3 // Copyright (c) 2000, 2001, Intel Corporation
4 // All rights reserved.
6 // Contributed 2/2/2000 by John Harrison, Ted Kubaska, Bob Norin, Shane Story,
7 // and Ping Tak Peter Tang of the Computational Software Lab, Intel Corporation.
11 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
12 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
13 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
14 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS
15 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
16 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
17 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
18 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
19 // OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR TORT (INCLUDING
20 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
21 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 // Intel Corporation is the author of this code, and requests that all
24 // problem reports or change requests be submitted to it directly at
25 // http://developer.intel.com/opensource.
28 //==============================================================
29 // 2/02/00: Initial version
30 // 4/04/00: Improved speed, corrected result for NaN input
31 // 12/22/00 Fixed so inexact flag is never set, and invalid is not set for
32 // qnans nor for inputs larger than 2^63.
35 //==============================================================
36 // double modf(double x, double *iptr)
37 // break a floating point x number into fraction and an exponent
39 // input floating point f8, address in r33
40 // output floating point f8 (x fraction), and *iptr (x integral part)
43 //==============================================================
45 // NO FRACTIONAL PART: HUGE
47 // for double-extended
48 // If the true exponent is greater than or equal 63
49 // 1003e ==> 1003e -ffff = 3f = 63(dec)
51 // If the true exponent is greater than or equal 52
52 // 10033 -ffff = 34 = 52(dec)
54 // If the true exponent is greater than or equal 23
55 // 10016 -ffff = 17 = 23(dec)
57 // we are already an integer (p9 true)
59 // NO INTEGER PART: SMALL
60 // Is f8 exponent less than register bias (that is, is it
61 // less than 1). If it is, get the right sign of
62 // zero and store this in iptr.
64 // CALCULATION: NOT HUGE, NOT SMALL
65 // To get the integer part
66 // Take the floating-point input and truncate
67 // then convert this integer to fp Call it MODF_INTEGER_PART
69 // Subtract MODF_INTEGER_PART from MODF_NORM_F8 to get fraction part
70 // Then put fraction part in f8
71 // put integer part MODF_INTEGER_PART into *iptr
74 //==============================================================
76 // predicate registers used:
80 // -----------------------+-----------------+-------------
81 // SMALL | NORMAL | HUGE
82 // p11 --------------->|<----- p12 ----->| <-------------- p9
83 // p10 --------------------------------->|
84 // p13 --------------------------------------------------->|
87 #include "libm_support.h"
89 // floating-point registers used:
91 MODF_FRACTION_PART = f10
92 MODF_INTEGER_PART = f11
93 MODF_INT_INTEGER_PART = f12
96 // general registers used
113 // Main path is p9, p11, p8 FALSE and p12 TRUE
115 // Assume input is normalized and get signexp
116 // Normalize input just in case
117 // Form exponent bias
120 getf.exp modf_signexp = f8
121 fnorm MODF_NORM_F8 = f8
122 addl modf_GR_FFFF = 0xffff, r0
124 // Get integer part of input
125 // Form exponent mask
128 fcvt.fx.trunc.s1 MODF_INT_INTEGER_PART = f8
129 mov modf_17_ones = 0x1ffff ;;
133 // qnan snan inf norm unorm 0 -+
134 // 1 1 1 0 0 0 11 = 0xe3 NAN_INF
135 // Form biased exponent where input only has an integer part
138 fclass.m.unc p6,p13 = f8, 0xe3
139 addl modf_GR_no_frac = 0x10033, r0 ;;
142 // Mask to get exponent
144 // qnan snan inf norm unorm 0 -+
145 // 0 0 0 0 1 0 11 = 0x0b UNORM
146 // Set p13 to indicate calculation path, else p6 if nan or inf
148 and modf_exp = modf_17_ones, modf_signexp
149 fclass.m.unc p8,p0 = f8, 0x0b
153 // p11 <== SMALL, no integer part, fraction is everyting
154 // p9 <== HUGE, no fraction part, integer is everything
155 // p12 <== NORMAL, fraction part and integer part
157 (p13) cmp.lt.unc p11,p10 = modf_exp, modf_GR_FFFF
162 // Is x inf? p6 if inf, p7 if nan
164 (p10) cmp.ge.unc p9,p12 = modf_exp, modf_GR_no_frac
165 (p6) fclass.m.unc p6,p7 = f8, 0x23
166 (p8) br.cond.spnt L(MODF_DENORM) ;;
170 // For HUGE set fraction to signed 0
173 (p9) fmerge.s f8 = f8,f0
176 // For HUGE set integer part to normalized input
179 (p9) fnorm.d MODF_INTEGER_PART = MODF_NORM_F8
183 // For SMALL set fraction to normalized input, integer part to signed 0
186 (p11) fmerge.s MODF_INTEGER_PART = f8,f0
191 (p11) fnorm.d f8 = MODF_NORM_F8
195 // For NORMAL float the integer part
198 (p12) fcvt.xf MODF_INTEGER_PART = MODF_INT_INTEGER_PART
202 // If x inf set integer part to INF, fraction to signed 0
204 (p6) stfd [r33] = MODF_NORM_F8
205 (p6) fmerge.s f8 = f8,f0
209 // If x nan set integer and fraction parts to NaN (quietized)
211 (p7) stfd [r33] = MODF_NORM_F8
212 (p7) fmerge.s f8 = MODF_NORM_F8, MODF_NORM_F8
217 (p9) stfd [r33] = MODF_INTEGER_PART
222 // For NORMAL compute fraction part
224 (p11) stfd [r33] = MODF_INTEGER_PART
225 (p12) fms.d.s0 f8 = MODF_NORM_F8,f1, MODF_INTEGER_PART
229 // For NORMAL test if fraction part is zero; if so append correct sign
232 (p12) fcmp.eq.unc p7,p0 = MODF_NORM_F8, MODF_INTEGER_PART
237 (p12) stfd [r33] = MODF_INTEGER_PART
242 // For NORMAL if fraction part is zero append sign of input
245 (p7) fmerge.s f8 = MODF_NORM_F8, f0
250 // If x unorm get signexp from normalized input
251 // If x unorm get integer part from normalized input
253 getf.exp modf_signexp = MODF_NORM_F8
254 fcvt.fx.trunc.s1 MODF_INT_INTEGER_PART = MODF_NORM_F8
258 // If x unorm mask to get exponent
260 and modf_exp = modf_17_ones, modf_signexp ;;
261 cmp.lt.unc p11,p10 = modf_exp, modf_GR_FFFF
266 (p10) cmp.ge.unc p9,p12 = modf_exp, modf_GR_no_frac
268 br.cond.spnt L(MODF_COMMON) ;;
272 ASM_SIZE_DIRECTIVE(modf)