aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/ia64/fpu/s_rint.S
blob: d04f06a31f05b2640e46a4a4372be1ee42a07cfd (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
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
.file "rint.s"

// Copyright (C) 2000, 2001, Intel Corporation
// All rights reserved.
// 
// Contributed 2/2/2000 by John Harrison, Ted Kubaska, Bob Norin, Shane Story,
// and Ping Tak Peter Tang of the Computational Software Lab, 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://developer.intel.com/opensource.
//
// History
//==============================================================
// 2/02/00: Initial version
// 2/08/01  Corrected behavior for all rounding modes.
//
// API
//==============================================================
// double rint(double x)

#include "libm_support.h"

//
// general registers used:  
//
rint_GR_FFFF      = r14
rint_GR_signexp   = r15
rint_GR_exponent  = r16
rint_GR_17ones    = r17
rint_GR_10033     = r18
rint_GR_fpsr      = r19
rint_GR_rcs0      = r20
rint_GR_rcs0_mask = r21


// predicate registers used: 
// p6-11

// floating-point registers used: 

RINT_NORM_f8      = f9                        
RINT_FFFF         = f10 
RINT_INEXACT      = f11 
RINT_FLOAT_INT_f8 = f12
RINT_INT_f8       = f13

// Overview of operation
//==============================================================

// double rint(double x)
// Return an integer value (represented as a double) that is x rounded to integer in current
// rounding mode 
// Inexact is set if x != rint(x)
// *******************************************************************************

// Set denormal flag for denormal input and
// and take denormal fault if necessary.

// Is the input an integer value already?

// double_extended
// if the exponent is >= 1003e => 3F(true) = 63(decimal)
// we have a significand of 64 bits 1.63-bits.
// If we multiply by 2^63, we no longer have a fractional part
// So input is an integer value already.

// double
// if the exponent is >= 10033 => 34(true) = 52(decimal)
// 34 + 3ff = 433
// we have a significand of 53 bits 1.52-bits. (implicit 1)
// If we multiply by 2^52, we no longer have a fractional part
// So input is an integer value already.

// single
// if the exponent is >= 10016 => 17(true) = 23(decimal)
// we have a significand of 53 bits 1.52-bits. (implicit 1)
// If we multiply by 2^52, we no longer have a fractional part
// So input is an integer value already.

// If x is NAN, ZERO, or INFINITY, then  return

// qnan snan inf norm     unorm 0 -+
// 1    1    1   0        0     1 11     0xe7


.align 32
.global rint#

.section .text
.proc  rint#
.align 32


rint: 
#ifdef _LIBC
.global __rint
.type __rint,@function
__rint:
#endif

{ .mfi
      mov rint_GR_fpsr = ar40           // Read the fpsr--need to check rc.s0
      fcvt.fx.s1     RINT_INT_f8  = f8
      addl            rint_GR_10033 = 0x10033, r0
}
{ .mfi
      mov        rint_GR_FFFF      = -1
      fnorm.s1        RINT_NORM_f8  = f8
      mov         rint_GR_17ones    = 0x1FFFF
;;
}

{ .mfi
      setf.sig    RINT_FFFF  = rint_GR_FFFF
      fclass.m.unc  p6,p0 = f8, 0xe7
      mov         rint_GR_rcs0_mask  = 0x0c00
;;
}

{ .mfb
	nop.m 999
(p6)  fnorm.d f8 = f8
(p6)  br.ret.spnt   b0    // Exit if x nan, inf, zero
;;
}

{ .mfi
	nop.m 999
      fcvt.xf         RINT_FLOAT_INT_f8   = RINT_INT_f8
	nop.i 999
;;
}

{ .mfi
      getf.exp rint_GR_signexp  = RINT_NORM_f8
      fcmp.eq.s0  p8,p0 = f8,f0      // Dummy op to set denormal
        nop.i 999
;;
}


{ .mii
	nop.m 999
	nop.i 999 
      and      rint_GR_exponent = rint_GR_signexp, rint_GR_17ones
;;
}

{ .mmi
      cmp.ge.unc      p7,p6 = rint_GR_exponent, rint_GR_10033
      and rint_GR_rcs0 = rint_GR_rcs0_mask, rint_GR_fpsr
	nop.i 999
;;
}

// Check to see if s0 rounding mode is round to nearest.  If not then set s2
// rounding mode to that of s0 and repeat conversions.
L(RINT_COMMON):
{ .mfb
      cmp.ne   p11,p0 = rint_GR_rcs0, r0
(p6) fclass.m.unc   p9,p10  = RINT_FLOAT_INT_f8, 0x07  // Test for result=0
(p11) br.cond.spnt L(RINT_NOT_ROUND_NEAREST)  // Branch if not round to nearest
;;
}

{ .mfi
	nop.m 999
(p6) fcmp.eq.unc.s1  p0,p8  = RINT_FLOAT_INT_f8, RINT_NORM_f8
	nop.i 999
}
{ .mfi
	nop.m 999
(p7) fnorm.d.s0   f8 = f8
	nop.i 999
;;
}

// If result is zero, merge sign of input
{ .mfi
     nop.m 999
(p9) fmerge.s f8 = f8, RINT_FLOAT_INT_f8
     nop.i 999
}
{ .mfi
      nop.m 999
(p10) fnorm.d f8 = RINT_FLOAT_INT_f8
     nop.i 999
;;
}

{ .mfb
     nop.m 999
(p8) fmpy.s0     RINT_INEXACT = RINT_FFFF,RINT_FFFF  // Dummy to set inexact
     br.ret.sptk    b0
;;
}

L(RINT_NOT_ROUND_NEAREST):
// Set rounding mode of s2 to that of s0
{ .mfi
      mov rint_GR_rcs0 = r0       // Clear so we don't come back here
      fsetc.s2     0x7f, 0x40
	nop.i 999
;;
}

{ .mfi
	nop.m 999
      fcvt.fx.s2     RINT_INT_f8  = f8
	nop.i 999
;;
}

{ .mfb
	nop.m 999
      fcvt.xf         RINT_FLOAT_INT_f8   = RINT_INT_f8
      br.cond.sptk  L(RINT_COMMON)
;;
}


.endp rint
ASM_SIZE_DIRECTIVE(rint)
#ifdef _LIBC
ASM_SIZE_DIRECTIVE(__rint)
#endif