src/hotspot/cpu/riscv/bytes_riscv.hpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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#ifndef CPU_RISCV_BYTES_RISCV_HPP
#define CPU_RISCV_BYTES_RISCV_HPP

#include "memory/allStatic.hpp"
#include "utilities/byteswap.hpp"

class Bytes: AllStatic {
 public:
  // Efficient reading and writing of unaligned unsigned data in platform-specific byte ordering
  // RISCV needs to check for alignment.

  static inline u2 get_native_u2(address p) {
    if ((intptr_t(p) & 1) == 0) {
      return *(u2*)p;
    } else {
      return ((u2)(p[1]) << 8) |
             ((u2)(p[0]));
    }
  }

  static inline u4 get_native_u4(address p) {
    switch (intptr_t(p) & 3) {
      case 0:
        return *(u4*)p;

      case 2:
        return ((u4)(((u2*)p)[1]) << 16) |
               ((u4)(((u2*)p)[0]));

      default:
        return ((u4)(p[3]) << 24) |
               ((u4)(p[2]) << 16) |
               ((u4)(p[1]) <<  8) |
               ((u4)(p[0]));
    }
  }

  static inline u8 get_native_u8(address p) {
    switch (intptr_t(p) & 7) {
      case 0:
        return *(u8*)p;

      case 4:
        return ((u8)(((u4*)p)[1]) << 32) |
               ((u8)(((u4*)p)[0]));

      case 2:
      case 6:
        return ((u8)(((u2*)p)[3]) << 48) |
               ((u8)(((u2*)p)[2]) << 32) |
               ((u8)(((u2*)p)[1]) << 16) |
               ((u8)(((u2*)p)[0]));

      default:
        return ((u8)(p[7]) << 56) |
               ((u8)(p[6]) << 48) |
               ((u8)(p[5]) << 40) |
               ((u8)(p[4]) << 32) |
               ((u8)(p[3]) << 24) |
               ((u8)(p[2]) << 16) |
               ((u8)(p[1]) <<  8) |
               ((u8)(p[0]));
    }
  }

  static inline void put_native_u2(address p, u2 x) {
    if ((intptr_t(p) & 1) == 0) {
      *(u2*)p = x;
    } else {
      p[1] = x >> 8;
      p[0] = x;
    }
  }

  static inline void put_native_u4(address p, u4 x) {
    switch (intptr_t(p) & 3) {
      case 0:
        *(u4*)p = x;
        break;

      case 2:
        ((u2*)p)[1] = x >> 16;
        ((u2*)p)[0] = x;
        break;

      default:
        ((u1*)p)[3] = x >> 24;
        ((u1*)p)[2] = x >> 16;
        ((u1*)p)[1] = x >>  8;
        ((u1*)p)[0] = x;
        break;
    }
  }

  static inline void put_native_u8(address p, u8 x) {
    switch (intptr_t(p) & 7) {
      case 0:
        *(u8*)p = x;
        break;

      case 4:
        ((u4*)p)[1] = x >> 32;
        ((u4*)p)[0] = x;
        break;

      case 2:
      case 6:
        ((u2*)p)[3] = x >> 48;
        ((u2*)p)[2] = x >> 32;
        ((u2*)p)[1] = x >> 16;
        ((u2*)p)[0] = x;
        break;

      default:
        ((u1*)p)[7] = x >> 56;
        ((u1*)p)[6] = x >> 48;
        ((u1*)p)[5] = x >> 40;
        ((u1*)p)[4] = x >> 32;
        ((u1*)p)[3] = x >> 24;
        ((u1*)p)[2] = x >> 16;
        ((u1*)p)[1] = x >>  8;
        ((u1*)p)[0] = x;
        break;
    }
  }

#ifndef VM_LITTLE_ENDIAN
#error RISC-V is little endian, the preprocessor macro VM_LITTLE_ENDIAN should be defined.
#endif

  // Efficient reading and writing of unaligned unsigned data in Java byte ordering (i.e. big-endian ordering)
  static inline u2 get_Java_u2(address p) { return byteswap(get_native_u2(p)); }
  static inline u4 get_Java_u4(address p) { return byteswap(get_native_u4(p)); }
  static inline u8 get_Java_u8(address p) { return byteswap(get_native_u8(p)); }

  static inline void put_Java_u2(address p, u2 x) { put_native_u2(p, byteswap(x)); }
  static inline void put_Java_u4(address p, u4 x) { put_native_u4(p, byteswap(x)); }
  static inline void put_Java_u8(address p, u8 x) { put_native_u8(p, byteswap(x)); }
};

#endif // CPU_RISCV_BYTES_RISCV_HPP