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dnl ARM64 mpn_divrem_1 and mpn_preinv_divrem_1.
dnl Contributed to the GNU project by Torbjörn Granlund.
dnl Copyright 2020 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')
dnl TODO
dnl * Handle the most significant quotient limb for the unnormalised case
dnl specially, just like in the C code. (It is very often 0.)
define(`qp_arg', x0)
define(`fn_arg', x1)
define(`np_arg', x2)
define(`n_arg', x3)
define(`d_arg', x4)
define(`dinv_arg', x5)
define(`cnt_arg', x6)
define(`qp', x19)
define(`np', x20)
define(`n', x21)
define(`d', x22)
define(`fn', x24)
define(`dinv', x0)
define(`cnt', x23)
define(`tnc', x8)
dnl mp_limb_t
dnl mpn_divrem_1 (mp_ptr qp, mp_size_t fn,
dnl mp_srcptr np, mp_size_t n,
dnl mp_limb_t d_unnorm)
dnl mp_limb_t
dnl mpn_preinv_divrem_1 (mp_ptr qp, mp_size_t fn,
dnl mp_srcptr np, mp_size_t n,
dnl mp_limb_t d_unnorm, mp_limb_t dinv, int cnt)
ASM_START()
PROLOGUE(mpn_preinv_divrem_1)
cbz n_arg, L(fz)
stp x29, x30, [sp, #-80]!
mov x29, sp
stp x19, x20, [sp, #16]
stp x21, x22, [sp, #32]
stp x23, x24, [sp, #48]
sub n, n_arg, #1
add x7, n, fn_arg
add np, np_arg, n, lsl #3
add qp, qp_arg, x7, lsl #3
mov fn, fn_arg
mov d, d_arg
mov dinv, dinv_arg
tbnz d_arg, #63, L(nentry)
mov cnt, cnt_arg
b L(uentry)
EPILOGUE()
PROLOGUE(mpn_divrem_1)
cbz n_arg, L(fz)
stp x29, x30, [sp, #-80]!
mov x29, sp
stp x19, x20, [sp, #16]
stp x21, x22, [sp, #32]
stp x23, x24, [sp, #48]
sub n, n_arg, #1
add x7, n, fn_arg
add np, np_arg, n, lsl #3
add qp, qp_arg, x7, lsl #3
mov fn, fn_arg
mov d, d_arg
tbnz d_arg, #63, L(normalised)
L(unnorm):
clz cnt, d
lsl x0, d, cnt
bl GSYM_PREFIX`'MPN(invert_limb)
L(uentry):
lsl d, d, cnt
ldr x7, [np], #-8
sub tnc, xzr, cnt
lsr x11, x7, tnc C r
lsl x1, x7, cnt
cbz n, L(uend)
L(utop):ldr x7, [np], #-8
add x2, x11, #1
mul x10, x11, dinv
umulh x17, x11, dinv
lsr x9, x7, tnc
orr x1, x1, x9
adds x10, x1, x10
adc x2, x2, x17
msub x11, d, x2, x1
lsl x1, x7, cnt
cmp x10, x11
add x14, x11, d
csel x11, x14, x11, cc
sbc x2, x2, xzr
cmp x11, d
bcs L(ufx)
L(uok): str x2, [qp], #-8
sub n, n, #1
cbnz n, L(utop)
L(uend):add x2, x11, #1
mul x10, x11, dinv
umulh x17, x11, dinv
adds x10, x1, x10
adc x2, x2, x17
msub x11, d, x2, x1
cmp x10, x11
add x14, x11, d
csel x11, x14, x11, cc
sbc x2, x2, xzr
subs x14, x11, d
adc x2, x2, xzr
csel x11, x14, x11, cs
str x2, [qp], #-8
cbnz fn, L(ftop)
lsr x0, x11, cnt
ldp x19, x20, [sp, #16]
ldp x21, x22, [sp, #32]
ldp x23, x24, [sp, #48]
ldp x29, x30, [sp], #80
ret
L(ufx): add x2, x2, #1
sub x11, x11, d
b L(uok)
L(normalised):
mov x0, d
bl GSYM_PREFIX`'MPN(invert_limb)
L(nentry):
ldr x7, [np], #-8
subs x14, x7, d
adc x2, xzr, xzr C hi q limb
csel x11, x14, x7, cs
b L(nok)
L(ntop):ldr x1, [np], #-8
add x2, x11, #1
mul x10, x11, dinv
umulh x17, x11, dinv
adds x10, x1, x10
adc x2, x2, x17
msub x11, d, x2, x1
cmp x10, x11
add x14, x11, d
csel x11, x14, x11, cc C remainder
sbc x2, x2, xzr
cmp x11, d
bcs L(nfx)
L(nok): str x2, [qp], #-8
sub n, n, #1
tbz n, #63, L(ntop)
L(nend):cbnz fn, L(frac)
mov x0, x11
ldp x19, x20, [sp, #16]
ldp x21, x22, [sp, #32]
ldp x23, x24, [sp, #48]
ldp x29, x30, [sp], #80
ret
L(nfx): add x2, x2, #1
sub x11, x11, d
b L(nok)
L(frac):mov cnt, #0
L(ftop):add x2, x11, #1
mul x10, x11, dinv
umulh x17, x11, dinv
add x2, x2, x17
msub x11, d, x2, xzr
cmp x10, x11
add x14, x11, d
csel x11, x14, x11, cc C remainder
sbc x2, x2, xzr
str x2, [qp], #-8
sub fn, fn, #1
cbnz fn, L(ftop)
lsr x0, x11, cnt
ldp x19, x20, [sp, #16]
ldp x21, x22, [sp, #32]
ldp x23, x24, [sp, #48]
ldp x29, x30, [sp], #80
ret
C Block zero. We need this for the degenerated case of n = 0, fn != 0.
L(fz): cbz fn_arg, L(zend)
L(ztop):str xzr, [qp_arg], #8
sub fn_arg, fn_arg, #1
cbnz fn_arg, L(ztop)
L(zend):mov x0, #0
ret
EPILOGUE()
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