gdb/mips-nat.c

   1 /* Low level DECstation interface to ptrace, for GDB when running native.
   2    Copyright 1988, 1989, 1991, 1992 Free Software Foundation, Inc.
   3    Contributed by Alessandro Forin(af@cs.cmu.edu) at CMU
   4    and by Per Bothner(bothner@cs.wisc.edu) at U.Wisconsin.
   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 2 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, write to the Free Software
  20 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  21
  22 #include "defs.h"
  23 #include "inferior.h"
  24 #include "gdbcore.h"
  25 #include <sys/ptrace.h>
  26 #include <setjmp.h>             /* For JB_XXX.  */
  27
  28 /* Size of elements in jmpbuf */
  29
  30 #define JB_ELEMENT_SIZE 4
  31
  32 /* Map gdb internal register number to ptrace ``address''.
  33    These ``addresses'' are defined in DECstation <sys/ptrace.h> */
  34
  35 #define REGISTER_PTRACE_ADDR(regno) \
  36    (regno < 32 ?                GPR_BASE + regno \
  37   : regno == PC_REGNUM ?        PC      \
  38   : regno == CAUSE_REGNUM ?     CAUSE   \
  39   : regno == HI_REGNUM ?        MMHI    \
  40   : regno == LO_REGNUM ?        MMLO    \
  41   : regno == FCRCS_REGNUM ?     FPC_CSR \
  42   : regno == FCRIR_REGNUM ?     FPC_EIR \
  43   : regno >= FP0_REGNUM ?       FPR_BASE + (regno - FP0_REGNUM) \
  44   : 0)
  45
  46 static const char zerobuf[MAX_REGISTER_RAW_SIZE];
  47
  48 /* Get all registers from the inferior */
  49
  50 void
  51 fetch_inferior_registers (regno)
  52      int regno;
  53 {
  54   register unsigned int regaddr;
  55   char buf[MAX_REGISTER_RAW_SIZE];
  56   register int i;
  57
  58   registers_fetched ();
  59
  60   for (regno = 1; regno < NUM_REGS; regno++)
  61     {
  62       regaddr = REGISTER_PTRACE_ADDR (regno);
  63       for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
  64         {
  65           *(int *) &buf[i] = ptrace (PT_READ_U, inferior_pid,
  66                                      (PTRACE_ARG3_TYPE) regaddr, 0);
  67           regaddr += sizeof (int);
  68         }
  69       supply_register (regno, buf);
  70     }
  71
  72   supply_register (ZERO_REGNUM, zerobuf);
  73   /* Frame ptr reg must appear to be 0; it is faked by stack handling code. */
  74   supply_register (FP_REGNUM, zerobuf);
  75 }
  76
  77 /* Store our register values back into the inferior.
  78    If REGNO is -1, do this for all registers.
  79    Otherwise, REGNO specifies which register (so we can save time).  */
  80
  81 void
  82 store_inferior_registers (regno)
  83      int regno;
  84 {
  85   register unsigned int regaddr;
  86   char buf[80];
  87
  88   if (regno == 0)
  89     return;
  90
  91   if (regno > 0)
  92     {
  93       regaddr = REGISTER_PTRACE_ADDR (regno);
  94       errno = 0;
  95       ptrace (PT_WRITE_U, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
  96               read_register (regno));
  97       if (errno != 0)
  98         {
  99           sprintf (buf, "writing register number %d", regno);
 100           perror_with_name (buf);
 101         }
 102     }
 103   else
 104     {
 105       for (regno = 0; regno < NUM_REGS; regno++)
 106         {
 107           if (regno == ZERO_REGNUM || regno == PS_REGNUM
 108               || regno == BADVADDR_REGNUM || regno == CAUSE_REGNUM
 109               || regno == FCRIR_REGNUM || regno == FP_REGNUM
 110               || (regno >= FIRST_EMBED_REGNUM && regno <= LAST_EMBED_REGNUM))
 111             continue;
 112           regaddr = register_addr (regno, 1);
 113           errno = 0;
 114           ptrace (6, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 115                   read_register (regno));
 116           if (errno != 0)
 117             {
 118               sprintf (buf, "writing all regs, number %d", regno);
 119               perror_with_name (buf);
 120             }
 121         }
 122     }
 123 }
 124
 125
 126 /* Figure out where the longjmp will land.
 127    We expect the first arg to be a pointer to the jmp_buf structure from which
 128    we extract the pc (JB_PC) that we will land at.  The pc is copied into PC.
 129    This routine returns true on success. */
 130
 131 int
 132 get_longjmp_target(pc)
 133      CORE_ADDR *pc;
 134 {
 135   CORE_ADDR jb_addr;
 136
 137   jb_addr = read_register(A0_REGNUM);
 138
 139   if (target_read_memory(jb_addr + JB_PC * JB_ELEMENT_SIZE, pc,
 140                          sizeof(CORE_ADDR)))
 141     return 0;
 142
 143   SWAP_TARGET_AND_HOST(pc, sizeof(CORE_ADDR));
 144
 145   return 1;
 146 }