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
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
|
.file "ilogbl.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
//==============================================================
// 02/03/00 Initial version
// 05/26/00 Fix bug when x a double-extended denormal;
// if x=0 call error routine, per C9X
// 08/15/00 Bundle added after call to __libm_error_support to properly
// set [the previously overwritten] GR_Parameter_RESULT.
// 01/20/01 Fixed result for x=0
// 05/20/02 Cleaned up namespace and sf0 syntax
// 01/20/03 Improved performance
//
// API
//==============================================================
// int ilogbl( long double x );
//
// Overview of operation
//==============================================================
// The ilogbl function extracts the exponent of x as an integer
// and returns it in r8
//
// ilogbl is similar to logbl but differs in the following ways:
// +-inf
// ilogbl: returns INT_MAX
// logbl: returns +inf
// Nan returns FP_LOGBNAN (which is either INT_MAX or INT_MIN)
// ilogbl: returns INT_MAX (7fffffff)
// logbl: returns QNAN (quietized SNAN)
// 0 returns FP_ILOGB0 (which is either INT_MIN or -INT_MAX)
// ilogbl: returns -INT_MAX (80000001)
// logbl: returns -inf, raises the divide-by-zero exception,
// and calls libm_error_support to set domain error
//
// Registers used
//==============================================================
// general registers used:
// r26 -> r39
// r36 -> r39 used as parameters to error path
//
// predicate registers used:
// p6 -> p10
// floating-point registers used:
// f9, f10, f11
// f8, input
rExpBias = r26
rExpMask = r27
rSignexp_x = r28
rExp_x = r29
rIntMax = r30
rExp_2to64 = r31
GR_SAVE_PFS = r32
rTrialResult = r33
GR_SAVE_B0 = r34
GR_SAVE_GP = r35
GR_Parameter_X = r36
GR_Parameter_Y = r37
GR_Parameter_RESULT = r38
GR_Parameter_TAG = r39
fTmp = f9
fNorm_x = f10
f2to64 = f11
.section .text
GLOBAL_LIBM_ENTRY(ilogbl)
// X NORMAL
// TrueExp_x = exp(f8) - 0xffff
// r8 = TrueExp_x
{ .mfi
getf.exp rSignexp_x = f8
fclass.m p8,p0 = f8, 0x0b // Test for x unorm
mov rExpBias = 0xffff // Exponent bias
}
{ .mfi
nop.m 0
fnorm.s1 fNorm_x = f8
mov rExpMask = 0x1ffff // Exponent mask
}
;;
// Form signexp of 2^64 in case need to scale denormal
{ .mfb
mov rExp_2to64 = 0x1003f
fclass.m p6,p9 = f8, 0x1e3 // Test x natval, nan, inf
(p8) br.cond.spnt ILOGB_DENORM // Branch if x unorm
}
;;
ILOGB_COMMON:
// Return here from ILOGB_DENORM
{ .mfi
and rExp_x = rSignexp_x, rExpMask // Get biased exponent
fclass.m p7,p10 = f8, 0x07 // Test x zero
nop.i 0
}
{ .mlx
nop.m 0
movl rIntMax = 0x000000007fffffff // Form INT_MAX
}
;;
.pred.rel "mutex",p6,p9
{ .mfi
(p9) sub r8 = rExp_x, rExpBias // Get true exponent for normal path
(p6) fma.s0 fTmp = f8, f8, f0 // Dummy to set Invalid flag
(p6) mov r8 = rIntMax // If nan, inf, return INT_MAX
}
{ .mbb
nop.m 0
(p7) br.cond.spnt ILOGB_ZERO // Branch if x zero
(p10) br.ret.sptk b0 // Exit if x not zero
}
;;
ILOGB_DENORM:
// Form 2^64 in case need to scale denormal
// Check to see if double-extended denormal
{ .mfi
setf.exp f2to64 = rExp_2to64
fclass.m p8,p0 = fNorm_x, 0x0b
nop.i 0
}
;;
{ .mfi
nop.m 0
fcmp.eq.s0 p7,p0 = f8, f0 // Dummy op to set denormal flag
nop.i 0
}
;;
// If double-extended denormal add 64 to exponent bias for scaling
// If double-extended denormal form x * 2^64 which is normal
{ .mfi
(p8) add rExpBias = 64, rExpBias
(p8) fmpy.s1 fNorm_x = fNorm_x, f2to64
nop.i 0
}
;;
// Logic is the same as normal path but use normalized input
{ .mib
getf.exp rSignexp_x = fNorm_x
nop.i 0
br.cond.sptk ILOGB_COMMON // Return to main path
}
;;
ILOGB_ZERO:
// Here if x zero
// Return INT_MIN, call error support
{ .mlx
alloc r32=ar.pfs,1,3,4,0
movl rTrialResult = 0x0000000080000000
}
{ .mib
mov GR_Parameter_TAG = 156 // Error code
nop.i 0
br.cond.sptk __libm_error_region // Call error support
}
;;
GLOBAL_LIBM_END(ilogbl)
LOCAL_LIBM_ENTRY(__libm_error_region)
.prologue
{ .mfi
add GR_Parameter_Y=-32,sp // Parameter 2 value
nop.f 0
.save ar.pfs,GR_SAVE_PFS
mov GR_SAVE_PFS=ar.pfs // Save ar.pfs
}
{ .mfi
.fframe 64
add sp=-64,sp // Create new stack
nop.f 0
mov GR_SAVE_GP=gp // Save gp
};;
{ .mmi
stfe [GR_Parameter_Y] = f0,16 // STORE Parameter 2 on stack
add GR_Parameter_X = 16,sp // Parameter 1 address
.save b0, GR_SAVE_B0
mov GR_SAVE_B0=b0 // Save b0
};;
.body
{ .mib
stfe [GR_Parameter_X] = f8 // STORE Parameter 1 on stack
add GR_Parameter_RESULT = 0,GR_Parameter_Y // Parameter 3 address
nop.b 0
}
{ .mib
stfe [GR_Parameter_Y] = f9 // Store Parameter 3 on stack
add GR_Parameter_Y = -16,GR_Parameter_Y
br.call.sptk b0=__libm_error_support# // Call error handling function
};;
{ .mmi
add GR_Parameter_RESULT = 48,sp
nop.m 0
nop.i 0
};;
{ .mmi
mov r8 = rTrialResult
.restore sp
add sp = 64,sp // Restore stack pointer
mov b0 = GR_SAVE_B0 // Restore return address
};;
{ .mib
mov gp = GR_SAVE_GP // Restore gp
mov ar.pfs = GR_SAVE_PFS // Restore ar.pfs
br.ret.sptk b0
};;
LOCAL_LIBM_END(__libm_error_region)
.type __libm_error_support#,@function
.global __libm_error_support#
|
