--- /dev/null
+/* -*- 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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