Save/restore registers to host during memory operations. Cache ROM data.

Because the debug port uses instructions for most operations, the debug code
will clobber registers used by the running program. Save and restore these
to avoid corrupting application data.

If the ROM file is known, use that to return data instead of fetching it
from the target to improve performance.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/lib/ccdbg-rom.c b/lib/ccdbg-rom.c
new file mode 100644
index 00000000..4559b4e7
--- /dev/null
+++ b/lib/ccdbg-rom.c
@@ -0,0 +1,63 @@
+/*
+ * Copyright © 2008 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "ccdbg.h"
+
+uint8_t
+ccdbg_set_rom(struct ccdbg *dbg, struct hex_image *rom)
+{
+	if (dbg->rom)
+		ccdbg_hex_image_free(dbg->rom);
+	dbg->rom = rom;
+	return 0;
+}
+
+uint8_t
+ccdbg_rom_contains(struct ccdbg *dbg, uint16_t addr, int nbytes)
+{
+	struct hex_image *rom = dbg->rom;
+	if (!rom)
+		return 0;
+	if (addr < rom->address || rom->address + rom->length < addr + nbytes)
+		return 0;
+	return 1;
+}
+
+uint8_t
+ccdbg_rom_replace_xmem(struct ccdbg *dbg,
+		       uint16_t addr, uint8_t *bytes, int nbytes)
+{
+	struct hex_image *rom = dbg->rom;
+	if (!rom)
+		return 0;
+	
+	if (rom->address < addr + nbytes && addr < rom->address + rom->length) {
+		int	start, stop;
+
+		start = addr;
+		if (addr < rom->address)
+			start = rom->address;
+		stop = addr + nbytes;
+		if (rom->address + rom->length < stop)
+			stop = rom->address + rom->length;
+		memcpy(bytes + start - addr, rom->data + start - rom->address,
+		       stop - start);
+		return 1;
+	}
+	return 0;
+}