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+.file "exp.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 
+// 3/07/00  exp(inf)  = inf but now does NOT call error support
+//          exp(-inf) = 0   but now does NOT call error support
+// 4/04/00  Unwind support added
+// 8/15/00  Bundle added after call to __libm_error_support to properly
+//          set [the previously overwritten] GR_Parameter_RESULT.
+// 11/30/00 Reworked to shorten main path, widen main path to include all
+//          args in normal range, and add quick exit for 0, nan, inf.
+// 12/05/00 Loaded constants earlier with setf to save 2 cycles.
+
+// API
+//==============================================================
+// double exp(double)
+
+// Overview of operation
+//==============================================================
+// Take the input x. w is "how many log2/128 in x?"
+//  w = x * 128/log2
+//  n = int(w)
+//  x = n log2/128 + r + delta
+
+//  n = 128M + index_1 + 2^4 index_2
+//  x = M log2 + (log2/128) index_1 + (log2/8) index_2 + r + delta
+
+//  exp(x) = 2^M  2^(index_1/128)  2^(index_2/8) exp(r) exp(delta)
+//       Construct 2^M
+//       Get 2^(index_1/128) from table_1;
+//       Get 2^(index_2/8)   from table_2;
+//       Calculate exp(r) by series
+//          r = x - n (log2/128)_high
+//          delta = - n (log2/128)_low
+//       Calculate exp(delta) as 1 + delta
+
+
+// Special values 
+//==============================================================
+// exp(+0)    = 1.0
+// exp(-0)    = 1.0
+
+// exp(+qnan) = +qnan 
+// exp(-qnan) = -qnan 
+// exp(+snan) = +qnan 
+// exp(-snan) = -qnan 
+
+// exp(-inf)  = +0 
+// exp(+inf)  = +inf
+
+// Overfow and Underfow
+//=======================
+// exp(-x) = smallest double normal when
+//     x = -708.396 = c086232bdd7abcd2
+
+// exp(x) = largest double normal when
+//     x = 709.7827 = 40862e42fefa39ef
+
+
+
+// Registers used
+//==============================================================
+// Floating Point registers used: 
+// f8, input
+// f9 -> f15,  f32 -> f60
+
+// General registers used: 
+// r32 -> r60 
+
+// Predicate registers used:
+// p6 -> p15
+
+#include "libm_support.h"
+
+// Assembly macros
+//==============================================================
+
+exp_GR_rshf                   = r33
+EXP_AD_TB1                    = r34
+EXP_AD_TB2                    = r35
+EXP_AD_P                      = r36
+
+exp_GR_N                      = r37
+exp_GR_index_1                = r38
+exp_GR_index_2_16             = r39
+
+exp_GR_biased_M               = r40
+exp_GR_index_1_16             = r41
+EXP_AD_T1                     = r42
+EXP_AD_T2                     = r43
+exp_GR_sig_inv_ln2            = r44
+
+exp_GR_17ones                 = r45
+exp_GR_one                    = r46
+exp_TB1_size                  = r47
+exp_TB2_size                  = r48
+exp_GR_rshf_2to56             = r49
+
+exp_GR_gt_ln                  = r50
+exp_GR_exp_2tom56             = r51
+
+exp_GR_17ones_m1              = r52
+
+GR_SAVE_B0                    = r53
+GR_SAVE_PFS                   = r54
+GR_SAVE_GP                    = r55
+GR_SAVE_SP                    = r56
+
+GR_Parameter_X                = r57
+GR_Parameter_Y                = r58
+GR_Parameter_RESULT           = r59
+GR_Parameter_TAG              = r60
+
+
+FR_X             = f10
+FR_Y             = f1
+FR_RESULT        = f8
+
+EXP_RSHF_2TO56   = f6
+EXP_INV_LN2_2TO63 = f7
+EXP_W_2TO56_RSH  = f9
+EXP_2TOM56       = f11
+exp_P4           = f12 
+exp_P3           = f13 
+exp_P2           = f14 
+exp_P1           = f15 
+
+exp_ln2_by_128_hi  = f33 
+exp_ln2_by_128_lo  = f34 
+
+EXP_RSHF           = f35
+EXP_Nfloat         = f36 
+exp_W              = f37
+exp_r              = f38
+exp_f              = f39
+
+exp_rsq            = f40
+exp_rcube          = f41
+
+EXP_2M             = f42
+exp_S1             = f43
+exp_T1             = f44
+
+EXP_MIN_DBL_OFLOW_ARG = f45
+EXP_MAX_DBL_ZERO_ARG  = f46
+EXP_MAX_DBL_NORM_ARG  = f47
+EXP_MAX_DBL_UFLOW_ARG = f48
+EXP_MIN_DBL_NORM_ARG  = f49
+exp_rP4pP3         = f50
+exp_P_lo           = f51
+exp_P_hi           = f52
+exp_P              = f53
+exp_S              = f54
+
+EXP_NORM_f8        = f56   
+
+exp_wre_urm_f8     = f57
+exp_ftz_urm_f8     = f57
+
+exp_gt_pln         = f58
+
+exp_S2             = f59
+exp_T2             = f60
+
+
+// Data tables
+//==============================================================
+
+#ifdef _LIBC
+.rodata
+#else
+.data
+#endif
+
+.align 16
+
+// ************* DO NOT CHANGE ORDER OF THESE TABLES ********************
+
+// double-extended 1/ln(2)
+// 3fff b8aa 3b29 5c17 f0bb be87fed0691d3e88
+// 3fff b8aa 3b29 5c17 f0bc 
+// For speed the significand will be loaded directly with a movl and setf.sig
+//   and the exponent will be bias+63 instead of bias+0.  Thus subsequent
+//   computations need to scale appropriately.
+// The constant 128/ln(2) is needed for the computation of w.  This is also 
+//   obtained by scaling the computations.
+//
+// Two shifting constants are loaded directly with movl and setf.d. 
+//   1. EXP_RSHF_2TO56 = 1.1000..00 * 2^(63-7) 
+//        This constant is added to x*1/ln2 to shift the integer part of
+//        x*128/ln2 into the rightmost bits of the significand.
+//        The result of this fma is EXP_W_2TO56_RSH.
+//   2. EXP_RSHF       = 1.1000..00 * 2^(63) 
+//        This constant is subtracted from EXP_W_2TO56_RSH * 2^(-56) to give
+//        the integer part of w, n, as a floating-point number.
+//        The result of this fms is EXP_Nfloat.
+
+
+exp_table_1:
+ASM_TYPE_DIRECTIVE(exp_table_1,@object)
+data8 0x40862e42fefa39f0 // smallest dbl overflow arg
+data8 0xc0874c0000000000 // approx largest arg for zero result
+data8 0x40862e42fefa39ef // largest dbl arg to give normal dbl result
+data8 0xc086232bdd7abcd3 // largest dbl underflow arg
+data8 0xc086232bdd7abcd2 // smallest dbl arg to give normal dbl result
+data8 0x0                // pad
+data8 0xb17217f7d1cf79ab , 0x00003ff7 // ln2/128 hi
+data8 0xc9e3b39803f2f6af , 0x00003fb7 // ln2/128 lo
+
+// Table 1 is 2^(index_1/128) where
+// index_1 goes from 0 to 15
+
+data8 0x8000000000000000 , 0x00003FFF
+data8 0x80B1ED4FD999AB6C , 0x00003FFF
+data8 0x8164D1F3BC030773 , 0x00003FFF
+data8 0x8218AF4373FC25EC , 0x00003FFF
+data8 0x82CD8698AC2BA1D7 , 0x00003FFF
+data8 0x8383594EEFB6EE37 , 0x00003FFF
+data8 0x843A28C3ACDE4046 , 0x00003FFF
+data8 0x84F1F656379C1A29 , 0x00003FFF
+data8 0x85AAC367CC487B15 , 0x00003FFF
+data8 0x8664915B923FBA04 , 0x00003FFF
+data8 0x871F61969E8D1010 , 0x00003FFF
+data8 0x87DB357FF698D792 , 0x00003FFF
+data8 0x88980E8092DA8527 , 0x00003FFF
+data8 0x8955EE03618E5FDD , 0x00003FFF
+data8 0x8A14D575496EFD9A , 0x00003FFF
+data8 0x8AD4C6452C728924 , 0x00003FFF
+ASM_SIZE_DIRECTIVE(exp_table_1)
+
+// Table 2 is 2^(index_1/8) where
+// index_2 goes from 0 to 7
+exp_table_2:
+ASM_TYPE_DIRECTIVE(exp_table_2,@object)
+data8 0x8000000000000000 , 0x00003FFF
+data8 0x8B95C1E3EA8BD6E7 , 0x00003FFF
+data8 0x9837F0518DB8A96F , 0x00003FFF
+data8 0xA5FED6A9B15138EA , 0x00003FFF
+data8 0xB504F333F9DE6484 , 0x00003FFF
+data8 0xC5672A115506DADD , 0x00003FFF
+data8 0xD744FCCAD69D6AF4 , 0x00003FFF
+data8 0xEAC0C6E7DD24392F , 0x00003FFF
+ASM_SIZE_DIRECTIVE (exp_table_2)
+
+
+exp_p_table:
+ASM_TYPE_DIRECTIVE(exp_p_table,@object)
+data8 0x3f8111116da21757 //P_4
+data8 0x3fa55555d787761c //P_3
+data8 0x3fc5555555555414 //P_2
+data8 0x3fdffffffffffd6a //P_1
+ASM_SIZE_DIRECTIVE(exp_p_table)
+
+
+.align 32
+.global exp#
+
+.section .text
+.proc  exp#
+.align 32
+exp: 
+#ifdef _LIBC
+.global __ieee754_exp#
+__ieee754_exp:
+#endif
+
+{ .mlx
+      alloc      r32=ar.pfs,1,24,4,0                               
+      movl exp_GR_sig_inv_ln2 = 0xb8aa3b295c17f0bc  // significand of 1/ln2
+}
+{ .mlx
+      addl       EXP_AD_TB1    = @ltoff(exp_table_1), gp
+      movl exp_GR_rshf_2to56 = 0x4768000000000000 ;;  // 1.10000 2^(63+56)
+}
+;;
+
+// We do this fnorm right at the beginning to take any enabled
+// faults and to normalize any input unnormals so that SWA is not taken.
+{ .mfi
+      ld8        EXP_AD_TB1    = [EXP_AD_TB1]
+      fclass.m   p8,p0 = f8,0x07  // Test for x=0
+      mov        exp_GR_17ones = 0x1FFFF                          
+}
+{ .mfi
+      mov        exp_TB1_size  = 0x100
+      fnorm      EXP_NORM_f8   = f8                                          
+      mov exp_GR_exp_2tom56 = 0xffff-56
+}
+;;
+
+// Form two constants we need
+//  1/ln2 * 2^63  to compute  w = x * 1/ln2 * 128 
+//  1.1000..000 * 2^(63+63-7) to right shift int(w) into the significand
+
+{ .mmf
+      setf.sig  EXP_INV_LN2_2TO63 = exp_GR_sig_inv_ln2 // form 1/ln2 * 2^63
+      setf.d  EXP_RSHF_2TO56 = exp_GR_rshf_2to56 // Form const 1.100 * 2^(63+56)
+      fclass.m   p9,p0 = f8,0x22  // Test for x=-inf
+}
+;;
+
+{ .mlx
+      setf.exp EXP_2TOM56 = exp_GR_exp_2tom56 // form 2^-56 for scaling Nfloat
+      movl exp_GR_rshf = 0x43e8000000000000   // 1.10000 2^63 for right shift
+}
+{ .mfb
+      mov        exp_TB2_size  = 0x80
+(p8)  fma.d      f8 = f1,f1,f0           // quick exit for x=0
+(p8)  br.ret.spnt b0
+;;
+}
+
+{ .mfi
+      ldfpd      EXP_MIN_DBL_OFLOW_ARG, EXP_MAX_DBL_ZERO_ARG = [EXP_AD_TB1],16
+      fclass.m   p10,p0 = f8,0x21  // Test for x=+inf
+      nop.i 999
+}
+{ .mfb
+      nop.m 999
+(p9)  fma.d      f8 = f0,f0,f0           // quick exit for x=-inf
+(p9)  br.ret.spnt b0
+;;                    
+}
+
+{ .mmf
+      ldfpd      EXP_MAX_DBL_NORM_ARG, EXP_MAX_DBL_UFLOW_ARG = [EXP_AD_TB1],16
+      setf.d  EXP_RSHF = exp_GR_rshf // Form right shift const 1.100 * 2^63
+      fclass.m   p11,p0 = f8,0xc3  // Test for x=nan
+;;
+}
+
+{ .mfb
+      ldfd      EXP_MIN_DBL_NORM_ARG = [EXP_AD_TB1],16
+      nop.f 999
+(p10) br.ret.spnt b0               // quick exit for x=+inf
+;;
+}
+
+{ .mfi
+      ldfe       exp_ln2_by_128_hi  = [EXP_AD_TB1],16
+      nop.f 999
+      nop.i 999
+;;
+}
+
+
+{ .mfb
+      ldfe       exp_ln2_by_128_lo  = [EXP_AD_TB1],16
+(p11) fmerge.s   f8 = EXP_NORM_f8, EXP_NORM_f8
+(p11) br.ret.spnt b0               // quick exit for x=nan
+;;
+}
+
+// After that last load, EXP_AD_TB1 points to the beginning of table 1
+
+// W = X * Inv_log2_by_128
+// By adding 1.10...0*2^63 we shift and get round_int(W) in significand.
+// We actually add 1.10...0*2^56 to X * Inv_log2 to do the same thing.
+
+{ .mfi
+      nop.m 999
+      fma.s1  EXP_W_2TO56_RSH  = EXP_NORM_f8, EXP_INV_LN2_2TO63, EXP_RSHF_2TO56
+      nop.i 999
+;;
+}
+
+
+// Divide arguments into the following categories:
+//  Certain Underflow/zero  p11 - -inf < x <= MAX_DBL_ZERO_ARG 
+//  Certain Underflow       p12 - MAX_DBL_ZERO_ARG < x <= MAX_DBL_UFLOW_ARG 
+//  Possible Underflow      p13 - MAX_DBL_UFLOW_ARG < x < MIN_DBL_NORM_ARG
+//  Certain Safe                - MIN_DBL_NORM_ARG <= x <= MAX_DBL_NORM_ARG
+//  Possible Overflow       p14 - MAX_DBL_NORM_ARG < x < MIN_DBL_OFLOW_ARG
+//  Certain Overflow        p15 - MIN_DBL_OFLOW_ARG <= x < +inf
+//
+// If the input is really a double arg, then there will never be "Possible
+// Underflow" or "Possible Overflow" arguments.
+//
+
+{ .mfi
+      add        EXP_AD_TB2 = exp_TB1_size, EXP_AD_TB1
+      fcmp.ge.s1  p15,p14 = EXP_NORM_f8,EXP_MIN_DBL_OFLOW_ARG
+      nop.i 999
+;;                        
+}
+
+{ .mfi
+      add        EXP_AD_P = exp_TB2_size, EXP_AD_TB2
+      fcmp.le.s1  p11,p12 = EXP_NORM_f8,EXP_MAX_DBL_ZERO_ARG
+      nop.i 999
+;;
+}
+
+{ .mfb
+      ldfpd      exp_P4, exp_P3  = [EXP_AD_P] ,16
+(p14) fcmp.gt.unc.s1  p14,p0 = EXP_NORM_f8,EXP_MAX_DBL_NORM_ARG
+(p15) br.cond.spnt L(EXP_CERTAIN_OVERFLOW)
+;;
+}
+
+
+// Nfloat = round_int(W) 
+// The signficand of EXP_W_2TO56_RSH contains the rounded integer part of W,
+// as a twos complement number in the lower bits (that is, it may be negative).
+// That twos complement number (called N) is put into exp_GR_N.
+
+// Since EXP_W_2TO56_RSH is scaled by 2^56, it must be multiplied by 2^-56
+// before the shift constant 1.10000 * 2^63 is subtracted to yield EXP_Nfloat.
+// Thus, EXP_Nfloat contains the floating point version of N
+
+
+{ .mfi
+      nop.m 999
+(p12) fcmp.le.unc  p12,p0 = EXP_NORM_f8,EXP_MAX_DBL_UFLOW_ARG
+      nop.i 999
+}
+{ .mfb
+      ldfpd      exp_P2, exp_P1  = [EXP_AD_P]                                  
+      fms.s1          EXP_Nfloat = EXP_W_2TO56_RSH, EXP_2TOM56, EXP_RSHF 
+(p11) br.cond.spnt L(EXP_CERTAIN_UNDERFLOW_ZERO)
+;;
+}
+
+{ .mfi
+      getf.sig        exp_GR_N        = EXP_W_2TO56_RSH
+(p13) fcmp.lt.unc  p13,p0 = EXP_NORM_f8,EXP_MIN_DBL_NORM_ARG
+      nop.i 999
+;;
+}
+
+
+// exp_GR_index_1 has index_1
+// exp_GR_index_2_16 has index_2 * 16
+// exp_GR_biased_M has M
+// exp_GR_index_1_16 has index_1 * 16
+
+// r2 has true M
+{ .mfi
+      and            exp_GR_index_1 = 0x0f, exp_GR_N
+      fnma.s1    exp_r   = EXP_Nfloat, exp_ln2_by_128_hi, EXP_NORM_f8 
+      shr            r2 = exp_GR_N,  0x7
+}
+{ .mfi
+      and            exp_GR_index_2_16 = 0x70, exp_GR_N
+      fnma.s1    exp_f   = EXP_Nfloat, exp_ln2_by_128_lo, f1 
+      nop.i 999
+;;                            
+}
+
+
+// EXP_AD_T1 has address of T1                           
+// EXP_AD_T2 has address if T2                            
+
+{ .mmi
+      addl           exp_GR_biased_M = 0xffff, r2 
+      add            EXP_AD_T2 = EXP_AD_TB2, exp_GR_index_2_16 
+      shladd         EXP_AD_T1 = exp_GR_index_1, 4, EXP_AD_TB1
+;;                            
+}
+
+
+// Create Scale = 2^M
+// r = x - Nfloat * ln2_by_128_hi 
+// f = 1 - Nfloat * ln2_by_128_lo 
+
+{ .mmi
+      setf.exp        EXP_2M = exp_GR_biased_M                              
+      ldfe       exp_T2  = [EXP_AD_T2]                                
+      nop.i 999
+;;
+}
+
+// Load T1 and T2
+{ .mfi
+      ldfe       exp_T1  = [EXP_AD_T1]                                
+      nop.f 999
+      nop.i 999
+;;
+}
+
+
+{ .mfi
+        nop.m 999
+        fma.s1           exp_rsq = exp_r, exp_r, f0 
+        nop.i 999
+}
+{ .mfi
+        nop.m 999
+        fma.s1        exp_rP4pP3 = exp_r, exp_P4, exp_P3               
+        nop.i 999
+;;
+}
+
+
+
+{ .mfi
+        nop.m 999
+        fma.s1           exp_rcube = exp_r, exp_rsq, f0 
+        nop.i 999 
+}
+{ .mfi
+        nop.m 999
+        fma.s1        exp_P_lo  = exp_r, exp_rP4pP3, exp_P2            
+        nop.i 999
+;;
+}
+
+
+{ .mfi
+        nop.m 999
+        fma.s1        exp_P_hi  = exp_rsq, exp_P1, exp_r              
+        nop.i 999
+}
+{ .mfi
+        nop.m 999
+        fma.s1        exp_S2  = exp_f,exp_T2,f0                       
+        nop.i 999
+;;
+}
+
+{ .mfi
+        nop.m 999
+        fma.s1        exp_S1  = EXP_2M,exp_T1,f0                      
+        nop.i 999
+;;
+}
+
+
+{ .mfi
+        nop.m 999
+        fma.s1        exp_P     = exp_rcube, exp_P_lo, exp_P_hi       
+        nop.i 999
+;;
+}
+
+{ .mfi
+        nop.m 999
+        fma.s1        exp_S   = exp_S1,exp_S2,f0                      
+        nop.i 999
+;;
+}
+
+{ .bbb
+(p12)   br.cond.spnt  L(EXP_CERTAIN_UNDERFLOW)
+(p13)   br.cond.spnt  L(EXP_POSSIBLE_UNDERFLOW)
+(p14)   br.cond.spnt  L(EXP_POSSIBLE_OVERFLOW)
+;;
+}
+
+
+{ .mfb
+        nop.m 999
+        fma.d      f8 = exp_S, exp_P, exp_S 
+        br.ret.sptk     b0 ;;               // Normal path exit 
+}
+
+
+L(EXP_POSSIBLE_OVERFLOW): 
+
+// We got an answer. EXP_MAX_DBL_NORM_ARG < x < EXP_MIN_DBL_OFLOW_ARG
+// overflow is a possibility, not a certainty
+
+{ .mfi
+	nop.m 999
+        fsetc.s2 0x7F,0x42                                          
+	nop.i 999 ;;
+}
+
+{ .mfi
+	nop.m 999
+        fma.d.s2      exp_wre_urm_f8 = exp_S, exp_P, exp_S          
+	nop.i 999 ;;
+}
+
+// We define an overflow when the answer with
+//    WRE set
+//    user-defined rounding mode
+// is ldn +1
+
+// Is the exponent 1 more than the largest double?
+// If so, go to ERROR RETURN, else get the answer and 
+// leave.
+
+// Largest double is 7FE (biased double)
+//                   7FE - 3FF + FFFF = 103FE
+// Create + largest_double_plus_ulp
+// Create - largest_double_plus_ulp
+// Calculate answer with WRE set.
+
+// Cases when answer is ldn+1  are as follows:
+//  ldn                   ldn+1
+// --+----------|----------+------------
+//              | 
+//    +inf          +inf      -inf
+//                  RN         RN
+//                             RZ 
+
+{ .mfi
+	nop.m 999
+        fsetc.s2 0x7F,0x40                                          
+        mov           exp_GR_gt_ln  = 0x103ff ;;                      
+}
+
+{ .mfi
+        setf.exp      exp_gt_pln    = exp_GR_gt_ln                 
+	nop.f 999
+	nop.i 999 ;;
+}
+
+{ .mfi
+	nop.m 999
+       fcmp.ge.unc.s1 p6, p0 =  exp_wre_urm_f8, exp_gt_pln 	  
+	nop.i 999 ;;
+}
+
+{ .mfb
+	nop.m 999
+	nop.f 999
+(p6)   br.cond.spnt L(EXP_CERTAIN_OVERFLOW) ;; // Branch if really overflow
+}
+
+{ .mfb
+	nop.m 999
+       fma.d        f8 = exp_S, exp_P, exp_S                      
+       br.ret.sptk     b0 ;;             // Exit if really no overflow
+}
+
+L(EXP_CERTAIN_OVERFLOW):
+{ .mmi
+      sub   exp_GR_17ones_m1 = exp_GR_17ones, r0, 1 ;;
+      setf.exp     f9 = exp_GR_17ones_m1
+      nop.i 999 ;;
+}
+
+{ .mfi
+      nop.m 999
+      fmerge.s FR_X = f8,f8
+      nop.i 999
+}
+{ .mfb
+      mov        GR_Parameter_TAG = 14
+      fma.d       FR_RESULT = f9, f9, f0    // Set I,O and +INF result
+      br.cond.sptk  __libm_error_region ;;                             
+}
+
+L(EXP_POSSIBLE_UNDERFLOW): 
+
+// We got an answer. EXP_MAX_DBL_UFLOW_ARG < x < EXP_MIN_DBL_NORM_ARG
+// underflow is a possibility, not a certainty
+
+// We define an underflow when the answer with
+//    ftz set
+// is zero (tiny numbers become zero)
+
+// Notice (from below) that if we have an unlimited exponent range,
+// then there is an extra machine number E between the largest denormal and
+// the smallest normal.
+
+// So if with unbounded exponent we round to E or below, then we are
+// tiny and underflow has occurred.
+
+// But notice that you can be in a situation where we are tiny, namely
+// rounded to E, but when the exponent is bounded we round to smallest
+// normal. So the answer can be the smallest normal with underflow.
+
+//                           E
+// -----+--------------------+--------------------+-----
+//      |                    |                    |
+//   1.1...10 2^-3fff    1.1...11 2^-3fff    1.0...00 2^-3ffe
+//   0.1...11 2^-3ffe                                   (biased, 1)
+//    largest dn                               smallest normal
+
+{ .mfi
+	nop.m 999
+       fsetc.s2 0x7F,0x41                                          
+	nop.i 999 ;;
+}
+{ .mfi
+	nop.m 999
+       fma.d.s2      exp_ftz_urm_f8 = exp_S, exp_P, exp_S          
+	nop.i 999 ;;
+}
+{ .mfi
+	nop.m 999
+       fsetc.s2 0x7F,0x40                                          
+	nop.i 999 ;;
+}
+{ .mfi
+	nop.m 999
+       fcmp.eq.unc.s1 p6, p0 =  exp_ftz_urm_f8, f0 	          
+	nop.i 999 ;;
+}
+{ .mfb
+	nop.m 999
+	nop.f 999
+(p6)   br.cond.spnt L(EXP_CERTAIN_UNDERFLOW) ;; // Branch if really underflow
+}
+{ .mfb
+	nop.m 999
+       fma.d        f8 = exp_S, exp_P, exp_S                      
+       br.ret.sptk     b0 ;;                // Exit if really no underflow
+}
+
+L(EXP_CERTAIN_UNDERFLOW):
+{ .mfi
+      nop.m 999
+      fmerge.s FR_X = f8,f8
+      nop.i 999
+}
+{ .mfb
+      mov        GR_Parameter_TAG = 15
+      fma.d       FR_RESULT  = exp_S, exp_P, exp_S // Set I,U and tiny result
+      br.cond.sptk  __libm_error_region ;;                             
+}
+
+L(EXP_CERTAIN_UNDERFLOW_ZERO):
+{ .mmi
+      mov   exp_GR_one = 1 ;;
+      setf.exp     f9 = exp_GR_one
+      nop.i 999 ;;
+}
+
+{ .mfi
+      nop.m 999
+      fmerge.s FR_X = f8,f8
+      nop.i 999
+}
+{ .mfb
+      mov        GR_Parameter_TAG = 15
+      fma.d       FR_RESULT = f9, f9, f0    // Set I,U and tiny (+0.0) result
+      br.cond.sptk  __libm_error_region ;;                             
+}
+
+.endp exp
+ASM_SIZE_DIRECTIVE(exp)
+
+
+.proc __libm_error_region
+__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] = FR_Y,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] = FR_X                  // STORE Parameter 1 on stack 
+        add   GR_Parameter_RESULT = 0,GR_Parameter_Y  // Parameter 3 address 
+	nop.b 0                                      
+}
+{ .mib
+        stfd [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
+        ldfd  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
+};; 
+
+.endp __libm_error_region
+ASM_SIZE_DIRECTIVE(__libm_error_region)
+.type   __libm_error_support#,@function
+.global __libm_error_support#