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363 lines
7.9 KiB
363 lines
7.9 KiB
.file "ldexp.s"
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// Copyright (c) 2000, 2001, Intel Corporation
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// All rights reserved.
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//
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// Contributed 2/2/2000 by John Harrison, Ted Kubaska, Bob Norin, Shane Story,
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// and Ping Tak Peter Tang of the Computational Software Lab, Intel Corporation.
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//
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// WARRANTY DISCLAIMER
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//
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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://developer.intel.com/opensource.
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//
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// History
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//==============================================================
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// 2/02/00 Initial version
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// 1/26/01 ldex pcompletely reworked and now standalone version
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//
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// API
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//==============================================================
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// double = ldexp (double x, int n)
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// input floating point f8 and int n (r33)
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// output floating point f8
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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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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_Result2 = f9
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FR_Result3 = f11
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FR_Norm_X = f12
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FR_Two_N = f14
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FR_Two_to_Big = f15
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GR_N_Biased = r15
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GR_Big = r16
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GR_NBig = r17
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GR_Scratch = r18
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GR_Scratch1 = r19
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GR_Bias = r20
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GR_N_as_int = r21
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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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.align 32
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.global ldexp
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.section .text
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.proc ldexp
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.align 32
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ldexp:
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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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alloc r32=ar.pfs,1,2,4,0
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fclass.m.unc p7,p0 = FR_Floating_X, 0xe7 //@snan | @qnan | @inf | @zero
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addl GR_Bias = 0x0FFFF,r0
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}
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//
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// Sign extend input
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// Is N zero?
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// Normalize x
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//
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{ .mfi
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cmp.eq.unc p6,p0 = r33,r0
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fnorm.s1 FR_Norm_X = FR_Floating_X
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sxt4 GR_N_as_int = r33
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}
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;;
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//
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// Normalize x
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// Branch and return special values.
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// Create -35000
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// Create 35000
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//
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{ .mfi
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addl GR_Big = 35000,r0
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nop.f 0
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add GR_N_Biased = GR_Bias,GR_N_as_int
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}
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{ .mfb
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addl GR_NBig = -35000,r0
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(p7) fma.d.s0 FR_Result = FR_Floating_X,f1, f0
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(p7) br.ret.spnt b0
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};;
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//
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// Build the exponent Bias
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// Return x when N = 0
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//
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{ .mfi
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setf.exp FR_Two_N = GR_N_Biased
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nop.f 0
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addl GR_Scratch1 = 0x063BF,r0
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}
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{ .mfb
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addl GR_Scratch = 0x019C3F,r0
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(p6) fma.d.s0 FR_Result = FR_Floating_X,f1, f0
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(p6) br.ret.spnt b0
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};;
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//
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// Create 2*big
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// Create 2**-big
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// Is N > 35000
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// Is N < -35000
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// Raise Denormal operand flag with compare
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// Main path, create 2**N
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//
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{ .mfi
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setf.exp FR_NBig = GR_Scratch1
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nop.f 0
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cmp.ge.unc p6, p0 = GR_N_as_int, GR_Big
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}
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{ .mfi
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setf.exp FR_Big = GR_Scratch
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fcmp.ge.s0 p0,p11 = FR_Floating_X,f0
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cmp.le.unc p8, p0 = GR_N_as_int, GR_NBig
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};;
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//
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// Adjust 2**N if N was very small or very large
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//
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{ .mfi
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nop.m 0
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(p6) fma.s1 FR_Two_N = FR_Big,f1,f0
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nop.i 0
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}
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{ .mlx
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nop.m 999
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movl GR_Scratch = 0x00000000000303FF
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};;
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{ .mfi
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nop.m 0
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(p8) fma.s1 FR_Two_N = FR_NBig,f1,f0
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nop.i 0
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}
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{ .mlx
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nop.m 999
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movl GR_Scratch1= 0x00000000000103FF
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};;
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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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nop.m 999
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fsetc.s3 0x7F,0x41
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nop.i 999
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}
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{ .mfi
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nop.m 999
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fsetc.s2 0x7F,0x42
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nop.i 999
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};;
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//
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// Do final operation
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//
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{ .mfi
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setf.exp FR_NBig = GR_Scratch
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fma.d.s0 FR_Result = FR_Two_N,FR_Norm_X,f0
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nop.i 999
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}
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{ .mfi
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nop.m 999
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fma.d.s3 FR_Result3 = FR_Two_N,FR_Norm_X,f0
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nop.i 999
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};;
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{ .mfi
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setf.exp FR_Big = GR_Scratch1
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fma.d.s2 FR_Result2 = FR_Two_N,FR_Norm_X,f0
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nop.i 999
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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 999
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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 999
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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 999
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fclass.m.unc p6, p0 = FR_Result3, 0x007
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nop.i 999
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}
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{ .mfi
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addl GR_Tag = 146, r0
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fcmp.ge.unc.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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// Detect masked underflow - Tiny + Inexact Only
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//
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{ .mfi
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nop.m 999
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(p6) fcmp.neq.unc.s1 p6, p0 = FR_Result , FR_Result2
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nop.i 999
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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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(p6) addl GR_Tag = 147, r0
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(p8) fcmp.le.unc.s1 p9, p10 = FR_Result2 , FR_NBig
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(p6) br.cond.spnt LDEXP_UNDERFLOW
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};;
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//
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// Branch out for overflow
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//
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{ .mbb
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nop.m 0
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(p7) br.cond.spnt LDEXP_OVERFLOW
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(p9) br.cond.spnt LDEXP_OVERFLOW
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};;
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//
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// Return from main path.
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//
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{ .mfb
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nop.m 999
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nop.f 0
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br.ret.sptk b0;;
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}
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.endp ldexp
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.proc __libm_error_region
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__libm_error_region:
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LDEXP_OVERFLOW:
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LDEXP_UNDERFLOW:
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//
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// Get stack address of N
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//
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.prologue
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{ .mfi
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add GR_Parameter_Y=-32,sp
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nop.f 0
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.save ar.pfs,GR_SAVE_PFS
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mov GR_SAVE_PFS=ar.pfs
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}
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//
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// Adjust sp
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//
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{ .mfi
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.fframe 64
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add sp=-64,sp
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nop.f 0
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mov GR_SAVE_GP=gp
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};;
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//
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// Store N on stack in correct position
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// Locate the address of x on stack
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//
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{ .mmi
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st8 [GR_Parameter_Y] = GR_N_as_int,16
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add GR_Parameter_X = 16,sp
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.save b0, GR_SAVE_B0
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mov GR_SAVE_B0=b0
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};;
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//
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// Store x on the stack.
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// Get address for result on stack.
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//
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.body
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{ .mib
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stfd [GR_Parameter_X] = FR_Norm_X
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add GR_Parameter_RESULT = 0,GR_Parameter_Y
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nop.b 0
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}
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{ .mib
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stfd [GR_Parameter_Y] = FR_Result
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add GR_Parameter_Y = -16,GR_Parameter_Y
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br.call.sptk b0=__libm_error_support#
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};;
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//
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// Get location of result on stack
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//
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{ .mmi
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nop.m 0
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nop.m 0
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add GR_Parameter_RESULT = 48,sp
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};;
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//
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// Get the new result
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//
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{ .mmi
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ldfd FR_Result = [GR_Parameter_RESULT]
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.restore
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add sp = 64,sp
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mov b0 = GR_SAVE_B0
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};;
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//
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// Restore gp, ar.pfs and return
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//
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{ .mib
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mov gp = GR_SAVE_GP
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mov ar.pfs = GR_SAVE_PFS
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br.ret.sptk b0
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};;
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.endp __libm_error_region
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.type __libm_error_support#,@function
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.global __libm_error_support#
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