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+.file "ilogb.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
+//==============================================================
+// 02/03/00 Initial version
+// 05/26/00 Fix bug when x a double-extended denormal;
+//          if x=0 call error routine, per C9X
+// 08/15/00 Bundle added after call to __libm_error_support to properly
+//          set [the previously overwritten] GR_Parameter_RESULT.
+// 01/20/01 Fixed result for x=0, corrected error tag value.
+// 05/20/02 Cleaned up namespace and sf0 syntax
+// 01/20/03 Improved performance
+//
+// API
+//==============================================================
+// int ilogb( double x );
+//
+// Overview of operation
+//==============================================================
+// The ilogb function extracts the exponent of x as an integer
+// and returns it in r8
+//
+// ilogb is similar to logb but differs in the following ways:
+//         +-inf
+//            ilogb: returns INT_MAX
+//             logb: returns +inf
+//         Nan  returns FP_LOGBNAN (which is either INT_MAX or INT_MIN)
+//            ilogb: returns INT_MAX (7fffffff)
+//             logb: returns QNAN (quietized SNAN)
+//         0    returns FP_ILOGB0 (which is either INT_MIN or -INT_MAX)
+//            ilogb: returns -INT_MAX (80000001)
+//             logb: returns -inf, raises the divide-by-zero exception,
+//                   and calls libm_error_support to set domain error
+//
+// Registers used
+//==============================================================
+// general registers used:
+// r26 -> r39
+// r36 -> r39 used as parameters to error path
+//
+// predicate registers used:
+// p6 -> p10
+// floating-point registers used:
+// f9, f10, f11
+// f8, input
+
+rExpBias            = r26
+rExpMask            = r27
+rSignexp_x          = r28
+rExp_x              = r29
+rIntMax             = r30
+rExp_2to64          = r31
+
+GR_SAVE_PFS         = r32
+rTrialResult        = r33
+GR_SAVE_B0          = r34
+GR_SAVE_GP          = r35
+
+GR_Parameter_X      = r36
+GR_Parameter_Y      = r37
+GR_Parameter_RESULT = r38
+GR_Parameter_TAG    = r39
+
+fTmp                = f9
+fNorm_x             = f10
+f2to64              = f11
+
+.section .text
+GLOBAL_LIBM_ENTRY(ilogb)
+
+// X NORMAL
+// TrueExp_x = exp(f8) - 0xffff
+// r8 = TrueExp_x
+{ .mfi
+      getf.exp        rSignexp_x = f8
+      fclass.m        p8,p0 = f8, 0x0b   // Test for x unorm
+      mov             rExpBias = 0xffff  // Exponent bias
+}
+{ .mfi
+      nop.m           0
+      fnorm.s1        fNorm_x = f8
+      mov             rExpMask = 0x1ffff // Exponent mask
+}
+;;
+
+// Form signexp of 2^64 in case need to scale denormal
+{ .mfb
+      mov             rExp_2to64 = 0x1003f
+      fclass.m        p6,p9 = f8, 0x1e3  // Test x natval, nan, inf
+(p8)  br.cond.spnt    ILOGB_DENORM       // Branch if x unorm
+}
+;;
+
+ILOGB_COMMON:
+// Return here from ILOGB_DENORM
+{ .mfi
+      and             rExp_x = rSignexp_x, rExpMask // Get biased exponent
+      fclass.m        p7,p10 = f8, 0x07   // Test x zero
+      nop.i           0
+}
+{ .mlx
+      nop.m           0
+      movl            rIntMax = 0x000000007fffffff // Form INT_MAX
+}
+;;
+
+.pred.rel "mutex",p6,p9
+{ .mfi
+(p9)  sub             r8 = rExp_x, rExpBias // Get true exponent for normal path
+(p6)  fma.s0          fTmp = f8, f8, f0     // Dummy to set Invalid flag
+(p6)  mov             r8 = rIntMax          // If nan, inf, return INT_MAX
+}
+{ .mbb
+      nop.m           0
+(p7)  br.cond.spnt    ILOGB_ZERO            // Branch if x zero
+(p10) br.ret.sptk     b0                    // Exit if x not zero
+}
+;;
+
+
+ILOGB_DENORM:
+// Form 2^64 in case need to scale denormal
+// Check to see if double-extended denormal
+{ .mfi
+      setf.exp        f2to64 = rExp_2to64
+      fclass.m        p8,p0 = fNorm_x, 0x0b
+      nop.i           0
+}
+;;
+
+{ .mfi
+      nop.m           0
+      fcmp.eq.s0      p7,p0 = f8, f0           // Dummy op to set denormal flag
+      nop.i           0
+}
+;;
+
+// If double-extended denormal add 64 to exponent bias for scaling
+// If double-extended denormal form x * 2^64 which is normal
+{ .mfi
+(p8)  add             rExpBias = 64, rExpBias
+(p8)  fmpy.s1         fNorm_x = fNorm_x, f2to64
+      nop.i           0
+}
+;;
+
+// Logic is the same as normal path but use normalized input
+{ .mib
+      getf.exp        rSignexp_x = fNorm_x
+      nop.i           0
+      br.cond.sptk    ILOGB_COMMON             // Return to main path
+}
+;;
+
+ILOGB_ZERO:
+// Here if x zero
+// Return INT_MIN, call error support
+
+{ .mlx
+      alloc           r32=ar.pfs,1,3,4,0
+      movl            rTrialResult = 0x0000000080000000
+}
+{ .mib
+      mov             GR_Parameter_TAG = 157  // Error code
+      nop.i           0
+      br.cond.sptk    __libm_error_region     // Call error support
+}
+;;
+
+GLOBAL_LIBM_END(ilogb)
+
+
+LOCAL_LIBM_ENTRY(__libm_error_region)
+.prologue
+
+{ .mfi
+        add   GR_Parameter_Y=-32,sp           // Parameter 2 value
+        nop.f 0
+.save   ar.pfs,GR_SAVE_PFS
+        mov  GR_SAVE_PFS=ar.pfs               // Save ar.pfs
+}
+{ .mfi
+.fframe 64
+        add sp=-64,sp                         // Create new stack
+        nop.f 0
+        mov GR_SAVE_GP=gp                     // Save gp
+};;
+
+{ .mmi
+        stfd [GR_Parameter_Y] = f0,16         // STORE Parameter 2 on stack
+        add GR_Parameter_X    = 16,sp         // Parameter 1 address
+.save   b0, GR_SAVE_B0
+        mov GR_SAVE_B0=b0                     // Save b0
+};;
+
+.body
+{ .mib
+        stfd [GR_Parameter_X] = f8            // STORE Parameter 1 on stack
+        add   GR_Parameter_RESULT = 0,GR_Parameter_Y    // Parameter 3 address
+        nop.b 0
+}
+{ .mib
+        stfd [GR_Parameter_Y] = f9            // 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
+        add   GR_Parameter_RESULT = 48,sp
+        nop.m 0
+        nop.i 0
+};;
+
+{ .mmi
+        mov   r8 = rTrialResult
+.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
+};;
+
+LOCAL_LIBM_END(__libm_error_region)
+
+
+.type   __libm_error_support#,@function
+.global __libm_error_support#