609 lines
13 KiB
ArmAsm
609 lines
13 KiB
ArmAsm
.file "remainderf.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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// 03/02/00 New algorithm
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// 04/04/00 Unwind support added
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// 07/21/00 Fixed quotient=2^{24*m+23} bug
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// 08/15/00 Bundle added after call to __libm_error_support to properly
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// set [the previously overwritten] GR_Parameter_RESULT.
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// 11/29/00 Set FR_Y to f9
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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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//
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// API
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//====================================================================
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// float remainderf(float,float);
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//
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// Overview of operation
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//====================================================================
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// remainder(a,b)=a-i*b,
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// where i is an integer such that, if b!=0 and a is finite,
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// |a/b-i|<=1/2. If |a/b-i|=1/2, i is even.
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//
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// Algorithm
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//====================================================================
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// a). eliminate special cases
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// b). if |a/b|<0.25 (first quotient estimate), return a
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// c). use single precision divide algorithm to get quotient q
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// rounded to 24 bits of precision
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// d). calculate partial remainders (using both q and q-ulp);
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// select one and RZ(a/b) based on the sign of |a|-|b|*q
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// e). if the exponent difference (exponent(a)-exponent(b))
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// is less than 24 (quotient estimate<2^{24}-2), use RZ(a/b)
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// and sticky bits to round to integer; exit loop and
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// calculate final remainder
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// f). if exponent(a)-exponent(b)>=24, select new value of a as
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// the partial remainder calculated using RZ(a/b);
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// repeat from c).
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//
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// Special cases
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//====================================================================
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// a=+/- Inf, or b=+/-0: return NaN, call libm_error_support
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// a=NaN or b=NaN: return NaN
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//
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// Registers used
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//====================================================================
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// Predicate registers: p6-p12
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// General registers: r2,r3,r28,r29,r32 (ar.pfs), r33-r39
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// Floating point registers: f6-f15
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//
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GR_SAVE_B0 = r33
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GR_SAVE_PFS = r34
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GR_SAVE_GP = r35
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GR_SAVE_SP = r36
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GR_Parameter_X = r37
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GR_Parameter_Y = r38
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GR_Parameter_RESULT = r39
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GR_Parameter_TAG = r40
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FR_X = f10
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FR_Y = f9
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FR_RESULT = f8
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.section .text
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GLOBAL_IEEE754_ENTRY(remainderf)
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// inputs in f8, f9
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// result in f8
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{ .mfi
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alloc r32=ar.pfs,1,4,4,0
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// f13=|a|
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fmerge.s f13=f0,f8
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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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// f14=|b|
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fmerge.s f14=f0,f9
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nop.i 0;;
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}
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{.mlx
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nop.m 0
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// r2=2^{24}-2
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movl r3=0x4b7ffffe;;
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}
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// Y +-NAN, +-inf, +-0? p11
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{ .mfi
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nop.m 999
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fclass.m.unc p11,p0 = f9, 0xe7
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nop.i 999
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}
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// qnan snan inf norm unorm 0 -+
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// 1 1 1 0 0 0 11
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// e 3
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// X +-NAN, +-inf, ? p9
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{ .mfi
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nop.m 999
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fclass.m.unc p9,p0 = f8, 0xe3
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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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mov f15=f0
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nop.i 0
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}
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{ .mfi
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// set p7=1
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cmp.eq.unc p7,p0=r0,r0
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// Step (1)
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// y0 = 1 / b in f10
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frcpa.s1 f10,p6=f13,f14
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nop.i 0;;
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}
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{.bbb
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(p9) br.cond.spnt FREM_X_NAN_INF
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(p11) br.cond.spnt FREM_Y_NAN_INF_ZERO
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nop.b 0
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} {.mfi
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nop.m 0
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// set D flag if a (f8) is denormal
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fnma.s0 f6=f8,f1,f8
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nop.i 0;;
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}
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.align 32
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remloop24:
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{ .mfi
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// f12=2^{24}-2
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setf.s f12=r3
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// Step (2)
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// q0 = a * y0 in f15
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(p6) fma.s1 f15=f13,f10,f0
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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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// Step (3)
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// e0 = 1 - b * y0 in f7
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(p6) fnma.s1 f7=f14,f10,f1
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nop.i 0;;
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}
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{.mlx
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nop.m 0
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// r2=1.25*2^{-24}
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movl r2=0x33a00000;;
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}
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{ .mfi
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nop.m 0
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// Step (4)
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// q1 = q0 + e0 * q0 in f6
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(p6) fma.s1 f6=f7,f15,f15
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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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// Step (5)
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// e1 = e0 * e0 in f7
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(p6) fma.s1 f7=f7,f7,f0
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nop.i 0;;
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}
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{.mii
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(p7) getf.exp r29=f15
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(p7) mov r28=0xfffd
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nop.i 0;;
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}
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{ .mfi
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// f15=1.25*2^{-24}
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setf.s f15=r2
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// Step (6)
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// q2 = q1 + e1 * q1 in f6
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(p6) fma.s1 f6=f7,f6,f6
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nop.i 0
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}
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{ .mfi
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mov r2=0x3e7
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// Step (7)
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// e2 = e1 * e1 in f7
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(p6) fma.s1 f7=f7,f7,f0
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nop.i 0;;
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}
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{.mmi
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// q<1/4 ? (i.e. expon< -2)
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(p7) cmp.gt.unc p7,p0=r28,r29
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nop.m 0
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// r2=0x3e7000000
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shl r2=r2,24;;
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}
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{.mfb
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// r2=0x3e7000001
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add r2=1,r2
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// if |a/b|<1/4, set D flag before returning
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(p7) fma.s.s0 f9=f9,f0,f8
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nop.b 0;;
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}
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{.mfb
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nop.m 0
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// can be combined with bundle above if sign of 0 or
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// FTZ enabled are not important
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(p7) fmerge.s f8=f8,f9
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// return if |a|<4*|b| (estimated quotient < 1/4)
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(p7) br.ret.spnt b0;;
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}
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{.mfi
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nop.m 0
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// set f8 to current a value | sign
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fmerge.s f8=f8,f13
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// r2=2^{-24}+2^{-48} (double prec.)
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shl r2=r2,28;;
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}
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{ .mfi
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// r29= -32+bias
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mov r29=0xffdf
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// Step (8)
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// q3 = q2 + e2 * q2 in f6
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(p6) fma.d.s1 f6=f7,f6,f6
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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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// Step (9)
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// q = q3 in f11
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(p6) fma.s.s1 f11=f6,f1,f0
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nop.i 0;;
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}
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{.mfi
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// f7=2^{-24}
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setf.d f7=r2
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// last step ? (q3<2^{24}-2 --> q<2^{24})
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fcmp.lt.unc.s1 p0,p12=f6,f12
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nop.i 0
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} {.mfi
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// f12=2^{-32}
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setf.exp f12=r29
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nop.f 0
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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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// r=a-b*q
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fnma.s1 f6=f14,f11,f13
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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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// q'=q-q*(1.25*2^{-24}) (q'=q-ulp)
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fnma.s.s1 f15=f11,f15,f11
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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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// r2=a-b*q'
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fnma.s1 f13=f14,f15,f13
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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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// r>0 iff q=RZ(a/b) and inexact
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fcmp.gt.unc.s1 p8,p0=f6,f0
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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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// r<0 iff q'=RZ(a/b) and inexact
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fcmp.lt.unc.s1 p9,p10=f6,f0
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nop.i 0;;
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}
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.pred.rel "mutex",p8,p9
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{.mfi
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nop.m 0
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// (p8) Q=q+(last iteration ? sticky bits:0)
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// i.e. Q=q+q*x (x=2^{-32} or 0)
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(p8) fma.s1 f11=f11,f12,f11
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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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// (p9) Q=q'+(last iteration ? sticky bits:0)
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// i.e. Q=q'+q'*x (x=2^{-24} or 0: if expon. difference=23, want to round back to q)
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(p9) fma.s1 f11=f15,f7,f15
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nop.i 0;;
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}
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{.mfb
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nop.m 0
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// (p9) set r=r2 (new a, if not last iteration)
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// (p10) new a =r
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(p10) mov f13=f6
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(p12) br.cond.sptk remloop24;;
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}
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// last iteration
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{.mfi
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nop.m 0
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// set f9=|b|*sgn(a)
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fmerge.s f9=f8,f9
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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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// round to integer
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fcvt.fx.s1 f11=f11
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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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// save sign of a
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fmerge.s f7=f8,f8
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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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// normalize
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fcvt.xf f11=f11
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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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// This can be removed if sign of 0 is not important
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// get remainder using sf1
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fnma.s.s1 f12=f9,f11,f8
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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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// get remainder
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fnma.s.s0 f8=f9,f11,f8
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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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// f12=0?
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// This can be removed if sign of 0 is not important
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fcmp.eq.unc.s1 p8,p0=f12,f0
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nop.i 0;;
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}
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{.mfb
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nop.m 0
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// if f8=0, set sign correctly
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// This can be removed if sign of 0 is not important
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(p8) fmerge.s f8=f7,f8
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// return
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br.ret.sptk b0;;
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}
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FREM_X_NAN_INF:
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// Y zero ?
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{.mfi
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nop.m 0
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fma.s1 f10=f9,f1,f0
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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.eq.unc.s1 p11,p0=f10,f0
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nop.i 0;;
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}
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{.mib
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nop.m 0
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nop.i 0
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// if Y zero
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(p11) br.cond.spnt FREM_Y_ZERO;;
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}
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// X infinity? Return QNAN indefinite
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{ .mfi
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nop.m 999
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fclass.m.unc p8,p0 = f8, 0x23
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nop.i 999
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}
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// X infinity? Return QNAN indefinite
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{ .mfi
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nop.m 999
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fclass.m.unc p11,p0 = f8, 0x23
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nop.i 999;;
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}
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// Y NaN ?
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{.mfi
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nop.m 999
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(p8) fclass.m.unc p0,p8=f9,0xc3
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nop.i 0;;
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}
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{.mfi
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nop.m 999
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// also set Denormal flag if necessary
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(p8) fma.s0 f9=f9,f1,f0
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nop.i 0
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}
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{ .mfi
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nop.m 999
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(p8) frcpa.s0 f8,p7 = f8,f8
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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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(p11) mov f10=f8
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nop.i 0
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}
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{ .mfi
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nop.m 999
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(p8) fma.s.s0 f8=f8,f1,f0
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nop.i 0 ;;
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}
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{ .mfb
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nop.m 999
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frcpa.s0 f8,p7=f8,f9
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(p11) br.cond.spnt EXP_ERROR_RETURN;;
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}
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{ .mib
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nop.m 0
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nop.i 0
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br.ret.spnt b0 ;;
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}
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FREM_Y_NAN_INF_ZERO:
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// Y INF
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{ .mfi
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nop.m 999
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fclass.m.unc p7,p0 = f9, 0x23
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nop.i 999 ;;
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}
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{ .mfb
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nop.m 999
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(p7) fma.s.s0 f8=f8,f1,f0
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(p7) br.ret.spnt b0 ;;
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}
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// Y NAN?
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{ .mfi
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nop.m 999
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fclass.m.unc p9,p0 = f9, 0xc3
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nop.i 999 ;;
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}
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{ .mfb
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nop.m 999
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(p9) fma.s.s0 f8=f9,f1,f0
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(p9) br.ret.spnt b0 ;;
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}
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FREM_Y_ZERO:
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// Y zero? Must be zero at this point
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// because it is the only choice left.
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// Return QNAN indefinite
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// X NAN?
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{ .mfi
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nop.m 999
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fclass.m.unc p9,p10 = f8, 0xc3
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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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(p10) fclass.nm p9,p10 = f8, 0xff
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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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(p9) frcpa.s0 f11,p7=f8,f0
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nop.i 0;;
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}
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{ .mfi
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nop.m 999
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(p10) frcpa.s0 f11,p7 = f0,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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fmerge.s f10 = f8, f8
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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.s.s0 f8=f11,f1,f0
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nop.i 999
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}
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EXP_ERROR_RETURN:
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{ .mib
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mov GR_Parameter_TAG = 125
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nop.i 999
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br.sptk __libm_error_region;;
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}
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GLOBAL_IEEE754_END(remainderf)
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LOCAL_LIBM_ENTRY(__libm_error_region)
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.prologue
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{ .mfi
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add GR_Parameter_Y=-32,sp // Parameter 2 value
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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 // Save ar.pfs
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}
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{ .mfi
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.fframe 64
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add sp=-64,sp // Create new stack
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nop.f 0
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mov GR_SAVE_GP=gp // Save gp
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};;
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{ .mmi
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stfs [GR_Parameter_Y] = FR_Y,16 // Save Parameter 2 on stack
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add GR_Parameter_X = 16,sp // Parameter 1 address
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.save b0, GR_SAVE_B0
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mov GR_SAVE_B0=b0 // Save b0
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};;
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.body
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|
{ .mib
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stfs [GR_Parameter_X] = FR_X // Store Parameter 1 on stack
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add GR_Parameter_RESULT = 0,GR_Parameter_Y
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|
nop.b 0 // Parameter 3 address
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}
|
|
{ .mib
|
|
stfs [GR_Parameter_Y] = FR_RESULT // Store Parameter 3 on stack
|
|
add GR_Parameter_Y = -16,GR_Parameter_Y
|
|
br.call.sptk b0=__libm_error_support#;; // Call error handling function
|
|
}
|
|
{ .mmi
|
|
nop.m 0
|
|
nop.m 0
|
|
add GR_Parameter_RESULT = 48,sp
|
|
};;
|
|
{ .mmi
|
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ldfs f8 = [GR_Parameter_RESULT] // Get return result off stack
|
|
.restore sp
|
|
add sp = 64,sp // Restore stack pointer
|
|
mov b0 = GR_SAVE_B0 // Restore return address
|
|
};;
|
|
{ .mib
|
|
mov gp = GR_SAVE_GP // Restore gp
|
|
mov ar.pfs = GR_SAVE_PFS // Restore ar.pfs
|
|
br.ret.sptk b0 // Return
|
|
};;
|
|
|
|
LOCAL_LIBM_END(__libm_error_region)
|
|
|
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.type __libm_error_support#,@function
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.global __libm_error_support#
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