153 lines
4.1 KiB
ArmAsm
153 lines
4.1 KiB
ArmAsm
.file "significand.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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//
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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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// 04/04/00 Unwind support added
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// 05/31/00 Fixed bug when x a double-extended denormal
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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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// double significand(double x)
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//
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// Overview of operation
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//==============================================================
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// If x = sig * 2**n with 1 <= sig < 2
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// significand returns sig
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//
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// predicate registers used:
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// p6, p7
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//
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// floating-point registers used:
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// f8, f9, f10
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.section .text
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GLOBAL_LIBM_ENTRY(significand)
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// qnan snan inf norm unorm 0 -+
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// 1 1 1 0 0 1 11
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// f10 gets f8(sign) with f1(exp,significand)
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{ .mfi
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nop.m 999
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fmerge.s f10 = f8,f1
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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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fnorm.s0 f9 = f8
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nop.i 999 ;;
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}
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// Test for denormal input
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{ .mfi
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nop.m 999
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fclass.m.unc p7,p0 = f8, 0x0b
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nop.i 999 ;;
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}
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// p6 = TRUE ==> x is not (nan,inf,0)
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// return sign(f8) exp(f1) significand(f8)
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// else x is (nan,inf,0)
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// return sign(f8) exp(f8) significand(f8), normalized.
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{ .mfi
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nop.m 999
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fclass.m.unc p0,p6 = f8, 0xe7
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nop.i 999 ;;
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}
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{ .mmb
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nop.m 999
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nop.m 999
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(p7) br.cond.spnt SIGNIFICAND_DENORM ;; // Branch if x denormal
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}
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{ .mfi
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nop.m 999
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(p6) fmerge.se f8 = f10,f8
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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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fnorm.d.s0 f8 = f8
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br.ret.sptk b0 ;;
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}
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SIGNIFICAND_DENORM:
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// Here if x denorm
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{ .mfi
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nop.m 999
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fmerge.se f8 = f10,f9
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nop.i 999 ;;
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}
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// Check if fnorm(x) still denormal, means x double-extended denormal
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{ .mfi
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nop.m 999
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fclass.m.unc p7,p0 = f9, 0x0b
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nop.i 999 ;;
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}
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// This will be the final result unless x double-extended denormal
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{ .mfi
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nop.m 999
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fnorm.d.s0 f8 = f8
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nop.i 999 ;;
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}
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// If x double-extended denorm, then significand ok, but must merge in
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// correct signexp
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{ .mfi
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nop.m 999
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(p7) fmerge.se f8 = f10,f8
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nop.i 999 ;;
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}
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// Final normalization if x double-extended denorm
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{ .mfb
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nop.m 999
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(p7) fnorm.d.s0 f8 = f8
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br.ret.sptk b0 ;;
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}
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GLOBAL_LIBM_END(significand)
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