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/* -*- asm -*- */
/*
* Copyright 2008 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
*
* GNU Radio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <gcell/spu/gc_spu_macs.h>
.file "memset.S"
/*
* Computes this, only a lot faster...
*
* void *
* memset(void *pv, int c, size_t n)
* {
* unsigned char *p = (unsigned char *) pv;
* size_t i;
* for (i = 0; i < n; i++)
* p[i] = c;
*
* return pv;
* }
*/
#define p_arg arg1 // we're going to clobber arg1 w/ the return value
#define c arg2 // the constant we're writing
#define n arg3 // how many bytes to write
#define p r13 // where we're writing
#define t0 r14
#define t1 r15
#define mask r16
#define old r17
#define an r18 // aligned n (n rounded down to mod 16 boundary)
#define next_p r19
#define cond1 r20
#define cond2 r21
#define m r22
#define r r23
PROC_ENTRY(memset)
// Hint the return from do_head, in case we go that way.
// There's pretty much nothing to can do to hint the branch to it.
hbrr do_head_br, head_complete
MR(p, p_arg) // leaves p, the return value, in the correct reg (r3)
BRZ_RETURN(n)
MODULO(t0, p, 16) // is p%16 == 0?
VSPLTB(c, c, 3) // splat byte in preferred slot of c into all slots
brnz t0, do_head // no, handle it
head_complete:
/*
* preconditions:
* p%16 == 0, n > 0
*/
hbrr middle_loop_br, middle_loop
ROUND_DOWN(an, n, 16) // an is "aligned n"
MODULO(n, n, 16) // what's left over in the last quad
brz an, do_tail // no whole quad words; skip to tail
clgti t0, an, 127 // an >= 128?
brz t0, middle2 // nope, go handle the cases between 0 and 112
/*
* 128 bytes / iteration
*/
.p2align 4
middle_loop:
ai an, an, -128
stqd c, 0*16(p)
ai next_p, p, 128
stqd c, 1*16(p)
cgti cond1, an, 127
stqd c, 2*16(p)
stqd c, 3*16(p)
stqd c, 4*16(p)
stqd c, 5*16(p)
stqd c, 6*16(p)
MR(p, next_p)
stqd c, 7*16-128(next_p)
or cond2, n, an
middle_loop_br:
brnz cond1, middle_loop
/*
* if an and n are both zero, return now
*/
BRZ_RETURN(cond2)
/*
* otherwise handle last of full quad words
*
* 0 <= an < 128, p%16 == 0
*/
middle2:
/*
* if an == 0, go handle the final non-full quadword
*/
brz an, do_tail
hbrr middle2_loop_br, middle2_loop
.p2align 3
middle2_loop:
ai next_p, p, 16
stqd c, 0(p)
ai an, an, -16
LMR(p, next_p)
middle2_loop_br:
brnz an, middle2_loop
/* We're done with the full quadwords. */
/*
* Handle the final partial quadword.
* We'll be modifying only the left hand portion of the quad.
*
* preconditions:
* an == 0, 0 <= n < 16, p%16 == 0
*/
do_tail:
HINT_RETURN(do_tail_ret)
il mask, -1
sfi t1, n, 16 // t1 = 16 - n
lqd old, 0(p)
shlqby mask, mask, t1
selb t0, old, c, mask
stqd t0, 0(p)
do_tail_ret:
RETURN()
/*
* ----------------------------------------------------------------
* Handle the first partial quadword
*
* preconditions:
* p%16 != 0
*
* postconditions:
* p%16 == 0 or n == 0
*
* |-- m --|
* +----------------+----------------+
* | //////// | |
* +----------------+----------------+
* |----- r -----|
* p
* ----------------------------------------------------------------
*/
do_head:
lqd old, 0(p)
MODULO_NEG(r, p, 16)
il mask, -1
UMIN(m, r, n)
shlqby mask, mask, m // 1's in the top, m*8 0's in the bottom
MR(t1, p)
sf t0, m, r // t0 = r - m
a p, p, m // p += m
rotqby mask, mask, t0 // rotate 0's to the right place
sf n, m, n // n -= m
selb t0, c, old, mask // merge
stqd t0, 0(t1)
BRZ_RETURN(n)
do_head_br:
br head_complete
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