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dnl x86 mpn_invert_limb
dnl Contributed to the GNU project by Niels Möller
dnl Copyright 2009, 2011, 2015 Free Software Foundation, Inc.
dnl This file is part of the GNU MP Library.
dnl
dnl The GNU MP Library is free software; you can redistribute it and/or modify
dnl it under the terms of either:
dnl
dnl * the GNU Lesser General Public License as published by the Free
dnl Software Foundation; either version 3 of the License, or (at your
dnl option) any later version.
dnl
dnl or
dnl
dnl * the GNU General Public License as published by the Free Software
dnl Foundation; either version 2 of the License, or (at your option) any
dnl later version.
dnl
dnl or both in parallel, as here.
dnl
dnl The GNU MP Library is distributed in the hope that it will be useful, but
dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
dnl for more details.
dnl
dnl You should have received copies of the GNU General Public License and the
dnl GNU Lesser General Public License along with the GNU MP Library. If not,
dnl see https://www.gnu.org/licenses/.
include(`../config.m4')
C cycles (approx) div
C P5 ?
C P6 model 0-8,10-12 ?
C P6 model 9 (Banias) ?
C P6 model 13 (Dothan) ?
C P4 model 0 (Willamette) ?
C P4 model 1 (?) ?
C P4 model 2 (Northwood) ?
C P4 model 3 (Prescott) ?
C P4 model 4 (Nocona) ?
C AMD K6 ?
C AMD K7 41 53
C AMD K8 ?
C TODO
C * These c/l numbers are for a non-PIC build. Consider falling back to using
C the 'div' instruction for PIC builds.
C * Perhaps use this file--or at least the algorithm--for more machines than k7.
C Register usage:
C Input D in %edi
C Current approximation is in %eax and/or %ecx
C %ebx and %edx are temporaries
C %esi and %ebp are unused
defframe(PARAM_DIVISOR,4)
ASM_START()
C Make approx_tab global to work around Apple relocation bug.
ifdef(`DARWIN',`
deflit(`approx_tab', MPN(invert_limb_tab))
GLOBL approx_tab')
TEXT
ALIGN(16)
PROLOGUE(mpn_invert_limb)
deflit(`FRAME', 0)
mov PARAM_DIVISOR, %eax
C Avoid push/pop on k7.
sub $8, %esp FRAME_subl_esp(8)
mov %ebx, (%esp)
mov %edi, 4(%esp)
mov %eax, %edi
shr $22, %eax
ifdef(`PIC',`
LEAL( approx_tab, %ebx)
movzwl -1024(%ebx, %eax, 2), %eax
',`
movzwl -1024+approx_tab(%eax, %eax), %eax C %eax = v0
')
C v1 = (v0 << 4) - ((v0*v0*d_21) >> 32) - 1
mov %eax, %ecx
imul %eax, %eax
mov %edi, %ebx
shr $11, %ebx
inc %ebx
mul %ebx
mov %edi, %ebx C Prepare
shr %ebx
sbb %eax, %eax
sub %eax, %ebx C %ebx = d_31, %eax = mask
shl $4, %ecx
dec %ecx
sub %edx, %ecx C %ecx = v1
C v_2 = (v1 << 15) + ((v1 *(2^48 - v1 * d31 + (v1 >> 1) & mask)) >> 33)
imul %ecx, %ebx
and %ecx, %eax
shr %eax
sub %ebx, %eax
mul %ecx
mov %edi, %eax C Prepare for next mul
shl $15, %ecx
shr %edx
add %edx, %ecx C %ecx = v2
mul %ecx
add %edi, %eax
mov %ecx, %eax
adc %edi, %edx
sub %edx, %eax C %eax = v3
mov (%esp), %ebx
mov 4(%esp), %edi
add $8, %esp
ret
EPILOGUE()
DEF_OBJECT(approx_tab,2)
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.value 0x4c7d,0x4c66,0x4c4f,0x4c38,0x4c21,0x4c0b,0x4bf4,0x4bde
.value 0x4bc7,0x4bb1,0x4b9a,0x4b84,0x4b6e,0x4b58,0x4b41,0x4b2b
.value 0x4b15,0x4aff,0x4ae9,0x4ad3,0x4abd,0x4aa8,0x4a92,0x4a7c
.value 0x4a66,0x4a51,0x4a3b,0x4a26,0x4a10,0x49fb,0x49e5,0x49d0
.value 0x49bb,0x49a6,0x4990,0x497b,0x4966,0x4951,0x493c,0x4927
.value 0x4912,0x48fe,0x48e9,0x48d4,0x48bf,0x48ab,0x4896,0x4881
.value 0x486d,0x4858,0x4844,0x482f,0x481b,0x4807,0x47f3,0x47de
.value 0x47ca,0x47b6,0x47a2,0x478e,0x477a,0x4766,0x4752,0x473e
.value 0x472a,0x4717,0x4703,0x46ef,0x46db,0x46c8,0x46b4,0x46a1
.value 0x468d,0x467a,0x4666,0x4653,0x4640,0x462c,0x4619,0x4606
.value 0x45f3,0x45e0,0x45cd,0x45ba,0x45a7,0x4594,0x4581,0x456e
.value 0x455b,0x4548,0x4536,0x4523,0x4510,0x44fe,0x44eb,0x44d8
.value 0x44c6,0x44b3,0x44a1,0x448f,0x447c,0x446a,0x4458,0x4445
.value 0x4433,0x4421,0x440f,0x43fd,0x43eb,0x43d9,0x43c7,0x43b5
.value 0x43a3,0x4391,0x437f,0x436d,0x435c,0x434a,0x4338,0x4327
.value 0x4315,0x4303,0x42f2,0x42e0,0x42cf,0x42bd,0x42ac,0x429b
.value 0x4289,0x4278,0x4267,0x4256,0x4244,0x4233,0x4222,0x4211
.value 0x4200,0x41ef,0x41de,0x41cd,0x41bc,0x41ab,0x419a,0x418a
.value 0x4179,0x4168,0x4157,0x4147,0x4136,0x4125,0x4115,0x4104
.value 0x40f4,0x40e3,0x40d3,0x40c2,0x40b2,0x40a2,0x4091,0x4081
.value 0x4071,0x4061,0x4050,0x4040,0x4030,0x4020,0x4010,0x4000
END_OBJECT(approx_tab)
ASM_END()
|
