lemire

	.globl	_compute_two            ; -- Begin function compute_two
	.p2align	2
_compute_two:                           ; @compute_two
	.cfi_startproc
; %bb.0:
Lloh0:
	adrp	x8, _M@PAGE
Lloh1:
	ldr	x8, [x8, _M@PAGEOFF]
	tst	x8, #0x7fffffffffffffff

lemire

# Copy this file as CMakeLists.txt in
# some directory. With a recent CMake
# (at least 3.15), in this directory do
#
# cmake -B build .
# cmake --build build
# ./build/repro
#
#
cmake_minimum_required(VERSION 3.15)

lemire

namespace {
/**
 * make_uint8x16_t initializes a SIMD register (uint8x16_t).
 * This is needed because, incredibly, the syntax uint8x16_t x = {1,2,3...}
 * is not recognized under Visual Studio! This is a workaround.
 * Using a std::initializer_list<uint8_t>  as a parameter resulted in
 * inefficient code. With the current approach, if the parameters are
 * compile-time constants,
 * GNU GCC compiles it to ldr, the same as uint8x16_t x = {1,2,3...}.

lemire

docker run -it --privileged ubuntu bash

apt-get update
apt-get install linux-tools-generic
/usr/lib/linux-tools/5.4.0-28-generic/perf stat ls

lemire

// returns true if the provided byte value is a
// "continuing" UTF-8 value, that is, if it starts with
// 0b10...
static inline bool is_utf8_continuing(char c) {
  // in 2 complement's notation, values start at 0b10000 (-128)... and
  // go up to 0b11111 (-1)... so we want all values from -128 to -65 (which is 0b10111111)
  return ((signed char)c) <= -65;
}

lemire

// prefetching can be useful for large documents
// where page walking becomes a significant overhead
#ifdef _MSC_VER
// annoyingly, Visual Studio does not appear to have a portable
// prefetch
#ifdef IS_ARM64
inline void prefetch(const void * p) {
  __prefetch(p);
}

lemire

package Main

import (
	"math"
	"reflect"
	"testing"

	"github.com/RoaringBitmap/roaring"
	"github.com/willf/bitset"
)

lemire

// this is more or less a port of travis_avx2_w to plain C

namespace {
// this is __m256i for people who don't have avx
struct poor__m256i {
    uint32_t val[8];
};

#ifndef really_inline

lemire

// the following works fine under clang:
#pragma clang attribute push(__attribute__((target("sse4.2,pclmul"))), apply_to=function)
void f(){}
#pragma clang attribute pop


////////////
/// The following DOES NOT WORK: 'error: expected unqualified-id'
//////////
namespace joe {

lemire

def f(x):
  r1 = (x + 212) % 256
  r2 = x | 32
  table = [44, 125, 0, 0, 192, 0, 0, 0, 0, 0, 0, 0, 0, 0, 58, 123 ]
  if ((r1&0x80)==0x80):
    r3 = 0
  else:
    r3 = table[r1& 0xF]
  r4 = r2 == r3
  return r4