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https://github.com/jart/cosmopolitan.git
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7e0a09feec
This change ports APE Loader to Linux AARCH64, so that Raspberry Pi users can run programs like redbean, without the executable needing to modify itself. Progress has also slipped into this change on the issue of making progress better conforming to user expectations and industry standards regarding which symbols we're allowed to declare
47 lines
1.8 KiB
C
47 lines
1.8 KiB
C
/* clang-format off */
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/* ===-- popcountti2.c - Implement __popcountti2 ----------------------------===
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*
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* The LLVM Compiler Infrastructure
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*
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* This file is dual licensed under the MIT and the University of Illinois Open
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* Source Licenses. See LICENSE.TXT for details.
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*
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* ===----------------------------------------------------------------------===
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*
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* This file implements __popcountti2 for the compiler_rt library.
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*
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* ===----------------------------------------------------------------------===
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*/
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__static_yoink("huge_compiler_rt_license");
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#include "third_party/compiler_rt/int_lib.h"
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#ifdef CRT_HAS_128BIT
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/* Returns: count of 1 bits */
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COMPILER_RT_ABI si_int
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__popcountti2(ti_int a)
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{
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tu_int x3 = (tu_int)a;
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x3 = x3 - ((x3 >> 1) & (((tu_int)0x5555555555555555uLL << 64) |
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0x5555555555555555uLL));
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/* Every 2 bits holds the sum of every pair of bits (64) */
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x3 = ((x3 >> 2) & (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL))
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+ (x3 & (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL));
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/* Every 4 bits holds the sum of every 4-set of bits (3 significant bits) (32) */
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x3 = (x3 + (x3 >> 4))
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& (((tu_int)0x0F0F0F0F0F0F0F0FuLL << 64) | 0x0F0F0F0F0F0F0F0FuLL);
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/* Every 8 bits holds the sum of every 8-set of bits (4 significant bits) (16) */
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du_int x2 = (du_int)(x3 + (x3 >> 64));
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/* Every 8 bits holds the sum of every 8-set of bits (5 significant bits) (8) */
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su_int x = (su_int)(x2 + (x2 >> 32));
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/* Every 8 bits holds the sum of every 8-set of bits (6 significant bits) (4) */
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x = x + (x >> 16);
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/* Every 8 bits holds the sum of every 8-set of bits (7 significant bits) (2) */
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/* Upper 16 bits are garbage */
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return (x + (x >> 8)) & 0xFF; /* (8 significant bits) */
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}
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#endif /* CRT_HAS_128BIT */
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