From ee7434d5f74210dda9615629dcb6f40ffc943783 Mon Sep 17 00:00:00 2001
From: ga <ga@oldell.fish>
Date: Wed, 16 Mar 2022 22:05:49 +0000
Subject: [PATCH] Make the break instruction useful. The previous
implementation could never move past it, as gdb knows it is in ROM and will
not replace it. Distinguish hard and soft breaks.
---
simavr/sim/sim_core.c | 12 +++---
simavr/sim/sim_gdb.c | 91 +++++++++++++++++++++++++++----------------
simavr/sim/sim_gdb.h | 1 +
3 files changed, 64 insertions(+), 40 deletions(-)
diff --git a/simavr/sim/sim_core.c b/simavr/sim/sim_core.c
index 4dae91e..a1a9ac9 100644
--- a/simavr/sim/sim_core.c
+++ b/simavr/sim/sim_core.c
@@ -164,7 +164,8 @@ uint8_t avr_core_watch_read(avr_t *avr, uint16_t addr)
"CORE: *** Wrapping read address "
"PC=%04x SP=%04x O=%04x Address %04x %% %04x --> %04x\n"
FONT_DEFAULT,
- avr->pc, _avr_sp_get(avr), _avr_flash_read16le(avr, avr->pc), addr, (avr->ramend + 1), addr % (avr->ramend + 1));
+ avr->pc, _avr_sp_get(avr), _avr_flash_read16le(avr, avr->pc),
+ addr, (avr->ramend + 1), addr % (avr->ramend + 1));
addr = addr % (avr->ramend + 1);
}
@@ -938,12 +939,9 @@ run_one_again:
case 0x9598: { // BREAK -- 1001 0101 1001 1000
STATE("break\n");
if (avr->gdb) {
- // if gdb is on, we break here as in here
- // and we do so until gdb restores the instruction
- // that was here before
- avr->state = cpu_StepDone;
- new_pc = avr->pc;
- cycle = 0;
+ // if gdb is on, break here.
+ avr->state = cpu_Stopped;
+ avr_gdb_handle_break(avr);
}
} break;
case 0x95a8: { // WDR -- Watchdog Reset -- 1001 0101 1010 1000
diff --git a/simavr/sim/sim_gdb.c b/simavr/sim/sim_gdb.c
index 40ed524..6d6ef97 100644
--- a/simavr/sim/sim_gdb.c
+++ b/simavr/sim/sim_gdb.c
@@ -201,22 +201,41 @@ gdb_send_reply(
send(g->s, reply, dst - reply + 3, 0);
}
+static void
+gdb_send_stop_status(
+ avr_gdb_t * g,
+ uint8_t signal,
+ const char * reason,
+ uint32_t * pp )
+{
+ avr_t * avr;
+ uint8_t sreg;
+ int n;
+ char cmd[64];
+
+ avr = g->avr;
+ READ_SREG_INTO(avr, sreg);
+
+ n = sprintf(cmd, "T%02x20:%02x;21:%02x%02x;22:%02x%02x%02x00;",
+ signal, sreg,
+ avr->data[R_SPL], avr->data[R_SPH],
+ avr->pc & 0xff, (avr->pc >> 8) & 0xff,
+ (avr->pc >> 16) & 0xff);
+ if (reason) {
+ if (pp)
+ sprintf(cmd + n, "%s:%x;", reason, *pp);
+ else
+ sprintf(cmd + n, "%s:;", reason);
+ }
+ gdb_send_reply(g, cmd);
+}
+
static void
gdb_send_quick_status(
avr_gdb_t * g,
uint8_t signal )
{
- char cmd[64];
- uint8_t sreg;
-
- READ_SREG_INTO(g->avr, sreg);
-
- sprintf(cmd, "T%02x20:%02x;21:%02x%02x;22:%02x%02x%02x00;",
- signal, sreg,
- g->avr->data[R_SPL], g->avr->data[R_SPH],
- g->avr->pc & 0xff, (g->avr->pc >> 8) & 0xff,
- (g->avr->pc >> 16) & 0xff);
- gdb_send_reply(g, cmd);
+ gdb_send_stop_status(g, signal, NULL, NULL);
}
static int
@@ -227,14 +246,14 @@ gdb_change_breakpoint(
uint32_t addr,
uint32_t size )
{
- DBG(printf("set %d kind %d addr %08x len %d\n", set, kind, addr, size);)
+ DBG(printf("%s kind %d addr %08x len %d\n", set ? "Set" : "Clear",
+ kind, addr, size);)
if (set) {
return gdb_watch_add_or_update(w, kind, addr, size);
} else {
return gdb_watch_rm(w, kind, addr);
}
-
return -1;
}
@@ -500,9 +519,9 @@ gdb_handle_command(
if (strncmp(cmd, "Supported", 9) == 0) {
/* If GDB asked what features we support, report back
* the features we support, which is just memory layout
- * information for now.
+ * information and stop reasons for now.
*/
- gdb_send_reply(g, "qXfer:memory-map:read+");
+ gdb_send_reply(g, "qXfer:memory-map:read+;swbreak+;hwbreak+");
break;
} else if (strncmp(cmd, "Attached", 8) == 0) {
/* Respond that we are attached to an existing process..
@@ -715,16 +734,19 @@ gdb_handle_command(
break;
}
} break;
- case 'k': // kill
- avr->state = cpu_Done;
- gdb_send_reply(g, "OK");
- break;
case 'D': // detach
- avr->state = cpu_Running;
+#ifdef DETACHABLE
+ if (avr->state = cpu_Stopped)
+ avr->state = cpu_Running;
gdb_send_reply(g, "OK");
close(g->s);
g->s = -1;
break;
+#endif
+ case 'k': // kill
+ avr->state = cpu_Done;
+ gdb_send_reply(g, "OK");
+ break;
case 'v':
handle_v(avr, g, cmd, length);
break;
@@ -828,6 +850,14 @@ gdb_network_handler(
return 1;
}
+/* Called on a hardware break instruction. */
+void avr_gdb_handle_break(avr_t *avr)
+{
+ avr_gdb_t *g = avr->gdb;
+
+ gdb_send_stop_status(g, 5, "hwbreak", NULL);
+}
+
/**
* If an applicable watchpoint exists for addr, stop the cpu and send a status report.
* type is one of AVR_GDB_WATCH_READ, AVR_GDB_WATCH_WRITE depending on the type of access.
@@ -839,6 +869,7 @@ avr_gdb_handle_watchpoints(
enum avr_gdb_watch_type type )
{
avr_gdb_t *g = avr->gdb;
+ uint32_t false_addr;
int i = gdb_watch_find_range(&g->watchpoints, addr);
if (i == -1) {
@@ -850,19 +881,13 @@ avr_gdb_handle_watchpoints(
addr, i, g->watchpoints.points[i].size, kind, type);)
if (kind & type) {
/* Send gdb reply (see GDB user manual appendix E.3). */
- char cmd[78];
- uint8_t sreg;
-
- READ_SREG_INTO(g->avr, sreg);
- sprintf(cmd, "T%02x20:%02x;21:%02x%02x;22:%02x%02x%02x00;%s:%06x;",
- 5, sreg,
- g->avr->data[R_SPL], g->avr->data[R_SPH],
- g->avr->pc & 0xff, (g->avr->pc>>8)&0xff, (g->avr->pc>>16)&0xff,
- kind & AVR_GDB_WATCH_ACCESS ? "awatch" :
- kind & AVR_GDB_WATCH_WRITE ? "watch" : "rwatch",
- addr | 0x800000);
- gdb_send_reply(g, cmd);
+ const char * what;
+
+ what = (kind & AVR_GDB_WATCH_ACCESS) ? "awatch" :
+ (kind & AVR_GDB_WATCH_WRITE) ? "watch" : "rwatch";
+ false_addr = addr + 0x800000;
+ gdb_send_stop_status(g, 5, what, &false_addr);
avr->state = cpu_Stopped;
}
}
@@ -879,7 +904,7 @@ avr_gdb_processor(
if (avr->state == cpu_Running &&
gdb_watch_find(&g->breakpoints, avr->pc) != -1) {
DBG(printf("avr_gdb_processor hit breakpoint at %08x\n", avr->pc);)
- gdb_send_quick_status(g, 5);
+ gdb_send_stop_status(g, 5, "hwbreak", NULL);
avr->state = cpu_Stopped;
} else if (avr->state == cpu_StepDone) {
gdb_send_quick_status(g, 0);
diff --git a/simavr/sim/sim_gdb.h b/simavr/sim/sim_gdb.h
index 4ff6430..2936df7 100644
--- a/simavr/sim/sim_gdb.h
+++ b/simavr/sim/sim_gdb.h
@@ -46,6 +46,7 @@ int avr_gdb_processor(avr_t * avr, int sleep);
// Called from sim_core.c
void avr_gdb_handle_watchpoints(avr_t * g, uint16_t addr, enum avr_gdb_watch_type type);
+void avr_gdb_handle_break(avr_t *);
#ifdef __cplusplus
};
--
2.39.5