~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP
M68000 Hi-Performance Microprocessor Division
M68060 Software Package
Production Release P1.00 -- October 10, 1994
M68060 Software Package Copyright © 1993, 1994 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 regsiter, 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