################################

	rts

# one or both of the operands is zero so the result is also zero.
# save the zero result to the register file and set the 'Z' ccode bit.
muls64_zero:
	clr.l		%d0
	clr.l		%d1

	mov.w		MUL64_CC(%a6),%d4
	andi.b		&0x10,%d4
	ori.b		&0x4,%d4
	mov.w		%d4,%cc			# set 'Z' ccode bit

	bra.b		muls64_end

#########################################################################
# XDEF ****************************************************************	#
#	_060LSP__cmp2_Ab_(): Emulate "cmp2.b An,<ea>".			#
#	_060LSP__cmp2_Aw_(): Emulate "cmp2.w An,<ea>".			#
#	_060LSP__cmp2_Al_(): Emulate "cmp2.l An,<ea>".			#
#	_060LSP__cmp2_Db_(): Emulate "cmp2.b Dn,<ea>".			#
#	_060LSP__cmp2_Dw_(): Emulate "cmp2.w Dn,<ea>".			#
#	_060LSP__cmp2_Dl_(): Emulate "cmp2.l Dn,<ea>".			#
#									#
#	This is the library version which is accessed as a subroutine	#
#	and therefore does not work exactly like the 680X0 "cmp2"	#
#	instruction.							#
#									#
# XREF ****************************************************************	#
#	None								#
#									#
# INPUT ***************************************************************	#
#	0x4(sp) = Rn							#
#	0x8(sp) = pointer to boundary pair				#
# 									#
# OUTPUT **************************************************************	#
#	cc = condition codes are set correctly				#
#									#
# ALGORITHM ***********************************************************	#
# 	In the interest of simplicity, all operands are converted to	#
# longword size whether the operation is byte, word, or long. The	#
# bounds are sign extended accordingly. If Rn is a data register, Rn is #
# also sign extended. If Rn is an address register, it need not be sign #
# extended since the full register is always used.			#
#	The condition codes are set correctly before the final "rts".	#
#									#
#########################################################################

set	CMP2_CC,	-4

	global 		_060LSP__cmp2_Ab_
_060LSP__cmp2_Ab_:

# PROLOGUE BEGIN ########################################################
	link.w		%a6,&-4
	movm.l		&0x3800,-(%sp)		# save d2-d4
#	fmovm.l		&0x0,-(%sp)		# save no fpregs
# PROLOGUE END ##########################################################

	mov.w		%cc,CMP2_CC(%a6)
	mov.l		0x8(%a6), %d2 		# get regval

	mov.b		([0xc,%a6],0x0),%d0
	mov.b		([0xc,%a6],0x1),%d1

	extb.l		%d0			# sign extend lo bnd
	extb.l		%d1			# sign extend hi bnd
	bra.w		l_cmp2_cmp		# go do the compare emulation

	global 		_060LSP__cmp2_Aw_
_060LSP__cmp2_Aw_:

# PROLOGUE BEGIN ########################################################
	link.w		%a6,&-4
	movm.l		&0x3800,-(%sp)		# save d2-d4
#	fmovm.l		&0x0,-(%sp)		# save no fpregs
# PROLOGUE END ##########################################################

	mov.w		%cc,CMP2_CC(%a6)
	mov.l		0x8(%a6), %d2 		# get regval

	mov.w		([0xc,%a6],0x0),%d0
	mov.w		([0xc,%a6],0x2),%d1

	ext.l		%d0			# sign extend lo bnd
	ext.l		%d1			# sign extend hi bnd
	bra.w		l_cmp2_cmp		# go do the compare emulation

	global 		_060LSP__cmp2_Al_
_060LSP__cmp2_Al_:

# PROLOGUE BEGIN ########################################################
	link.w		%a6,&-4
	movm.l		&0x3800,-(%sp)		# save d2-d4
#	fmovm.l		&0x0,-(%sp)		# save no fpregs
# PROLOGUE END ##########################################################

	mov.w		%cc,CMP2_CC(%a6)
	mov.l		0x8(%a6), %d2 		# get regval

	mov.l		([0xc,%a6],0x0),%d0
	mov.l		([0xc,%a6],0x4),%d1
	bra.w		l_cmp2_cmp		# go do the compare emulation

	global 		_060LSP__cmp2_Db_
_060LSP__cmp2_Db_:

# PROLOGUE BEGIN ########################################################
	link.w		%a6,&-4
	movm.l		&0x3800,-(%sp)		# save d2-d4
#	fmovm.l		&0x0,-(%sp)		# save no fpregs
# PROLOGUE END ##########################################################

	mov.w		%cc,CMP2_CC(%a6)
	mov.l		0x8(%a6), %d2 		# get regval

	mov.b		([0xc,%a6],0x0),%d0
	mov.b		([0xc,%a6],0x1),%d1

	extb.l		%d0			# sign extend lo bnd
	extb.l		%d1			# sign extend hi bnd

# operation is a data register compare.
# sign extend byte to long so we can do simple longword compares.
	extb.l		%d2			# sign extend data byte
	bra.w		l_cmp2_cmp		# go do the compare emulation

	global 		_060LSP__cmp2_Dw_
_060LSP__cmp2_Dw_:

# PROLOGUE BEGIN ########################################################
	link.w		%a6,&-4
	movm.l		&0x3800,-(%sp)		# save d2-d4
#	fmovm.l		&0x0,-(%sp)		# save no fpregs
# PROLOGUE END ##########################################################

	mov.w		%cc,CMP2_CC(%a6)
	mov.l		0x8(%a6), %d2 		# get regval

	mov.w		([0xc,%a6],0x0),%d0
	mov.w		([0xc,%a6],0x2),%d1

	ext.l		%d0			# sign extend lo bnd
	ext.l		%d1			# sign extend hi bnd

# operation is a data register compare.
# sign extend word to long so we can do simple longword compares.
	ext.l		%d2			# sign extend data word
	bra.w		l_cmp2_cmp		# go emulate compare

	global 		_060LSP__cmp2_Dl_
_060LSP__cmp2_Dl_:

# PROLOGUE BEGIN ########################################################
	link.w		%a6,&-4
	movm.l		&0x3800,-(%sp)		# save d2-d4
#	fmovm.l		&0x0,-(%sp)		# save no fpregs
# PROLOGUE END ##########################################################

	mov.w		%cc,CMP2_CC(%a6)
	mov.l		0x8(%a6), %d2 		# get regval

	mov.l		([0xc,%a6],0x0),%d0
	mov.l		([0xc,%a6],0x4),%d1

#
# To set the ccodes correctly:
# 	(1) save 'Z' bit from (Rn - lo)
#	(2) save 'Z' and 'N' bits from ((hi - lo) - (Rn - hi))
#	(3) keep 'X', 'N', and 'V' from before instruction
#	(4) combine ccodes
#
l_cmp2_cmp:
	sub.l		%d0, %d2		# (Rn - lo)
	mov.w		%cc, %d3		# fetch resulting ccodes
	andi.b		&0x4, %d3		# keep 'Z' bit
	sub.l		%d0, %d1		# (hi - lo)
	cmp.l	 	%d1,%d2			# ((hi - lo) - (Rn - hi))

	mov.w		%cc, %d4		# fetch resulting ccodes
	or.b		%d4, %d3		# combine w/ earlier ccodes
	andi.b		&0x5, %d3		# keep 'Z' and 'N'

	mov.w		CMP2_CC(%a6), %d4	# fetch old ccodes
	andi.b		&0x1a, %d4		# keep 'X','N','V' bits
	or.b		%d3, %d4		# insert new ccodes
	mov.w		%d4,%cc			# save new ccodes

# EPILOGUE BEGIN ########################################################
#	fmovm.l		(%sp)+,&0x0		# restore no fpregs
	movm.l		(%sp)+,&0x001c		# restore d2-d4
	unlk		%a6
# EPILOGUE END ##########################################################

	rts