.file "libm_frexp.s"// Copyright (c) 2000 - 2003, Intel Corporation// All rights reserved.//// Contributed 2000 by the Intel Numerics Group, Intel Corporation//// Redistribution and use in source and binary forms, with or without// modification, are permitted provided that the following conditions are// met://// * Redistributions of source code must retain the above copyright// notice, this list of conditions and the following disclaimer.//// * Redistributions in binary form must reproduce the above copyright// notice, this list of conditions and the following disclaimer in the// documentation and/or other materials provided with the distribution.//// * The name of Intel Corporation may not be used to endorse or promote// products derived from this software without specific prior written// permission.// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY // OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR TORT (INCLUDING// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. // // Intel Corporation is the author of this code, and requests that all// problem reports or change requests be submitted to it directly at // http://www.intel.com/software/products/opensource/libraries/num.htm.//// History//==============================================================// 02/02/00 Initial version// 03/20/00 Improved speed// 06/01/00 Fixed bug when x a double-extended denormal// 12/08/00 Corrected label on .endp// 01/23/02 Added handling for int 32 or 64 bits// 05/20/02 Cleaned up namespace and sf0 syntax// 02/10/03 Reordered header: .section, .global, .proc, .align//// API//==============================================================// double __libm_frexp(double x, int* y, int int_type)// input  floating point f8, pointer to y (r33), int int_type (r34)// output floating point f8, returns the fraction of x, 0.5 <= fraction < 1.0// output int* y, returns the true exponent of x//// int_type = 0 if int is 32 bits// int_type = 1 if int is 64 bits//// int* y is returned as a 32 bit integer if int_type = 0// int* y is returned as a 64 bit integer if int_type = 1//// Overview of operation//==============================================================// break a floating point x number into fraction and an exponent// The fraction is returned as a double// The exponent is returned as an integer pointed to by y//    This is a true (not a biased exponent) but 0fffe is subtracted//    as a bias instead of 0xffff. This is because the fraction returned//    is between 0.5 and 1.0, not the expected IEEE range.//// The fraction is 0.5 <= fraction < 1.0//// Registers used//==============================================================//// general registers: // r14  exponent bias for x negative// r15  exponent bias for x positive// r16  signexp of x// r17  exponent mask// r18  exponent of x// r19  exponent result// r20  signexp of 2^64// r32  on input contains the 64-bit IEEE double that is in f8// r33  on input pointer to 32-bit or 64-bit integer for exponent// r34  on input contains 0 if output int is 32 bits, else output int is 64 bits//// predicate registers:// p6   set if x is Nan, zero, or infinity// p7   set if x negative// p8   set if x positive// p9   set if x double-extended denormal// p10  set if int_type = 0, 32-bit integer// p11  set if int_type = 1, 64-bit integer//// floating-point registers:// f8  input, output// f9  normalized x// f10 signexp for significand result for x positive// f11 signexp for significand result for x negative// f12 2^64.section .textGLOBAL_LIBM_ENTRY(__libm_frexp)// Set signexp for significand result for x>0// If x is a NaN, zero, or infinity, return it.// Put 0 in the int pointer.// x NAN, ZERO, INFINITY?// Set signexp for significand result for x<0{ .mfi        mov         r15 = 0x0fffe        fclass.m    p6,p7 = f8, 0xe7        mov         r14 = 0x2fffe}// Form signexp of 2^64 in case x double-extended denormal// Save the normalized value of input in f9// The normalization also sets fault flags and takes faults if necessary{ .mfi        mov         r20 = 0x1003f        fnorm.s0    f9 = f8         nop.i 999 ;;}// Move signexp for significand result for x>0 to FP reg// Form 2^64 in case x double-extended denormal{ .mmi        setf.exp    f10 = r15        setf.exp    f12 = r20        nop.i 999 ;;}// Move signexp for significand result for x<0 to FP reg// p7 if x<0, else p8// If x=0,nan,inf, set p10 if output int to be 32 bits, or set p11 if 64 bits{ .mfi        setf.exp    f11 = r14(p7)    fcmp.lt.s0  p7,p8 = f8,f0(p6)    cmp.eq.unc  p10,p11 = r34, r0 ;; }// If x NAN, ZERO, INFINITY, set *y=0 and exit{ .mmb(p10)   st4         [r33] = r0      // Store *y=0 as 32-bit integer(p11)   st8         [r33] = r0      // Store *y=0 as 64-bit integer(p6)    br.ret.spnt b0 ;;}// Form exponent mask// Test for fnorm(x) denormal, means x double-extended denormal{ .mfi        mov         r17 = 0x1ffff        fclass.m    p9,p0 = f9, 0x0b        nop.i 999 ;;}// If x double-extended denormal add 64 to exponent bias for scaling// If x double-extended denormal multiply x * 2^64 which is normal// Set p10 if output int to be 32 bits, or set p11 if 64 bits{ .mfi(p9)    add         r15 = 64, r15(p9)    fmpy.s0     f9 = f9, f12        cmp.eq      p10,p11 = r34, r0 ;; }// true exponent stored to int pointer// the bias is treated as 0xfffe instead of // normal 0xffff because we want the significand// to be in the range <=0.5 sig < 1.0// Store the value of the exponent at the pointer in r33// If x>0 form significand result { .mfi        nop.m 999(p8)    fmerge.se   f8 = f10,f9        nop.i 999  ;;}// Get signexp of normalized x// If x<0 form significand result { .mfi        getf.exp    r16 = f9(p7)    fmerge.se   f8 = f11,f9        nop.i 999  ;;}// Get exp of normalized x// Subtract off bias to get true exponent of x{ .mmi        and         r18 = r17,r16 ;;        sub         r19 = r18,r15        nop.i 999  ;;}// Store int *y as a 32-bit integer// Make the value a double{ .mfi(p10)   st4         [r33] = r19        // Store *y as 32-bit integer        fnorm.d.s0  f8 = f8        nop.i 999}{ .mfb(p11)   st8         [r33] = r19        // Store *y as 64-bit integer        nop.f 999        br.ret.sptk b0 ;;}GLOBAL_LIBM_END(__libm_frexp)