| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* memset.S |
| 2 | * Copyright (C) 2003-2007 Analog Devices Inc., All Rights Reserved. |
| 3 | * |
| 4 | * This file is subject to the terms and conditions of the GNU Library General |
| 5 | * Public License. See the file "COPYING.LIB" in the main directory of this |
| 6 | * archive for more details. |
| 7 | * |
| 8 | * Non-LGPL License also available as part of VisualDSP++ |
| 9 | * http://www.analog.com/processors/resources/crosscore/visualDspDevSoftware.html |
| 10 | */ |
| 11 | |
| 12 | #include <sysdep.h> |
| 13 | |
| 14 | /* void *memset(void *s, int c, size_t n); |
| 15 | * R0 = address (s) (leave unchanged to form result) |
| 16 | * R1 = filler byte (c) |
| 17 | * R2 = count (n) |
| 18 | * |
| 19 | * Note: Favours word aligned data. |
| 20 | */ |
| 21 | |
| 22 | .text |
| 23 | |
| 24 | .align 2 |
| 25 | |
| 26 | .weak _memset |
| 27 | ENTRY(_memset) |
| 28 | P0 = R0 ; /* P0 = address */ |
| 29 | P2 = R2 ; /* P2 = count */ |
| 30 | R3 = R0 + R2; /* end */ |
| 31 | CC = R2 <= 7(IU); |
| 32 | IF CC JUMP .Ltoo_small; |
| 33 | R1 = R1.B (Z); /* R1 = fill char */ |
| 34 | R2 = 3; |
| 35 | R2 = R0 & R2; /* addr bottom two bits */ |
| 36 | CC = R2 == 0; /* AZ set if zero. */ |
| 37 | IF !CC JUMP .Lforce_align ; /* Jump if addr not aligned. */ |
| 38 | |
| 39 | .Laligned: |
| 40 | P1 = P2 >> 2; /* count = n/4 */ |
| 41 | R2 = R1 << 8; /* create quad filler */ |
| 42 | R2.L = R2.L + R1.L(NS); |
| 43 | R2.H = R2.L + R1.H(NS); |
| 44 | P2 = R3; |
| 45 | |
| 46 | LSETUP (.Lquad_loop , .Lquad_loop) LC0=P1; |
| 47 | .Lquad_loop: |
| 48 | [P0++] = R2; |
| 49 | |
| 50 | CC = P0 == P2; |
| 51 | IF !CC JUMP .Lbytes_left; |
| 52 | RTS; |
| 53 | |
| 54 | .Lbytes_left: |
| 55 | R2 = R3; /* end point */ |
| 56 | R3 = P0; /* current position */ |
| 57 | R2 = R2 - R3; /* bytes left */ |
| 58 | P2 = R2; |
| 59 | |
| 60 | .Ltoo_small: |
| 61 | CC = P2 == 0; /* Check zero count */ |
| 62 | IF CC JUMP .Lfinished; /* Unusual */ |
| 63 | |
| 64 | .Lbytes: |
| 65 | LSETUP (.Lbyte_loop , .Lbyte_loop) LC0=P2; |
| 66 | .Lbyte_loop: |
| 67 | B[P0++] = R1; |
| 68 | |
| 69 | .Lfinished: |
| 70 | RTS; |
| 71 | |
| 72 | .Lforce_align: |
| 73 | CC = BITTST (R0, 0); /* odd byte */ |
| 74 | R0 = 4; |
| 75 | R0 = R0 - R2; |
| 76 | P1 = R0; |
| 77 | R0 = P0; /* Recover return address */ |
| 78 | IF !CC JUMP .Lskip1; |
| 79 | B[P0++] = R1; |
| 80 | .Lskip1: |
| 81 | CC = R2 <= 2; /* 2 bytes */ |
| 82 | P2 -= P1; /* reduce count */ |
| 83 | IF !CC JUMP .Laligned; |
| 84 | B[P0++] = R1; |
| 85 | B[P0++] = R1; |
| 86 | JUMP .Laligned; |
| 87 | |
| 88 | .size _memset,.-_memset |
| 89 | |
| 90 | libc_hidden_def (memset) |