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* lex.c (search_line_fast): Provide Neon-optimized version for ARM. 

From-SVN: r185702
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Richard Earnshaw 2012-03-22 17:54:55 +00:00 committed by Richard Earnshaw
parent b31a2c5a3a
commit e75b54a2d9
2 changed files with 67 additions and 0 deletions
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4
libcpp/ChangeLog
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@ -1,3 +1,7 @@
2012-03-22 Richard Earnshaw <rearnsha@arm.com>
* lex.c (search_line_fast): Provide Neon-optimized version for ARM.
2012-03-14 Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
* lex.c: Remove Solaris 8 reference.

63
libcpp/lex.c
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@ -629,6 +629,69 @@ search_line_fast (const uchar *s, const uchar *end ATTRIBUTE_UNUSED)
}
}
#elif defined (__ARM_NEON__)
#include "arm_neon.h"
static const uchar *
search_line_fast (const uchar *s, const uchar *end ATTRIBUTE_UNUSED)
{
const uint8x16_t repl_nl = vdupq_n_u8 ('\n');
const uint8x16_t repl_cr = vdupq_n_u8 ('\r');
const uint8x16_t repl_bs = vdupq_n_u8 ('\\');
const uint8x16_t repl_qm = vdupq_n_u8 ('?');
const uint8x16_t xmask = (uint8x16_t) vdupq_n_u64 (0x8040201008040201ULL);
unsigned int misalign, found, mask;
const uint8_t *p;
uint8x16_t data;
/* Align the source pointer. */
misalign = (uintptr_t)s & 15;
p = (const uint8_t *)((uintptr_t)s & -16);
data = vld1q_u8 (p);
/* Create a mask for the bytes that are valid within the first
16-byte block. The Idea here is that the AND with the mask
within the loop is "free", since we need some AND or TEST
insn in order to set the flags for the branch anyway. */
mask = (-1u << misalign) & 0xffff;
/* Main loop, processing 16 bytes at a time. */
goto start;
do
{
uint8x8_t l;
uint16x4_t m;
uint32x2_t n;
uint8x16_t t, u, v, w;
p += 16;
data = vld1q_u8 (p);
mask = 0xffff;
start:
t = vceqq_u8 (data, repl_nl);
u = vceqq_u8 (data, repl_cr);
v = vorrq_u8 (t, vceqq_u8 (data, repl_bs));
w = vorrq_u8 (u, vceqq_u8 (data, repl_qm));
t = vandq_u8 (vorrq_u8 (v, w), xmask);
l = vpadd_u8 (vget_low_u8 (t), vget_high_u8 (t));
m = vpaddl_u8 (l);
n = vpaddl_u16 (m);
found = vget_lane_u32 ((uint32x2_t) vorr_u64 ((uint64x1_t) n,
vshr_n_u64 ((uint64x1_t) n, 24)), 0);
found &= mask;
}
while (!found);
/* FOUND contains 1 in bits for which we matched a relevant
character. Conversion to the byte index is trivial. */
found = __builtin_ctz (found);
return (const uchar *)p + found;
}
#else
/* We only have one accellerated alternative. Use a direct call so that