arch/arc/include/uapi/asm/swab.h

   1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2 /*
   3  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * vineetg: May 2011
  10  *  -Support single cycle endian-swap insn in ARC700 4.10
  11  *
  12  * vineetg: June 2009
  13  *  -Better htonl implementation (5 instead of 9 ALU instructions)
  14  *  -Hardware assisted single cycle bswap (Use Case of ARC custom instrn)
  15  */
  16
  17 #ifndef __ASM_ARC_SWAB_H
  18 #define __ASM_ARC_SWAB_H
  19
  20 #include <linux/types.h>
  21
  22 /* Native single cycle endian swap insn */
  23 #ifdef CONFIG_ARC_HAS_SWAPE
  24
  25 #define __arch_swab32(x)                \
  26 ({                                      \
  27         unsigned int tmp = x;           \
  28         __asm__(                        \
  29         "       swape   %0, %1  \n"     \
  30         : "=r" (tmp)                    \
  31         : "r" (tmp));                   \
  32         tmp;                            \
  33 })
  34
  35 #else
  36
  37 /* Several ways of Endian-Swap Emulation for ARC
  38  * 0: kernel generic
  39  * 1: ARC optimised "C"
  40  * 2: ARC Custom instruction
  41  */
  42 #define ARC_BSWAP_TYPE  1
  43
  44 #if (ARC_BSWAP_TYPE == 1)               /******* Software only ********/
  45
  46 /* The kernel default implementation of htonl is
  47  *              return  x<<24 | x>>24 |
  48  *               (x & (__u32)0x0000ff00UL)<<8 | (x & (__u32)0x00ff0000UL)>>8;
  49  *
  50  * This generates 9 instructions on ARC (excluding the ld/st)
  51  *
  52  * 8051fd8c:    ld     r3,[r7,20]       ; Mem op : Get the value to be swapped
  53  * 8051fd98:    asl    r5,r3,24         ; get  3rd Byte
  54  * 8051fd9c:    lsr    r2,r3,24         ; get  0th Byte
  55  * 8051fda0:    and    r4,r3,0xff00
  56  * 8051fda8:    asl    r4,r4,8          ; get 1st Byte
  57  * 8051fdac:    and    r3,r3,0x00ff0000
  58  * 8051fdb4:    or     r2,r2,r5         ; combine 0th and 3rd Bytes
  59  * 8051fdb8:    lsr    r3,r3,8          ; 2nd Byte at correct place in Dst Reg
  60  * 8051fdbc:    or     r2,r2,r4         ; combine 0,3 Bytes with 1st Byte
  61  * 8051fdc0:    or     r2,r2,r3         ; combine 0,3,1 Bytes with 2nd Byte
  62  * 8051fdc4:    st     r2,[r1,20]       ; Mem op : save result back to mem
  63  *
  64  * Joern suggested a better "C" algorithm which is great since
  65  * (1) It is portable to any architecure
  66  * (2) At the same time it takes advantage of ARC ISA (rotate intrns)
  67  */
  68
  69 #define __arch_swab32(x)                                        \
  70 ({      unsigned long __in = (x), __tmp;                        \
  71         __tmp = __in << 8 | __in >> 24; /* ror tmp,in,24 */     \
  72         __in = __in << 24 | __in >> 8; /* ror in,in,8 */        \
  73         __tmp ^= __in;                                          \
  74         __tmp &= 0xff00ff;                                      \
  75         __tmp ^ __in;                                           \
  76 })
  77
  78 #elif (ARC_BSWAP_TYPE == 2)     /* Custom single cycle bswap instruction */
  79
  80 #define __arch_swab32(x)                                                \
  81 ({                                                                      \
  82         unsigned int tmp = x;                                           \
  83         __asm__(                                                        \
  84         "       .extInstruction bswap, 7, 0x00, SUFFIX_NONE, SYNTAX_2OP \n"\
  85         "       bswap  %0, %1                                           \n"\
  86         : "=r" (tmp)                                                    \
  87         : "r" (tmp));                                                   \
  88         tmp;                                                            \
  89 })
  90
  91 #endif /* ARC_BSWAP_TYPE=zzz */
  92
  93 #endif /* CONFIG_ARC_HAS_SWAPE */
  94
  95 #if !defined(__STRICT_ANSI__) || defined(__KERNEL__)
  96 #define __SWAB_64_THRU_32__
  97 #endif
  98
  99 #endif