swab.h (2837B) - Raw
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 architecture 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