||	gen_except.sa 3.7 1/16/92||	gen_except --- FPSP routine to detect reportable exceptions||	This routine compares the exception enable byte of the|	user_fpcr on the stack with the exception status byte|	of the user_fpsr.||	Any routine which may report an exceptions must load|	the stack frame in memory with the exceptional operand(s).||	Priority for exceptions is:||	Highest:	bsun|			snan|			operr|			ovfl|			unfl|			dz|			inex2|	Lowest:		inex1||	Note: The IEEE standard specifies that inex2 is to be|	reported if ovfl occurs and the ovfl enable bit is not|	set but the inex2 enable bit is.|||		Copyright (C) Motorola, Inc. 1990|			All Rights Reserved||	THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA|	The copyright notice above does not evidence any|	actual or intended publication of such source code.GEN_EXCEPT:    |idnt    2,1 | Motorola 040 Floating Point Software Package	|section 8#include "fpsp.h"	|xref	real_trace	|xref	fpsp_done	|xref	fpsp_fmt_errorexc_tbl:	.long	bsun_exc	.long	commonE1	.long	commonE1	.long	ovfl_unfl	.long	ovfl_unfl	.long	commonE1	.long	commonE3	.long	commonE3	.long	no_match	.global	gen_exceptgen_except:	cmpib	#IDLE_SIZE-4,1(%a7)	|test for idle frame	beq	do_check		|go handle idle frame	cmpib	#UNIMP_40_SIZE-4,1(%a7)	|test for orig unimp frame	beqs	unimp_x			|go handle unimp frame	cmpib	#UNIMP_41_SIZE-4,1(%a7)	|test for rev unimp frame	beqs	unimp_x			|go handle unimp frame	cmpib	#BUSY_SIZE-4,1(%a7)	|if size <> $60, fmt error	bnel	fpsp_fmt_error	leal	BUSY_SIZE+LOCAL_SIZE(%a7),%a1 |init a1 so fpsp.h|					;equates will work| Fix up the new busy frame with entries from the unimp frame|	movel	ETEMP_EX(%a6),ETEMP_EX(%a1) |copy etemp from unimp	movel	ETEMP_HI(%a6),ETEMP_HI(%a1) |frame to busy frame	movel	ETEMP_LO(%a6),ETEMP_LO(%a1)	movel	CMDREG1B(%a6),CMDREG1B(%a1) |set inst in frame to unimp	movel	CMDREG1B(%a6),%d0		|fix cmd1b to make it	andl	#0x03c30000,%d0		|work for cmd3b	bfextu	CMDREG1B(%a6){#13:#1},%d1	|extract bit 2	lsll	#5,%d1	swap	%d1	orl	%d1,%d0			|put it in the right place	bfextu	CMDREG1B(%a6){#10:#3},%d1	|extract bit 3,4,5	lsll	#2,%d1	swap	%d1	orl	%d1,%d0			|put them in the right place	movel	%d0,CMDREG3B(%a1)		|in the busy frame|| Or in the FPSR from the emulation with the USER_FPSR on the stack.|	fmovel	%FPSR,%d0	orl	%d0,USER_FPSR(%a6)	movel	USER_FPSR(%a6),FPSR_SHADOW(%a1) |set exc bits	orl	#sx_mask,E_BYTE(%a1)	bra	do_clean|| Frame is an unimp frame possible resulting from an fmove <ea>,fp0| that caused an exception|| a1 is modified to point into the new frame allowing fpsp equates| to be valid.|unimp_x:	cmpib	#UNIMP_40_SIZE-4,1(%a7)	|test for orig unimp frame	bnes	test_rev	leal	UNIMP_40_SIZE+LOCAL_SIZE(%a7),%a1	bras	unimp_contest_rev:	cmpib	#UNIMP_41_SIZE-4,1(%a7)	|test for rev unimp frame	bnel	fpsp_fmt_error		|if not $28 or $30	leal	UNIMP_41_SIZE+LOCAL_SIZE(%a7),%a1unimp_con:|| Fix up the new unimp frame with entries from the old unimp frame|	movel	CMDREG1B(%a6),CMDREG1B(%a1) |set inst in frame to unimp|| Or in the FPSR from the emulation with the USER_FPSR on the stack.|	fmovel	%FPSR,%d0	orl	%d0,USER_FPSR(%a6)	bra	do_clean|| Frame is idle, so check for exceptions reported through| USER_FPSR and set the unimp frame accordingly.| A7 must be incremented to the point before the| idle fsave vector to the unimp vector.|do_check:	addl	#4,%a7			|point A7 back to unimp frame|| Or in the FPSR from the emulation with the USER_FPSR on the stack.|	fmovel	%FPSR,%d0	orl	%d0,USER_FPSR(%a6)|| On a busy frame, we must clear the nmnexc bits.|	cmpib	#BUSY_SIZE-4,1(%a7)	|check frame type	bnes	check_fr		|if busy, clr nmnexc	clrw	NMNEXC(%a6)		|clr nmnexc & nmcexc	btstb	#5,CMDREG1B(%a6)		|test for fmove out	bnes	frame_com	movel	USER_FPSR(%a6),FPSR_SHADOW(%a6) |set exc bits	orl	#sx_mask,E_BYTE(%a6)	bras	frame_comcheck_fr:	cmpb	#UNIMP_40_SIZE-4,1(%a7)	beqs	frame_com	clrw	NMNEXC(%a6)frame_com:	moveb	FPCR_ENABLE(%a6),%d0	|get fpcr enable byte	andb	FPSR_EXCEPT(%a6),%d0	|and in the fpsr exc byte	bfffo	%d0{#24:#8},%d1		|test for first set bit	leal	exc_tbl,%a0		|load jmp table address	subib	#24,%d1			|normalize bit offset to 0-8	movel	(%a0,%d1.w*4),%a0		|load routine address based|					;based on first enabled exc	jmp	(%a0)			|jump to routine|| Bsun is not possible in unimp or unsupp|bsun_exc:	bra	do_clean|| The typical work to be done to the unimp frame to report an| exception is to set the E1/E3 byte and clr the U flag.| commonE1 does this for E1 exceptions, which are snan,| operr, and dz.  commonE3 does this for E3 exceptions, which| are inex2 and inex1, and also clears the E1 exception bit| left over from the unimp exception.|commonE1:	bsetb	#E1,E_BYTE(%a6)		|set E1 flag	bra	commonE			|go clean and exitcommonE3:	tstb	UFLG_TMP(%a6)		|test flag for unsup/unimp state	bnes	unsE3uniE3:	bsetb	#E3,E_BYTE(%a6)		|set E3 flag	bclrb	#E1,E_BYTE(%a6)		|clr E1 from unimp	bra	commonEunsE3:	tstb	RES_FLG(%a6)	bnes	unsE3_0unsE3_1:	bsetb	#E3,E_BYTE(%a6)		|set E3 flagunsE3_0:	bclrb	#E1,E_BYTE(%a6)		|clr E1 flag	movel	CMDREG1B(%a6),%d0	andl	#0x03c30000,%d0		|work for cmd3b	bfextu	CMDREG1B(%a6){#13:#1},%d1	|extract bit 2	lsll	#5,%d1	swap	%d1	orl	%d1,%d0			|put it in the right place	bfextu	CMDREG1B(%a6){#10:#3},%d1	|extract bit 3,4,5	lsll	#2,%d1	swap	%d1	orl	%d1,%d0			|put them in the right place	movel	%d0,CMDREG3B(%a6)		|in the busy framecommonE:	bclrb	#UFLAG,T_BYTE(%a6)	|clr U flag from unimp	bra	do_clean		|go clean and exit|| No bits in the enable byte match existing exceptions.  Check for| the case of the ovfl exc without the ovfl enabled, but with| inex2 enabled.|no_match:	btstb	#inex2_bit,FPCR_ENABLE(%a6) |check for ovfl/inex2 case	beqs	no_exc			|if clear, exit	btstb	#ovfl_bit,FPSR_EXCEPT(%a6) |now check ovfl	beqs	no_exc			|if clear, exit	bras	ovfl_unfl		|go to unfl_ovfl to determine if|					;it is an unsupp or unimp exc| No exceptions are to be reported.  If the instruction was| unimplemented, no FPU restore is necessary.  If it was| unsupported, we must perform the restore.no_exc:	tstb	UFLG_TMP(%a6)	|test flag for unsupp/unimp state	beqs	uni_no_excuns_no_exc:	tstb	RES_FLG(%a6)	|check if frestore is needed	bne	do_clean	|if clear, no frestore neededuni_no_exc:	moveml	USER_DA(%a6),%d0-%d1/%a0-%a1	fmovemx USER_FP0(%a6),%fp0-%fp3	fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar	unlk	%a6	bra	finish_up|| Unsupported Data Type Handler:| Ovfl:|   An fmoveout that results in an overflow is reported this way.| Unfl:|   An fmoveout that results in an underflow is reported this way.|| Unimplemented Instruction Handler:| Ovfl:|   Only scosh, setox, ssinh, stwotox, and scale can set overflow in|   this manner.| Unfl:|   Stwotox, setox, and scale can set underflow in this manner.|   Any of the other Library Routines such that f(x)=x in which|   x is an extended denorm can report an underflow exception.|   It is the responsibility of the exception-causing exception|   to make sure that WBTEMP is correct.||   The exceptional operand is in FP_SCR1.|ovfl_unfl:	tstb	UFLG_TMP(%a6)	|test flag for unsupp/unimp state	beqs	ofuf_con|| The caller was from an unsupported data type trap.  Test if the| caller set CU_ONLY.  If so, the exceptional operand is expected in| FPTEMP, rather than WBTEMP.|	tstb	CU_ONLY(%a6)		|test if inst is cu-only	beq	unsE3|	move.w	#$fe,CU_SAVEPC(%a6)	clrb	CU_SAVEPC(%a6)	bsetb	#E1,E_BYTE(%a6)		|set E1 exception flag	movew	ETEMP_EX(%a6),FPTEMP_EX(%a6)	movel	ETEMP_HI(%a6),FPTEMP_HI(%a6)	movel	ETEMP_LO(%a6),FPTEMP_LO(%a6)	bsetb	#fptemp15_bit,DTAG(%a6)	|set fpte15	bclrb	#UFLAG,T_BYTE(%a6)	|clr U flag from unimp	bra	do_clean		|go clean and exitofuf_con:	moveb	(%a7),VER_TMP(%a6)	|save version number	cmpib	#BUSY_SIZE-4,1(%a7)	|check for busy frame	beqs	busy_fr			|if unimp, grow to busy	cmpib	#VER_40,(%a7)		|test for orig unimp frame	bnes	try_41			|if not, test for rev frame	moveql	#13,%d0			|need to zero 14 lwords	bras	ofuf_fintry_41:	cmpib	#VER_41,(%a7)		|test for rev unimp frame	bnel	fpsp_fmt_error		|if neither, exit with error	moveql	#11,%d0			|need to zero 12 lwordsofuf_fin:	clrl	(%a7)loop1:	clrl	-(%a7)			|clear and dec a7	dbra	%d0,loop1	moveb	VER_TMP(%a6),(%a7)	moveb	#BUSY_SIZE-4,1(%a7)		|write busy fmt word.busy_fr:	movel	FP_SCR1(%a6),WBTEMP_EX(%a6)	|write	movel	FP_SCR1+4(%a6),WBTEMP_HI(%a6)	|exceptional op to	movel	FP_SCR1+8(%a6),WBTEMP_LO(%a6)	|wbtemp	bsetb	#E3,E_BYTE(%a6)			|set E3 flag	bclrb	#E1,E_BYTE(%a6)			|make sure E1 is clear	bclrb	#UFLAG,T_BYTE(%a6)		|clr U flag	movel	USER_FPSR(%a6),FPSR_SHADOW(%a6)	orl	#sx_mask,E_BYTE(%a6)	movel	CMDREG1B(%a6),%d0		|fix cmd1b to make it	andl	#0x03c30000,%d0		|work for cmd3b	bfextu	CMDREG1B(%a6){#13:#1},%d1	|extract bit 2	lsll	#5,%d1	swap	%d1	orl	%d1,%d0			|put it in the right place	bfextu	CMDREG1B(%a6){#10:#3},%d1	|extract bit 3,4,5	lsll	#2,%d1	swap	%d1	orl	%d1,%d0			|put them in the right place	movel	%d0,CMDREG3B(%a6)		|in the busy frame|| Check if the frame to be restored is busy or unimp.|** NOTE *** Bug fix for errata (0d43b #3)| If the frame is unimp, we must create a busy frame to| fix the bug with the nmnexc bits in cases in which they| are set by a previous instruction and not cleared by| the save. The frame will be unimp only if the final| instruction in an emulation routine caused the exception| by doing an fmove <ea>,fp0.  The exception operand, in| internal format, is in fptemp.|do_clean:	cmpib	#UNIMP_40_SIZE-4,1(%a7)	bnes	do_con	moveql	#13,%d0			|in orig, need to zero 14 lwords	bras	do_builddo_con:	cmpib	#UNIMP_41_SIZE-4,1(%a7)	bnes	do_restore		|frame must be busy	moveql	#11,%d0			|in rev, need to zero 12 lwordsdo_build:	moveb	(%a7),VER_TMP(%a6)	clrl	(%a7)loop2:	clrl	-(%a7)			|clear and dec a7	dbra	%d0,loop2|| Use a1 as pointer into new frame.  a6 is not correct if an unimp or| busy frame was created as the result of an exception on the final| instruction of an emulation routine.|| We need to set the nmcexc bits if the exception is E1. Otherwise,| the exc taken will be inex2.|	leal	BUSY_SIZE+LOCAL_SIZE(%a7),%a1	|init a1 for new frame	moveb	VER_TMP(%a6),(%a7)	|write busy fmt word	moveb	#BUSY_SIZE-4,1(%a7)	movel	FP_SCR1(%a6),WBTEMP_EX(%a1)	|write	movel	FP_SCR1+4(%a6),WBTEMP_HI(%a1)	|exceptional op to	movel	FP_SCR1+8(%a6),WBTEMP_LO(%a1)	|wbtemp|	btst.b	#E1,E_BYTE(%a1)|	beq.b	do_restore	bfextu	USER_FPSR(%a6){#17:#4},%d0	|get snan/operr/ovfl/unfl bits	bfins	%d0,NMCEXC(%a1){#4:#4}	|and insert them in nmcexc	movel	USER_FPSR(%a6),FPSR_SHADOW(%a1) |set exc bits	orl	#sx_mask,E_BYTE(%a1)do_restore:	moveml	USER_DA(%a6),%d0-%d1/%a0-%a1	fmovemx USER_FP0(%a6),%fp0-%fp3	fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar	frestore (%a7)+	tstb	RES_FLG(%a6)	|RES_FLG indicates a "continuation" frame	beq	cont	bsr	bug1384cont:	unlk	%a6|| If trace mode enabled, then go to trace handler.  This handler| cannot have any fp instructions.  If there are fp inst's and an| exception has been restored into the machine then the exception| will occur upon execution of the fp inst.  This is not desirable| in the kernel (supervisor mode).  See MC68040 manual Section 9.3.8.|finish_up:	btstb	#7,(%a7)		|test T1 in SR	bnes	g_trace	btstb	#6,(%a7)		|test T0 in SR	bnes	g_trace	bral	fpsp_done|| Change integer stack to look like trace stack| The address of the instruction that caused the| exception is already in the integer stack (is| the same as the saved friar)|| If the current frame is already a 6-word stack then all| that needs to be done is to change the vector# to TRACE.| If the frame is only a 4-word stack (meaning we got here| on an Unsupported data type exception), then we need to grow| the stack an extra 2 words and get the FPIAR from the FPU.|g_trace:	bftst	EXC_VEC-4(%sp){#0:#4}	bne	g_easy	subw	#4,%sp		| make room	movel	4(%sp),(%sp)	movel	8(%sp),4(%sp)	subw	#BUSY_SIZE,%sp	fsave	(%sp)	fmovel	%fpiar,BUSY_SIZE+EXC_EA-4(%sp)	frestore (%sp)	addw	#BUSY_SIZE,%spg_easy:	movew	#TRACE_VEC,EXC_VEC-4(%a7)	bral	real_trace||  This is a work-around for hardware bug 1384.|bug1384:	link	%a5,#0	fsave	-(%sp)	cmpib	#0x41,(%sp)	| check for correct frame	beq	frame_41	bgt	nofix		| if more advanced mask, do nadaframe_40:	tstb	1(%sp)		| check to see if idle	bne	notidleidle40:	clrl	(%sp)		| get rid of old fsave frame        movel  %d1,USER_D1(%a6)  | save d1	movew	#8,%d1		| place unimp frame insteadloop40:	clrl	-(%sp)	dbra	%d1,loop40        movel  USER_D1(%a6),%d1  | restore d1	movel	#0x40280000,-(%sp)	frestore (%sp)+	unlk	%a5	rtsframe_41:	tstb	1(%sp)		| check to see if idle	bne	notidleidle41:	clrl	(%sp)		| get rid of old fsave frame        movel  %d1,USER_D1(%a6)  | save d1	movew	#10,%d1		| place unimp frame insteadloop41:	clrl	-(%sp)	dbra	%d1,loop41        movel  USER_D1(%a6),%d1  | restore d1	movel	#0x41300000,-(%sp)	frestore (%sp)+	unlk	%a5	rtsnotidle:	bclrb	#etemp15_bit,-40(%a5)	frestore (%sp)+	unlk	%a5	rtsnofix:	frestore (%sp)+	unlk	%a5	rts	|end