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/* memset.S
* Copyright (C) 2003, 2005, 2006 Analog Devices Inc., All Rights Reserved.
*
* This file is subject to the terms and conditions of the GNU Library General
* Public License. See the file "COPYING.LIB" in the main directory of this
* archive for more details.
*
* Non-LGPL License also available as part of VisualDSP++
* http://www.analog.com/processors/resources/crosscore/visualDspDevSoftware.html
*/
/* void *memset(void *s, int c, size_t n);
* R0 = address (s) (leave unchanged to form result)
* R1 = filler byte (c)
* R2 = count (n)
*
* Note: Favours word aligned data.
*/
.text
.align 2
.global _memset
.type _memset, STT_FUNC
_memset:
P0 = R0 ; // P0 = address
P2 = R2 ; // P2 = count
R3 = R0 + R2; // end
CC = R2 <= 7(IU);
IF CC JUMP too_small;
R1 = R1.B (Z); // R1 = fill char
R2 = 3;
R2 = R0 & R2; // addr bottom two bits
CC = R2 == 0; // AZ set if zero.
IF !CC JUMP force_align ; // Jump if addr not aligned.
aligned:
P1 = P2 >> 2; // count = n/4
R2 = R1 << 8; // create quad filler
R2.L = R2.L + R1.L(NS);
R2.H = R2.L + R1.H(NS);
P2 = R3;
LSETUP (quad_loop , quad_loop) LC0=P1;
quad_loop:
[P0++] = R2;
CC = P0 == P2;
IF !CC JUMP bytes_left;
RTS;
bytes_left:
R2 = R3; // end point
R3 = P0; // current position
R2 = R2 - R3; // bytes left
P2 = R2;
too_small:
CC = P2 == 0; //Check zero count
IF CC JUMP finished; // Unusual
bytes: LSETUP (byte_loop , byte_loop) LC0=P2;
byte_loop: B[P0++] = R1;
finished:
RTS;
force_align:
CC = BITTST (R0, 0 ); // odd byte
R0 = 4;
R0 = R0 - R2;
P1 = R0;
R0 = P0; // Recover return address
IF !CC JUMP skip1;
B[P0++] = R1;
skip1:
CC = R2 <= 2; // 2 bytes
P2 -= P1; // reduce count
IF !CC JUMP aligned;
B[P0++] = R1;
B[P0++] = R1;
JUMP aligned;
.size _memset,.-_memset
libc_hidden_def (memset)
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