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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/m68k/fpsp040/sgetem.S |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/m68k/fpsp040/sgetem.S')
-rw-r--r-- | arch/m68k/fpsp040/sgetem.S | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/arch/m68k/fpsp040/sgetem.S b/arch/m68k/fpsp040/sgetem.S new file mode 100644 index 000000000000..0fcbd045ba75 --- /dev/null +++ b/arch/m68k/fpsp040/sgetem.S | |||
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1 | | | ||
2 | | sgetem.sa 3.1 12/10/90 | ||
3 | | | ||
4 | | The entry point sGETEXP returns the exponent portion | ||
5 | | of the input argument. The exponent bias is removed | ||
6 | | and the exponent value is returned as an extended | ||
7 | | precision number in fp0. sGETEXPD handles denormalized | ||
8 | | numbers. | ||
9 | | | ||
10 | | The entry point sGETMAN extracts the mantissa of the | ||
11 | | input argument. The mantissa is converted to an | ||
12 | | extended precision number and returned in fp0. The | ||
13 | | range of the result is [1.0 - 2.0). | ||
14 | | | ||
15 | | | ||
16 | | Input: Double-extended number X in the ETEMP space in | ||
17 | | the floating-point save stack. | ||
18 | | | ||
19 | | Output: The functions return exp(X) or man(X) in fp0. | ||
20 | | | ||
21 | | Modified: fp0. | ||
22 | | | ||
23 | | | ||
24 | | Copyright (C) Motorola, Inc. 1990 | ||
25 | | All Rights Reserved | ||
26 | | | ||
27 | | THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA | ||
28 | | The copyright notice above does not evidence any | ||
29 | | actual or intended publication of such source code. | ||
30 | |||
31 | |SGETEM idnt 2,1 | Motorola 040 Floating Point Software Package | ||
32 | |||
33 | |section 8 | ||
34 | |||
35 | #include "fpsp.h" | ||
36 | |||
37 | |xref nrm_set | ||
38 | |||
39 | | | ||
40 | | This entry point is used by the unimplemented instruction exception | ||
41 | | handler. It points a0 to the input operand. | ||
42 | | | ||
43 | | | ||
44 | | | ||
45 | | SGETEXP | ||
46 | | | ||
47 | |||
48 | .global sgetexp | ||
49 | sgetexp: | ||
50 | movew LOCAL_EX(%a0),%d0 |get the exponent | ||
51 | bclrl #15,%d0 |clear the sign bit | ||
52 | subw #0x3fff,%d0 |subtract off the bias | ||
53 | fmovew %d0,%fp0 |move the exp to fp0 | ||
54 | rts | ||
55 | |||
56 | .global sgetexpd | ||
57 | sgetexpd: | ||
58 | bclrb #sign_bit,LOCAL_EX(%a0) | ||
59 | bsr nrm_set |normalize (exp will go negative) | ||
60 | movew LOCAL_EX(%a0),%d0 |load resulting exponent into d0 | ||
61 | subw #0x3fff,%d0 |subtract off the bias | ||
62 | fmovew %d0,%fp0 |move the exp to fp0 | ||
63 | rts | ||
64 | | | ||
65 | | | ||
66 | | This entry point is used by the unimplemented instruction exception | ||
67 | | handler. It points a0 to the input operand. | ||
68 | | | ||
69 | | | ||
70 | | | ||
71 | | SGETMAN | ||
72 | | | ||
73 | | | ||
74 | | For normalized numbers, leave the mantissa alone, simply load | ||
75 | | with an exponent of +/- $3fff. | ||
76 | | | ||
77 | .global sgetman | ||
78 | sgetman: | ||
79 | movel USER_FPCR(%a6),%d0 | ||
80 | andil #0xffffff00,%d0 |clear rounding precision and mode | ||
81 | fmovel %d0,%fpcr |this fpcr setting is used by the 882 | ||
82 | movew LOCAL_EX(%a0),%d0 |get the exp (really just want sign bit) | ||
83 | orw #0x7fff,%d0 |clear old exp | ||
84 | bclrl #14,%d0 |make it the new exp +-3fff | ||
85 | movew %d0,LOCAL_EX(%a0) |move the sign & exp back to fsave stack | ||
86 | fmovex (%a0),%fp0 |put new value back in fp0 | ||
87 | rts | ||
88 | |||
89 | | | ||
90 | | For denormalized numbers, shift the mantissa until the j-bit = 1, | ||
91 | | then load the exponent with +/1 $3fff. | ||
92 | | | ||
93 | .global sgetmand | ||
94 | sgetmand: | ||
95 | movel LOCAL_HI(%a0),%d0 |load ms mant in d0 | ||
96 | movel LOCAL_LO(%a0),%d1 |load ls mant in d1 | ||
97 | bsr shft |shift mantissa bits till msbit is set | ||
98 | movel %d0,LOCAL_HI(%a0) |put ms mant back on stack | ||
99 | movel %d1,LOCAL_LO(%a0) |put ls mant back on stack | ||
100 | bras sgetman | ||
101 | |||
102 | | | ||
103 | | SHFT | ||
104 | | | ||
105 | | Shifts the mantissa bits until msbit is set. | ||
106 | | input: | ||
107 | | ms mantissa part in d0 | ||
108 | | ls mantissa part in d1 | ||
109 | | output: | ||
110 | | shifted bits in d0 and d1 | ||
111 | shft: | ||
112 | tstl %d0 |if any bits set in ms mant | ||
113 | bnes upper |then branch | ||
114 | | ;else no bits set in ms mant | ||
115 | tstl %d1 |test if any bits set in ls mant | ||
116 | bnes cont |if set then continue | ||
117 | bras shft_end |else return | ||
118 | cont: | ||
119 | movel %d3,-(%a7) |save d3 | ||
120 | exg %d0,%d1 |shift ls mant to ms mant | ||
121 | bfffo %d0{#0:#32},%d3 |find first 1 in ls mant to d0 | ||
122 | lsll %d3,%d0 |shift first 1 to integer bit in ms mant | ||
123 | movel (%a7)+,%d3 |restore d3 | ||
124 | bras shft_end | ||
125 | upper: | ||
126 | |||
127 | moveml %d3/%d5/%d6,-(%a7) |save registers | ||
128 | bfffo %d0{#0:#32},%d3 |find first 1 in ls mant to d0 | ||
129 | lsll %d3,%d0 |shift ms mant until j-bit is set | ||
130 | movel %d1,%d6 |save ls mant in d6 | ||
131 | lsll %d3,%d1 |shift ls mant by count | ||
132 | movel #32,%d5 | ||
133 | subl %d3,%d5 |sub 32 from shift for ls mant | ||
134 | lsrl %d5,%d6 |shift off all bits but those that will | ||
135 | | ;be shifted into ms mant | ||
136 | orl %d6,%d0 |shift the ls mant bits into the ms mant | ||
137 | moveml (%a7)+,%d3/%d5/%d6 |restore registers | ||
138 | shft_end: | ||
139 | rts | ||
140 | |||
141 | |end | ||