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

*	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.
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*
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*
*	You are hereby granted a copyright license to use, modify, and
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*
*	x_unsupp.sa 3.3 7/1/91
*
*	fpsp_unsupp --- FPSP handler for unsupported data type exception
*
* Trap vector #55	(See table 8-1 Mc68030 User's manual).	
* Invoked when the user program encounters a data format (packed) that
* hardware does not support or a data type (denormalized numbers or un-
* normalized numbers).
* Normalizes denorms and unnorms, unpacks packed numbers then stores 
* them back into the machine to let the 040 finish the operation.  
*
* Unsupp calls two routines:
* 	1. get_op -  gets the operand(s)
* 	2. res_func - restore the function back into the 040 or
* 			if fmove.p fpm,<ea> then pack source (fpm)
* 			and store in users memory <ea>.
*
*  Input: Long fsave stack frame
*

X_UNSUPP	IDNT    2,1 Motorola 040 Floating Point Software Package

	section	8

	include	fpsp.h

	xref	get_op
	xref	res_func
	xref	gen_except
	xref	fpsp_fmt_error

	xdef	fpsp_unsupp
fpsp_unsupp:
*
	link		a6,#-LOCAL_SIZE
	fsave		-(a7)
	movem.l		d0-d1/a0-a1,USER_DA(a6)
	fmovem.x	fp0-fp3,USER_FP0(a6)
	fmovem.l	fpcr/fpsr/fpiar,USER_FPCR(a6)


	move.b		(a7),VER_TMP(a6) ;save version number
	move.b		(a7),d0		;test for valid version num
	andi.b		#$f0,d0		;test for $4x
	cmpi.b		#VER_4,d0	;must be $4x or exit
	bne.l		fpsp_fmt_error

	fmove.l		#0,FPSR		;clear all user status bits
	fmove.l		#0,FPCR		;clear all user control bits
*
*	The following lines are used to ensure that the FPSR
*	exception byte and condition codes are clear before proceeding,
*	except in the case of fmove, which leaves the cc's intact.
*
unsupp_con:
	move.l		USER_FPSR(a6),d1
	btst		#5,CMDREG1B(a6)	;looking for fmove out
	bne		fmove_con
	and.l		#$FF00FF,d1	;clear all but aexcs and qbyte
	bra.b		end_fix
fmove_con:
	and.l		#$0FFF40FF,d1	;clear all but cc's, snan bit, aexcs, and qbyte
end_fix:
	move.l		d1,USER_FPSR(a6)

	st		UFLG_TMP(a6)	;set flag for unsupp data

	bsr.l		get_op		;everything okay, go get operand(s)
	bsr.l		res_func	;fix up stack frame so can restore it
	clr.l		-(a7)
	move.b		VER_TMP(a6),(a7) ;move idle fmt word to top of stack
	bra.l		gen_except
*
	end