| /* |

| * File: memset.S |

| * |

| * Copyright 2004-2007 Analog Devices Inc. |

| * Enter bugs at http://blackfin.uclinux.org/ |

| * |

| * This program 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 2 of the License, or |

| * (at your option) any later version. |

| * |

| * This program 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, see the file COPYING, or write |

| * to the Free Software Foundation, Inc., |

| * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |

| */ |

| |

| .align 2 |

| |

| /* |

| * C Library function MEMSET |

| * R0 = address (leave unchanged to form result) |

| * R1 = filler byte |

| * R2 = count |

| * Favours word aligned data. |

| */ |

| |

| .globl _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 .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 |