m68k/fpsp040/gen_except.S

4 |	gen_except --- FPSP routine to detect reportable exceptions
6 |	This routine compares the exception enable byte of the
7 |	user_fpcr on the stack with the exception status byte
8 |	of the user_fpsr.
11 |	the stack frame in memory with the exceptional operand(s).
24 |	Note: The IEEE standard specifies that inex2 is to be
25 |	reported if ovfl occurs and the ovfl enable bit is not
26 |	set but the inex2 enable bit is.
32 |       For details on the license for this file, please see the
58 	cmpib	#IDLE_SIZE-4,1(%a7)	|test for idle frame
59 	beq	do_check		|go handle idle frame
60 	cmpib	#UNIMP_40_SIZE-4,1(%a7)	|test for orig unimp frame
61 	beqs	unimp_x			|go handle unimp frame
62 	cmpib	#UNIMP_41_SIZE-4,1(%a7)	|test for rev unimp frame
63 	beqs	unimp_x			|go handle unimp frame
64 	cmpib	#BUSY_SIZE-4,1(%a7)	|if size <> $60, fmt error
68 | Fix up the new busy frame with entries from the unimp frame
79 	orl	%d1,%d0			|put it in the right place
83 	orl	%d1,%d0			|put them in the right place
84 	movel	%d0,CMDREG3B(%a1)		|in the busy frame
86 | Or in the FPSR from the emulation with the USER_FPSR on the stack.
98 | a1 is modified to point into the new frame allowing fpsp equates
102 	cmpib	#UNIMP_40_SIZE-4,1(%a7)	|test for orig unimp frame
107 	cmpib	#UNIMP_41_SIZE-4,1(%a7)	|test for rev unimp frame
113 | Fix up the new unimp frame with entries from the old unimp frame
117 | Or in the FPSR from the emulation with the USER_FPSR on the stack.
125 | USER_FPSR and set the unimp frame accordingly.
126 | A7 must be incremented to the point before the
127 | idle fsave vector to the unimp vector.
133 | Or in the FPSR from the emulation with the USER_FPSR on the stack.
138 | On a busy frame, we must clear the nmnexc bits.
140 	cmpib	#BUSY_SIZE-4,1(%a7)	|check frame type
149 	cmpb	#UNIMP_40_SIZE-4,1(%a7)
154 	andb	FPSR_EXCEPT(%a6),%d0	|and in the fpsr exc byte
157 	subib	#24,%d1			|normalize bit offset to 0-8
159 |					;based on first enabled exc
167 | The typical work to be done to the unimp frame to report an
168 | exception is to set the E1/E3 byte and clr the U flag.
171 | are inex2 and inex1, and also clears the E1 exception bit
172 | left over from the unimp exception.
176 	bra	commonE			|go clean and exit
198 	orl	%d1,%d0			|put it in the right place
202 	orl	%d1,%d0			|put them in the right place
203 	movel	%d0,CMDREG3B(%a6)		|in the busy frame
207 	bra	do_clean		|go clean and exit
209 | No bits in the enable byte match existing exceptions.  Check for
210 | the case of the ovfl exc without the ovfl enabled, but with
218 	bras	ovfl_unfl		|go to unfl_ovfl to determine if
221 | No exceptions are to be reported.  If the instruction was
223 | unsupported, we must perform the restore.
231 	moveml	USER_DA(%a6),%d0-%d1/%a0-%a1
232 	fmovemx USER_FP0(%a6),%fp0-%fp3
249 |   Any of the other Library Routines such that f(x)=x in which
251 |   It is the responsibility of the exception-causing exception
254 |   The exceptional operand is in FP_SCR1.
260 | The caller was from an unsupported data type trap.  Test if the
261 | caller set CU_ONLY.  If so, the exceptional operand is expected in
264 	tstb	CU_ONLY(%a6)		|test if inst is cu-only
274 	bra	do_clean		|go clean and exit
278 	cmpib	#BUSY_SIZE-4,1(%a7)	|check for busy frame
292 	clrl	-(%a7)			|clear and dec a7
295 	moveb	#BUSY_SIZE-4,1(%a7)		|write busy fmt word.
310 	orl	%d1,%d0			|put it in the right place
314 	orl	%d1,%d0			|put them in the right place
315 	movel	%d0,CMDREG3B(%a6)		|in the busy frame
318 | Check if the frame to be restored is busy or unimp.
320 | If the frame is unimp, we must create a busy frame to
321 | fix the bug with the nmnexc bits in cases in which they
323 | the save. The frame will be unimp only if the final
324 | instruction in an emulation routine caused the exception
325 | by doing an fmove <ea>,fp0.  The exception operand, in
329 	cmpib	#UNIMP_40_SIZE-4,1(%a7)
334 	cmpib	#UNIMP_41_SIZE-4,1(%a7)
342 	clrl	-(%a7)			|clear and dec a7
346 | busy frame was created as the result of an exception on the final
349 | We need to set the nmcexc bits if the exception is E1. Otherwise,
350 | the exc taken will be inex2.
354 	moveb	#BUSY_SIZE-4,1(%a7)
366 	moveml	USER_DA(%a6),%d0-%d1/%a0-%a1
367 	fmovemx USER_FP0(%a6),%fp0-%fp3
376 | If trace mode enabled, then go to trace handler.  This handler
378 | exception has been restored into the machine then the exception
379 | will occur upon execution of the fp inst.  This is not desirable
380 | in the kernel (supervisor mode).  See MC68040 manual Section 9.3.8.
390 | The address of the instruction that caused the
391 | exception is already in the integer stack (is
392 | the same as the saved friar)
394 | If the current frame is already a 6-word stack then all
395 | that needs to be done is to change the vector# to TRACE.
396 | If the frame is only a 4-word stack (meaning we got here
397 | on an Unsupported data type exception), then we need to grow
398 | the stack an extra 2 words and get the FPIAR from the FPU.
401 	bftst	EXC_VEC-4(%sp){#0:#4}
409 	fmovel	%fpiar,BUSY_SIZE+EXC_EA-4(%sp)
414 	movew	#TRACE_VEC,EXC_VEC-4(%a7)
417 |  This is a work-around for hardware bug 1384.
421 	fsave	-(%sp)
433 loop40:	clrl	-(%sp)
436 	movel	#0x40280000,-(%sp)
448 loop41:	clrl	-(%sp)
451 	movel	#0x41300000,-(%sp)
457 	bclrb	#etemp15_bit,-40(%a5)