xref: /src/sys/arch/m68k/fpsp/get_op.sa

*	$NetBSD: get_op.sa,v 1.3 1994/10/26 07:49:09 cgd Exp $

*	MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP
*	M68000 Hi-Performance Microprocessor Division
*	M68040 Software Package 
*
*	M68040 Software Package Copyright (c) 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.

*
*	get_op.sa 3.6 5/19/92
*
*	get_op.sa 3.5 4/26/91
*
*  Description: This routine is called by the unsupported format/data
* type exception handler ('unsupp' - vector 55) and the unimplemented
* instruction exception handler ('unimp' - vector 11).  'get_op'
* determines the opclass (0, 2, or 3) and branches to the
* opclass handler routine.  See 68881/2 User's Manual table 4-11
* for a description of the opclasses.
*
* For UNSUPPORTED data/format (exception vector 55) and for
* UNIMPLEMENTED instructions (exception vector 11) the following
* applies:
*
* - For unnormormalized numbers (opclass 0, 2, or 3) the
* number(s) is normalized and the operand type tag is updated.
*		
* - For a packed number (opclass 2) the number is unpacked and the
* operand type tag is updated.
*
* - For denormalized numbers (opclass 0 or 2) the number(s) is not
* changed but passed to the next module.  The next module for
* unimp is do_func, the next module for unsupp is res_func.
*
* For UNSUPPORTED data/format (exception vector 55) only the
* following applies:
*
* - If there is a move out with a packed number (opclass 3) the
* number is packed and written to user memory.  For the other
* opclasses the number(s) are written back to the fsave stack
* and the instruction is then restored back into the '040.  The
* '040 is then able to complete the instruction.
*
* For example:
* fadd.x fpm,fpn where the fpm contains an unnormalized number.
* The '040 takes an unsupported data trap and gets to this
* routine.  The number is normalized, put back on the stack and
* then an frestore is done to restore the instruction back into
* the '040.  The '040 then re-executes the fadd.x fpm,fpn with
* a normalized number in the source and the instruction is
* successful.
*		
* Next consider if in the process of normalizing the un-
* normalized number it becomes a denormalized number.  The
* routine which converts the unnorm to a norm (called mk_norm)
* detects this and tags the number as a denorm.  The routine
* res_func sees the denorm tag and converts the denorm to a
* norm.  The instruction is then restored back into the '040
* which re_executess the instruction.
*

GET_OP    IDNT    2,1 Motorola 040 Floating Point Software Package

	section	8

	include	fpsp.h

	xdef	PIRN,PIRZRM,PIRP
	xdef	SMALRN,SMALRZRM,SMALRP
	xdef	BIGRN,BIGRZRM,BIGRP

PIRN:
	dc.l $40000000,$c90fdaa2,$2168c235    ;pi
PIRZRM:
	dc.l $40000000,$c90fdaa2,$2168c234    ;pi
PIRP:
	dc.l $40000000,$c90fdaa2,$2168c235    ;pi

*round to nearest
SMALRN:
	dc.l $3ffd0000,$9a209a84,$fbcff798    ;log10(2)
	dc.l $40000000,$adf85458,$a2bb4a9a    ;e
	dc.l $3fff0000,$b8aa3b29,$5c17f0bc    ;log2(e)
	dc.l $3ffd0000,$de5bd8a9,$37287195    ;log10(e)
	dc.l $00000000,$00000000,$00000000    ;0.0
* round to zero;round to negative infinity
SMALRZRM:
	dc.l $3ffd0000,$9a209a84,$fbcff798    ;log10(2)
	dc.l $40000000,$adf85458,$a2bb4a9a    ;e
	dc.l $3fff0000,$b8aa3b29,$5c17f0bb    ;log2(e)
	dc.l $3ffd0000,$de5bd8a9,$37287195    ;log10(e)
	dc.l $00000000,$00000000,$00000000    ;0.0
* round to positive infinity
SMALRP:
	dc.l $3ffd0000,$9a209a84,$fbcff799    ;log10(2)
	dc.l $40000000,$adf85458,$a2bb4a9b    ;e
	dc.l $3fff0000,$b8aa3b29,$5c17f0bc    ;log2(e)
	dc.l $3ffd0000,$de5bd8a9,$37287195    ;log10(e)
	dc.l $00000000,$00000000,$00000000    ;0.0

*round to nearest
BIGRN:
	dc.l $3ffe0000,$b17217f7,$d1cf79ac    ;ln(2)
	dc.l $40000000,$935d8ddd,$aaa8ac17    ;ln(10)
	dc.l $3fff0000,$80000000,$00000000    ;10 ^ 0

	xdef	PTENRN
PTENRN:
	dc.l $40020000,$A0000000,$00000000    ;10 ^ 1
	dc.l $40050000,$C8000000,$00000000    ;10 ^ 2
	dc.l $400C0000,$9C400000,$00000000    ;10 ^ 4
	dc.l $40190000,$BEBC2000,$00000000    ;10 ^ 8
	dc.l $40340000,$8E1BC9BF,$04000000    ;10 ^ 16
	dc.l $40690000,$9DC5ADA8,$2B70B59E    ;10 ^ 32
	dc.l $40D30000,$C2781F49,$FFCFA6D5    ;10 ^ 64
	dc.l $41A80000,$93BA47C9,$80E98CE0    ;10 ^ 128
	dc.l $43510000,$AA7EEBFB,$9DF9DE8E    ;10 ^ 256
	dc.l $46A30000,$E319A0AE,$A60E91C7    ;10 ^ 512
	dc.l $4D480000,$C9767586,$81750C17    ;10 ^ 1024
	dc.l $5A920000,$9E8B3B5D,$C53D5DE5    ;10 ^ 2048
	dc.l $75250000,$C4605202,$8A20979B    ;10 ^ 4096
*round to minus infinity
BIGRZRM:
	dc.l $3ffe0000,$b17217f7,$d1cf79ab    ;ln(2)
	dc.l $40000000,$935d8ddd,$aaa8ac16    ;ln(10)
	dc.l $3fff0000,$80000000,$00000000    ;10 ^ 0

	xdef	PTENRM
PTENRM:
	dc.l $40020000,$A0000000,$00000000    ;10 ^ 1
	dc.l $40050000,$C8000000,$00000000    ;10 ^ 2
	dc.l $400C0000,$9C400000,$00000000    ;10 ^ 4
	dc.l $40190000,$BEBC2000,$00000000    ;10 ^ 8
	dc.l $40340000,$8E1BC9BF,$04000000    ;10 ^ 16
	dc.l $40690000,$9DC5ADA8,$2B70B59D    ;10 ^ 32
	dc.l $40D30000,$C2781F49,$FFCFA6D5    ;10 ^ 64
	dc.l $41A80000,$93BA47C9,$80E98CDF    ;10 ^ 128
	dc.l $43510000,$AA7EEBFB,$9DF9DE8D    ;10 ^ 256
	dc.l $46A30000,$E319A0AE,$A60E91C6    ;10 ^ 512
	dc.l $4D480000,$C9767586,$81750C17    ;10 ^ 1024
	dc.l $5A920000,$9E8B3B5D,$C53D5DE5    ;10 ^ 2048
	dc.l $75250000,$C4605202,$8A20979A    ;10 ^ 4096
*round to positive infinity
BIGRP:
	dc.l $3ffe0000,$b17217f7,$d1cf79ac    ;ln(2)
	dc.l $40000000,$935d8ddd,$aaa8ac17    ;ln(10)
	dc.l $3fff0000,$80000000,$00000000    ;10 ^ 0

	xdef	PTENRP
PTENRP:
	dc.l $40020000,$A0000000,$00000000    ;10 ^ 1
	dc.l $40050000,$C8000000,$00000000    ;10 ^ 2
	dc.l $400C0000,$9C400000,$00000000    ;10 ^ 4
	dc.l $40190000,$BEBC2000,$00000000    ;10 ^ 8
	dc.l $40340000,$8E1BC9BF,$04000000    ;10 ^ 16
	dc.l $40690000,$9DC5ADA8,$2B70B59E    ;10 ^ 32
	dc.l $40D30000,$C2781F49,$FFCFA6D6    ;10 ^ 64
	dc.l $41A80000,$93BA47C9,$80E98CE0    ;10 ^ 128
	dc.l $43510000,$AA7EEBFB,$9DF9DE8E    ;10 ^ 256
	dc.l $46A30000,$E319A0AE,$A60E91C7    ;10 ^ 512
	dc.l $4D480000,$C9767586,$81750C18    ;10 ^ 1024
	dc.l $5A920000,$9E8B3B5D,$C53D5DE6    ;10 ^ 2048
	dc.l $75250000,$C4605202,$8A20979B    ;10 ^ 4096

	xref	nrm_zero
	xref	decbin
	xref	round

	xdef    get_op
	xdef    uns_getop
	xdef    uni_getop
get_op:
	clr.b	DY_MO_FLG(a6)
	tst.b	UFLG_TMP(a6)	;test flag for unsupp/unimp state
	beq.b	uni_getop

uns_getop:
	btst.b	#direction_bit,CMDREG1B(a6)
	bne.w	opclass3	;branch if a fmove out (any kind)
	btst.b	#6,CMDREG1B(a6)
	beq.b	uns_notpacked

	bfextu	CMDREG1B(a6){3:3},d0
	cmp.b	#3,d0
	beq.w	pack_source	;check for a packed src op, branch if so
uns_notpacked:
	bsr	chk_dy_mo	;set the dyadic/monadic flag
	tst.b	DY_MO_FLG(a6)
	beq.b	src_op_ck	;if monadic, go check src op
*				;else, check dst op (fall through)

	btst.b	#7,DTAG(a6)
	beq.b	src_op_ck	;if dst op is norm, check src op
	bra.b	dst_ex_dnrm	;else, handle destination unnorm/dnrm

uni_getop:
	bfextu	CMDREG1B(a6){0:6},d0 ;get opclass and src fields
	cmpi.l	#$17,d0		;if op class and size fields are $17, 
*				;it is FMOVECR; if not, continue
*
* If the instruction is fmovecr, exit get_op.  It is handled
* in do_func and smovecr.sa.
*
	bne.w	not_fmovecr	;handle fmovecr as an unimplemented inst
	rts

not_fmovecr:
	btst.b	#E1,E_BYTE(a6)	;if set, there is a packed operand
	bne.w	pack_source	;check for packed src op, branch if so

* The following lines of are coded to optimize on normalized operands
	move.b	STAG(a6),d0
	or.b	DTAG(a6),d0	;check if either of STAG/DTAG msb set
	bmi.b	dest_op_ck	;if so, some op needs to be fixed
	rts

dest_op_ck:
	btst.b	#7,DTAG(a6)	;check for unsupported data types in
	beq.b	src_op_ck	;the destination, if not, check src op
	bsr	chk_dy_mo	;set dyadic/monadic flag
	tst.b	DY_MO_FLG(a6)	;
	beq.b	src_op_ck	;if monadic, check src op
*
* At this point, destination has an extended denorm or unnorm.
*
dst_ex_dnrm:
	move.w	FPTEMP_EX(a6),d0 ;get destination exponent
	andi.w	#$7fff,d0	;mask sign, check if exp = 0000
	beq.b	src_op_ck	;if denorm then check source op.
*				;denorms are taken care of in res_func 
*				;(unsupp) or do_func (unimp)
*				;else unnorm fall through
	lea.l	FPTEMP(a6),a0	;point a0 to dop - used in mk_norm
	bsr	mk_norm		;go normalize - mk_norm returns:
*				;L_SCR1{7:5} = operand tag 
*				;	(000 = norm, 100 = denorm)
*				;L_SCR1{4} = fpte15 or ete15 
*				;	0 = exp >  $3fff
*				;	1 = exp <= $3fff
*				;and puts the normalized num back 
*				;on the fsave stack
*
	move.b L_SCR1(a6),DTAG(a6) ;write the new tag & fpte15 
*				;to the fsave stack and fall 
*				;through to check source operand
*
src_op_ck:
	btst.b	#7,STAG(a6)
	beq.w	end_getop	;check for unsupported data types on the
*				;source operand
	btst.b	#5,STAG(a6)
	bne.b	src_sd_dnrm	;if bit 5 set, handle sgl/dbl denorms
*
* At this point only unnorms or extended denorms are possible.
*
src_ex_dnrm:
	move.w	ETEMP_EX(a6),d0 ;get source exponent
	andi.w	#$7fff,d0	;mask sign, check if exp = 0000
	beq.w	end_getop	;if denorm then exit, denorms are 
*				;handled in do_func
	lea.l	ETEMP(a6),a0	;point a0 to sop - used in mk_norm
	bsr	mk_norm		;go normalize - mk_norm returns:
*				;L_SCR1{7:5} = operand tag 
*				;	(000 = norm, 100 = denorm)
*				;L_SCR1{4} = fpte15 or ete15 
*				;	0 = exp >  $3fff
*				;	1 = exp <= $3fff
*				;and puts the normalized num back 
*				;on the fsave stack
*
	move.b	L_SCR1(a6),STAG(a6) ;write the new tag & ete15 
	rts			;end_getop

*
* At this point, only single or double denorms are possible.
* If the inst is not fmove, normalize the source.  If it is,
* do nothing to the input.
*
src_sd_dnrm:
	btst.b	#4,CMDREG1B(a6)	;differentiate between sgl/dbl denorm
	bne.b	is_double
is_single:
	move.w	#$3f81,d1	;write bias for sgl denorm
	bra.b	common		;goto the common code
is_double:
	move.w	#$3c01,d1	;write the bias for a dbl denorm
common:
	btst.b	#sign_bit,ETEMP_EX(a6) ;grab sign bit of mantissa
	beq.b	pos	
	bset	#15,d1		;set sign bit because it is negative
pos:
	move.w	d1,ETEMP_EX(a6)
*				;put exponent on stack

	move.w	CMDREG1B(a6),d1
	and.w	#$e3ff,d1	;clear out source specifier
	or.w	#$0800,d1	;set source specifier to extended prec
	move.w	d1,CMDREG1B(a6)	;write back to the command word in stack
*				;this is needed to fix unsupp data stack
	lea.l	ETEMP(a6),a0	;point a0 to sop
	
	bsr	mk_norm		;convert sgl/dbl denorm to norm
	move.b	L_SCR1(a6),STAG(a6) ;put tag into source tag reg - d0
	rts			;end_getop
*
* At this point, the source is definitely packed, whether
* instruction is dyadic or monadic is still unknown
*
pack_source:
	move.l	FPTEMP_LO(a6),ETEMP(a6)	;write ms part of packed 
*				;number to etemp slot
	bsr	chk_dy_mo	;set dyadic/monadic flag
	bsr	unpack

	tst.b	DY_MO_FLG(a6)
	beq.b	end_getop	;if monadic, exit
*				;else, fix FPTEMP
pack_dya:
	bfextu	CMDREG1B(a6){6:3},d0 ;extract dest fp reg
	move.l	#7,d1
	sub.l	d0,d1
	clr.l	d0
	bset.l	d1,d0		;set up d0 as a dynamic register mask
	fmovem.x d0,FPTEMP(a6)	;write to FPTEMP

	btst.b	#7,DTAG(a6)	;check dest tag for unnorm or denorm
	bne.w	dst_ex_dnrm	;else, handle the unnorm or ext denorm
*
* Dest is not denormalized.  Check for norm, and set fpte15 
* accordingly.
*
	move.b	DTAG(a6),d0
	andi.b	#$f0,d0		;strip to only dtag:fpte15
	tst.b	d0		;check for normalized value
	bne.b	end_getop	;if inf/nan/zero leave get_op
	move.w	FPTEMP_EX(a6),d0
	andi.w	#$7fff,d0
	cmpi.w	#$3fff,d0	;check if fpte15 needs setting
	bge.b	end_getop	;if >= $3fff, leave fpte15=0
	or.b	#$10,DTAG(a6)
	bra.b	end_getop

*
* At this point, it is either an fmoveout packed, unnorm or denorm
*
opclass3:
	clr.b	DY_MO_FLG(a6)	;set dyadic/monadic flag to monadic
	bfextu	CMDREG1B(a6){4:2},d0
	cmpi.b	#3,d0
	bne.w	src_ex_dnrm	;if not equal, must be unnorm or denorm
*				;else it is a packed move out
*				;exit
end_getop:
	rts

*
* Sets the DY_MO_FLG correctly. This is used only on if it is an
* unuspported data type exception.  Set if dyadic.
*
chk_dy_mo:
	move.w	CMDREG1B(a6),d0	
	btst.l	#5,d0		;testing extension command word
	beq.b	set_mon		;if bit 5 = 0 then monadic
	btst.l	#4,d0		;know that bit 5 = 1
	beq.b	set_dya		;if bit 4 = 0 then dyadic
	andi.w	#$007f,d0	;get rid of all but extension bits {6:0}
	cmpi.w 	#$0038,d0	;if extension = $38 then fcmp (dyadic)
	bne.b	set_mon
set_dya:
	st.b	DY_MO_FLG(a6)	;set the inst flag type to dyadic
	rts
set_mon:
	clr.b	DY_MO_FLG(a6)	;set the inst flag type to monadic
	rts
*
*	MK_NORM
*
* Normalizes unnormalized numbers, sets tag to norm or denorm, sets unfl
* exception if denorm.
*
* CASE opclass 0x0 unsupp
*	mk_norm till msb set
*	set tag = norm
*
* CASE opclass 0x0 unimp
*	mk_norm till msb set or exp = 0
*	if integer bit = 0
*	   tag = denorm
*	else
*	   tag = norm
*
* CASE opclass 011 unsupp
*	mk_norm till msb set or exp = 0
*	if integer bit = 0
*	   tag = denorm
*	   set unfl_nmcexe = 1
*	else
*	   tag = norm
*
* if exp <= $3fff
*   set ete15 or fpte15 = 1
* else set ete15 or fpte15 = 0

* input:
*	a0 = points to operand to be normalized
* output:
*	L_SCR1{7:5} = operand tag (000 = norm, 100 = denorm)
*	L_SCR1{4}   = fpte15 or ete15 (0 = exp > $3fff, 1 = exp <=$3fff)
*	the normalized operand is placed back on the fsave stack
mk_norm:	
	clr.l	L_SCR1(a6)
	bclr.b	#sign_bit,LOCAL_EX(a0)
	sne	LOCAL_SGN(a0)	;transform into internal extended format

	cmpi.b	#$2c,1+EXC_VEC(a6) ;check if unimp
	bne.b	uns_data	;branch if unsupp
	bsr	uni_inst	;call if unimp (opclass 0x0)
	bra.b	reload
uns_data:
	btst.b	#direction_bit,CMDREG1B(a6) ;check transfer direction
	bne.b	bit_set		;branch if set (opclass 011)
	bsr	uns_opx		;call if opclass 0x0
	bra.b	reload
bit_set:
	bsr	uns_op3		;opclass 011
reload:
	cmp.w	#$3fff,LOCAL_EX(a0) ;if exp > $3fff
	bgt.b	end_mk		;   fpte15/ete15 already set to 0
	bset.b	#4,L_SCR1(a6)	;else set fpte15/ete15 to 1
*				;calling routine actually sets the 
*				;value on the stack (along with the 
*				;tag), since this routine doesn't 
*				;know if it should set ete15 or fpte15
*				;ie, it doesn't know if this is the 
*				;src op or dest op.
end_mk:
	bfclr	LOCAL_SGN(a0){0:8}
	beq.b	end_mk_pos
	bset.b	#sign_bit,LOCAL_EX(a0) ;convert back to IEEE format
end_mk_pos:
	rts
*
*     CASE opclass 011 unsupp
*
uns_op3:
	bsr	nrm_zero	;normalize till msb = 1 or exp = zero
	btst.b	#7,LOCAL_HI(a0)	;if msb = 1
	bne.b	no_unfl		;then branch
set_unfl:
	or.b	#dnrm_tag,L_SCR1(a6) ;set denorm tag
	bset.b	#unfl_bit,FPSR_EXCEPT(a6) ;set unfl exception bit
no_unfl:
	rts
*
*     CASE opclass 0x0 unsupp
*
uns_opx:
	bsr	nrm_zero	;normalize the number
	btst.b	#7,LOCAL_HI(a0)	;check if integer bit (j-bit) is set 
	beq.b	uns_den		;if clear then now have a denorm
uns_nrm:
	or.b	#norm_tag,L_SCR1(a6) ;set tag to norm
	rts
uns_den:
	or.b	#dnrm_tag,L_SCR1(a6) ;set tag to denorm
	rts
*
*     CASE opclass 0x0 unimp
*
uni_inst:
	bsr	nrm_zero
	btst.b	#7,LOCAL_HI(a0)	;check if integer bit (j-bit) is set 
	beq.b	uni_den		;if clear then now have a denorm
uni_nrm:
	or.b	#norm_tag,L_SCR1(a6) ;set tag to norm
	rts
uni_den:
	or.b	#dnrm_tag,L_SCR1(a6) ;set tag to denorm
	rts

*
*	Decimal to binary conversion
*
* Special cases of inf and NaNs are completed outside of decbin.  
* If the input is an snan, the snan bit is not set.
* 
* input:
*	ETEMP(a6)	- points to packed decimal string in memory
* output:
*	fp0	- contains packed string converted to extended precision
*	ETEMP	- same as fp0
unpack:
	move.w	CMDREG1B(a6),d0	;examine command word, looking for fmove's
	and.w	#$3b,d0
	beq	move_unpack	;special handling for fmove: must set FPSR_CC

	move.w	ETEMP(a6),d0	;get word with inf information
	bfextu	d0{20:12},d1	;get exponent into d1
	cmpi.w	#$0fff,d1	;test for inf or NaN
	bne.b	try_zero	;if not equal, it is not special
	bfextu	d0{17:3},d1	;get SE and y bits into d1
	cmpi.w	#7,d1		;SE and y bits must be on for special
	bne.b	try_zero	;if not on, it is not special
*input is of the special cases of inf and NaN
	tst.l	ETEMP_HI(a6)	;check ms mantissa
	bne.b	fix_nan		;if non-zero, it is a NaN
	tst.l	ETEMP_LO(a6)	;check ls mantissa
	bne.b	fix_nan		;if non-zero, it is a NaN
	bra.w	finish		;special already on stack
fix_nan:
	btst.b	#signan_bit,ETEMP_HI(a6) ;test for snan
	bne.w	finish
	or.l	#snaniop_mask,USER_FPSR(a6) ;always set snan if it is so
	bra.w	finish
try_zero:
	move.w	ETEMP_EX+2(a6),d0 ;get word 4
	andi.w	#$000f,d0	;clear all but last ni(y)bble
	tst.w	d0		;check for zero.
	bne.w	not_spec
	tst.l	ETEMP_HI(a6)	;check words 3 and 2
	bne.w	not_spec
	tst.l	ETEMP_LO(a6)	;check words 1 and 0
	bne.w	not_spec
	tst.l	ETEMP(a6)	;test sign of the zero
	bge.b	pos_zero
	move.l	#$80000000,ETEMP(a6) ;write neg zero to etemp
	clr.l	ETEMP_HI(a6)
	clr.l	ETEMP_LO(a6)
	bra.w	finish
pos_zero:
	clr.l	ETEMP(a6)
	clr.l	ETEMP_HI(a6)
	clr.l	ETEMP_LO(a6)
	bra.w	finish

not_spec:
	fmovem.x fp0-fp1,-(a7)	;save fp0 - decbin returns in it
	bsr	decbin
	fmove.x fp0,ETEMP(a6)	;put the unpacked sop in the fsave stack
	fmovem.x (a7)+,fp0-fp1
	fmove.l	#0,FPSR		;clr fpsr from decbin
	bra	finish

*
* Special handling for packed move in:  Same results as all other
* packed cases, but we must set the FPSR condition codes properly.
*
move_unpack:
	move.w	ETEMP(a6),d0	;get word with inf information
	bfextu	d0{20:12},d1	;get exponent into d1
	cmpi.w	#$0fff,d1	;test for inf or NaN
	bne.b	mtry_zero	;if not equal, it is not special
	bfextu	d0{17:3},d1	;get SE and y bits into d1
	cmpi.w	#7,d1		;SE and y bits must be on for special
	bne.b	mtry_zero	;if not on, it is not special
*input is of the special cases of inf and NaN
	tst.l	ETEMP_HI(a6)	;check ms mantissa
	bne.b	mfix_nan		;if non-zero, it is a NaN
	tst.l	ETEMP_LO(a6)	;check ls mantissa
	bne.b	mfix_nan		;if non-zero, it is a NaN
*input is inf
	or.l	#inf_mask,USER_FPSR(a6) ;set I bit
	tst.l	ETEMP(a6)	;check sign
	bge.w	finish
	or.l	#neg_mask,USER_FPSR(a6) ;set N bit
	bra.w	finish		;special already on stack
mfix_nan:
	or.l	#nan_mask,USER_FPSR(a6) ;set NaN bit
	move.b	#nan_tag,STAG(a6)	;set stag to NaN
	btst.b	#signan_bit,ETEMP_HI(a6) ;test for snan
	bne.b	mn_snan
	or.l	#snaniop_mask,USER_FPSR(a6) ;set snan bit
	btst.b	#snan_bit,FPCR_ENABLE(a6) ;test for snan enabled
	bne.b	mn_snan
	bset.b	#signan_bit,ETEMP_HI(a6) ;force snans to qnans
mn_snan:
	tst.l	ETEMP(a6)	;check for sign
	bge.w	finish		;if clr, go on
	or.l	#neg_mask,USER_FPSR(a6) ;set N bit
	bra.w	finish

mtry_zero:
	move.w	ETEMP_EX+2(a6),d0 ;get word 4
	andi.w	#$000f,d0	;clear all but last ni(y)bble
	tst.w	d0		;check for zero.
	bne.b	mnot_spec
	tst.l	ETEMP_HI(a6)	;check words 3 and 2
	bne.b	mnot_spec
	tst.l	ETEMP_LO(a6)	;check words 1 and 0
	bne.b	mnot_spec
	tst.l	ETEMP(a6)	;test sign of the zero
	bge.b	mpos_zero
	or.l	#neg_mask+z_mask,USER_FPSR(a6) ;set N and Z
	move.l	#$80000000,ETEMP(a6) ;write neg zero to etemp
	clr.l	ETEMP_HI(a6)
	clr.l	ETEMP_LO(a6)
	bra.b	finish
mpos_zero:
	or.l	#z_mask,USER_FPSR(a6) ;set Z
	clr.l	ETEMP(a6)
	clr.l	ETEMP_HI(a6)
	clr.l	ETEMP_LO(a6)
	bra.b	finish

mnot_spec:
	fmovem.x fp0-fp1,-(a7)	;save fp0 ,fp1 - decbin returns in fp0
	bsr	decbin
	fmove.x fp0,ETEMP(a6)
*				;put the unpacked sop in the fsave stack
	fmovem.x (a7)+,fp0-fp1

finish:
	move.w	CMDREG1B(a6),d0	;get the command word
	and.w	#$fbff,d0	;change the source specifier field to 
*				;extended (was packed).
	move.w	d0,CMDREG1B(a6)	;write command word back to fsave stack
*				;we need to do this so the 040 will 
*				;re-execute the inst. without taking 
*				;another packed trap.

fix_stag:
*Converted result is now in etemp on fsave stack, now set the source 
*tag (stag) 
*	if (ete =$7fff) then INF or NAN
*		if (etemp = $x.0----0) then
*			stag = INF
*		else
*			stag = NAN
*	else
*		if (ete = $0000) then
*			stag = ZERO
*		else
*			stag = NORM
*
* Note also that the etemp_15 bit (just right of the stag) must
* be set accordingly.  
*
	move.w		ETEMP_EX(a6),d1
	andi.w		#$7fff,d1   ;strip sign
	cmp.w  		#$7fff,d1
	bne.b  		z_or_nrm
	move.l		ETEMP_HI(a6),d1
	bne.b		is_nan
	move.l		ETEMP_LO(a6),d1
	bne.b		is_nan
is_inf:
	move.b		#$40,STAG(a6)
	move.l		#$40,d0
	rts
is_nan:
	move.b		#$60,STAG(a6)
	move.l		#$60,d0
	rts
z_or_nrm:
	tst.w		d1  
	bne.b		is_nrm
is_zro:
* For a zero, set etemp_15
	move.b		#$30,STAG(a6)
	move.l		#$20,d0
	rts
is_nrm:
* For a norm, check if the exp <= $3fff; if so, set etemp_15
	cmpi.w		#$3fff,d1
	ble.b		set_bit15
	clr.b		STAG(a6)
	bra.b		end_is_nrm
set_bit15:
	move.b		#$10,STAG(a6)
end_is_nrm:
	clr.l		d0
end_fix:
	rts
 
end_get:
	rts
	end