| blob | af620d45f8fbc8f4f0ac6cb85ff77f55a7ee599c |
1 .file "libm_scalblnf.s"
4 // Copyright (c) 2001 - 2003, Intel Corporation
5 // All rights reserved.
6 //
7 // Contributed 2001 by the Intel Numerics Group, Intel Corporation
8 //
9 // Redistribution and use in source and binary forms, with or without
10 // modification, are permitted provided that the following conditions are
11 // met:
12 //
13 // * Redistributions of source code must retain the above copyright
14 // notice, this list of conditions and the following disclaimer.
15 //
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.
19 //
20 // * The name of Intel Corporation may not be used to endorse or promote
21 // products derived from this software without specific prior written
22 // permission.
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
27 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS
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34 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 //
36 // Intel Corporation is the author of this code, and requests that all
37 // problem reports or change requests be submitted to it directly at
38 // http://www.intel.com/software/products/opensource/libraries/num.htm.
39 //
40 // History
41 //==============================================================
42 // 08/03/01 Initial version
43 // 08/23/01 Corrected error tag number
44 // 02/06/02 Corrected to handle 32- or 64-bit integers
45 // 05/20/02 Cleaned up namespace and sf0 syntax
46 // 02/10/03 Reordered header: .section, .global, .proc, .align
47 // 08/25/03 Improved performance
48 //
49 // API
50 //==============================================================
51 // float __libm_scalblnf (float x, long int n, int long_int_type)
52 // input floating point f8 and long int n (r33)
53 // input long_int_type = 0 if long int defined as 32 bits, = 1 if 64 bits
54 // output floating point f8
55 //
56 // Returns x* 2**n using an fma and detects overflow
57 // and underflow.
58 //
59 //
60 // Strategy:
61 // Compute biased exponent of result exp_Result = N + exp_X
62 // Break into ranges:
63 // exp_Result > 0x1007e -> Certain overflow
64 // exp_Result = 0x1007e -> Possible overflow
65 // 0x0ff81 <= exp_Result < 0x1007e -> No over/underflow (main path)
66 // 0x0ff81 - 23 <= exp_Result < 0x0ff81 -> Possible underflow
67 // exp_Result < 0x0ff81 - 23 -> Certain underflow
69 FR_Big = f6
70 FR_NBig = f7
71 FR_Floating_X = f8
72 FR_Result = f8
73 FR_Result2 = f9
74 FR_Result3 = f10
75 FR_Norm_X = f11
76 FR_Two_N = f12
78 GR_neg_ov_limit= r14
79 GR_N_Biased = r15
80 GR_Big = r16
81 GR_NBig = r17
82 GR_exp_Result = r18
83 GR_pos_ov_limit= r19
84 GR_Bias = r20
85 GR_N_as_int = r21
86 GR_signexp_X = r22
87 GR_exp_X = r23
88 GR_exp_mask = r24
89 GR_max_exp = r25
90 GR_min_exp = r26
91 GR_min_den_exp = r27
93 GR_SAVE_B0 = r32
94 GR_SAVE_GP = r33
95 GR_SAVE_PFS = r34
96 GR_Parameter_X = r35
97 GR_Parameter_Y = r36
98 GR_Parameter_RESULT = r37
99 GR_Tag = r38
101 .section .text
102 GLOBAL_LIBM_ENTRY(__libm_scalblnf)
104 //
105 // Is x NAN, INF, ZERO, +-?
106 // Build the exponent Bias
107 //
108 { .mfi
109 getf.exp GR_signexp_X = FR_Floating_X // Get signexp of x
110 fclass.m p6,p0 = FR_Floating_X, 0xe7 // @snan | @qnan | @inf | @zero
111 mov GR_Bias = 0x0ffff
112 }
113 //
114 // Normalize x
115 // Is long integer type 32 bits?
116 //
117 { .mfi
118 mov GR_Big = 35000 // If N this big then certain overflow
119 fnorm.s1 FR_Norm_X = FR_Floating_X
120 cmp.eq p8,p9 = r34,r0
121 }
122 ;;
124 // Sign extend N if long int is 32 bits
125 { .mfi
126 (p9) mov GR_N_as_int = r33 // Copy N if long int is 64 bits
127 fclass.m p9,p0 = FR_Floating_X, 0x0b // Test for x=unorm
128 (p8) sxt4 GR_N_as_int = r33 // Sign extend N if long int is 32 bits
129 }
130 { .mfi
131 mov GR_NBig = -35000 // If N this small then certain underflow
132 nop.f 0
133 mov GR_max_exp = 0x1007e // Exponent of maximum float
134 }
135 ;;
137 // Create biased exponent for 2**N
138 { .mfi
139 add GR_N_Biased = GR_Bias,GR_N_as_int
140 nop.f 0
141 cmp.ge p7, p0 = GR_N_as_int, GR_Big // Certain overflow?
142 }
143 { .mib
144 cmp.le p8, p0 = GR_N_as_int, GR_NBig // Certain underflow?
145 mov GR_min_exp = 0x0ff81 // Exponent of minimum float
146 (p9) br.cond.spnt SCALBNF_UNORM // Branch if x=unorm
147 }
148 ;;
150 SCALBNF_COMMON:
151 // Main path continues. Also return here from x=unorm path.
152 // Create 2**N
153 .pred.rel "mutex",p7,p8
154 { .mfi
155 setf.exp FR_Two_N = GR_N_Biased
156 nop.f 0
157 (p7) mov GR_N_as_int = GR_Big // Limit max N
158 }
159 { .mfi
160 (p8) mov GR_N_as_int = GR_NBig // Limit min N
161 nop.f 0
162 (p8) cmp.eq p7,p0 = r0,r0 // Set p7 if |N| big
163 }
164 ;;
166 //
167 // Create biased exponent for 2**N for N big
168 // Is N zero?
169 //
170 { .mfi
171 (p7) add GR_N_Biased = GR_Bias,GR_N_as_int
172 nop.f 0
173 cmp.eq.or p6,p0 = r33,r0
174 }
175 { .mfi
176 mov GR_pos_ov_limit = 0x1007f // Exponent for positive overflow
177 nop.f 0
178 mov GR_exp_mask = 0x1ffff // Exponent mask
179 }
180 ;;
182 //
183 // Create 2**N for N big
184 // Return x when N = 0 or X = Nan, Inf, Zero
185 //
186 { .mfi
187 (p7) setf.exp FR_Two_N = GR_N_Biased
188 nop.f 0
189 mov GR_min_den_exp = 0x0ff81 - 23 // Exponent of min denorm float
190 }
191 { .mfb
192 and GR_exp_X = GR_exp_mask, GR_signexp_X
193 (p6) fma.s.s0 FR_Result = FR_Floating_X, f1, f0
194 (p6) br.ret.spnt b0
195 }
196 ;;
198 //
199 // Raise Denormal operand flag with compare
200 // Compute biased result exponent
201 //
202 { .mfi
203 add GR_exp_Result = GR_exp_X, GR_N_as_int
204 fcmp.ge.s0 p0,p11 = FR_Floating_X,f0
205 mov GR_neg_ov_limit = 0x3007f // Exponent for negative overflow
206 }
207 ;;
209 //
210 // Do final operation
211 //
212 { .mfi
213 cmp.lt p7,p6 = GR_exp_Result, GR_max_exp // Test no overflow
214 fma.s.s0 FR_Result = FR_Two_N,FR_Norm_X,f0
215 cmp.lt p9,p0 = GR_exp_Result, GR_min_den_exp // Test sure underflow
216 }
217 { .mfb
218 nop.m 0
219 nop.f 0
220 (p9) br.cond.spnt SCALBNF_UNDERFLOW // Branch if certain underflow
221 }
222 ;;
224 { .mib
225 (p6) cmp.gt.unc p6,p8 = GR_exp_Result, GR_max_exp // Test sure overflow
226 (p7) cmp.ge.unc p7,p9 = GR_exp_Result, GR_min_exp // Test no over/underflow
227 (p7) br.ret.sptk b0 // Return from main path
228 }
229 ;;
231 { .bbb
232 (p6) br.cond.spnt SCALBNF_OVERFLOW // Branch if certain overflow
233 (p8) br.cond.spnt SCALBNF_POSSIBLE_OVERFLOW // Branch if possible overflow
234 (p9) br.cond.spnt SCALBNF_POSSIBLE_UNDERFLOW // Branch if possible underflow
235 }
236 ;;
238 // Here if possible underflow.
239 // Resulting exponent: 0x0ff81-23 <= exp_Result < 0x0ff81
240 SCALBNF_POSSIBLE_UNDERFLOW:
241 //
242 // Here if possible overflow.
243 // Resulting exponent: 0x1007e = exp_Result
244 SCALBNF_POSSIBLE_OVERFLOW:
246 // Set up necessary status fields
247 //
248 // S0 user supplied status
249 // S2 user supplied status + WRE + TD (Overflows)
250 // S3 user supplied status + FZ + TD (Underflows)
251 //
252 { .mfi
253 nop.m 0
254 fsetc.s3 0x7F,0x41
255 nop.i 0
256 }
257 { .mfi
258 nop.m 0
259 fsetc.s2 0x7F,0x42
260 nop.i 0
261 }
262 ;;
264 //
265 // Do final operation with s2 and s3
266 //
267 { .mfi
268 setf.exp FR_NBig = GR_neg_ov_limit
269 fma.s.s3 FR_Result3 = FR_Two_N,FR_Norm_X,f0
270 nop.i 0
271 }
272 { .mfi
273 setf.exp FR_Big = GR_pos_ov_limit
274 fma.s.s2 FR_Result2 = FR_Two_N,FR_Norm_X,f0
275 nop.i 0
276 }
277 ;;
279 // Check for overflow or underflow.
280 // Restore s3
281 // Restore s2
282 //
283 { .mfi
284 nop.m 0
285 fsetc.s3 0x7F,0x40
286 nop.i 0
287 }
288 { .mfi
289 nop.m 0
290 fsetc.s2 0x7F,0x40
291 nop.i 0
292 }
293 ;;
295 //
296 // Is the result zero?
297 //
298 { .mfi
299 nop.m 0
300 fclass.m p6, p0 = FR_Result3, 0x007
301 nop.i 0
302 }
303 { .mfi
304 nop.m 0
305 fcmp.ge.s1 p7, p8 = FR_Result2 , FR_Big
306 nop.i 0
307 }
308 ;;
310 //
311 // Detect masked underflow - Tiny + Inexact Only
312 //
313 { .mfi
314 nop.m 0
315 (p6) fcmp.neq.unc.s1 p6, p0 = FR_Result , FR_Result2
316 nop.i 0
317 }
318 ;;
320 //
321 // Is result bigger the allowed range?
322 // Branch out for underflow
323 //
324 { .mfb
325 nop.m 0
326 (p8) fcmp.le.unc.s1 p9, p10 = FR_Result2 , FR_NBig
327 (p6) br.cond.spnt SCALBNF_UNDERFLOW
328 }
329 ;;
331 //
332 // Branch out for overflow
333 //
334 { .bbb
335 (p7) br.cond.spnt SCALBNF_OVERFLOW
336 (p9) br.cond.spnt SCALBNF_OVERFLOW
337 br.ret.sptk b0 // Return from main path.
338 }
339 ;;
341 // Here if result overflows
342 SCALBNF_OVERFLOW:
343 { .mib
344 alloc r32=ar.pfs,3,0,4,0
345 addl GR_Tag = 205, r0 // Set error tag for overflow
346 br.cond.sptk __libm_error_region // Call error support for overflow
347 }
348 ;;
350 // Here if result underflows
351 SCALBNF_UNDERFLOW:
352 { .mib
353 alloc r32=ar.pfs,3,0,4,0
354 addl GR_Tag = 206, r0 // Set error tag for underflow
355 br.cond.sptk __libm_error_region // Call error support for underflow
356 }
357 ;;
359 // Here if x=unorm
360 SCALBNF_UNORM:
361 { .mib
362 getf.exp GR_signexp_X = FR_Norm_X // Get signexp of normalized x
363 nop.i 0
364 br.cond.sptk SCALBNF_COMMON // Return to main path
365 }
366 ;;
369 GLOBAL_LIBM_END(__libm_scalblnf)
370 LOCAL_LIBM_ENTRY(__libm_error_region)
372 //
373 // Get stack address of N
374 //
375 .prologue
376 { .mfi
377 add GR_Parameter_Y=-32,sp
378 nop.f 0
379 .save ar.pfs,GR_SAVE_PFS
380 mov GR_SAVE_PFS=ar.pfs
381 }
382 //
383 // Adjust sp
384 //
385 { .mfi
386 .fframe 64
387 add sp=-64,sp
388 nop.f 0
389 mov GR_SAVE_GP=gp
390 };;
392 //
393 // Store N on stack in correct position
394 // Locate the address of x on stack
395 //
396 { .mmi
397 st8 [GR_Parameter_Y] = GR_N_as_int,16
398 add GR_Parameter_X = 16,sp
399 .save b0, GR_SAVE_B0
400 mov GR_SAVE_B0=b0
401 };;
403 //
404 // Store x on the stack.
405 // Get address for result on stack.
406 //
407 .body
408 { .mib
409 stfs [GR_Parameter_X] = FR_Norm_X
410 add GR_Parameter_RESULT = 0,GR_Parameter_Y
411 nop.b 0
412 }
413 { .mib
414 stfs [GR_Parameter_Y] = FR_Result
415 add GR_Parameter_Y = -16,GR_Parameter_Y
416 br.call.sptk b0=__libm_error_support#
417 };;
419 //
420 // Get location of result on stack
421 //
422 { .mmi
423 add GR_Parameter_RESULT = 48,sp
424 nop.m 0
425 nop.i 0
426 };;
428 //
429 // Get the new result
430 //
431 { .mmi
432 ldfs FR_Result = [GR_Parameter_RESULT]
433 .restore sp
434 add sp = 64,sp
435 mov b0 = GR_SAVE_B0
436 };;
438 //
439 // Restore gp, ar.pfs and return
440 //
441 { .mib
442 mov gp = GR_SAVE_GP
443 mov ar.pfs = GR_SAVE_PFS
444 br.ret.sptk b0
445 };;
447 LOCAL_LIBM_END(__libm_error_region)
449 .type __libm_error_support#,@function
450 .global __libm_error_support#