| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* memcmp.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 | /* int memcmp(const void *s1, const void *s2, size_t n); |
| 15 | * R0 = First Address (s1) |
| 16 | * R1 = Second Address (s2) |
| 17 | * R2 = count (n) |
| 18 | * |
| 19 | * Favours word aligned data. |
| 20 | */ |
| 21 | |
| 22 | .text |
| 23 | |
| 24 | .align 2 |
| 25 | |
| 26 | .weak _memcmp |
| 27 | ENTRY(_memcmp) |
| 28 | I1 = P3; |
| 29 | P0 = R0; /* P0 = s1 address */ |
| 30 | P3 = R1; /* P3 = s2 Address */ |
| 31 | P2 = R2 ; /* P2 = count */ |
| 32 | CC = R2 <= 7(IU); |
| 33 | IF CC JUMP .Ltoo_small; |
| 34 | I0 = R1; /* s2 */ |
| 35 | R1 = R1 | R0; /* OR addresses together */ |
| 36 | R1 <<= 30; /* check bottom two bits */ |
| 37 | CC = AZ; /* AZ set if zero. */ |
| 38 | IF !CC JUMP .Lbytes ; /* Jump if addrs not aligned. */ |
| 39 | |
| 40 | P1 = P2 >> 2; /* count = n/4 */ |
| 41 | R3 = 3; |
| 42 | R2 = R2 & R3; /* remainder */ |
| 43 | P2 = R2; /* set remainder */ |
| 44 | |
| 45 | LSETUP (.Lquad_loop_s, .Lquad_loop_e) LC0=P1; |
| 46 | .Lquad_loop_s: |
| 47 | #if !defined(__WORKAROUND_AVOID_DAG1) |
| 48 | MNOP || R0 = [P0++] || R1 = [I0++]; |
| 49 | #else |
| 50 | R0 = [P0++]; |
| 51 | R1 = [I0++]; |
| 52 | #endif |
| 53 | CC = R0 == R1; |
| 54 | IF !CC JUMP .Lquad_different; |
| 55 | .Lquad_loop_e: |
| 56 | NOP; |
| 57 | |
| 58 | P3 = I0; /* s2 */ |
| 59 | .Ltoo_small: |
| 60 | CC = P2 == 0; /* Check zero count*/ |
| 61 | IF CC JUMP .Lfinished; /* very unlikely*/ |
| 62 | |
| 63 | .Lbytes: |
| 64 | LSETUP (.Lbyte_loop_s, .Lbyte_loop_e) LC0=P2; |
| 65 | .Lbyte_loop_s: |
| 66 | R1 = B[P3++](Z); /* *s2 */ |
| 67 | R0 = B[P0++](Z); /* *s1 */ |
| 68 | CC = R0 == R1; |
| 69 | IF !CC JUMP .Ldifferent; |
| 70 | .Lbyte_loop_e: |
| 71 | NOP; |
| 72 | |
| 73 | .Ldifferent: |
| 74 | R0 = R0 - R1; |
| 75 | P3 = I1; |
| 76 | RTS; |
| 77 | |
| 78 | .Lquad_different: |
| 79 | /* We've read two quads which don't match. |
| 80 | * Can't just compare them, because we're |
| 81 | * a little-endian machine, so the MSBs of |
| 82 | * the regs occur at later addresses in the |
| 83 | * string. |
| 84 | * Arrange to re-read those two quads again, |
| 85 | * byte-by-byte. |
| 86 | */ |
| 87 | P0 += -4; /* back up to the start of the */ |
| 88 | P3 = I0; /* quads, and increase the*/ |
| 89 | P2 += 4; /* remainder count*/ |
| 90 | P3 += -4; |
| 91 | JUMP .Lbytes; |
| 92 | |
| 93 | .Lfinished: |
| 94 | R0 = 0; |
| 95 | P3 = I1; |
| 96 | RTS; |
| 97 | |
| 98 | .size _memcmp,.-_memcmp |
| 99 | |
| 100 | libc_hidden_def (memcmp) |
| 101 | |
| 102 | #ifdef __UCLIBC_SUSV3_LEGACY__ |
| 103 | weak_alias (memcmp,bcmp) |
| 104 | #endif |