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.
9 // Redistribution and use in source and binary forms, with or without
10 // modification, are permitted provided that the following conditions are
13 // * Redistributions of source code must retain the above copyright
14 // notice, this list of conditions and the following disclaimer.
16 // * Redistributions in binary form must reproduce the above copyright
17 // notice, this list of conditions and the following disclaimer in the
18 // documentation and/or other materials provided with the distribution.
20 // * The name of Intel Corporation may not be used to endorse or promote
21 // products derived from this software without specific prior written
24 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
25 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
26 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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38 // http://developer.intel.com/opensource.
41 //==============================================================
42 // 2/02/00: Initial version
43 // 4/04/00: Improved speed, corrected result for NaN input
44 // 12/22/00 Fixed so inexact flag is never set, and invalid is not set for
45 // qnans nor for inputs larger than 2^63.
48 //==============================================================
49 // float modff(float x, float *iptr)
50 // break a floating point x number into fraction and an exponent
52 // input floating point f8, address in r33
53 // output floating point f8 (x fraction), and *iptr (x integral part)
56 //==============================================================
58 // NO FRACTIONAL PART: HUGE
60 // for double-extended
61 // If the true exponent is greater than or equal 63
62 // 1003e ==> 1003e -ffff = 3f = 63(dec)
64 // If the true exponent is greater than or equal 52
65 // 10033 -ffff = 34 = 52(dec)
67 // If the true exponent is greater than or equal 23
68 // 10016 -ffff = 17 = 23(dec)
70 // we are already an integer (p9 true)
72 // NO INTEGER PART: SMALL
73 // Is f8 exponent less than register bias (that is, is it
74 // less than 1). If it is, get the right sign of
75 // zero and store this in iptr.
77 // CALCULATION: NOT HUGE, NOT SMALL
78 // To get the integer part
79 // Take the floating-point input and truncate
80 // then convert this integer to fp Call it MODF_INTEGER_PART
82 // Subtract MODF_INTEGER_PART from MODF_NORM_F8 to get fraction part
83 // Then put fraction part in f8
84 // put integer part MODF_INTEGER_PART into *iptr
87 //==============================================================
89 // predicate registers used:
93 // -----------------------+-----------------+-------------
94 // SMALL | NORMAL | HUGE
95 // p11 --------------->|<----- p12 ----->| <-------------- p9
96 // p10 --------------------------------->|
97 // p13 --------------------------------------------------->|
100 #include "libm_support.h"
102 // floating-point registers used:
104 MODF_FRACTION_PART = f10
105 MODF_INTEGER_PART = f11
106 MODF_INT_INTEGER_PART = f12
109 // general registers used
111 modf_GR_no_frac = r15
126 // Main path is p9, p11, p8 FALSE and p12 TRUE
128 // Assume input is normalized and get signexp
129 // Normalize input just in case
130 // Form exponent bias
133 getf.exp modf_signexp = f8
134 fnorm MODF_NORM_F8 = f8
135 addl modf_GR_FFFF = 0xffff, r0
137 // Get integer part of input
138 // Form exponent mask
141 fcvt.fx.trunc.s1 MODF_INT_INTEGER_PART = f8
142 mov modf_17_ones = 0x1ffff ;;
146 // qnan snan inf norm unorm 0 -+
147 // 1 1 1 0 0 0 11 = 0xe3 NAN_INF
148 // Form biased exponent where input only has an integer part
151 fclass.m.unc p6,p13 = f8, 0xe3
152 addl modf_GR_no_frac = 0x10016, r0 ;;
155 // Mask to get exponent
157 // qnan snan inf norm unorm 0 -+
158 // 0 0 0 0 1 0 11 = 0x0b UNORM
159 // Set p13 to indicate calculation path, else p6 if nan or inf
161 and modf_exp = modf_17_ones, modf_signexp
162 fclass.m.unc p8,p0 = f8, 0x0b
166 // p11 <== SMALL, no integer part, fraction is everyting
167 // p9 <== HUGE, no fraction part, integer is everything
168 // p12 <== NORMAL, fraction part and integer part
170 (p13) cmp.lt.unc p11,p10 = modf_exp, modf_GR_FFFF
175 // Is x inf? p6 if inf, p7 if nan
177 (p10) cmp.ge.unc p9,p12 = modf_exp, modf_GR_no_frac
178 (p6) fclass.m.unc p6,p7 = f8, 0x23
179 (p8) br.cond.spnt L(MODF_DENORM) ;;
183 // For HUGE set fraction to signed 0
186 (p9) fmerge.s f8 = f8,f0
189 // For HUGE set integer part to normalized input
192 (p9) fnorm.s MODF_INTEGER_PART = MODF_NORM_F8
196 // For SMALL set fraction to normalized input, integer part to signed 0
199 (p11) fmerge.s MODF_INTEGER_PART = f8,f0
204 (p11) fnorm.s f8 = MODF_NORM_F8
208 // For NORMAL float the integer part
211 (p12) fcvt.xf MODF_INTEGER_PART = MODF_INT_INTEGER_PART
215 // If x inf set integer part to INF, fraction to signed 0
217 (p6) stfs [r33] = MODF_NORM_F8
218 (p6) fmerge.s f8 = f8,f0
222 // If x nan set integer and fraction parts to NaN (quietized)
224 (p7) stfs [r33] = MODF_NORM_F8
225 (p7) fmerge.s f8 = MODF_NORM_F8, MODF_NORM_F8
230 (p9) stfs [r33] = MODF_INTEGER_PART
235 // For NORMAL compute fraction part
237 (p11) stfs [r33] = MODF_INTEGER_PART
238 (p12) fms.s.s0 f8 = MODF_NORM_F8,f1, MODF_INTEGER_PART
242 // For NORMAL test if fraction part is zero; if so append correct sign
245 (p12) fcmp.eq.unc p7,p0 = MODF_NORM_F8, MODF_INTEGER_PART
250 (p12) stfs [r33] = MODF_INTEGER_PART
255 // For NORMAL if fraction part is zero append sign of input
258 (p7) fmerge.s f8 = MODF_NORM_F8, f0
263 // If x unorm get signexp from normalized input
264 // If x unorm get integer part from normalized input
266 getf.exp modf_signexp = MODF_NORM_F8
267 fcvt.fx.trunc.s1 MODF_INT_INTEGER_PART = MODF_NORM_F8
271 // If x unorm mask to get exponent
273 and modf_exp = modf_17_ones, modf_signexp ;;
274 cmp.lt.unc p11,p10 = modf_exp, modf_GR_FFFF
279 (p10) cmp.ge.unc p9,p12 = modf_exp, modf_GR_no_frac
281 br.cond.spnt L(MODF_COMMON) ;;
285 ASM_SIZE_DIRECTIVE(modff)