sysdeps/ia64/fpu/s_ilogbl.S

   1 .file "ilogbl.s"
   2
   3 // Copyright (C) 2000, 2001, Intel Corporation
   4 // All rights reserved.
   5 //
   6 // Contributed 2/2/2000 by John Harrison, Ted Kubaska, Bob Norin, Shane Story,
   7 // and Ping Tak Peter Tang of the Computational Software Lab, Intel Corporation.
   8 //
   9 // Redistribution and use in source and binary forms, with or without
  10 // modification, are permitted provided that the following conditions are
  11 // met:
  12 //
  13 // * Redistributions of source code must retain the above copyright
  14 // notice, this list of conditions and the following disclaimer.
  15 //
  16 // * Redistributions in binary form must reproduce the above copyright
  17 // notice, this list of conditions and the following disclaimer in the
  18 // documentation and/or other materials provided with the distribution.
  19 //
  20 // * The name of Intel Corporation may not be used to endorse or promote
  21 // products derived from this software without specific prior written
  22 // permission.
  23 //
  24 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  25 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  26 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  27 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS
  28 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  29 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  30 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  31 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  32 // OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR TORT (INCLUDING
  33 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  34 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35 //
  36 // Intel Corporation is the author of this code, and requests that all
  37 // problem reports or change requests be submitted to it directly at
  38 // http://developer.intel.com/opensource.
  39 //
  40 // History
  41 //==============================================================
  42 // 2/03/00  Initial version
  43 // 5/26/00  Fix bug when x a double-extended denormal;
  44 //          if x=0 call error routine, per C9X
  45 // 8/15/00  Bundle added after call to __libm_error_support to properly
  46 //          set [the previously overwritten] GR_Parameter_RESULT.
  47 // 1/20/01  Fixed result for x=0
  48
  49 .align 32
  50 .global ilogbl#
  51
  52 .section .text
  53 .proc  ilogbl#
  54 .align 32
  55
  56 // API
  57 //==============================================================
  58 // int = ilogbl(double_extended)
  59
  60 // Overview of operation
  61 //==============================================================
  62 // ilogbl computes log2(x) as an int
  63 // and returns it in r8
  64
  65 // ilogbl is similar to logbl but differs in the  following ways:
  66 //         +-inf
  67 //            ilogbl: returns INT_MAX
  68 //             logbl: returns +inf
  69 //         Nan  returns FP_ILOGBNAN (which is either INT_MAX or INT_MIN)
  70 //            ilogbl: returns INT_MAX (7fffffff)
  71 //             logbl: returns QNAN (quieted SNAN)
  72 //         0    returns FP_ILOGB0 (which is either INT_MIN or -INT_MAX)
  73 //            ilogbl: returns INT_MIN (80000000)
  74 //             logbl: returns -inf
  75
  76 // Registers used
  77 //==============================================================
  78
  79 // general local registers:
  80 // ar.pfs r32
  81 // r33 -> r37
  82 // r38 -> r41 used as parameters to error path
  83
  84 // predicate registers used:
  85 // p6 - x nan, inf
  86 // p7 - x 0
  87 // p8 - x norm, unorm
  88 // p9 - x unorm
  89
  90 // floating-point registers used:
  91 // f8 - f10
  92
  93 #include "libm_support.h"
  94
  95 GR_SAVE_PFS         = r32
  96 GR_SAVE_B0          = r34
  97 GR_SAVE_GP          = r35
  98 GR_Parameter_X      = r38
  99 GR_Parameter_Y      = r39
 100 GR_Parameter_RESULT = r40
 101 GR_Parameter_TAG    = r41
 102
 103 FR_X                = f8
 104 FR_Y                = f0
 105 FR_RESULT           = f0
 106
 107
 108 ilogbl:
 109
 110 // Form signexp of 2^64 in case need to scale denormal
 111 { .mmf
 112       alloc          r32=ar.pfs,1,5,4,0
 113 (p0)  mov      r37 = 0x1003f
 114 (p0)  fnorm    f9 = f8 ;;
 115 }
 116
 117 // Form 2^64 in case need to scale denormal
 118 { .mfi
 119 (p0)  setf.exp f10 = r37
 120 (p0)  fclass.m.unc p7, p8 = f8, 0xe3
 121 (p0)  mov      r34 = 0xffff ;;
 122 }
 123
 124 // qnan snan inf norm     unorm 0 -+
 125 // 1    1    1   0        0     0 11
 126 // e                      3
 127 // X ZERO, returns INT_MIN
 128 // X INF or NAN, returns INT_MAX
 129
 130 { .mfi
 131 (p0)  mov      r35 = 0x1ffff
 132 (p8)    fclass.m.unc p6, p8 = f8, 0x07
 133         nop.i 999 ;;
 134 }
 135 { .mlx
 136         nop.m 999
 137 (p7)    movl r8 = 0x000000007fffffff ;;
 138 }
 139
 140 { .mib
 141         nop.m 999
 142         nop.i 999
 143 (p6)    br.cond.spnt  L(ILOGB_ZERO) ;;
 144 }
 145
 146 // Test for denormal
 147 { .mfi
 148         nop.m 999
 149 (p8)    fclass.m.unc p9, p0 = f9, 0x0b
 150         nop.i 999 ;;
 151 }
 152
 153 L(ILOGB_COMMON):
 154 // X NORMAL returns true exponent
 155 { .mmi
 156         nop.m 999
 157 (p8)    getf.exp r33 = f9
 158         nop.i 999 ;;
 159 }
 160
 161 // If denormal add 64 to exponent bias for scaling
 162 { .mfb
 163 (p9)    add     r34 = 64, r34
 164         nop.f 999
 165 (p9)    br.cond.spnt  L(ILOGB_DENORM) ;;
 166 }
 167
 168 { .mmi
 169 (p8)    and      r36 = r35, r33
 170         nop.m 999
 171         nop.i 999 ;;
 172 }
 173
 174 { .mib
 175 (p8)    sub r8 = r36, r34
 176         nop.i 999
 177 (p0)    br.ret.sptk    b0 ;;
 178 }
 179
 180 L(ILOGB_DENORM):
 181 // Here if x denormal
 182 // Form x * 2^64 which is normal
 183 // Return to common code
 184 { .mfb
 185         cmp.eq p8,p9 = r0,r0
 186         fmpy f9 = f9, f10
 187         br.cond.sptk  L(ILOGB_COMMON) ;;
 188 }
 189
 190 // X ZERO
 191 // return INT_MIN, call error support
 192 L(ILOGB_ZERO):
 193 {.mlx
 194       mov            GR_Parameter_TAG = 156
 195 (p6)  movl r33 = 0x0000000080000000 ;;
 196 };;
 197 .endp ilogbl
 198 ASM_SIZE_DIRECTIVE(ilogbl)
 199
 200 .proc __libm_error_region
 201 __libm_error_region:
 202 .prologue
 203 { .mfi
 204         add   GR_Parameter_Y=-32,sp             // Parameter 2 value
 205         nop.f 0
 206 .save   ar.pfs,GR_SAVE_PFS
 207         mov  GR_SAVE_PFS=ar.pfs                 // Save ar.pfs
 208 }
 209 { .mfi
 210 .fframe 64
 211         add sp=-64,sp                           // Create new stack
 212         nop.f 0
 213         mov GR_SAVE_GP=gp                       // Save gp
 214 };;
 215 { .mmi
 216         stfe [GR_Parameter_Y] = FR_Y,16         // Save Parameter 2 on stack
 217         add GR_Parameter_X = 16,sp              // Parameter 1 address
 218 .save   b0, GR_SAVE_B0
 219         mov GR_SAVE_B0=b0                       // Save b0
 220 };;
 221 .body
 222 { .mib
 223         stfe [GR_Parameter_X] = FR_X            // Store Parameter 1 on stack
 224         add   GR_Parameter_RESULT = 0,GR_Parameter_Y
 225         nop.b 0                                 // Parameter 3 address
 226 }
 227 { .mib
 228         stfe [GR_Parameter_Y] = FR_RESULT      // Store Parameter 3 on stack
 229         add   GR_Parameter_Y = -16,GR_Parameter_Y
 230         br.call.sptk b0=__libm_error_support#  // Call error handling function
 231 };;
 232 { .mmi
 233         nop.m 0
 234         nop.m 0
 235         add   GR_Parameter_RESULT = 48,sp
 236 };;
 237 { .mmi
 238         mov   r8 = r33                         // Store result
 239 .restore sp
 240         add   sp = 64,sp                       // Restore stack pointer
 241         mov   b0 = GR_SAVE_B0                  // Restore return address
 242 };;
 243 { .mib
 244         mov   gp = GR_SAVE_GP                  // Restore gp
 245         mov   ar.pfs = GR_SAVE_PFS             // Restore ar.pfs
 246         br.ret.sptk     b0                     // Return
 247 };;
 248
 249 .endp __libm_error_region
 250 ASM_SIZE_DIRECTIVE(__libm_error_region)
 251
 252 .type   __libm_error_support#,@function
 253 .global __libm_error_support#