1 .file "libm_scalblnf.s"
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40 //==============================================================
41 // 08/03/01 Initial version
42 // 08/23/01 Corrected error tag number
43 // 02/06/02 Corrected to handle 32- or 64-bit integers
44 // 05/20/02 Cleaned up namespace and sf0 syntax
45 // 02/10/03 Reordered header: .section, .global, .proc, .align
46 // 08/25/03 Improved performance
49 //==============================================================
50 // float __libm_scalblnf (float x, long int n, int long_int_type)
51 // input floating point f8 and long int n (r33)
52 // input long_int_type = 0 if long int defined as 32 bits, = 1 if 64 bits
53 // output floating point f8
55 // Returns x* 2**n using an fma and detects overflow
60 // Compute biased exponent of result exp_Result = N + exp_X
62 // exp_Result > 0x1007e -> Certain overflow
63 // exp_Result = 0x1007e -> Possible overflow
64 // 0x0ff81 <= exp_Result < 0x1007e -> No over/underflow (main path)
65 // 0x0ff81 - 23 <= exp_Result < 0x0ff81 -> Possible underflow
66 // exp_Result < 0x0ff81 - 23 -> Certain underflow
97 GR_Parameter_RESULT = r37
101 GLOBAL_LIBM_ENTRY(__libm_scalblnf)
104 // Is x NAN, INF, ZERO, +-?
105 // Build the exponent Bias
108 getf.exp GR_signexp_X = FR_Floating_X // Get signexp of x
109 fclass.m p6,p0 = FR_Floating_X, 0xe7 // @snan | @qnan | @inf | @zero
110 mov GR_Bias = 0x0ffff
114 // Is long integer type 32 bits?
117 mov GR_Big = 35000 // If N this big then certain overflow
118 fnorm.s1 FR_Norm_X = FR_Floating_X
119 cmp.eq p8,p9 = r34,r0
123 // Sign extend N if long int is 32 bits
125 (p9) mov GR_N_as_int = r33 // Copy N if long int is 64 bits
126 fclass.m p9,p0 = FR_Floating_X, 0x0b // Test for x=unorm
127 (p8) sxt4 GR_N_as_int = r33 // Sign extend N if long int is 32 bits
130 mov GR_NBig = -35000 // If N this small then certain underflow
132 mov GR_max_exp = 0x1007e // Exponent of maximum float
136 // Create biased exponent for 2**N
138 add GR_N_Biased = GR_Bias,GR_N_as_int
140 cmp.ge p7, p0 = GR_N_as_int, GR_Big // Certain overflow?
143 cmp.le p8, p0 = GR_N_as_int, GR_NBig // Certain underflow?
144 mov GR_min_exp = 0x0ff81 // Exponent of minimum float
145 (p9) br.cond.spnt SCALBNF_UNORM // Branch if x=unorm
150 // Main path continues. Also return here from x=unorm path.
152 .pred.rel "mutex",p7,p8
154 setf.exp FR_Two_N = GR_N_Biased
156 (p7) mov GR_N_as_int = GR_Big // Limit max N
159 (p8) mov GR_N_as_int = GR_NBig // Limit min N
161 (p8) cmp.eq p7,p0 = r0,r0 // Set p7 if |N| big
166 // Create biased exponent for 2**N for N big
170 (p7) add GR_N_Biased = GR_Bias,GR_N_as_int
172 cmp.eq.or p6,p0 = r33,r0
175 mov GR_pos_ov_limit = 0x1007f // Exponent for positive overflow
177 mov GR_exp_mask = 0x1ffff // Exponent mask
182 // Create 2**N for N big
183 // Return x when N = 0 or X = Nan, Inf, Zero
186 (p7) setf.exp FR_Two_N = GR_N_Biased
188 mov GR_min_den_exp = 0x0ff81 - 23 // Exponent of min denorm float
191 and GR_exp_X = GR_exp_mask, GR_signexp_X
192 (p6) fma.s.s0 FR_Result = FR_Floating_X, f1, f0
198 // Raise Denormal operand flag with compare
199 // Compute biased result exponent
202 add GR_exp_Result = GR_exp_X, GR_N_as_int
203 fcmp.ge.s0 p0,p11 = FR_Floating_X,f0
204 mov GR_neg_ov_limit = 0x3007f // Exponent for negative overflow
209 // Do final operation
212 cmp.lt p7,p6 = GR_exp_Result, GR_max_exp // Test no overflow
213 fma.s.s0 FR_Result = FR_Two_N,FR_Norm_X,f0
214 cmp.lt p9,p0 = GR_exp_Result, GR_min_den_exp // Test sure underflow
219 (p9) br.cond.spnt SCALBNF_UNDERFLOW // Branch if certain underflow
224 (p6) cmp.gt.unc p6,p8 = GR_exp_Result, GR_max_exp // Test sure overflow
225 (p7) cmp.ge.unc p7,p9 = GR_exp_Result, GR_min_exp // Test no over/underflow
226 (p7) br.ret.sptk b0 // Return from main path
231 (p6) br.cond.spnt SCALBNF_OVERFLOW // Branch if certain overflow
232 (p8) br.cond.spnt SCALBNF_POSSIBLE_OVERFLOW // Branch if possible overflow
233 (p9) br.cond.spnt SCALBNF_POSSIBLE_UNDERFLOW // Branch if possible underflow
237 // Here if possible underflow.
238 // Resulting exponent: 0x0ff81-23 <= exp_Result < 0x0ff81
239 SCALBNF_POSSIBLE_UNDERFLOW:
241 // Here if possible overflow.
242 // Resulting exponent: 0x1007e = exp_Result
243 SCALBNF_POSSIBLE_OVERFLOW:
245 // Set up necessary status fields
247 // S0 user supplied status
248 // S2 user supplied status + WRE + TD (Overflows)
249 // S3 user supplied status + FZ + TD (Underflows)
264 // Do final operation with s2 and s3
267 setf.exp FR_NBig = GR_neg_ov_limit
268 fma.s.s3 FR_Result3 = FR_Two_N,FR_Norm_X,f0
272 setf.exp FR_Big = GR_pos_ov_limit
273 fma.s.s2 FR_Result2 = FR_Two_N,FR_Norm_X,f0
278 // Check for overflow or underflow.
295 // Is the result zero?
299 fclass.m p6, p0 = FR_Result3, 0x007
304 fcmp.ge.s1 p7, p8 = FR_Result2 , FR_Big
310 // Detect masked underflow - Tiny + Inexact Only
314 (p6) fcmp.neq.unc.s1 p6, p0 = FR_Result , FR_Result2
320 // Is result bigger the allowed range?
321 // Branch out for underflow
325 (p8) fcmp.le.unc.s1 p9, p10 = FR_Result2 , FR_NBig
326 (p6) br.cond.spnt SCALBNF_UNDERFLOW
331 // Branch out for overflow
334 (p7) br.cond.spnt SCALBNF_OVERFLOW
335 (p9) br.cond.spnt SCALBNF_OVERFLOW
336 br.ret.sptk b0 // Return from main path.
340 // Here if result overflows
343 alloc r32=ar.pfs,3,0,4,0
344 addl GR_Tag = 205, r0 // Set error tag for overflow
345 br.cond.sptk __libm_error_region // Call error support for overflow
349 // Here if result underflows
352 alloc r32=ar.pfs,3,0,4,0
353 addl GR_Tag = 206, r0 // Set error tag for underflow
354 br.cond.sptk __libm_error_region // Call error support for underflow
361 getf.exp GR_signexp_X = FR_Norm_X // Get signexp of normalized x
363 br.cond.sptk SCALBNF_COMMON // Return to main path
368 GLOBAL_LIBM_END(__libm_scalblnf)
369 LOCAL_LIBM_ENTRY(__libm_error_region)
372 // Get stack address of N
376 add GR_Parameter_Y=-32,sp
378 .save ar.pfs,GR_SAVE_PFS
379 mov GR_SAVE_PFS=ar.pfs
392 // Store N on stack in correct position
393 // Locate the address of x on stack
396 st8 [GR_Parameter_Y] = GR_N_as_int,16
397 add GR_Parameter_X = 16,sp
403 // Store x on the stack.
404 // Get address for result on stack.
408 stfs [GR_Parameter_X] = FR_Norm_X
409 add GR_Parameter_RESULT = 0,GR_Parameter_Y
413 stfs [GR_Parameter_Y] = FR_Result
414 add GR_Parameter_Y = -16,GR_Parameter_Y
415 br.call.sptk b0=__libm_error_support#
419 // Get location of result on stack
422 add GR_Parameter_RESULT = 48,sp
428 // Get the new result
431 ldfs FR_Result = [GR_Parameter_RESULT]
438 // Restore gp, ar.pfs and return
442 mov ar.pfs = GR_SAVE_PFS
446 LOCAL_LIBM_END(__libm_error_region)
448 .type __libm_error_support#,@function
449 .global __libm_error_support#