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600 lines
14 KiB
ArmAsm
600 lines
14 KiB
ArmAsm
.file "scalb.s"
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// Copyright (c) 2000 - 2003, Intel Corporation
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// All rights reserved.
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//
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// Contributed 2000 by the Intel Numerics Group, Intel Corporation
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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//
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// * Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in the
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// documentation and/or other materials provided with the distribution.
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//
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// * The name of Intel Corporation may not be used to endorse or promote
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// products derived from this software without specific prior written
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// permission.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS
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// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR TORT (INCLUDING
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// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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// Intel Corporation is the author of this code, and requests that all
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// problem reports or change requests be submitted to it directly at
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// http://www.intel.com/software/products/opensource/libraries/num.htm.
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//
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// History
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//==============================================================
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// 02/02/00 Initial version
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// 01/26/01 Scalb completely reworked and now standalone version
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// 05/20/02 Cleaned up namespace and sf0 syntax
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// 02/10/03 Reordered header: .section, .global, .proc, .align
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// 08/06/03 Improved performance
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//
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// API
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//==============================================================
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// double = scalb (double x, double n)
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// input floating point f8 and floating point f9
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// output floating point f8
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//
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// int_type = 0 if int is 32 bits
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// int_type = 1 if int is 64 bits
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//
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// Returns x* 2**n using an fma and detects overflow
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// and underflow.
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//
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//
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// Strategy:
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// Compute biased exponent of result exp_Result = N + exp_X
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// Break into ranges:
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// exp_Result > 0x103fe -> Certain overflow
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// exp_Result = 0x103fe -> Possible overflow
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// 0x0fc01 <= exp_Result < 0x103fe -> No over/underflow (main path)
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// 0x0fc01 - 52 <= exp_Result < 0x0fc01 -> Possible underflow
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// exp_Result < 0x0fc01 - 52 -> Certain underflow
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FR_Big = f6
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FR_NBig = f7
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FR_Floating_X = f8
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FR_Result = f8
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FR_Floating_N = f9
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FR_Result2 = f9
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FR_Result3 = f10
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FR_Norm_X = f11
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FR_Two_N = f12
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FR_N_float_int = f13
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FR_Norm_N = f14
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GR_neg_ov_limit= r14
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GR_big_exp = r14
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GR_N_Biased = r15
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GR_Big = r16
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GR_exp_Result = r18
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GR_pos_ov_limit= r19
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GR_exp_sure_ou = r19
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GR_Bias = r20
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GR_N_as_int = r21
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GR_signexp_X = r22
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GR_exp_X = r23
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GR_exp_mask = r24
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GR_max_exp = r25
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GR_min_exp = r26
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GR_min_den_exp = r27
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GR_Scratch = r28
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GR_signexp_N = r29
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GR_exp_N = r30
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GR_SAVE_B0 = r32
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GR_SAVE_GP = r33
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GR_SAVE_PFS = r34
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GR_Parameter_X = r35
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GR_Parameter_Y = r36
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GR_Parameter_RESULT = r37
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GR_Tag = r38
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.section .text
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GLOBAL_IEEE754_ENTRY(scalb)
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//
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// Is x NAN, INF, ZERO, +-?
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// Build the exponent Bias
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//
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{ .mfi
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getf.exp GR_signexp_N = FR_Floating_N // Get signexp of n
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fclass.m p6,p0 = FR_Floating_X, 0xe7 // @snan | @qnan | @inf | @zero
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mov GR_Bias = 0x0ffff
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}
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{ .mfi
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mov GR_Big = 35000 // If N this big then certain overflow
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fcvt.fx.trunc.s1 FR_N_float_int = FR_Floating_N // Get N in significand
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nop.i 0
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}
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;;
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{ .mfi
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getf.exp GR_signexp_X = FR_Floating_X // Get signexp of x
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fclass.m p7,p0 = FR_Floating_N, 0x0b // Test for n=unorm
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nop.i 0
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}
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//
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// Normalize n
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//
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{ .mfi
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mov GR_exp_mask = 0x1ffff // Exponent mask
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fnorm.s1 FR_Norm_N = FR_Floating_N
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nop.i 0
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}
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;;
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//
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// Is n NAN, INF, ZERO, +-?
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//
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{ .mfi
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mov GR_big_exp = 0x1003e // Exponent at which n is integer
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fclass.m p9,p0 = FR_Floating_N, 0xe7 // @snan | @qnan | @inf | @zero
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mov GR_max_exp = 0x103fe // Exponent of maximum double
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}
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//
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// Normalize x
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//
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{ .mfb
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nop.m 0
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fnorm.s1 FR_Norm_X = FR_Floating_X
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(p7) br.cond.spnt SCALB_N_UNORM // Branch if n=unorm
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}
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;;
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SCALB_COMMON1:
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// Main path continues. Also return here from u=unorm path.
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// Handle special cases if x = Nan, Inf, Zero
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{ .mfb
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nop.m 0
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fcmp.lt.s1 p7,p0 = FR_Floating_N, f0 // Test N negative
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(p6) br.cond.spnt SCALB_NAN_INF_ZERO
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}
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;;
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// Handle special cases if n = Nan, Inf, Zero
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{ .mfi
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getf.sig GR_N_as_int = FR_N_float_int // Get n from significand
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fclass.m p8,p0 = FR_Floating_X, 0x0b // Test for x=unorm
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mov GR_exp_sure_ou = 0x1000e // Exp_N where x*2^N sure over/under
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}
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{ .mfb
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mov GR_min_exp = 0x0fc01 // Exponent of minimum double
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fcvt.xf FR_N_float_int = FR_N_float_int // Convert N to FP integer
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(p9) br.cond.spnt SCALB_NAN_INF_ZERO
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}
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;;
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{ .mmi
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and GR_exp_N = GR_exp_mask, GR_signexp_N // Get exponent of N
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(p7) sub GR_Big = r0, GR_Big // Limit for N
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nop.i 0
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}
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;;
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{ .mib
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cmp.lt p9,p0 = GR_exp_N, GR_big_exp // N possible non-integer?
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cmp.ge p6,p0 = GR_exp_N, GR_exp_sure_ou // N certain over/under?
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(p8) br.cond.spnt SCALB_X_UNORM // Branch if x=unorm
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}
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;;
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SCALB_COMMON2:
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// Main path continues. Also return here from x=unorm path.
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// Create biased exponent for 2**N
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{ .mmi
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(p6) mov GR_N_as_int = GR_Big // Limit N
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;;
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add GR_N_Biased = GR_Bias,GR_N_as_int
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nop.i 0
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}
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;;
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{ .mfi
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setf.exp FR_Two_N = GR_N_Biased // Form 2**N
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(p9) fcmp.neq.unc.s1 p9,p0 = FR_Norm_N, FR_N_float_int // Test if N an integer
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and GR_exp_X = GR_exp_mask, GR_signexp_X // Get exponent of X
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}
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;;
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//
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// Compute biased result exponent
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// Branch if N is not an integer
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//
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{ .mib
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add GR_exp_Result = GR_exp_X, GR_N_as_int
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mov GR_min_den_exp = 0x0fc01 - 52 // Exponent of min denorm dble
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(p9) br.cond.spnt SCALB_N_NOT_INT
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}
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;;
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//
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// Raise Denormal operand flag with compare
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// Do final operation
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//
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{ .mfi
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cmp.lt p7,p6 = GR_exp_Result, GR_max_exp // Test no overflow
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fcmp.ge.s0 p0,p11 = FR_Floating_X,FR_Floating_N // Dummy to set denorm
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cmp.lt p9,p0 = GR_exp_Result, GR_min_den_exp // Test sure underflow
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}
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{ .mfb
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nop.m 0
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fma.d.s0 FR_Result = FR_Two_N,FR_Norm_X,f0
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(p9) br.cond.spnt SCALB_UNDERFLOW // Branch if certain underflow
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}
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;;
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{ .mib
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(p6) cmp.gt.unc p6,p8 = GR_exp_Result, GR_max_exp // Test sure overflow
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(p7) cmp.ge.unc p7,p9 = GR_exp_Result, GR_min_exp // Test no over/underflow
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(p7) br.ret.sptk b0 // Return from main path
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}
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;;
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{ .bbb
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(p6) br.cond.spnt SCALB_OVERFLOW // Branch if certain overflow
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(p8) br.cond.spnt SCALB_POSSIBLE_OVERFLOW // Branch if possible overflow
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(p9) br.cond.spnt SCALB_POSSIBLE_UNDERFLOW // Branch if possible underflow
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}
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;;
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// Here if possible underflow.
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// Resulting exponent: 0x0fc01-52 <= exp_Result < 0x0fc01
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SCALB_POSSIBLE_UNDERFLOW:
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//
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// Here if possible overflow.
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// Resulting exponent: 0x103fe = exp_Result
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SCALB_POSSIBLE_OVERFLOW:
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// Set up necessary status fields
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//
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// S0 user supplied status
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// S2 user supplied status + WRE + TD (Overflows)
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// S3 user supplied status + FZ + TD (Underflows)
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//
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{ .mfi
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mov GR_pos_ov_limit = 0x103ff // Exponent for positive overflow
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fsetc.s3 0x7F,0x41
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nop.i 0
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}
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{ .mfi
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mov GR_neg_ov_limit = 0x303ff // Exponent for negative overflow
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fsetc.s2 0x7F,0x42
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nop.i 0
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}
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;;
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//
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// Do final operation with s2 and s3
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//
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{ .mfi
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setf.exp FR_NBig = GR_neg_ov_limit
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fma.d.s3 FR_Result3 = FR_Two_N,FR_Norm_X,f0
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nop.i 0
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}
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{ .mfi
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setf.exp FR_Big = GR_pos_ov_limit
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fma.d.s2 FR_Result2 = FR_Two_N,FR_Norm_X,f0
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nop.i 0
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}
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;;
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// Check for overflow or underflow.
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// Restore s3
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// Restore s2
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//
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{ .mfi
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nop.m 0
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fsetc.s3 0x7F,0x40
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nop.i 0
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}
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{ .mfi
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nop.m 0
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fsetc.s2 0x7F,0x40
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nop.i 0
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}
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;;
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//
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// Is the result zero?
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//
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{ .mfi
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nop.m 0
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fclass.m p6, p0 = FR_Result3, 0x007
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nop.i 0
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}
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{ .mfi
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nop.m 0
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fcmp.ge.s1 p7, p8 = FR_Result2 , FR_Big
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nop.i 0
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}
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;;
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//
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// Detect masked underflow - Tiny + Inexact Only
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//
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{ .mfi
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nop.m 0
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(p6) fcmp.neq.unc.s1 p6, p0 = FR_Result , FR_Result2
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nop.i 0
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}
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;;
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//
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// Is result bigger the allowed range?
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// Branch out for underflow
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//
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{ .mfb
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nop.m 0
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(p8) fcmp.le.unc.s1 p9, p10 = FR_Result2 , FR_NBig
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(p6) br.cond.spnt SCALB_UNDERFLOW
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}
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;;
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//
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// Branch out for overflow
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//
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{ .bbb
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(p7) br.cond.spnt SCALB_OVERFLOW
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(p9) br.cond.spnt SCALB_OVERFLOW
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br.ret.sptk b0 // Return from main path.
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}
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;;
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// Here if result overflows
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SCALB_OVERFLOW:
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{ .mib
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alloc r32=ar.pfs,3,0,4,0
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addl GR_Tag = 53, r0 // Set error tag for overflow
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br.cond.sptk __libm_error_region // Call error support for overflow
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}
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;;
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// Here if result underflows
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SCALB_UNDERFLOW:
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{ .mib
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alloc r32=ar.pfs,3,0,4,0
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addl GR_Tag = 54, r0 // Set error tag for underflow
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br.cond.sptk __libm_error_region // Call error support for underflow
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}
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;;
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SCALB_NAN_INF_ZERO:
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//
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// Before entry, N has been converted to a fp integer in significand of
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// FR_N_float_int
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//
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// Convert N_float_int to floating point value
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//
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{ .mfi
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getf.sig GR_N_as_int = FR_N_float_int
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fclass.m p6,p0 = FR_Floating_N, 0xc3 //@snan | @qnan
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nop.i 0
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}
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{ .mfi
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addl GR_Scratch = 1,r0
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fcvt.xf FR_N_float_int = FR_N_float_int
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nop.i 0
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}
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;;
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{ .mfi
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nop.m 0
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fclass.m p7,p0 = FR_Floating_X, 0xc3 //@snan | @qnan
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shl GR_Scratch = GR_Scratch,63
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}
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;;
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{ .mfi
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nop.m 0
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fclass.m p8,p0 = FR_Floating_N, 0x21 // @inf
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nop.i 0
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}
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{ .mfi
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nop.m 0
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fclass.m p9,p0 = FR_Floating_N, 0x22 // @-inf
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nop.i 0
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}
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;;
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//
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// Either X or N is a Nan, return result and possible raise invalid.
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//
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{ .mfb
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nop.m 0
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(p6) fma.d.s0 FR_Result = FR_Floating_N,FR_Floating_X,f0
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(p6) br.ret.spnt b0
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}
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;;
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{ .mfb
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nop.m 0
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(p7) fma.d.s0 FR_Result = FR_Floating_N,FR_Floating_X,f0
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(p7) br.ret.spnt b0
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}
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;;
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//
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// If N + Inf do something special
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// For N = -Inf, create Int
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//
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{ .mfb
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nop.m 0
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(p8) fma.d.s0 FR_Result = FR_Floating_X, FR_Floating_N,f0
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(p8) br.ret.spnt b0
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}
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{ .mfi
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nop.m 0
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(p9) fnma.d.s0 FR_Floating_N = FR_Floating_N, f1, f0
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nop.i 0
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}
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;;
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//
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// If N==-Inf,return x/(-N)
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//
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{ .mfb
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cmp.ne p7,p0 = GR_N_as_int,GR_Scratch
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(p9) frcpa.s0 FR_Result,p0 = FR_Floating_X,FR_Floating_N
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(p9) br.ret.spnt b0
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}
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;;
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//
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// Is N an integer.
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//
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{ .mfi
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nop.m 0
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(p7) fcmp.neq.unc.s1 p7,p0 = FR_Norm_N, FR_N_float_int
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nop.i 0
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}
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;;
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//
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// If N not an int, return NaN and raise invalid.
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//
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{ .mfb
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nop.m 0
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(p7) frcpa.s0 FR_Result,p0 = f0,f0
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(p7) br.ret.spnt b0
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}
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;;
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//
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// Always return x in other path.
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//
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{ .mfb
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nop.m 0
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fma.d.s0 FR_Result = FR_Floating_X,f1,f0
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br.ret.sptk b0
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}
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;;
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// Here if n not int
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// Return NaN and raise invalid.
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SCALB_N_NOT_INT:
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{ .mfb
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nop.m 0
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frcpa.s0 FR_Result,p0 = f0,f0
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br.ret.sptk b0
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}
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;;
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// Here if n=unorm
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SCALB_N_UNORM:
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{ .mfb
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getf.exp GR_signexp_N = FR_Norm_N // Get signexp of normalized n
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fcvt.fx.trunc.s1 FR_N_float_int = FR_Norm_N // Get N in significand
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br.cond.sptk SCALB_COMMON1 // Return to main path
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}
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;;
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// Here if x=unorm
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SCALB_X_UNORM:
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{ .mib
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getf.exp GR_signexp_X = FR_Norm_X // Get signexp of normalized x
|
|
nop.i 0
|
|
br.cond.sptk SCALB_COMMON2 // Return to main path
|
|
}
|
|
;;
|
|
|
|
GLOBAL_IEEE754_END(scalb)
|
|
LOCAL_LIBM_ENTRY(__libm_error_region)
|
|
|
|
//
|
|
// Get stack address of N
|
|
//
|
|
.prologue
|
|
{ .mfi
|
|
add GR_Parameter_Y=-32,sp
|
|
nop.f 0
|
|
.save ar.pfs,GR_SAVE_PFS
|
|
mov GR_SAVE_PFS=ar.pfs
|
|
}
|
|
//
|
|
// Adjust sp
|
|
//
|
|
{ .mfi
|
|
.fframe 64
|
|
add sp=-64,sp
|
|
nop.f 0
|
|
mov GR_SAVE_GP=gp
|
|
};;
|
|
|
|
//
|
|
// Store N on stack in correct position
|
|
// Locate the address of x on stack
|
|
//
|
|
{ .mmi
|
|
stfd [GR_Parameter_Y] = FR_Norm_N,16
|
|
add GR_Parameter_X = 16,sp
|
|
.save b0, GR_SAVE_B0
|
|
mov GR_SAVE_B0=b0
|
|
};;
|
|
|
|
//
|
|
// Store x on the stack.
|
|
// Get address for result on stack.
|
|
//
|
|
.body
|
|
{ .mib
|
|
stfd [GR_Parameter_X] = FR_Norm_X
|
|
add GR_Parameter_RESULT = 0,GR_Parameter_Y
|
|
nop.b 0
|
|
}
|
|
{ .mib
|
|
stfd [GR_Parameter_Y] = FR_Result
|
|
add GR_Parameter_Y = -16,GR_Parameter_Y
|
|
br.call.sptk b0=__libm_error_support#
|
|
};;
|
|
|
|
//
|
|
// Get location of result on stack
|
|
//
|
|
{ .mmi
|
|
add GR_Parameter_RESULT = 48,sp
|
|
nop.m 0
|
|
nop.i 0
|
|
};;
|
|
|
|
//
|
|
// Get the new result
|
|
//
|
|
{ .mmi
|
|
ldfd FR_Result = [GR_Parameter_RESULT]
|
|
.restore sp
|
|
add sp = 64,sp
|
|
mov b0 = GR_SAVE_B0
|
|
};;
|
|
|
|
//
|
|
// Restore gp, ar.pfs and return
|
|
//
|
|
{ .mib
|
|
mov gp = GR_SAVE_GP
|
|
mov ar.pfs = GR_SAVE_PFS
|
|
br.ret.sptk b0
|
|
};;
|
|
|
|
LOCAL_LIBM_END(__libm_error_region)
|
|
|
|
.type __libm_error_support#,@function
|
|
.global __libm_error_support#
|