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
19 X_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
32 fpsp_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
67 fix_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
75 ck_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)
82 fix_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
96 not_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
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