gdb/arch/aarch64-scalable-linux.c

   1 /* Common Linux arch-specific functionality for AArch64 scalable
   2    extensions: SVE and SME.
   3
   4    Copyright (C) 2023-2024 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "arch/aarch64-scalable-linux.h"
  22 #include "arch/aarch64.h"
  23 #include "gdbsupport/byte-vector.h"
  24 #include "gdbsupport/common-regcache.h"
  25
  26 /* See arch/aarch64-scalable-linux.h  */
  27
  28 bool
  29 sve_state_is_empty (const struct reg_buffer_common *reg_buf)
  30 {
  31   /* Instead of allocating a buffer with the size of the current vector
  32      length, just use a buffer that is big enough for all cases.  */
  33   gdb_byte zero_buffer[256];
  34
  35   /* Zero it out.  */
  36   memset (zero_buffer, 0, 256);
  37
  38   /* Are any of the Z registers set (non-zero) after the first 128 bits?  */
  39   for (int i = 0; i < AARCH64_SVE_Z_REGS_NUM; i++)
  40     {
  41       if (!reg_buf->raw_compare (AARCH64_SVE_Z0_REGNUM + i, zero_buffer,
  42                                  V_REGISTER_SIZE))
  43         return false;
  44     }
  45
  46   /* Are any of the P registers set (non-zero)?  */
  47   for (int i = 0; i < AARCH64_SVE_P_REGS_NUM; i++)
  48     {
  49       if (!reg_buf->raw_compare (AARCH64_SVE_P0_REGNUM + i, zero_buffer, 0))
  50         return false;
  51     }
  52
  53   /* Is the FFR register set (non-zero)?  */
  54   return reg_buf->raw_compare (AARCH64_SVE_FFR_REGNUM, zero_buffer, 0);
  55 }