1/* 2 * File: arch/blackfin/lib/memset.S 3 * Based on: 4 * Author: 5 * 6 * Created: 7 * Description: 8 * 9 * Modified: 10 * Copyright 2004-2006 Analog Devices Inc. 11 * 12 * Bugs: Enter bugs at http://blackfin.uclinux.org/ 13 * 14 * This program is free software; you can redistribute it and/or modify 15 * it under the terms of the GNU General Public License as published by 16 * the Free Software Foundation; either version 2 of the License, or 17 * (at your option) any later version. 18 * 19 * This program is distributed in the hope that it will be useful, 20 * but WITHOUT ANY WARRANTY; without even the implied warranty of 21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 22 * GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with this program; if not, see the file COPYING, or write 26 * to the Free Software Foundation, Inc., 27 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 28 */ 29 30#include <linux/linkage.h> 31 32.align 2 33 34#ifdef CONFIG_MEMSET_L1 35.section .l1.text 36#else 37.text 38#endif 39 40/* 41 * C Library function MEMSET 42 * R0 = address (leave unchanged to form result) 43 * R1 = filler byte 44 * R2 = count 45 * Favours word aligned data. 46 */ 47 48ENTRY(_memset) 49 P0 = R0 ; /* P0 = address */ 50 P2 = R2 ; /* P2 = count */ 51 R3 = R0 + R2; /* end */ 52 CC = R2 <= 7(IU); 53 IF CC JUMP .Ltoo_small; 54 R1 = R1.B (Z); /* R1 = fill char */ 55 R2 = 3; 56 R2 = R0 & R2; /* addr bottom two bits */ 57 CC = R2 == 0; /* AZ set if zero. */ 58 IF !CC JUMP .Lforce_align ; /* Jump if addr not aligned. */ 59 60.Laligned: 61 P1 = P2 >> 2; /* count = n/4 */ 62 R2 = R1 << 8; /* create quad filler */ 63 R2.L = R2.L + R1.L(NS); 64 R2.H = R2.L + R1.H(NS); 65 P2 = R3; 66 67 LSETUP (.Lquad_loop , .Lquad_loop) LC0=P1; 68.Lquad_loop: 69 [P0++] = R2; 70 71 CC = P0 == P2; 72 IF !CC JUMP .Lbytes_left; 73 RTS; 74 75.Lbytes_left: 76 R2 = R3; /* end point */ 77 R3 = P0; /* current position */ 78 R2 = R2 - R3; /* bytes left */ 79 P2 = R2; 80 81.Ltoo_small: 82 CC = P2 == 0; /* Check zero count */ 83 IF CC JUMP .Lfinished; /* Unusual */ 84 85.Lbytes: 86 LSETUP (.Lbyte_loop , .Lbyte_loop) LC0=P2; 87.Lbyte_loop: 88 B[P0++] = R1; 89 90.Lfinished: 91 RTS; 92 93.Lforce_align: 94 CC = BITTST (R0, 0); /* odd byte */ 95 R0 = 4; 96 R0 = R0 - R2; 97 P1 = R0; 98 R0 = P0; /* Recover return address */ 99 IF !CC JUMP .Lskip1; 100 B[P0++] = R1; 101.Lskip1: 102 CC = R2 <= 2; /* 2 bytes */ 103 P2 -= P1; /* reduce count */ 104 IF !CC JUMP .Laligned; 105 B[P0++] = R1; 106 B[P0++] = R1; 107 JUMP .Laligned; 108 109ENDPROC(_memset) 110