From 78b65086b9e1bcb23863206afb4d709d7dde5181 Mon Sep 17 00:00:00 2001
From: ga <ga@oldell.fish>
Date: Fri, 13 May 2022 21:46:32 +0100
Subject: [PATCH] Speed execution with GDB by running a burst of instructions
before checking for input from GDB. Discussed in #489.
---
simavr/sim/sim_gdb.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/simavr/sim/sim_gdb.c b/simavr/sim/sim_gdb.c
index ec950e6..cd2196e 100644
--- a/simavr/sim/sim_gdb.c
+++ b/simavr/sim/sim_gdb.c
@@ -47,12 +47,17 @@ typedef struct {
} points[WATCH_LIMIT];
} avr_gdb_watchpoints_t;
+/* How many AVR instructions to execute before looking for gdb input. */
+
+#define GDB_BURST 256
+
typedef struct avr_gdb_t {
avr_t * avr;
- int listen; // listen socket
- int s; // current gdb connection
+ int burst_count; // Current instruction burst size
+ int listen; // listen socket
+ int s; // current gdb connection
- avr_gdb_watchpoints_t breakpoints;
+ avr_gdb_watchpoints_t breakpoints;
avr_gdb_watchpoints_t watchpoints;
// These are used by gdb's "info io_registers" command.
@@ -789,6 +794,7 @@ gdb_network_handler(
int max;
FD_ZERO(&read_set);
+ g->burst_count = 0; // Reset burst count
if (g->s != -1) {
FD_SET(g->s, &read_set);
max = g->s + 1;
@@ -934,8 +940,12 @@ avr_gdb_processor(
} else if (avr->state == cpu_StepDone) {
gdb_send_quick_status(g, 0);
avr->state = cpu_Stopped;
+ } else {
+ /* Look for gdb input every GDB_BURST instructions. */
+
+ if (sleep == 0 && g->burst_count++ < GDB_BURST)
+ return 0;
}
- // this also sleeps for a bit
return gdb_network_handler(g, sleep);
}
--
2.39.5