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Diffstat (limited to 'libc/arch-mips/string/mips-string-ops.h')
| -rw-r--r-- | libc/arch-mips/string/mips-string-ops.h | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/libc/arch-mips/string/mips-string-ops.h b/libc/arch-mips/string/mips-string-ops.h new file mode 100644 index 0000000..50f7e3a --- /dev/null +++ b/libc/arch-mips/string/mips-string-ops.h @@ -0,0 +1,148 @@ +/* + * Copyright (c) 2010 MIPS Technologies, Inc. + * + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer + * in the documentation and/or other materials provided with + * the distribution. + * * Neither the name of MIPS Technologies Inc. nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef __MIPS_STRING_OPS_H +#define __MIPS_STRING_OPS_H + /* This definition of the byte bitfields uses the + assumption that the layout of the bitfields is + equivalent to the layout in memory. Generally, + for the MIPS ABIs, this is true. If you compile + the strcmp.c file with -DSMOKE_TEST_NEW_STRCMP, + this assumption will be tested. + + Also, regardless of char signedness, ANSI C dictates that + strcmp() treats each character as unsigned char. For + strlen and the like, signedness doesn't matter. + + Also, this code assumes that there are 8-bits per 'char'. */ + +#if __mips64 +typedef struct bits +{ + unsigned B0:8, B1:8, B2:8, B3:8, B4:8, B5:8, B6:8, B7:8; +} bits_t; +#else +typedef struct bits +{ + unsigned B0:8, B1:8, B2:8, B3:8; +} bits_t; +#endif + +#ifndef _ULW + /* for MIPS GCC, there is no unaligned builtins - so this code forces + the compiler to treat the pointer access as unaligned. */ +struct ulw +{ + unsigned b; +} __attribute__ ((packed)); + +#define _ULW(__x) ((struct ulw *) ((char *)(&__x)))->b; +#endif + +/* This union assumes that small structures can be in registers. If + not, then memory accesses will be done - not optimal, but ok. */ +typedef union +{ + unsigned v; + bits_t b; +} bitfields_t; + +#ifndef detect_zero +/* __mips_dsp, __mips_dspr2, and __mips64 are predefined by + the compiler, based on command line options. */ +#if (__mips_dsp || __mips_dspr2) && !__mips64 +#define __mips_using_dsp 1 + +/* DSP 4-lane (8 unsigned bits per line) subtract and saturate + * Intrinsic operation. How this works: + * Given a 4-byte string of "ABC\0", subtract this as + * an unsigned integer from 0x01010101: + * 0x01010101 + * - 0x41424300 + * ----------- + ( 0xbfbebe01 <-- answer without saturation + * 0x00000001 <-- answer with saturation + * When this 4-lane vector is treated as an unsigned int value, + * a non-zero answer indicates the presence of a zero in the + * original 4-byte argument. */ + +typedef signed char v4i8 __attribute__ ((vector_size (4))); + +#define detect_zero(__x,__y,__01s,__80s)\ + ((unsigned) __builtin_mips_subu_s_qb((v4i8) __01s,(v4i8) __x)) + + /* sets all 4 lanes to requested byte. */ +#define set_byte_lanes(__x) ((unsigned) __builtin_mips_repl_qb(__x)) + + /* sets all 4 lanes to 0x01. */ +#define def_and_set_01(__x) unsigned __x = (unsigned) __builtin_mips_repl_qb(0x01) + + /* sets all 4 lanes to 0x80. Not needed when subu_s.qb used. */ +#define def_and_set_80(__x) /* do nothing */ + +#else + /* this version, originally published in the 80's, uses + a reverse-carry-set like determination of the zero byte. + The steps are, for __x = 0x31ff0001: + __x - _01s = 0x30fdff00 + ~__x = 0xce00fffe + ((__x - _01s) & ~__x) = 0x0000ff00 + x & _80s = 0x00008000 <- byte 3 was zero + Some implementaions naively assume that characters are + always 7-bit unsigned ASCII. With that assumption, the + "& ~x" is usually discarded. Since character strings + are 8-bit, the and is needed to catch the case of + a false positive when the byte is 0x80. */ + +#define detect_zero(__x,__y,_01s,_80s)\ + ((unsigned) (((__x) - _01s) & ~(__x)) & _80s) + +#if __mips64 +#define def_and_set_80(__x) unsigned __x = 0x8080808080808080ul +#define def_and_set_01(__x) unsigned __x = 0x0101010101010101ul +#else +#define def_and_set_80(__x) unsigned __x = 0x80808080ul +#define def_and_set_01(__x) unsigned __x = 0x01010101ul +#endif + +#endif +#endif + +/* dealing with 'void *' conversions without using extra variables. */ +#define get_byte(__x,__idx) (((unsigned char *) (__x))[__idx]) +#define set_byte(__x,__idx,__fill) ((unsigned char *) (__x))[__idx] = (__fill) +#define get_word(__x,__idx) (((unsigned *) (__x))[__idx]) +#define set_word(__x,__idx,__fill) ((unsigned *) (__x))[__idx] = (__fill) +#define inc_ptr_as(__type,__x,__inc) __x = (void *) (((__type) __x) + (__inc)) +#define cvt_ptr_to(__type,__x) ((__type) (__x)) + +#endif |