summaryrefslogtreecommitdiff
path: root/sysdeps/ia64/fpu/s_significand.S
blob: 720e043e5cb348445da37a1a8061a5bda2388b73 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
.file "significand.s"


// Copyright (c) 2000 - 2003, Intel Corporation
// All rights reserved.
//
// Contributed 2000 by the Intel Numerics Group, Intel Corporation
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// * The name of Intel Corporation may not be used to endorse or promote
// products derived from this software without specific prior written
// permission.

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS 
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 
// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
// 
// Intel Corporation is the author of this code, and requests that all
// problem reports or change requests be submitted to it directly at 
// http://www.intel.com/software/products/opensource/libraries/num.htm.
//
// History
//==============================================================
// 02/02/00 Initial version
// 04/04/00 Unwind support added
// 05/31/00 Fixed bug when x a double-extended denormal
// 05/20/02 Cleaned up namespace and sf0 syntax
// 02/10/03 Reordered header: .section, .global, .proc, .align
//
// API
//==============================================================
// double significand(double x)
//
// Overview of operation
//==============================================================
// If x = sig * 2**n with 1 <= sig < 2
// significand returns sig
//
// predicate registers used: 
// p6, p7
//
// floating-point registers used:  
// f8, f9, f10 

.section .text
GLOBAL_LIBM_ENTRY(significand)

// qnan snan inf norm     unorm 0 -+
// 1    1    1   0        0     1 11

// f10 gets f8(sign) with f1(exp,significand)
{ .mfi
      nop.m 999
      fmerge.s       f10 = f8,f1               
      nop.i 999
}
{ .mfi
      nop.m 999
      fnorm.s0          f9  = f8                  
      nop.i 999 ;;
}

// Test for denormal input
{ .mfi
      nop.m 999
      fclass.m.unc   p7,p0 = f8, 0x0b
      nop.i 999 ;;
}

// p6 = TRUE ==> x is not (nan,inf,0)
//               return sign(f8) exp(f1) significand(f8)
// else          x is (nan,inf,0)
//               return sign(f8) exp(f8) significand(f8), normalized.
{ .mfi
      nop.m 999
      fclass.m.unc   p0,p6 = f8, 0xe7          
      nop.i 999 ;;
}

{ .mmb
      nop.m 999
      nop.m 999
(p7)  br.cond.spnt SIGNIFICAND_DENORM ;; // Branch if x denormal
}

{ .mfi
      nop.m 999
(p6)  fmerge.se      f8 = f10,f8
      nop.i 999 ;;
}

{ .mfb
      nop.m 999
      fnorm.d.s0        f8 = f8                   
      br.ret.sptk    b0 ;;
}

SIGNIFICAND_DENORM:
// Here if x denorm
{ .mfi
      nop.m 999
      fmerge.se      f8 = f10,f9
      nop.i 999 ;;
}

// Check if fnorm(x) still denormal, means x double-extended denormal
{ .mfi
      nop.m 999
      fclass.m.unc   p7,p0 = f9, 0x0b
      nop.i 999 ;;
}

// This will be the final result unless x double-extended denormal
{ .mfi
      nop.m 999
      fnorm.d.s0        f8 = f8
      nop.i 999 ;;
}

// If x double-extended denorm, then significand ok, but must merge in
//    correct signexp
{ .mfi
      nop.m 999
(p7)  fmerge.se      f8 = f10,f8
      nop.i 999 ;;
}

// Final normalization if x double-extended denorm
{ .mfb
      nop.m 999
(p7)  fnorm.d.s0        f8 = f8
      br.ret.sptk    b0 ;;
}

GLOBAL_LIBM_END(significand)