target/avr/gdbstub.c

   1 /*
   2  * QEMU AVR gdbstub
   3  *
   4  * Copyright (c) 2016-2020 Michael Rolnik
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see
  18  * <http://www.gnu.org/licenses/lgpl-2.1.html>
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "exec/gdbstub.h"
  23
  24 int avr_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
  25 {
  26     AVRCPU *cpu = AVR_CPU(cs);
  27     CPUAVRState *env = &cpu->env;
  28
  29     /*  R */
  30     if (n < 32) {
  31         return gdb_get_reg8(mem_buf, env->r[n]);
  32     }
  33
  34     /*  SREG */
  35     if (n == 32) {
  36         uint8_t sreg = cpu_get_sreg(env);
  37
  38         return gdb_get_reg8(mem_buf, sreg);
  39     }
  40
  41     /*  SP */
  42     if (n == 33) {
  43         return gdb_get_reg16(mem_buf, env->sp & 0x0000ffff);
  44     }
  45
  46     /*  PC */
  47     if (n == 34) {
  48         return gdb_get_reg32(mem_buf, env->pc_w * 2);
  49     }
  50
  51     return 0;
  52 }
  53
  54 int avr_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
  55 {
  56     AVRCPU *cpu = AVR_CPU(cs);
  57     CPUAVRState *env = &cpu->env;
  58
  59     /*  R */
  60     if (n < 32) {
  61         env->r[n] = *mem_buf;
  62         return 1;
  63     }
  64
  65     /*  SREG */
  66     if (n == 32) {
  67         cpu_set_sreg(env, *mem_buf);
  68         return 1;
  69     }
  70
  71     /*  SP */
  72     if (n == 33) {
  73         env->sp = lduw_p(mem_buf);
  74         return 2;
  75     }
  76
  77     /*  PC */
  78     if (n == 34) {
  79         env->pc_w = ldl_p(mem_buf) / 2;
  80         return 4;
  81     }
  82
  83     return 0;
  84 }
  85
  86 vaddr avr_cpu_gdb_adjust_breakpoint(CPUState *cpu, vaddr addr)
  87 {
  88     /*
  89      * This is due to some strange GDB behavior
  90      * Let's assume main has address 0x100:
  91      * b main   - sets breakpoint at address 0x00000100 (code)
  92      * b *0x100 - sets breakpoint at address 0x00800100 (data)
  93      *
  94      * Force all breakpoints into code space.
  95      */
  96     return addr % OFFSET_DATA;
  97 }