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dnl IA-64 mpn_mod_34lsub1
dnl Contributed to the GNU project by Torbjorn Granlund.
dnl Copyright 2003-2005, 2010 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/limb
C Itanium: ?
C Itanium 2: 1
C INPUT PARAMETERS
define(`up', `r32')
define(`n', `r33')
C Some useful aliases for registers we use
define(`u0',`r14') define(`u1',`r15') define(`u2',`r16')
define(`a0',`r17') define(`a1',`r18') define(`a2',`r19')
define(`c0',`r20') define(`c1',`r21') define(`c2',`r22')
C This is a fairly simple-minded implementation. One could approach 0.67 c/l
C with a more sophisticated implementation. If we're really crazy, we could
C super-unroll, storing carries just in predicate registers, then copy them to
C a general register, and population count them from there. That'd bring us
C close to 3 insn/limb, for nearly 0.5 c/l.
C Computing n/3 needs 16 cycles, which is a lot of startup overhead.
C We therefore use a plain while-style loop:
C add n = -3, n
C cmp.le p9, p0 = 3, n
C (p9) br.cond .Loop
C Alternatively, we could table n/3 for, say, n < 256, and predicate the
C 16-cycle code.
C The summing-up code at the end was written quickly, and could surely be
C vastly improved.
ASM_START()
PROLOGUE(mpn_mod_34lsub1)
.prologue
.save ar.lc, r2
.body
ifdef(`HAVE_ABI_32',`
addp4 up = 0, up C M I
nop.m 0
zxt4 n = n C I
;;
')
ifelse(0,1,`
movl r14 = 0xAAAAAAAAAAAAAAAB
;;
setf.sig f6 = r14
setf.sig f7 = r33
;;
xmpy.hu f6 = f6, f7
;;
getf.sig r8 = f6
;;
shr.u r8 = r8, 1 C Loop count
;;
mov.i ar.lc = r8
')
ld8 u0 = [up], 8
cmp.ne p9, p0 = 1, n
(p9) br L(gt1)
;;
shr.u r8 = u0, 48
dep.z r27 = u0, 0, 48
;;
add r8 = r8, r27
br.ret.sptk.many b0
L(gt1):
{.mmi; nop.m 0
mov a0 = 0
add n = -2, n
}{.mmi; mov c0 = 0
mov c1 = 0
mov c2 = 0
;;
}{.mmi; ld8 u1 = [up], 8
mov a1 = 0
cmp.ltu p6, p0 = r0, r0 C clear p6
}{.mmb; cmp.gt p9, p0 = 3, n
mov a2 = 0
(p9) br.cond.dptk L(end)
;;
}
ALIGN(32)
L(top):
{.mmi; ld8 u2 = [up], 8
(p6) add c0 = 1, c0
cmp.ltu p7, p0 = a0, u0
}{.mmb; sub a0 = a0, u0
add n = -3, n
nop.b 0
;;
}{.mmi; ld8 u0 = [up], 8
(p7) add c1 = 1, c1
cmp.ltu p8, p0 = a1, u1
}{.mmb; sub a1 = a1, u1
cmp.le p9, p0 = 3, n
nop.b 0
;;
}{.mmi; ld8 u1 = [up], 8
(p8) add c2 = 1, c2
cmp.ltu p6, p0 = a2, u2
}{.mmb; sub a2 = a2, u2
nop.m 0
dnl br.cloop.dptk L(top)
(p9) br.cond.dptk L(top)
;;
}
L(end):
cmp.eq p10, p0 = 0, n
cmp.eq p11, p0 = 1, n
(p10) br L(0)
L(2):
{.mmi; ld8 u2 = [up], 8
(p6) add c0 = 1, c0
cmp.ltu p7, p0 = a0, u0
}{.mmb; sub a0 = a0, u0
nop.m 0
(p11) br L(1)
;;
} ld8 u0 = [up], 8
(p7) add c1 = 1, c1
cmp.ltu p8, p0 = a1, u1
sub a1 = a1, u1
;;
(p8) add c2 = 1, c2
cmp.ltu p6, p0 = a2, u2
sub a2 = a2, u2
;;
(p6) add c0 = 1, c0
cmp.ltu p7, p0 = a0, u0
sub a0 = a0, u0
;;
(p7) add c1 = 1, c1
br L(com)
L(1):
(p7) add c1 = 1, c1
cmp.ltu p8, p0 = a1, u1
sub a1 = a1, u1
;;
(p8) add c2 = 1, c2
cmp.ltu p6, p0 = a2, u2
sub a2 = a2, u2
;;
(p6) add c0 = 1, c0
br L(com)
L(0):
(p6) add c0 = 1, c0
cmp.ltu p7, p0 = a0, u0
sub a0 = a0, u0
;;
(p7) add c1 = 1, c1
cmp.ltu p8, p0 = a1, u1
sub a1 = a1, u1
;;
(p8) add c2 = 1, c2
L(com):
C | a2 | a1 | a0 |
C | | | | |
shr.u r24 = a0, 48 C 16 bits
shr.u r25 = a1, 32 C 32 bits
shr.u r26 = a2, 16 C 48 bits
;;
shr.u r10 = c0, 48 C 16 bits, always zero
shr.u r11 = c1, 32 C 32 bits
shr.u r30 = c2, 16 C 48 bits
;;
dep.z r27 = a0, 0, 48 C 48 bits
dep.z r28 = a1, 16, 32 C 48 bits
dep.z r29 = a2, 32, 16 C 48 bits
dep.z r31 = c0, 0, 48 C 48 bits
dep.z r14 = c1, 16, 32 C 48 bits
dep.z r15 = c2, 32, 16 C 48 bits
;;
{.mmi; add r24 = r24, r25
add r26 = r26, r27
add r28 = r28, r29
}{.mmi; add r10 = r10, r11
add r30 = r30, r31
add r14 = r14, r15
;;
}
movl r8 = 0xffffffffffff0
add r24 = r24, r26
add r10 = r10, r30
;;
add r24 = r24, r28
add r10 = r10, r14
;;
sub r8 = r8, r24
;;
add r8 = r8, r10
br.ret.sptk.many b0
EPILOGUE()
ASM_END()
|
