xref: /openbmc/linux/arch/m68k/fpsp040/x_fline.S (revision e00d82d0)
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
104