/* memset.S * Copyright (C) 2003-2007 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 */ #include <sysdep.h> /* 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 .weak _memset ENTRY(_memset) P0 = R0 ; /* P0 = address */ P2 = R2 ; /* P2 = count */ R3 = R0 + R2; /* end */ CC = R2 <= 7(IU); IF CC JUMP .Ltoo_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 .Lforce_align ; /* Jump if addr not aligned. */ .Laligned: 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 (.Lquad_loop , .Lquad_loop) LC0=P1; .Lquad_loop: [P0++] = R2; CC = P0 == P2; IF !CC JUMP .Lbytes_left; RTS; .Lbytes_left: R2 = R3; /* end point */ R3 = P0; /* current position */ R2 = R2 - R3; /* bytes left */ P2 = R2; .Ltoo_small: CC = P2 == 0; /* Check zero count */ IF CC JUMP .Lfinished; /* Unusual */ .Lbytes: LSETUP (.Lbyte_loop , .Lbyte_loop) LC0=P2; .Lbyte_loop: B[P0++] = R1; .Lfinished: RTS; .Lforce_align: CC = BITTST (R0, 0); /* odd byte */ R0 = 4; R0 = R0 - R2; P1 = R0; R0 = P0; /* Recover return address */ IF !CC JUMP .Lskip1; B[P0++] = R1; .Lskip1: CC = R2 <= 2; /* 2 bytes */ P2 -= P1; /* reduce count */ IF !CC JUMP .Laligned; B[P0++] = R1; B[P0++] = R1; JUMP .Laligned; .size _memset,.-_memset libc_hidden_def (memset)