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 "gdbstub/helpers.h"
23 #include "cpu.h"
24
avr_cpu_gdb_read_register(CPUState * cs,GByteArray * mem_buf,int n)25 int avr_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
26 {
27 CPUAVRState *env = cpu_env(cs);
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
avr_cpu_gdb_write_register(CPUState * cs,uint8_t * mem_buf,int n)54 int avr_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
55 {
56 CPUAVRState *env = cpu_env(cs);
57
58 /* R */
59 if (n < 32) {
60 env->r[n] = *mem_buf;
61 return 1;
62 }
63
64 /* SREG */
65 if (n == 32) {
66 cpu_set_sreg(env, *mem_buf);
67 return 1;
68 }
69
70 /* SP */
71 if (n == 33) {
72 env->sp = lduw_le_p(mem_buf);
73 return 2;
74 }
75
76 /* PC */
77 if (n == 34) {
78 env->pc_w = ldl_le_p(mem_buf) / 2;
79 return 4;
80 }
81
82 return 0;
83 }
84
avr_cpu_gdb_adjust_breakpoint(CPUState * cpu,vaddr addr)85 vaddr avr_cpu_gdb_adjust_breakpoint(CPUState *cpu, vaddr addr)
86 {
87 /*
88 * This is due to some strange GDB behavior
89 * Let's assume main has address 0x100:
90 * b main - sets breakpoint at address 0x00000100 (code)
91 * b *0x100 - sets breakpoint at address 0x00800100 (data)
92 *
93 * Force all breakpoints into code space.
94 */
95 return addr % OFFSET_DATA;
96 }
97