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Commit | Line | Data |
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3f0606ad | 1 | /* |
155fd766 | 2 | * File: memset.S |
3f0606ad | 3 | * |
155fd766 AL |
4 | * Copyright 2004-2007 Analog Devices Inc. |
5 | * Enter bugs at http://blackfin.uclinux.org/ | |
3f0606ad | 6 | * |
1a459660 | 7 | * SPDX-License-Identifier: GPL-2.0+ |
3f0606ad AL |
8 | */ |
9 | ||
3f0606ad AL |
10 | .align 2 |
11 | ||
12 | /* | |
13 | * C Library function MEMSET | |
14 | * R0 = address (leave unchanged to form result) | |
15 | * R1 = filler byte | |
16 | * R2 = count | |
17 | * Favours word aligned data. | |
18 | */ | |
19 | ||
20 | .globl _memset; | |
5b22163f | 21 | .type _memset, STT_FUNC; |
3f0606ad AL |
22 | _memset: |
23 | P0 = R0 ; /* P0 = address */ | |
24 | P2 = R2 ; /* P2 = count */ | |
25 | R3 = R0 + R2; /* end */ | |
26 | CC = R2 <= 7(IU); | |
27 | IF CC JUMP .Ltoo_small; | |
28 | R1 = R1.B (Z); /* R1 = fill char */ | |
29 | R2 = 3; | |
30 | R2 = R0 & R2; /* addr bottom two bits */ | |
31 | CC = R2 == 0; /* AZ set if zero. */ | |
32 | IF !CC JUMP .Lforce_align ; /* Jump if addr not aligned. */ | |
33 | ||
34 | .Laligned: | |
35 | P1 = P2 >> 2; /* count = n/4 */ | |
36 | R2 = R1 << 8; /* create quad filler */ | |
37 | R2.L = R2.L + R1.L(NS); | |
38 | R2.H = R2.L + R1.H(NS); | |
39 | P2 = R3; | |
40 | ||
41 | LSETUP (.Lquad_loop , .Lquad_loop) LC0=P1; | |
42 | .Lquad_loop: | |
43 | [P0++] = R2; | |
44 | ||
45 | CC = P0 == P2; | |
46 | IF !CC JUMP .Lbytes_left; | |
47 | RTS; | |
48 | ||
49 | .Lbytes_left: | |
50 | R2 = R3; /* end point */ | |
51 | R3 = P0; /* current position */ | |
52 | R2 = R2 - R3; /* bytes left */ | |
53 | P2 = R2; | |
54 | ||
55 | .Ltoo_small: | |
56 | CC = P2 == 0; /* Check zero count */ | |
57 | IF CC JUMP .Lfinished; /* Unusual */ | |
58 | ||
59 | .Lbytes: | |
60 | LSETUP (.Lbyte_loop , .Lbyte_loop) LC0=P2; | |
61 | .Lbyte_loop: | |
62 | B[P0++] = R1; | |
63 | ||
64 | .Lfinished: | |
65 | RTS; | |
66 | ||
67 | .Lforce_align: | |
68 | CC = BITTST (R0, 0); /* odd byte */ | |
69 | R0 = 4; | |
70 | R0 = R0 - R2; | |
71 | P1 = R0; | |
72 | R0 = P0; /* Recover return address */ | |
73 | IF !CC JUMP .Lskip1; | |
74 | B[P0++] = R1; | |
75 | .Lskip1: | |
76 | CC = R2 <= 2; /* 2 bytes */ | |
77 | P2 -= P1; /* reduce count */ | |
78 | IF !CC JUMP .Laligned; | |
79 | B[P0++] = R1; | |
80 | B[P0++] = R1; | |
81 | JUMP .Laligned; | |
5b22163f MF |
82 | |
83 | .size _memset, .-_memset |