sysdeps/ia64/fpu/e_ilogbl.S

   1 .file "ilogbl.s"
   2
   3
   4 // Copyright (c) 2000 - 2003, Intel Corporation
   5 // All rights reserved.
   6 //
   7 //
   8 // Redistribution and use in source and binary forms, with or without
   9 // modification, are permitted provided that the following conditions are
  10 // met:
  11 //
  12 // * Redistributions of source code must retain the above copyright
  13 // notice, this list of conditions and the following disclaimer.
  14 //
  15 // * Redistributions in binary form must reproduce the above copyright
  16 // notice, this list of conditions and the following disclaimer in the
  17 // documentation and/or other materials provided with the distribution.
  18 //
  19 // * The name of Intel Corporation may not be used to endorse or promote
  20 // products derived from this software without specific prior written
  21 // permission.
  22
  23 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  26 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS
  27 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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  29 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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  33 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34 //
  35 // Intel Corporation is the author of this code, and requests that all
  36 // problem reports or change requests be submitted to it directly at
  37 // http://www.intel.com/software/products/opensource/libraries/num.htm.
  38 //
  39 // History
  40 //==============================================================
  41 // 02/03/00 Initial version
  42 // 05/26/00 Fix bug when x a double-extended denormal;
  43 //          if x=0 call error routine, per C9X
  44 // 08/15/00 Bundle added after call to __libm_error_support to properly
  45 //          set [the previously overwritten] GR_Parameter_RESULT.
  46 // 01/20/01 Fixed result for x=0
  47 // 05/20/02 Cleaned up namespace and sf0 syntax
  48 // 01/20/03 Improved performance
  49 //
  50 // API
  51 //==============================================================
  52 // int ilogbl( long double x );
  53 //
  54 // Overview of operation
  55 //==============================================================
  56 // The ilogbl function extracts the exponent of x as an integer
  57 // and returns it in r8
  58 //
  59 // ilogbl is similar to logbl but differs in the following ways:
  60 //         +-inf
  61 //            ilogbl: returns INT_MAX
  62 //             logbl: returns +inf
  63 //         Nan  returns FP_LOGBNAN (which is either INT_MAX or INT_MIN)
  64 //            ilogbl: returns INT_MAX (7fffffff)
  65 //             logbl: returns QNAN (quietized SNAN)
  66 //         0    returns FP_ILOGB0 (which is either INT_MIN or -INT_MAX)
  67 //            ilogbl: returns -INT_MAX (80000001)
  68 //             logbl: returns -inf, raises the divide-by-zero exception,
  69 //                   and calls libm_error_support to set domain error
  70 //
  71 // Registers used
  72 //==============================================================
  73 // general registers used:
  74 // r26 -> r39
  75 // r36 -> r39 used as parameters to error path
  76 //
  77 // predicate registers used:
  78 // p6 -> p10
  79 // floating-point registers used:
  80 // f9, f10, f11
  81 // f8, input
  82
  83 rExpBias            = r26
  84 rExpMask            = r27
  85 rSignexp_x          = r28
  86 rExp_x              = r29
  87 rIntMax             = r30
  88 rExp_2to64          = r31
  89
  90 GR_SAVE_PFS         = r32
  91 rTrialResult        = r33
  92 GR_SAVE_B0          = r34
  93 GR_SAVE_GP          = r35
  94
  95 GR_Parameter_X      = r36
  96 GR_Parameter_Y      = r37
  97 GR_Parameter_RESULT = r38
  98 GR_Parameter_TAG    = r39
  99
 100 fTmp                = f9
 101 fNorm_x             = f10
 102 f2to64              = f11
 103
 104 .section .text
 105 GLOBAL_LIBM_ENTRY(__ieee754_ilogbl)
 106
 107 // X NORMAL
 108 // TrueExp_x = exp(f8) - 0xffff
 109 // r8 = TrueExp_x
 110 { .mfi
 111       getf.exp        rSignexp_x = f8
 112       fclass.m        p8,p0 = f8, 0x0b   // Test for x unorm
 113       mov             rExpBias = 0xffff  // Exponent bias
 114 }
 115 { .mfi
 116       nop.m           0
 117       fnorm.s1        fNorm_x = f8
 118       mov             rExpMask = 0x1ffff // Exponent mask
 119 }
 120 ;;
 121
 122 // Form signexp of 2^64 in case need to scale denormal
 123 { .mfb
 124       mov             rExp_2to64 = 0x1003f
 125       fclass.m        p6,p9 = f8, 0x1e3  // Test x natval, nan, inf
 126 (p8)  br.cond.spnt    ILOGB_DENORM       // Branch if x unorm
 127 }
 128 ;;
 129
 130 ILOGB_COMMON:
 131 // Return here from ILOGB_DENORM
 132 { .mfi
 133       and             rExp_x = rSignexp_x, rExpMask // Get biased exponent
 134       fclass.m        p7,p10 = f8, 0x07   // Test x zero
 135       nop.i           0
 136 }
 137 { .mlx
 138       nop.m           0
 139       movl            rIntMax = 0x000000007fffffff // Form INT_MAX
 140 }
 141 ;;
 142
 143 .pred.rel "mutex",p6,p9
 144 { .mfi
 145 (p9)  sub             r8 = rExp_x, rExpBias // Get true exponent for normal path
 146 (p6)  fma.s0          fTmp = f8, f8, f0     // Dummy to set Invalid flag
 147 (p6)  mov             r8 = rIntMax          // If nan, inf, return INT_MAX
 148 }
 149 { .mbb
 150       nop.m           0
 151 (p7)  br.cond.spnt    ILOGB_ZERO            // Branch if x zero
 152 (p10) br.ret.sptk     b0                    // Exit if x not zero
 153 }
 154 ;;
 155
 156
 157 ILOGB_DENORM:
 158 // Form 2^64 in case need to scale denormal
 159 // Check to see if double-extended denormal
 160 { .mfi
 161       setf.exp        f2to64 = rExp_2to64
 162       fclass.m        p8,p0 = fNorm_x, 0x0b
 163       nop.i           0
 164 }
 165 ;;
 166
 167 { .mfi
 168       nop.m           0
 169       fcmp.eq.s0      p7,p0 = f8, f0           // Dummy op to set denormal flag
 170       nop.i           0
 171 }
 172 ;;
 173
 174 // If double-extended denormal add 64 to exponent bias for scaling
 175 // If double-extended denormal form x * 2^64 which is normal
 176 { .mfi
 177 (p8)  add             rExpBias = 64, rExpBias
 178 (p8)  fmpy.s1         fNorm_x = fNorm_x, f2to64
 179       nop.i           0
 180 }
 181 ;;
 182
 183 // Logic is the same as normal path but use normalized input
 184 { .mib
 185       getf.exp        rSignexp_x = fNorm_x
 186       nop.i           0
 187       br.cond.sptk    ILOGB_COMMON             // Return to main path
 188 }
 189 ;;
 190
 191 ILOGB_ZERO:
 192 // Here if x zero
 193 // Return INT_MIN, call error support
 194
 195 { .mlx
 196       alloc           r32=ar.pfs,1,3,4,0
 197       movl            rTrialResult = 0x0000000080000000
 198 }
 199 { .mib
 200       mov             GR_Parameter_TAG = 156  // Error code
 201       nop.i           0
 202       br.cond.sptk    __libm_error_region     // Call error support
 203 }
 204 ;;
 205
 206 GLOBAL_LIBM_END(__ieee754_ilogbl)
 207
 208
 209 LOCAL_LIBM_ENTRY(__libm_error_region)
 210 .prologue
 211
 212 { .mfi
 213         add   GR_Parameter_Y=-32,sp           // Parameter 2 value
 214         nop.f 0
 215 .save   ar.pfs,GR_SAVE_PFS
 216         mov  GR_SAVE_PFS=ar.pfs               // Save ar.pfs
 217 }
 218 { .mfi
 219 .fframe 64
 220         add sp=-64,sp                         // Create new stack
 221         nop.f 0
 222         mov GR_SAVE_GP=gp                     // Save gp
 223 };;
 224
 225 { .mmi
 226         stfe [GR_Parameter_Y] = f0,16         // STORE Parameter 2 on stack
 227         add GR_Parameter_X    = 16,sp         // Parameter 1 address
 228 .save   b0, GR_SAVE_B0
 229         mov GR_SAVE_B0=b0                     // Save b0
 230 };;
 231
 232 .body
 233 { .mib
 234         stfe [GR_Parameter_X] = f8            // STORE Parameter 1 on stack
 235         add   GR_Parameter_RESULT = 0,GR_Parameter_Y    // Parameter 3 address
 236         nop.b 0
 237 }
 238 { .mib
 239         stfe [GR_Parameter_Y] = f9            // Store Parameter 3 on stack
 240         add   GR_Parameter_Y = -16,GR_Parameter_Y
 241         br.call.sptk b0=__libm_error_support# // Call error handling function
 242 };;
 243
 244 { .mmi
 245         add   GR_Parameter_RESULT = 48,sp
 246         nop.m 0
 247         nop.i 0
 248 };;
 249
 250 { .mmi
 251         mov   r8 = rTrialResult
 252 .restore sp
 253         add   sp = 64,sp                       // Restore stack pointer
 254         mov   b0 = GR_SAVE_B0                  // Restore return address
 255 };;
 256
 257 { .mib
 258         mov   gp = GR_SAVE_GP                  // Restore gp
 259         mov   ar.pfs = GR_SAVE_PFS             // Restore ar.pfs
 260         br.ret.sptk   b0
 261 };;
 262
 263 LOCAL_LIBM_END(__libm_error_region)
 264
 265
 266 .type   __libm_error_support#,@function
 267 .global __libm_error_support#