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+.file "libm_frexp_4.s"
+
+// Copyright (c) 2000, 2001, Intel Corporation
+// All rights reserved.
+// 
+// Contributed 2/2/2000 by John Harrison, Ted Kubaska, Bob Norin, Shane Story,
+// and Ping Tak Peter Tang of the Computational Software Lab, Intel Corporation.
+// 
+// WARRANTY DISCLAIMER
+// 
+// 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://developer.intel.com/opensource.
+//
+// History
+//==============================================================
+// 2/02/00: Initial version
+// 3/20/00: Improved speed
+// 6/01/00: Fixed bug when x a double-extended denormal
+// 12/08/00 Corrected label on .endp
+//
+// API
+//==============================================================
+// double frexp(double x, int* y)
+// double __libm_frexp_4(double x, int* y)
+//   where int* y is a 32-bit integer
+//
+// 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 integer for exponent
+//
+// 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
+//
+// 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
+
+#include "libm_support.h"
+
+.align 32
+.global __libm_frexp_4#
+
+.section .text
+.proc  __libm_frexp_4#
+.align 32
+
+__libm_frexp_4: 
+
+// 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
+(p0)    mov         r15 = 0x0fffe
+(p0)    fclass.m.unc p6,p0 = f8, 0xe7
+(p0)    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
+(p0)    mov         r20 = 0x1003f
+(p0)    fnorm       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
+(p0)    setf.exp    f10 = r15
+(p0)    setf.exp    f12 = r20
+        nop.i 999 ;;
+}
+
+// Move signexp for significand result for x<0 to FP reg
+// If x NAN, ZERO, INFINITY, set *y=0 as a 32-bit integer, and exit
+{ .mmb
+(p0)    setf.exp    f11 = r14
+(p6)    st4         [r33] = r0
+(p6)    br.ret.spnt b0 ;;
+}
+
+// Form exponent mask
+// p7 if x<0, else p8
+{ .mfi
+(p0)    mov         r17 = 0x1ffff
+(p0)    fcmp.lt.unc p7,p8 = f8,f0
+        nop.i 999 ;;
+}
+
+// Test for fnorm(x) denormal, means x double-extended denormal
+{ .mfi
+        nop.m 999
+(p0)    fclass.m.unc 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
+{ .mfi
+(p9)    add         r15 = 64, r15
+(p9)    fmpy        f9 = f9, f12
+        nop.i 999 ;;
+}
+
+// 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
+(p0)    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
+(p0)    and         r18 = r17,r16 ;;
+(p0)    sub         r19 = r18,r15
+        nop.i 999  ;;
+}
+
+// Store int y as a 32-bit integer
+// Make the value a double
+{ .mfb
+(p0)    st4         [r33] = r19
+(p0)    fnorm.d     f8 = f8
+(p0)    br.ret.sptk b0 ;;
+}
+
+.endp __libm_frexp_4
+ASM_SIZE_DIRECTIVE(__libm_frexp_4)