mpn/x86/invert_limb.asm

   1  dnl  x86 mpn_invert_limb
   2
   3 dnl  Contributed to the GNU project by Niels Möller
   4
   5 dnl  Copyright 2009 Free Software Foundation, Inc.
   6 dnl
   7 dnl  This file is part of the GNU MP Library.
   8 dnl
   9 dnl  The GNU MP Library is free software; you can redistribute it and/or
  10 dnl  modify it under the terms of the GNU Lesser General Public License as
  11 dnl  published by the Free Software Foundation; either version 3 of the
  12 dnl  License, or (at your option) any later version.
  13 dnl
  14 dnl  The GNU MP Library is distributed in the hope that it will be useful,
  15 dnl  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 dnl  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17 dnl  Lesser General Public License for more details.
  18 dnl
  19 dnl  You should have received a copy of the GNU Lesser General Public License
  20 dnl  along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.
  21
  22 include(`../config.m4')
  23
  24 C            cycles (approx)    div
  25 C K7:            46             53
  26
  27 C Register usage:
  28
  29 C Input D in %edi
  30 C Current approximation is in %eax and/or %ecx
  31 C %ebx and %edx are temporaries.
  32 C %esi and %ebp is unused.
  33
  34 defframe(PARAM_DIVISOR,4)
  35
  36 ASM_START()
  37
  38 C Make approx_tab global to work around Apple relocation bug.
  39 ifdef(`DARWIN',`
  40         define(`approx_tab', MPN(invert_limb_tab))
  41         GLOBL   approx_tab')
  42
  43         TEXT
  44         ALIGN(16)
  45 PROLOGUE(mpn_invert_limb)
  46 deflit(`FRAME', 0)
  47         C Adding the push of %ebp and the corresponding pop seems to
  48         C reduce running time from 46 to 43 cycles on K7. Don't know
  49         C if this is a benchmark artefact or some alignment issue.
  50
  51         push    %ebx    FRAME_pushl()
  52         C push  %ebp    FRAME_pushl()
  53         push    %edi    FRAME_pushl()
  54
  55         mov     PARAM_DIVISOR, %edi
  56         mov     %edi, %eax
  57         shr     $22, %eax
  58 ifdef(`PIC',`
  59         LEA(    approx_tab, %ebx)
  60         movzwl  -1024(%ebx, %eax, 2), %eax
  61 ',`
  62         movzwl  -1024+approx_tab(%eax, %eax), %eax      C %eax = v0
  63 ')
  64
  65         C v1 = (v0 << 4) - ((v0*v0*d_21) >> 32) - 1
  66         mov     %eax, %ecx
  67         imul    %eax, %eax
  68         mov     %edi, %ebx
  69         shr     $11, %ebx
  70         inc     %ebx
  71         mul     %ebx
  72         mov     %edi, %ebx                              C Prepare
  73         shr     %ebx
  74         sbb     %eax, %eax
  75         sub     %eax, %ebx                              C %ebx = d_31, %eax = mask
  76         shl     $4, %ecx
  77         dec     %ecx
  78         sub     %edx, %ecx                              C %ecx = v1
  79
  80         C v_2 = (v1 << 15) + ((v1 *(2^48 - v1 * d31 + (v1 >> 1) & mask)) >> 33)
  81         imul    %ecx, %ebx
  82         and     %ecx, %eax
  83         shr     %eax
  84         sub     %ebx, %eax
  85         mul     %ecx
  86         mov     %edi, %eax                              C Prepare for next mul
  87         shl     $15, %ecx
  88         shr     %edx
  89         add     %edx, %ecx                              C %ecx = v2
  90
  91         mul     %ecx
  92         add     %edi, %eax
  93         mov     %ecx, %eax
  94         adc     %edi, %edx
  95         sub     %edx, %eax                              C %eax = v3
  96
  97         pop     %edi
  98         C pop   %ebp
  99         pop     %ebx
 100
 101         ret
 102
 103 EPILOGUE()
 104
 105 DEF_OBJECT(approx_tab,2)
 106         .value  0x7fe1,0x7fa1,0x7f61,0x7f22,0x7ee3,0x7ea4,0x7e65,0x7e27
 107         .value  0x7de9,0x7dab,0x7d6d,0x7d30,0x7cf3,0x7cb6,0x7c79,0x7c3d
 108         .value  0x7c00,0x7bc4,0x7b89,0x7b4d,0x7b12,0x7ad7,0x7a9c,0x7a61
 109         .value  0x7a27,0x79ec,0x79b2,0x7979,0x793f,0x7906,0x78cc,0x7894
 110         .value  0x785b,0x7822,0x77ea,0x77b2,0x777a,0x7742,0x770b,0x76d3
 111         .value  0x769c,0x7665,0x762f,0x75f8,0x75c2,0x758c,0x7556,0x7520
 112         .value  0x74ea,0x74b5,0x7480,0x744b,0x7416,0x73e2,0x73ad,0x7379
 113         .value  0x7345,0x7311,0x72dd,0x72aa,0x7277,0x7243,0x7210,0x71de
 114         .value  0x71ab,0x7179,0x7146,0x7114,0x70e2,0x70b1,0x707f,0x704e
 115         .value  0x701c,0x6feb,0x6fba,0x6f8a,0x6f59,0x6f29,0x6ef9,0x6ec8
 116         .value  0x6e99,0x6e69,0x6e39,0x6e0a,0x6ddb,0x6dab,0x6d7d,0x6d4e
 117         .value  0x6d1f,0x6cf1,0x6cc2,0x6c94,0x6c66,0x6c38,0x6c0a,0x6bdd
 118         .value  0x6bb0,0x6b82,0x6b55,0x6b28,0x6afb,0x6acf,0x6aa2,0x6a76
 119         .value  0x6a49,0x6a1d,0x69f1,0x69c6,0x699a,0x696e,0x6943,0x6918
 120         .value  0x68ed,0x68c2,0x6897,0x686c,0x6842,0x6817,0x67ed,0x67c3
 121         .value  0x6799,0x676f,0x6745,0x671b,0x66f2,0x66c8,0x669f,0x6676
 122         .value  0x664d,0x6624,0x65fc,0x65d3,0x65aa,0x6582,0x655a,0x6532
 123         .value  0x650a,0x64e2,0x64ba,0x6493,0x646b,0x6444,0x641c,0x63f5
 124         .value  0x63ce,0x63a7,0x6381,0x635a,0x6333,0x630d,0x62e7,0x62c1
 125         .value  0x629a,0x6275,0x624f,0x6229,0x6203,0x61de,0x61b8,0x6193
 126         .value  0x616e,0x6149,0x6124,0x60ff,0x60da,0x60b6,0x6091,0x606d
 127         .value  0x6049,0x6024,0x6000,0x5fdc,0x5fb8,0x5f95,0x5f71,0x5f4d
 128         .value  0x5f2a,0x5f07,0x5ee3,0x5ec0,0x5e9d,0x5e7a,0x5e57,0x5e35
 129         .value  0x5e12,0x5def,0x5dcd,0x5dab,0x5d88,0x5d66,0x5d44,0x5d22
 130         .value  0x5d00,0x5cde,0x5cbd,0x5c9b,0x5c7a,0x5c58,0x5c37,0x5c16
 131         .value  0x5bf5,0x5bd4,0x5bb3,0x5b92,0x5b71,0x5b51,0x5b30,0x5b10
 132         .value  0x5aef,0x5acf,0x5aaf,0x5a8f,0x5a6f,0x5a4f,0x5a2f,0x5a0f
 133         .value  0x59ef,0x59d0,0x59b0,0x5991,0x5972,0x5952,0x5933,0x5914
 134         .value  0x58f5,0x58d6,0x58b7,0x5899,0x587a,0x585b,0x583d,0x581f
 135         .value  0x5800,0x57e2,0x57c4,0x57a6,0x5788,0x576a,0x574c,0x572e
 136         .value  0x5711,0x56f3,0x56d5,0x56b8,0x569b,0x567d,0x5660,0x5643
 137         .value  0x5626,0x5609,0x55ec,0x55cf,0x55b2,0x5596,0x5579,0x555d
 138         .value  0x5540,0x5524,0x5507,0x54eb,0x54cf,0x54b3,0x5497,0x547b
 139         .value  0x545f,0x5443,0x5428,0x540c,0x53f0,0x53d5,0x53b9,0x539e
 140         .value  0x5383,0x5368,0x534c,0x5331,0x5316,0x52fb,0x52e0,0x52c6
 141         .value  0x52ab,0x5290,0x5276,0x525b,0x5240,0x5226,0x520c,0x51f1
 142         .value  0x51d7,0x51bd,0x51a3,0x5189,0x516f,0x5155,0x513b,0x5121
 143         .value  0x5108,0x50ee,0x50d5,0x50bb,0x50a2,0x5088,0x506f,0x5056
 144         .value  0x503c,0x5023,0x500a,0x4ff1,0x4fd8,0x4fbf,0x4fa6,0x4f8e
 145         .value  0x4f75,0x4f5c,0x4f44,0x4f2b,0x4f13,0x4efa,0x4ee2,0x4eca
 146         .value  0x4eb1,0x4e99,0x4e81,0x4e69,0x4e51,0x4e39,0x4e21,0x4e09
 147         .value  0x4df1,0x4dda,0x4dc2,0x4daa,0x4d93,0x4d7b,0x4d64,0x4d4d
 148         .value  0x4d35,0x4d1e,0x4d07,0x4cf0,0x4cd8,0x4cc1,0x4caa,0x4c93
 149         .value  0x4c7d,0x4c66,0x4c4f,0x4c38,0x4c21,0x4c0b,0x4bf4,0x4bde
 150         .value  0x4bc7,0x4bb1,0x4b9a,0x4b84,0x4b6e,0x4b58,0x4b41,0x4b2b
 151         .value  0x4b15,0x4aff,0x4ae9,0x4ad3,0x4abd,0x4aa8,0x4a92,0x4a7c
 152         .value  0x4a66,0x4a51,0x4a3b,0x4a26,0x4a10,0x49fb,0x49e5,0x49d0
 153         .value  0x49bb,0x49a6,0x4990,0x497b,0x4966,0x4951,0x493c,0x4927
 154         .value  0x4912,0x48fe,0x48e9,0x48d4,0x48bf,0x48ab,0x4896,0x4881
 155         .value  0x486d,0x4858,0x4844,0x482f,0x481b,0x4807,0x47f3,0x47de
 156         .value  0x47ca,0x47b6,0x47a2,0x478e,0x477a,0x4766,0x4752,0x473e
 157         .value  0x472a,0x4717,0x4703,0x46ef,0x46db,0x46c8,0x46b4,0x46a1
 158         .value  0x468d,0x467a,0x4666,0x4653,0x4640,0x462c,0x4619,0x4606
 159         .value  0x45f3,0x45e0,0x45cd,0x45ba,0x45a7,0x4594,0x4581,0x456e
 160         .value  0x455b,0x4548,0x4536,0x4523,0x4510,0x44fe,0x44eb,0x44d8
 161         .value  0x44c6,0x44b3,0x44a1,0x448f,0x447c,0x446a,0x4458,0x4445
 162         .value  0x4433,0x4421,0x440f,0x43fd,0x43eb,0x43d9,0x43c7,0x43b5
 163         .value  0x43a3,0x4391,0x437f,0x436d,0x435c,0x434a,0x4338,0x4327
 164         .value  0x4315,0x4303,0x42f2,0x42e0,0x42cf,0x42bd,0x42ac,0x429b
 165         .value  0x4289,0x4278,0x4267,0x4256,0x4244,0x4233,0x4222,0x4211
 166         .value  0x4200,0x41ef,0x41de,0x41cd,0x41bc,0x41ab,0x419a,0x418a
 167         .value  0x4179,0x4168,0x4157,0x4147,0x4136,0x4125,0x4115,0x4104
 168         .value  0x40f4,0x40e3,0x40d3,0x40c2,0x40b2,0x40a2,0x4091,0x4081
 169         .value  0x4071,0x4061,0x4050,0x4040,0x4030,0x4020,0x4010,0x4000
 170 END_OBJECT(approx_tab)