x_fline.S

  1|
  2|	x_fline.sa 3.3 1/10/91
  3|
  4|	fpsp_fline --- FPSP handler for fline exception
  5|
  6|	First determine if the exception is one of the unimplemented
  7|	floating point instructions.  If so, let fpsp_unimp handle it.
  8|	Next, determine if the instruction is an fmovecr with a non-zero
  9|	<ea> field.  If so, handle here and return.  Otherwise, it
 10|	must be a real F-line exception.
 11|
 12
 13|		Copyright (C) Motorola, Inc. 1990
 14|			All Rights Reserved
 15|
 16|       For details on the license for this file, please see the
 17|       file, README, in this same directory.
 18
 19X_FLINE:	|idnt    2,1 | Motorola 040 Floating Point Software Package
 20
 21	|section	8
 22
 23#include "fpsp.h"
 24
 25	|xref	real_fline
 26	|xref	fpsp_unimp
 27	|xref	uni_2
 28	|xref	mem_read
 29	|xref	fpsp_fmt_error
 30
 31	.global	fpsp_fline
 32fpsp_fline:
 33|
 34|	check for unimplemented vector first.  Use EXC_VEC-4 because
 35|	the equate is valid only after a 'link a6' has pushed one more
 36|	long onto the stack.
 37|
 38	cmpw	#UNIMP_VEC,EXC_VEC-4(%a7)
 39	beql	fpsp_unimp
 40
 41|
 42|	fmovecr with non-zero <ea> handling here
 43|
 44	subl	#4,%a7		|4 accounts for 2-word difference
 45|				;between six word frame (unimp) and
 46|				;four word frame
 47	link	%a6,#-LOCAL_SIZE
 48	fsave	-(%a7)
 49	moveml	%d0-%d1/%a0-%a1,USER_DA(%a6)
 50	moveal	EXC_PC+4(%a6),%a0	|get address of fline instruction
 51	leal	L_SCR1(%a6),%a1	|use L_SCR1 as scratch
 52	movel	#4,%d0
 53	addl	#4,%a6		|to offset the sub.l #4,a7 above so that
 54|				;a6 can point correctly to the stack frame
 55|				;before branching to mem_read
 56	bsrl	mem_read
 57	subl	#4,%a6
 58	movel	L_SCR1(%a6),%d0	|d0 contains the fline and command word
 59	bfextu	%d0{#4:#3},%d1	|extract coprocessor id
 60	cmpib	#1,%d1		|check if cpid=1
 61	bne	not_mvcr	|exit if not
 62	bfextu	%d0{#16:#6},%d1
 63	cmpib	#0x17,%d1		|check if it is an FMOVECR encoding
 64	bne	not_mvcr
 65|				;if an FMOVECR instruction, fix stack
 66|				;and go to FPSP_UNIMP
 67fix_stack:
 68	cmpib	#VER_40,(%a7)	|test for orig unimp frame
 69	bnes	ck_rev
 70	subl	#UNIMP_40_SIZE-4,%a7 |emulate an orig fsave
 71	moveb	#VER_40,(%a7)
 72	moveb	#UNIMP_40_SIZE-4,1(%a7)
 73	clrw	2(%a7)
 74	bras	fix_con
 75ck_rev:
 76	cmpib	#VER_41,(%a7)	|test for rev unimp frame
 77	bnel	fpsp_fmt_error	|if not $40 or $41, exit with error
 78	subl	#UNIMP_41_SIZE-4,%a7 |emulate a rev fsave
 79	moveb	#VER_41,(%a7)
 80	moveb	#UNIMP_41_SIZE-4,1(%a7)
 81	clrw	2(%a7)
 82fix_con:
 83	movew	EXC_SR+4(%a6),EXC_SR(%a6) |move stacked sr to new position
 84	movel	EXC_PC+4(%a6),EXC_PC(%a6) |move stacked pc to new position
 85	fmovel	EXC_PC(%a6),%FPIAR |point FPIAR to fline inst
 86	movel	#4,%d1
 87	addl	%d1,EXC_PC(%a6)	|increment stacked pc value to next inst
 88	movew	#0x202c,EXC_VEC(%a6) |reformat vector to unimp
 89	clrl	EXC_EA(%a6)	|clear the EXC_EA field
 90	movew	%d0,CMDREG1B(%a6) |move the lower word into CMDREG1B
 91	clrl	E_BYTE(%a6)
 92	bsetb	#UFLAG,T_BYTE(%a6)
 93	moveml	USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
 94	bral	uni_2
 95
 96not_mvcr:
 97	moveml	USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
 98	frestore (%a7)+
 99	unlk	%a6
100	addl	#4,%a7
101	bral	real_fline
102
103	|end