4 // Copyright (c) 2000 - 2003, Intel Corporation
5 // All rights reserved.
8 // Redistribution and use in source and binary forms, with or without
9 // modification, are permitted provided that the following conditions are
12 // * Redistributions of source code must retain the above copyright
13 // notice, this list of conditions and the following disclaimer.
15 // * Redistributions in binary form must reproduce the above copyright
16 // notice, this list of conditions and the following disclaimer in the
17 // documentation and/or other materials provided with the distribution.
19 // * The name of Intel Corporation may not be used to endorse or promote
20 // products derived from this software without specific prior written
23 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS
27 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
28 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
29 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
30 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
31 // OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR TORT (INCLUDING
32 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 // Intel Corporation is the author of this code, and requests that all
36 // problem reports or change requests be submitted to it directly at
37 // http://www.intel.com/software/products/opensource/libraries/num.htm.
40 //==============================================================
41 // 02/02/00 Initial version
42 // 04/04/00 Improved speed, corrected result for NaN input
43 // 12/22/00 Fixed so inexact flag is never set, and invalid is not set for
44 // qnans nor for inputs larger than 2^63.
45 // 05/20/02 Cleaned up namespace and sf0 syntax
46 // 02/10/03 Reordered header: .section, .global, .proc, .align
49 //==============================================================
50 // double modf(double x, double *iptr)
51 // break a floating point x number into fraction and an exponent
53 // input floating point f8, address in r33
54 // output floating point f8 (x fraction), and *iptr (x integral part)
57 //==============================================================
59 // NO FRACTIONAL PART: HUGE
61 // for double-extended
62 // If the true exponent is greater than or equal 63
63 // 1003e ==> 1003e -ffff = 3f = 63(dec)
65 // If the true exponent is greater than or equal 52
66 // 10033 -ffff = 34 = 52(dec)
68 // If the true exponent is greater than or equal 23
69 // 10016 -ffff = 17 = 23(dec)
71 // we are already an integer (p9 true)
73 // NO INTEGER PART: SMALL
74 // Is f8 exponent less than register bias (that is, is it
75 // less than 1). If it is, get the right sign of
76 // zero and store this in iptr.
78 // CALCULATION: NOT HUGE, NOT SMALL
79 // To get the integer part
80 // Take the floating-point input and truncate
81 // then convert this integer to fp Call it MODF_INTEGER_PART
83 // Subtract MODF_INTEGER_PART from MODF_NORM_F8 to get fraction part
84 // Then put fraction part in f8
85 // put integer part MODF_INTEGER_PART into *iptr
88 //==============================================================
90 // predicate registers used:
94 // -----------------------+-----------------+-------------
95 // SMALL | NORMAL | HUGE
96 // p11 --------------->|<----- p12 ----->| <-------------- p9
97 // p10 --------------------------------->|
98 // p13 --------------------------------------------------->|
101 // floating-point registers used:
103 MODF_FRACTION_PART = f10
104 MODF_INTEGER_PART = f11
105 MODF_INT_INTEGER_PART = f12
108 // general registers used
110 modf_GR_no_frac = r15
118 GLOBAL_LIBM_ENTRY(modf)
120 // Main path is p9, p11, p8 FALSE and p12 TRUE
122 // Assume input is normalized and get signexp
123 // Normalize input just in case
124 // Form exponent bias
126 getf.exp modf_signexp = f8
127 fnorm.s0 MODF_NORM_F8 = f8
128 addl modf_GR_FFFF = 0xffff, r0
130 // Get integer part of input
131 // Form exponent mask
134 fcvt.fx.trunc.s1 MODF_INT_INTEGER_PART = f8
135 mov modf_17_ones = 0x1ffff ;;
139 // qnan snan inf norm unorm 0 -+
140 // 1 1 1 0 0 0 11 = 0xe3 NAN_INF
141 // Form biased exponent where input only has an integer part
144 fclass.m.unc p6,p13 = f8, 0xe3
145 addl modf_GR_no_frac = 0x10033, r0 ;;
148 // Mask to get exponent
150 // qnan snan inf norm unorm 0 -+
151 // 0 0 0 0 1 0 11 = 0x0b UNORM
152 // Set p13 to indicate calculation path, else p6 if nan or inf
154 and modf_exp = modf_17_ones, modf_signexp
155 fclass.m.unc p8,p0 = f8, 0x0b
159 // p11 <== SMALL, no integer part, fraction is everyting
160 // p9 <== HUGE, no fraction part, integer is everything
161 // p12 <== NORMAL, fraction part and integer part
163 (p13) cmp.lt.unc p11,p10 = modf_exp, modf_GR_FFFF
168 // Is x inf? p6 if inf, p7 if nan
170 (p10) cmp.ge.unc p9,p12 = modf_exp, modf_GR_no_frac
171 (p6) fclass.m.unc p6,p7 = f8, 0x23
172 (p8) br.cond.spnt MODF_DENORM ;;
176 // For HUGE set fraction to signed 0
179 (p9) fmerge.s f8 = f8,f0
182 // For HUGE set integer part to normalized input
185 (p9) fnorm.d.s0 MODF_INTEGER_PART = MODF_NORM_F8
189 // For SMALL set fraction to normalized input, integer part to signed 0
192 (p11) fmerge.s MODF_INTEGER_PART = f8,f0
197 (p11) fnorm.d.s0 f8 = MODF_NORM_F8
201 // For NORMAL float the integer part
204 (p12) fcvt.xf MODF_INTEGER_PART = MODF_INT_INTEGER_PART
208 // If x inf set integer part to INF, fraction to signed 0
210 (p6) stfd [r33] = MODF_NORM_F8
211 (p6) fmerge.s f8 = f8,f0
215 // If x nan set integer and fraction parts to NaN (quietized)
217 (p7) stfd [r33] = MODF_NORM_F8
218 (p7) fmerge.s f8 = MODF_NORM_F8, MODF_NORM_F8
223 (p9) stfd [r33] = MODF_INTEGER_PART
228 // For NORMAL compute fraction part
230 (p11) stfd [r33] = MODF_INTEGER_PART
231 (p12) fms.d.s0 f8 = MODF_NORM_F8,f1, MODF_INTEGER_PART
235 // For NORMAL test if fraction part is zero; if so append correct sign
238 (p12) fcmp.eq.unc.s0 p7,p0 = MODF_NORM_F8, MODF_INTEGER_PART
243 (p12) stfd [r33] = MODF_INTEGER_PART
248 // For NORMAL if fraction part is zero append sign of input
251 (p7) fmerge.s f8 = MODF_NORM_F8, f0
256 // If x unorm get signexp from normalized input
257 // If x unorm get integer part from normalized input
259 getf.exp modf_signexp = MODF_NORM_F8
260 fcvt.fx.trunc.s1 MODF_INT_INTEGER_PART = MODF_NORM_F8
264 // If x unorm mask to get exponent
266 and modf_exp = modf_17_ones, modf_signexp ;;
267 cmp.lt.unc p11,p10 = modf_exp, modf_GR_FFFF
272 (p10) cmp.ge.unc p9,p12 = modf_exp, modf_GR_no_frac
274 br.cond.spnt MODF_COMMON ;;
277 GLOBAL_LIBM_END(modf)
278 libm_alias_double_other (modf, modf)