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 Unwind support added
31 // 8/15/00 Bundle added after call to __libm_error_support to properly
32 // set [the previously overwritten] GR_Parameter_RESULT.
34 // *********************************************************************
36 // Function: log1p(x) = ln(x+1), for double precision x values
38 // *********************************************************************
40 // Accuracy: Very accurate for double precision values
42 // *********************************************************************
46 // Floating-Point Registers: f8 (Input and Return Value)
49 // General Purpose Registers:
51 // r54-r57 (Used to pass arguments to error handling routine)
53 // Predicate Registers: p6-p15
55 // *********************************************************************
57 // IEEE Special Conditions:
59 // Denormal fault raised on denormal inputs
60 // Overflow exceptions cannot occur
61 // Underflow exceptions raised when appropriate for log1p
62 // (Error Handling Routine called for underflow)
63 // Inexact raised when appropriate by algorithm
71 // log1p(EM_special Values) = QNaN
73 // *********************************************************************
75 // Computation is based on the following kernel.
77 // ker_log_64( in_FR : X,
80 // in_GR : Expo_Range,
88 // The method consists of three cases.
90 // If |X+Em1| < 2^(-80) use case log1p_small;
91 // elseif |X+Em1| < 2^(-7) use case log_near1;
92 // else use case log_regular;
96 // log( 1 + (X+Em1) ) can be approximated by (X+Em1).
100 // log( 1 + (X+Em1) ) can be approximated by a simple polynomial
101 // in W = X+Em1. This polynomial resembles the truncated Taylor
102 // series W - W^/2 + W^3/3 - ...
106 // Here we use a table lookup method. The basic idea is that in
107 // order to compute log(Arg) for an argument Arg in [1,2), we
108 // construct a value G such that G*Arg is close to 1 and that
109 // log(1/G) is obtainable easily from a table of values calculated
112 // log(Arg) = log(1/G) + log(G*Arg)
113 // = log(1/G) + log(1 + (G*Arg - 1))
115 // Because |G*Arg - 1| is small, the second term on the right hand
116 // side can be approximated by a short polynomial. We elaborate
117 // this method in four steps.
119 // Step 0: Initialization
121 // We need to calculate log( E + X ). Obtain N, S_hi, S_lo such that
123 // E + X = 2^N * ( S_hi + S_lo ) exactly
125 // where S_hi in [1,2) and S_lo is a correction to S_hi in the sense
126 // that |S_lo| <= ulp(S_hi).
128 // Step 1: Argument Reduction
130 // Based on S_hi, obtain G_1, G_2, G_3 from a table and calculate
132 // G := G_1 * G_2 * G_3
133 // r := (G * S_hi - 1) + G * S_lo
135 // These G_j's have the property that the product is exactly
136 // representable and that |r| < 2^(-12) as a result.
138 // Step 2: Approximation
141 // log(1 + r) is approximated by a short polynomial poly(r).
143 // Step 3: Reconstruction
146 // Finally, log( E + X ) is given by
148 // log( E + X ) = log( 2^N * (S_hi + S_lo) )
149 // ~=~ N*log(2) + log(1/G) + log(1 + r)
150 // ~=~ N*log(2) + log(1/G) + poly(r).
152 // **** Algorithm ****
156 // Although log(1 + (X+Em1)) is basically X+Em1, we would like to
157 // preserve the inexactness nature as well as consistent behavior
158 // under different rounding modes. Note that this case can only be
159 // taken if E is set to be 1.0. In this case, Em1 is zero, and that
160 // X can be very tiny and thus the final result can possibly underflow.
161 // Thus, we compare X against a threshold that is dependent on the
162 // input Expo_Range. If |X| is smaller than this threshold, we set
165 // The result is returned as Y_hi, Y_lo, and in the case of SAFE
166 // is FALSE, an additional value Scale is also returned.
169 // Threshold := Threshold_Table( Expo_Range )
170 // Tiny := Tiny_Table( Expo_Range )
172 // If ( |W| > Threshold ) then
183 // One may think that Y_lo should be -W*W/2; however, it does not matter
184 // as Y_lo will be rounded off completely except for the correct effect in
185 // directed rounding. Clearly -W*W is simplier to compute. Moreover,
186 // because of the difference in exponent value, Y_hi + Y_lo or
187 // Y_hi + Scale*Y_lo is always inexact.
191 // Here we compute a simple polynomial. To exploit parallelism, we split
192 // the polynomial into two portions.
198 // Y_hi := W + Wsq*(P_1 + W*(P_2 + W*(P_3 + W*P_4))
199 // Y_lo := W6*(P_5 + W*(P_6 + W*(P_7 + W*P_8)))
200 // set lsb(Y_lo) to be 1
204 // We present the algorithm in four steps.
206 // Step 0. Initialization
207 // ----------------------
210 // N := unbaised exponent of Z
211 // S_hi := 2^(-N) * Z
212 // S_lo := 2^(-N) * { (max(X,E)-Z) + min(X,E) }
214 // Note that S_lo is always 0 for the case E = 0.
216 // Step 1. Argument Reduction
217 // --------------------------
221 // Z = 2^N * S_hi = 2^N * 1.d_1 d_2 d_3 ... d_63
223 // We obtain G_1, G_2, G_3 by the following steps.
226 // Define X_0 := 1.d_1 d_2 ... d_14. This is extracted
229 // Define A_1 := 1.d_1 d_2 d_3 d_4. This is X_0 truncated
232 // Define index_1 := [ d_1 d_2 d_3 d_4 ].
234 // Fetch Z_1 := (1/A_1) rounded UP in fixed point with
235 // fixed point lsb = 2^(-15).
236 // Z_1 looks like z_0.z_1 z_2 ... z_15
237 // Note that the fetching is done using index_1.
238 // A_1 is actually not needed in the implementation
239 // and is used here only to explain how is the value
242 // Fetch G_1 := (1/A_1) truncated to 21 sig. bits.
243 // floating pt. Again, fetching is done using index_1. A_1
244 // explains how G_1 is defined.
246 // Calculate X_1 := X_0 * Z_1 truncated to lsb = 2^(-14)
247 // = 1.0 0 0 0 d_5 ... d_14
248 // This is accomplised by integer multiplication.
249 // It is proved that X_1 indeed always begin
250 // with 1.0000 in fixed point.
253 // Define A_2 := 1.0 0 0 0 d_5 d_6 d_7 d_8. This is X_1
254 // truncated to lsb = 2^(-8). Similar to A_1,
255 // A_2 is not needed in actual implementation. It
256 // helps explain how some of the values are defined.
258 // Define index_2 := [ d_5 d_6 d_7 d_8 ].
260 // Fetch Z_2 := (1/A_2) rounded UP in fixed point with
261 // fixed point lsb = 2^(-15). Fetch done using index_2.
262 // Z_2 looks like z_0.z_1 z_2 ... z_15
264 // Fetch G_2 := (1/A_2) truncated to 21 sig. bits.
267 // Calculate X_2 := X_1 * Z_2 truncated to lsb = 2^(-14)
268 // = 1.0 0 0 0 0 0 0 0 d_9 d_10 ... d_14
269 // This is accomplised by integer multiplication.
270 // It is proved that X_2 indeed always begin
271 // with 1.00000000 in fixed point.
274 // Define A_3 := 1.0 0 0 0 0 0 0 0 d_9 d_10 d_11 d_12 d_13 1.
275 // This is 2^(-14) + X_2 truncated to lsb = 2^(-13).
277 // Define index_3 := [ d_9 d_10 d_11 d_12 d_13 ].
279 // Fetch G_3 := (1/A_3) truncated to 21 sig. bits.
280 // floating pt. Fetch is done using index_3.
282 // Compute G := G_1 * G_2 * G_3.
284 // This is done exactly since each of G_j only has 21 sig. bits.
288 // r := (G*S_hi - 1) + G*S_lo using 2 FMA operations.
290 // thus, r approximates G*(S_hi+S_lo) - 1 to within a couple of
294 // Step 2. Approximation
295 // ---------------------
297 // This step computes an approximation to log( 1 + r ) where r is the
298 // reduced argument just obtained. It is proved that |r| <= 1.9*2^(-13);
299 // thus log(1+r) can be approximated by a short polynomial:
301 // log(1+r) ~=~ poly = r + Q1 r^2 + ... + Q4 r^5
304 // Step 3. Reconstruction
305 // ----------------------
307 // This step computes the desired result of log(X+E):
309 // log(X+E) = log( 2^N * (S_hi + S_lo) )
310 // = N*log(2) + log( S_hi + S_lo )
311 // = N*log(2) + log(1/G) +
312 // log(1 + C*(S_hi+S_lo) - 1 )
314 // log(2), log(1/G_j) are stored as pairs of (single,double) numbers:
315 // log2_hi, log2_lo, log1byGj_hi, log1byGj_lo. The high parts are
316 // single-precision numbers and the low parts are double precision
317 // numbers. These have the property that
319 // N*log2_hi + SUM ( log1byGj_hi )
321 // is computable exactly in double-extended precision (64 sig. bits).
324 // Y_hi := N*log2_hi + SUM ( log1byGj_hi )
325 // Y_lo := poly_hi + [ poly_lo +
326 // ( SUM ( log1byGj_lo ) + N*log2_lo ) ]
327 // set lsb(Y_lo) to be 1
330 #include "libm_support.h"
338 // P_7, P_6, P_5, P_4, P_3, P_2, and P_1
342 ASM_TYPE_DIRECTIVE(Constants_P,@object)
343 data4 0xEFD62B15,0xE3936754,0x00003FFB,0x00000000
344 data4 0xA5E56381,0x8003B271,0x0000BFFC,0x00000000
345 data4 0x73282DB0,0x9249248C,0x00003FFC,0x00000000
346 data4 0x47305052,0xAAAAAA9F,0x0000BFFC,0x00000000
347 data4 0xCCD17FC9,0xCCCCCCCC,0x00003FFC,0x00000000
348 data4 0x00067ED5,0x80000000,0x0000BFFD,0x00000000
349 data4 0xAAAAAAAA,0xAAAAAAAA,0x00003FFD,0x00000000
350 data4 0xFFFFFFFE,0xFFFFFFFF,0x0000BFFD,0x00000000
351 ASM_SIZE_DIRECTIVE(Constants_P)
353 // log2_hi, log2_lo, Q_4, Q_3, Q_2, and Q_1
357 ASM_TYPE_DIRECTIVE(Constants_Q,@object)
358 data4 0x00000000,0xB1721800,0x00003FFE,0x00000000
359 data4 0x4361C4C6,0x82E30865,0x0000BFE2,0x00000000
360 data4 0x328833CB,0xCCCCCAF2,0x00003FFC,0x00000000
361 data4 0xA9D4BAFB,0x80000077,0x0000BFFD,0x00000000
362 data4 0xAAABE3D2,0xAAAAAAAA,0x00003FFD,0x00000000
363 data4 0xFFFFDAB7,0xFFFFFFFF,0x0000BFFD,0x00000000
364 ASM_SIZE_DIRECTIVE(Constants_Q)
366 // Z1 - 16 bit fixed, G1 and H1 - IEEE single
370 ASM_TYPE_DIRECTIVE(Constants_Z_G_H_h1,@object)
371 data4 0x00008000,0x3F800000,0x00000000,0x00000000,0x00000000,0x00000000
372 data4 0x00007879,0x3F70F0F0,0x3D785196,0x00000000,0x617D741C,0x3DA163A6
373 data4 0x000071C8,0x3F638E38,0x3DF13843,0x00000000,0xCBD3D5BB,0x3E2C55E6
374 data4 0x00006BCB,0x3F579430,0x3E2FF9A0,0x00000000,0xD86EA5E7,0xBE3EB0BF
375 data4 0x00006667,0x3F4CCCC8,0x3E647FD6,0x00000000,0x86B12760,0x3E2E6A8C
376 data4 0x00006187,0x3F430C30,0x3E8B3AE7,0x00000000,0x5C0739BA,0x3E47574C
377 data4 0x00005D18,0x3F3A2E88,0x3EA30C68,0x00000000,0x13E8AF2F,0x3E20E30F
378 data4 0x0000590C,0x3F321640,0x3EB9CEC8,0x00000000,0xF2C630BD,0xBE42885B
379 data4 0x00005556,0x3F2AAAA8,0x3ECF9927,0x00000000,0x97E577C6,0x3E497F34
380 data4 0x000051EC,0x3F23D708,0x3EE47FC5,0x00000000,0xA6B0A5AB,0x3E3E6A6E
381 data4 0x00004EC5,0x3F1D89D8,0x3EF8947D,0x00000000,0xD328D9BE,0xBDF43E3C
382 data4 0x00004BDB,0x3F17B420,0x3F05F3A1,0x00000000,0x0ADB090A,0x3E4094C3
383 data4 0x00004925,0x3F124920,0x3F0F4303,0x00000000,0xFC1FE510,0xBE28FBB2
384 data4 0x0000469F,0x3F0D3DC8,0x3F183EBF,0x00000000,0x10FDE3FA,0x3E3A7895
385 data4 0x00004445,0x3F088888,0x3F20EC80,0x00000000,0x7CC8C98F,0x3E508CE5
386 data4 0x00004211,0x3F042108,0x3F29516A,0x00000000,0xA223106C,0xBE534874
387 ASM_SIZE_DIRECTIVE(Constants_Z_G_H_h1)
389 // Z2 - 16 bit fixed, G2 and H2 - IEEE single
393 ASM_TYPE_DIRECTIVE(Constants_Z_G_H_h2,@object)
394 data4 0x00008000,0x3F800000,0x00000000,0x00000000,0x00000000,0x00000000
395 data4 0x00007F81,0x3F7F00F8,0x3B7F875D,0x00000000,0x22C42273,0x3DB5A116
396 data4 0x00007F02,0x3F7E03F8,0x3BFF015B,0x00000000,0x21F86ED3,0x3DE620CF
397 data4 0x00007E85,0x3F7D08E0,0x3C3EE393,0x00000000,0x484F34ED,0xBDAFA07E
398 data4 0x00007E08,0x3F7C0FC0,0x3C7E0586,0x00000000,0x3860BCF6,0xBDFE07F0
399 data4 0x00007D8D,0x3F7B1880,0x3C9E75D2,0x00000000,0xA78093D6,0x3DEA370F
400 data4 0x00007D12,0x3F7A2328,0x3CBDC97A,0x00000000,0x72A753D0,0x3DFF5791
401 data4 0x00007C98,0x3F792FB0,0x3CDCFE47,0x00000000,0xA7EF896B,0x3DFEBE6C
402 data4 0x00007C20,0x3F783E08,0x3CFC15D0,0x00000000,0x409ECB43,0x3E0CF156
403 data4 0x00007BA8,0x3F774E38,0x3D0D874D,0x00000000,0xFFEF71DF,0xBE0B6F97
404 data4 0x00007B31,0x3F766038,0x3D1CF49B,0x00000000,0x5D59EEE8,0xBE080483
405 data4 0x00007ABB,0x3F757400,0x3D2C531D,0x00000000,0xA9192A74,0x3E1F91E9
406 data4 0x00007A45,0x3F748988,0x3D3BA322,0x00000000,0xBF72A8CD,0xBE139A06
407 data4 0x000079D1,0x3F73A0D0,0x3D4AE46F,0x00000000,0xF8FBA6CF,0x3E1D9202
408 data4 0x0000795D,0x3F72B9D0,0x3D5A1756,0x00000000,0xBA796223,0xBE1DCCC4
409 data4 0x000078EB,0x3F71D488,0x3D693B9D,0x00000000,0xB6B7C239,0xBE049391
410 ASM_SIZE_DIRECTIVE(Constants_Z_G_H_h2)
412 // G3 and H3 - IEEE single and h3 -IEEE double
416 ASM_TYPE_DIRECTIVE(Constants_Z_G_H_h3,@object)
417 data4 0x3F7FFC00,0x38800100,0x562224CD,0x3D355595
418 data4 0x3F7FF400,0x39400480,0x06136FF6,0x3D8200A2
419 data4 0x3F7FEC00,0x39A00640,0xE8DE9AF0,0x3DA4D68D
420 data4 0x3F7FE400,0x39E00C41,0xB10238DC,0xBD8B4291
421 data4 0x3F7FDC00,0x3A100A21,0x3B1952CA,0xBD89CCB8
422 data4 0x3F7FD400,0x3A300F22,0x1DC46826,0xBDB10707
423 data4 0x3F7FCC08,0x3A4FF51C,0xF43307DB,0x3DB6FCB9
424 data4 0x3F7FC408,0x3A6FFC1D,0x62DC7872,0xBD9B7C47
425 data4 0x3F7FBC10,0x3A87F20B,0x3F89154A,0xBDC3725E
426 data4 0x3F7FB410,0x3A97F68B,0x62B9D392,0xBD93519D
427 data4 0x3F7FAC18,0x3AA7EB86,0x0F21BD9D,0x3DC18441
428 data4 0x3F7FA420,0x3AB7E101,0x2245E0A6,0xBDA64B95
429 data4 0x3F7F9C20,0x3AC7E701,0xAABB34B8,0x3DB4B0EC
430 data4 0x3F7F9428,0x3AD7DD7B,0x6DC40A7E,0x3D992337
431 data4 0x3F7F8C30,0x3AE7D474,0x4F2083D3,0x3DC6E17B
432 data4 0x3F7F8438,0x3AF7CBED,0x811D4394,0x3DAE314B
433 data4 0x3F7F7C40,0x3B03E1F3,0xB08F2DB1,0xBDD46F21
434 data4 0x3F7F7448,0x3B0BDE2F,0x6D34522B,0xBDDC30A4
435 data4 0x3F7F6C50,0x3B13DAAA,0xB1F473DB,0x3DCB0070
436 data4 0x3F7F6458,0x3B1BD766,0x6AD282FD,0xBDD65DDC
437 data4 0x3F7F5C68,0x3B23CC5C,0xF153761A,0xBDCDAB83
438 data4 0x3F7F5470,0x3B2BC997,0x341D0F8F,0xBDDADA40
439 data4 0x3F7F4C78,0x3B33C711,0xEBC394E8,0x3DCD1BD7
440 data4 0x3F7F4488,0x3B3BBCC6,0x52E3E695,0xBDC3532B
441 data4 0x3F7F3C90,0x3B43BAC0,0xE846B3DE,0xBDA3961E
442 data4 0x3F7F34A0,0x3B4BB0F4,0x785778D4,0xBDDADF06
443 data4 0x3F7F2CA8,0x3B53AF6D,0xE55CE212,0x3DCC3ED1
444 data4 0x3F7F24B8,0x3B5BA620,0x9E382C15,0xBDBA3103
445 data4 0x3F7F1CC8,0x3B639D12,0x5C5AF197,0x3D635A0B
446 data4 0x3F7F14D8,0x3B6B9444,0x71D34EFC,0xBDDCCB19
447 data4 0x3F7F0CE0,0x3B7393BC,0x52CD7ADA,0x3DC74502
448 data4 0x3F7F04F0,0x3B7B8B6D,0x7D7F2A42,0xBDB68F17
449 ASM_SIZE_DIRECTIVE(Constants_Z_G_H_h3)
452 // Exponent Thresholds and Tiny Thresholds
453 // for 8, 11, 15, and 17 bit exponents
457 // 0 (8 bits) 2^(-126)
458 // 1 (11 bits) 2^(-1022)
459 // 2 (15 bits) 2^(-16382)
460 // 3 (17 bits) 2^(-16382)
466 // 0 (8 bits) 2^(-16382)
467 // 1 (11 bits) 2^(-16382)
468 // 2 (15 bits) 2^(-16382)
469 // 3 (17 bits) 2^(-16382)
474 ASM_TYPE_DIRECTIVE(Constants_Threshold,@object)
475 data4 0x00000000,0x80000000,0x00003F81,0x00000000
476 data4 0x00000000,0x80000000,0x00000001,0x00000000
477 data4 0x00000000,0x80000000,0x00003C01,0x00000000
478 data4 0x00000000,0x80000000,0x00000001,0x00000000
479 data4 0x00000000,0x80000000,0x00000001,0x00000000
480 data4 0x00000000,0x80000000,0x00000001,0x00000000
481 data4 0x00000000,0x80000000,0x00000001,0x00000000
482 data4 0x00000000,0x80000000,0x00000001,0x00000000
483 ASM_SIZE_DIRECTIVE(Constants_Threshold)
487 ASM_TYPE_DIRECTIVE(Constants_1_by_LN10,@object)
488 data4 0x37287195,0xDE5BD8A9,0x00003FFD,0x00000000
489 data4 0xACCF70C8,0xD56EAABE,0x00003FBD,0x00000000
490 ASM_SIZE_DIRECTIVE(Constants_1_by_LN10)
565 FR_Output_X_tmp = f99
593 GR_Parameter_RESULT = r56
595 GR_Parameter_TAG = r57
609 alloc r32 = ar.pfs,0,22,4,0
610 (p0) fsub.s1 FR_Neg_One = f0,f1
611 (p0) cmp.eq.unc p7, p0 = r0, r0
615 (p0) cmp.ne.unc p14, p0 = r0, r0
616 (p0) fnorm.s1 FR_X_Prime = FR_Input_X
617 (p0) cmp.eq.unc p15, p0 = r0, r0 ;;
622 (p0) fclass.m.unc p6, p0 = FR_Input_X, 0x1E3
629 (p0) fclass.nm.unc p10, p0 = FR_Input_X, 0x1FF
636 (p0) fcmp.eq.unc.s1 p9, p0 = FR_Input_X, f0
642 (p0) fadd FR_Em1 = f0,f0
648 (p0) fadd FR_E = f0,f1
654 (p0) fcmp.eq.unc.s1 p8, p0 = FR_Input_X, FR_Neg_One
660 (p0) fcmp.lt.unc.s1 p13, p0 = FR_Input_X, FR_Neg_One
669 (p0) fadd.s1 FR_Z = FR_X_Prime, FR_E
675 (p0) movl GR_Table_Scale = 0x0000000000000018 ;;
681 // Create E = 1 and Em1 = 0
682 // Check for X == 0, meaning log(1+0)
683 // Check for X < -1, meaning log(negative)
684 // Check for X == -1, meaning log(0)
686 // Identify NatVals, NaNs, Infs.
687 // Identify EM unsupporteds.
688 // Identify Negative values - us S1 so as
689 // not to raise denormal operand exception
690 // Set p15 to true for log1p
691 // Set p14 to false for log1p
692 // Set p7 true for log and log1p
694 (p0) addl GR_Table_Base = @ltoff(Constants_Z_G_H_h1#),gp
700 (p0) fmax.s1 FR_AA = FR_X_Prime, FR_E
705 ld8 GR_Table_Base = [GR_Table_Base]
706 (p0) fmin.s1 FR_BB = FR_X_Prime, FR_E
712 (p0) fadd.s1 FR_W = FR_X_Prime, FR_Em1
714 // Begin load of constants base
715 // FR_Z = Z = |x| + E
716 // FR_W = W = |x| + Em1
720 (p6) br.cond.spnt L(LOG_64_special) ;;
726 (p10) br.cond.spnt L(LOG_64_unsupported) ;;
732 (p13) br.cond.spnt L(LOG_64_negative) ;;
736 (p0) getf.sig GR_signif = FR_Z
738 (p9) br.cond.spnt L(LOG_64_one) ;;
744 (p8) br.cond.spnt L(LOG_64_zero) ;;
748 (p0) getf.exp GR_N = FR_Z
750 // Raise possible denormal operand exception
753 // This function computes ln( x + e )
754 // Input FR 1: FR_X = FR_Input_X
755 // Input FR 2: FR_E = FR_E
756 // Input FR 3: FR_Em1 = FR_Em1
757 // Input GR 1: GR_Expo_Range = GR_Expo_Range = 1
758 // Output FR 4: FR_Y_hi
759 // Output FR 5: FR_Y_lo
760 // Output FR 6: FR_Scale
761 // Output PR 7: PR_Safe
763 (p0) fsub.s1 FR_S_lo = FR_AA, FR_Z
765 // signif = getf.sig(Z)
768 (p0) extr.u GR_Table_ptr = GR_signif, 59, 4 ;;
773 (p0) fmerge.se FR_S_hi = f1,FR_Z
774 (p0) extr.u GR_X_0 = GR_signif, 49, 15
779 (p0) addl GR_Table_Base1 = @ltoff(Constants_Z_G_H_h2#),gp
785 ld8 GR_Table_Base1 = [GR_Table_Base1]
786 (p0) movl GR_Bias = 0x000000000000FFFF ;;
791 (p0) fabs FR_abs_W = FR_W
792 (p0) pmpyshr2.u GR_Table_ptr = GR_Table_ptr,GR_Table_Scale,0
798 // Branch out for special input values
800 (p0) fcmp.lt.unc.s0 p8, p0 = FR_Input_X, f0
807 // X_0 = extr.u(signif,49,15)
808 // Index1 = extr.u(signif,59,4)
810 (p0) fadd.s1 FR_S_lo = FR_S_lo, FR_BB
818 // Offset_to_Z1 = 24 * Index1
819 // For performance, don't use result
820 // for 3 or 4 cycles.
822 (p0) add GR_Table_ptr = GR_Table_ptr, GR_Table_Base ;;
825 // Add Base to Offset for Z1
829 (p0) ld4 GR_Z_1 = [GR_Table_ptr],4 ;;
830 (p0) ldfs FR_G = [GR_Table_ptr],4
835 (p0) ldfs FR_H = [GR_Table_ptr],8 ;;
836 (p0) ldfd FR_h = [GR_Table_ptr],0
837 (p0) pmpyshr2.u GR_X_1 = GR_X_0,GR_Z_1,15
841 // Get Base of Table2
845 (p0) getf.exp GR_M = FR_abs_W
854 // M = getf.exp(abs_W)
856 // X_1 = pmpyshr2(X_0,Z_1,15)
858 (p0) sub GR_M = GR_M, GR_Bias ;;
867 (p0) cmp.gt.unc p11, p0 = -80, GR_M
868 (p0) cmp.gt.unc p12, p0 = -7, GR_M ;;
869 (p0) extr.u GR_Index2 = GR_X_1, 6, 4 ;;
875 // if -80 > M, set p11
876 // Index2 = extr.u(X_1,6,4)
877 // if -7 > M, set p12
880 (p0) pmpyshr2.u GR_Index2 = GR_Index2,GR_Table_Scale,0
881 (p11) br.cond.spnt L(log1p_small) ;;
887 (p12) br.cond.spnt L(log1p_near) ;;
891 (p0) sub GR_N = GR_N, GR_Bias
893 // poly_lo = r * poly_lo
895 (p0) add GR_Perturb = 0x1, r0 ;;
896 (p0) sub GR_ScaleN = GR_Bias, GR_N
900 (p0) setf.sig FR_float_N = GR_N
903 // Prepare Index2 - pmpyshr2.u(X_1,Z_2,15)
906 // Branch for -80 > M
908 (p0) add GR_Index2 = GR_Index2, GR_Table_Base1
912 (p0) setf.exp FR_two_negN = GR_ScaleN
914 (p0) addl GR_Table_Base = @ltoff(Constants_Z_G_H_h3#),gp
918 // Index2 points to Z2
923 (p0) ld4 GR_Z_2 = [GR_Index2],4
924 ld8 GR_Table_Base = [GR_Table_Base]
931 // Tablebase points to Table3
935 (p0) ldfs FR_G_tmp = [GR_Index2],4 ;;
938 // pmpyshr2 X_2= (X_1,Z_2,15)
939 // float_N = setf.sig(N)
942 (p0) ldfs FR_H_tmp = [GR_Index2],8
947 // two_negN = setf.exp(scaleN)
952 (p0) ldfd FR_h_tmp = [GR_Index2],0
954 (p0) pmpyshr2.u GR_X_2 = GR_X_1,GR_Z_2,15 ;;
959 (p0) extr.u GR_Index3 = GR_X_2, 1, 5 ;;
964 // Index3 = extr.u(X_2,1,5)
966 (p0) shladd GR_Index3 = GR_Index3,4,GR_Table_Base
973 // float_N = fcvt.xf(float_N)
976 (p0) addl GR_Table_Base = @ltoff(Constants_Q#),gp ;;
980 ld8 GR_Table_Base = [GR_Table_Base]
986 (p0) ldfe FR_log2_hi = [GR_Table_Base],16
987 (p0) fmpy.s1 FR_S_lo = FR_S_lo, FR_two_negN
999 (p0) ldfe FR_log2_lo = [GR_Table_Base],16
1000 (p0) fmpy.s1 FR_G = FR_G, FR_G_tmp ;;
1004 (p0) ldfs FR_G_tmp = [GR_Index3],4
1010 (p0) ldfe FR_Q4 = [GR_Table_Base],16
1011 (p0) fadd.s1 FR_h = FR_h, FR_h_tmp ;;
1015 (p0) ldfe FR_Q3 = [GR_Table_Base],16
1016 (p0) fadd.s1 FR_H = FR_H, FR_H_tmp
1021 (p0) ldfs FR_H_tmp = [GR_Index3],4
1022 (p0) ldfe FR_Q2 = [GR_Table_Base],16
1024 // Comput Index for Table3
1025 // S_lo = S_lo * two_negN
1027 (p0) fcvt.xf FR_float_N = FR_float_N ;;
1030 // If S_lo == 0, set p8 false
1032 // Load ptr to table of polynomial coeff.
1036 (p0) ldfd FR_h_tmp = [GR_Index3],0
1037 (p0) ldfe FR_Q1 = [GR_Table_Base],0
1038 (p0) fcmp.eq.unc.s1 p0, p8 = FR_S_lo, f0 ;;
1043 (p0) fmpy.s1 FR_G = FR_G, FR_G_tmp
1049 (p0) fadd.s1 FR_H = FR_H, FR_H_tmp
1055 (p0) fms.s1 FR_r = FR_G, FR_S_hi, f1
1061 (p0) fadd.s1 FR_h = FR_h, FR_h_tmp
1067 (p0) fma.s1 FR_Y_hi = FR_float_N, FR_log2_hi, FR_H
1079 (p8) fma.s1 FR_r = FR_G, FR_S_lo, FR_r
1086 // poly_lo = r * Q4 + Q3
1089 (p0) fma.s1 FR_h = FR_float_N, FR_log2_lo, FR_h
1096 // If (S_lo!=0) r = s_lo * G + r
1098 (p0) fma.s1 FR_poly_lo = FR_r, FR_Q4, FR_Q3
1102 // Create a 0x00000....01
1103 // poly_lo = poly_lo * rsq + h
1107 (p0) setf.sig FR_dummy = GR_Perturb
1108 (p0) fmpy.s1 FR_rsq = FR_r, FR_r
1115 // h = N * log2_lo + h
1116 // Y_hi = n * log2_hi + H
1118 (p0) fma.s1 FR_poly_lo = FR_poly_lo, FR_r, FR_Q2
1124 (p0) fma.s1 FR_poly_hi = FR_Q1, FR_rsq, FR_r
1131 // poly_lo = r * poly_o + Q2
1132 // poly_hi = Q1 * rsq + r
1134 (p0) fmpy.s1 FR_poly_lo = FR_poly_lo, FR_r
1140 (p0) fma.s1 FR_poly_lo = FR_poly_lo, FR_rsq, FR_h
1146 (p0) fadd.s1 FR_Y_lo = FR_poly_hi, FR_poly_lo
1148 // Create the FR for a binary "or"
1149 // Y_lo = poly_hi + poly_lo
1151 // (p0) for FR_dummy = FR_Y_lo,FR_dummy ;;
1153 // Turn the lsb of Y_lo ON
1155 // (p0) fmerge.se FR_Y_lo = FR_Y_lo,FR_dummy ;;
1157 // Merge the new lsb into Y_lo, for alone doesn't
1159 (p0) br.cond.sptk L(LOG_main) ;;
1168 // /*******************************************************/
1169 // /*********** Branch log1p_near ************************/
1170 // /*******************************************************/
1171 (p0) addl GR_Table_Base = @ltoff(Constants_P#),gp ;;
1174 // Load base address of poly. coeff.
1178 ld8 GR_Table_Base = [GR_Table_Base]
1183 (p0) add GR_Table_ptr = 0x40,GR_Table_Base
1185 // Address tables with separate pointers
1187 (p0) ldfe FR_P8 = [GR_Table_Base],16
1192 (p0) ldfe FR_P4 = [GR_Table_ptr],16
1197 (p0) ldfe FR_P7 = [GR_Table_Base],16
1202 (p0) ldfe FR_P3 = [GR_Table_ptr],16
1207 (p0) ldfe FR_P6 = [GR_Table_Base],16
1208 (p0) fmpy.s1 FR_wsq = FR_W, FR_W ;;
1212 (p0) ldfe FR_P2 = [GR_Table_ptr],16
1219 (p0) fma.s1 FR_Y_hi = FR_W, FR_P4, FR_P3
1226 // Y_hi = p4 * w + p3
1230 (p0) ldfe FR_P5 = [GR_Table_Base],16
1231 (p0) fma.s1 FR_Y_lo = FR_W, FR_P8, FR_P7
1236 (p0) ldfe FR_P1 = [GR_Table_ptr],16
1240 // Y_lo = p8 * w + P7
1242 (p0) fmpy.s1 FR_w4 = FR_wsq, FR_wsq
1248 (p0) fma.s1 FR_Y_hi = FR_W, FR_Y_hi, FR_P2
1254 (p0) fma.s1 FR_Y_lo = FR_W, FR_Y_lo, FR_P6
1255 (p0) add GR_Perturb = 0x1, r0 ;;
1262 // Y_hi = y_hi * w + p2
1263 // Y_lo = y_lo * w + p6
1264 // Create perturbation bit
1266 (p0) fmpy.s1 FR_w6 = FR_w4, FR_wsq
1272 (p0) fma.s1 FR_Y_hi = FR_W, FR_Y_hi, FR_P1
1276 // Y_hi = y_hi * w + p1
1281 (p0) setf.sig FR_Q4 = GR_Perturb
1282 (p0) fma.s1 FR_Y_lo = FR_W, FR_Y_lo, FR_P5
1288 (p0) fma.s1 FR_Y_hi = FR_wsq,FR_Y_hi, FR_W
1295 // Y_hi = y_hi * wsq + w
1296 // Y_lo = y_lo * w + p5
1298 (p0) fmpy.s1 FR_Y_lo = FR_w6, FR_Y_lo
1302 // (p0) for FR_dummy = FR_Y_lo,FR_dummy ;;
1304 // Set lsb on: Taken out to improve performance
1306 // (p0) fmerge.se FR_Y_lo = FR_Y_lo,FR_dummy ;;
1308 // Make sure it's on in Y_lo also. Taken out to improve
1311 (p0) br.cond.sptk L(LOG_main) ;;
1320 // /*******************************************************/
1321 // /*********** Branch log1p_small ***********************/
1322 // /*******************************************************/
1323 (p0) addl GR_Table_Base = @ltoff(Constants_Threshold#),gp
1328 (p0) mov FR_Em1 = FR_W
1329 (p0) cmp.eq.unc p7, p0 = r0, r0 ;;
1333 ld8 GR_Table_Base = [GR_Table_Base]
1334 (p0) movl GR_Expo_Range = 0x0000000000000002 ;;
1338 // Set Expo_Range = 0 for single
1339 // Set Expo_Range = 2 for double
1340 // Set Expo_Range = 4 for double-extended
1344 (p0) shladd GR_Table_Base = GR_Expo_Range,4,GR_Table_Base ;;
1345 (p0) ldfe FR_Threshold = [GR_Table_Base],16
1351 (p0) movl GR_Bias = 0x000000000000FF9B ;;
1355 (p0) ldfe FR_Tiny = [GR_Table_Base],0
1362 (p0) fcmp.gt.unc.s1 p13, p12 = FR_abs_W, FR_Threshold
1368 (p13) fnmpy.s1 FR_Y_lo = FR_W, FR_W
1374 (p13) fadd FR_SCALE = f0, f1
1380 (p12) fsub.s1 FR_Y_lo = f0, FR_Tiny
1381 (p12) cmp.ne.unc p7, p0 = r0, r0
1385 (p12) setf.exp FR_SCALE = GR_Bias
1391 // Set p7 to SAFE = FALSE
1392 // Set Scale = 2^-100
1396 (p0) fma.d.s0 FR_Input_X = FR_Y_lo,FR_SCALE,FR_Y_hi
1405 (p0) fmpy.d.s0 FR_Input_X = FR_Input_X, f0
1411 // Raise divide by zero for +/-0 input.
1416 (p0) mov GR_Parameter_TAG = 140
1418 // If we have log1p(0), return -Inf.
1420 (p0) fsub.s0 FR_Output_X_tmp = f0, f1
1425 (p0) frcpa.s0 FR_Output_X_tmp, p8 = FR_Output_X_tmp, f0
1426 (p0) br.cond.sptk L(LOG_ERROR_Support) ;;
1434 // Return -Inf or value from handler.
1436 (p0) fclass.m.unc p7, p0 = FR_Input_X, 0x1E1
1442 // Check for Natval, QNan, SNaN, +Inf
1444 (p7) fmpy.d.s0 f8 = FR_Input_X, f1
1446 // For SNaN raise invalid and return QNaN.
1447 // For QNaN raise invalid and return QNaN.
1448 // For +Inf return +Inf.
1455 // For -Inf raise invalid and return QNaN.
1459 (p0) mov GR_Parameter_TAG = 141
1460 (p0) fmpy.d.s0 FR_Output_X_tmp = FR_Input_X, f0
1461 (p0) br.cond.sptk L(LOG_ERROR_Support) ;;
1465 // Report that log1p(-Inf) computed
1468 L(LOG_64_unsupported):
1471 // Return generated NaN or other value .
1476 (p0) fmpy.d.s0 FR_Input_X = FR_Input_X, f0
1477 (p0) br.ret.sptk b0 ;;
1485 // Deal with x < 0 in a special way
1487 (p0) frcpa.s0 FR_Output_X_tmp, p8 = f0, f0
1489 // Deal with x < 0 in a special way - raise
1490 // invalid and produce QNaN indefinite.
1492 (p0) mov GR_Parameter_TAG = 141
1496 ASM_SIZE_DIRECTIVE(log1p)
1498 .proc __libm_error_region
1499 __libm_error_region:
1500 L(LOG_ERROR_Support):
1505 add GR_Parameter_Y=-32,sp // Parameter 2 value
1507 .save ar.pfs,GR_SAVE_PFS
1508 mov GR_SAVE_PFS=ar.pfs // Save ar.pfs
1512 add sp=-64,sp // Create new stack
1514 mov GR_SAVE_GP=gp // Save gp
1520 stfd [GR_Parameter_Y] = f0,16 // STORE Parameter 2 on stack
1521 add GR_Parameter_X = 16,sp // Parameter 1 address
1522 .save b0, GR_SAVE_B0
1523 mov GR_SAVE_B0=b0 // Save b0
1529 stfd [GR_Parameter_X] =FR_Input_X // STORE Parameter 1 on stack
1530 add GR_Parameter_RESULT = 0,GR_Parameter_Y // Parameter 3 address
1534 stfd [GR_Parameter_Y] = FR_Output_X_tmp // STORE Parameter 3 on stack
1535 add GR_Parameter_Y = -16,GR_Parameter_Y
1536 br.call.sptk b0=__libm_error_support# // Call error handling function
1541 add GR_Parameter_RESULT = 48,sp
1546 ldfd FR_Input_X = [GR_Parameter_RESULT] // Get return result off stack
1548 add sp = 64,sp // Restore stack pointer
1549 mov b0 = GR_SAVE_B0 // Restore return address
1552 mov gp = GR_SAVE_GP // Restore gp
1553 mov ar.pfs = GR_SAVE_PFS // Restore ar.pfs
1557 .endp __libm_error_region
1558 ASM_SIZE_DIRECTIVE(__libm_error_region)
1560 .proc __libm_LOG_main
1565 // kernel_log_64 computes ln(X + E)
1570 (p7) fadd.d.s0 FR_Input_X = FR_Y_lo,FR_Y_hi
1577 (p14) addl GR_Table_Base = @ltoff(Constants_1_by_LN10#),gp ;;
1582 (p14) ld8 GR_Table_Base = [GR_Table_Base]
1587 (p14) ldfe FR_1LN10_hi = [GR_Table_Base],16 ;;
1588 (p14) ldfe FR_1LN10_lo = [GR_Table_Base]
1594 (p14) fmpy.s1 FR_Output_X_tmp = FR_Y_lo,FR_1LN10_hi
1600 (p14) fma.s1 FR_Output_X_tmp = FR_Y_hi,FR_1LN10_lo,FR_Output_X_tmp
1606 (p14) fma.d.s0 FR_Input_X = FR_Y_hi,FR_1LN10_hi,FR_Output_X_tmp
1607 (p0) br.ret.sptk b0 ;;
1609 .endp __libm_LOG_main
1610 ASM_SIZE_DIRECTIVE(__libm_LOG_main)
1613 .type __libm_error_support#,@function
1614 .global __libm_error_support#