|
  |	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
  |
  |
  
  |		Copyright (C) Motorola, Inc. 1990
  |			All Rights Reserved
  |

  |       For details on the license for this file, please see the
  |       file, README, in this same directory.

  
  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
  
  	.global	fpsp_unsupp
  fpsp_unsupp:
  |
  	link		%a6,#-LOCAL_SIZE
  	fsave		-(%a7)
  	moveml		%d0-%d1/%a0-%a1,USER_DA(%a6)
  	fmovemx	%fp0-%fp3,USER_FP0(%a6)
  	fmoveml	%fpcr/%fpsr/%fpiar,USER_FPCR(%a6)
  
  
  	moveb		(%a7),VER_TMP(%a6) |save version number
  	moveb		(%a7),%d0		|test for valid version num
  	andib		#0xf0,%d0		|test for $4x
  	cmpib		#VER_4,%d0	|must be $4x or exit
  	bnel		fpsp_fmt_error
  
  	fmovel		#0,%FPSR		|clear all user status bits
  	fmovel		#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:
  	movel		USER_FPSR(%a6),%d1
  	btst		#5,CMDREG1B(%a6)	|looking for fmove out
  	bne		fmove_con
  	andl		#0xFF00FF,%d1	|clear all but aexcs and qbyte
  	bras		end_fix
  fmove_con:
  	andl		#0x0FFF40FF,%d1	|clear all but cc's, snan bit, aexcs, and qbyte
  end_fix:
  	movel		%d1,USER_FPSR(%a6)
  
  	st		UFLG_TMP(%a6)	|set flag for unsupp data
  
  	bsrl		get_op		|everything okay, go get operand(s)
  	bsrl		res_func	|fix up stack frame so can restore it
  	clrl		-(%a7)
  	moveb		VER_TMP(%a6),(%a7) |move idle fmt word to top of stack
  	bral		gen_except
  |
  	|end