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, 128 insertions, 0 deletions

diff --git a/lib/ccdbg-state.c b/lib/ccdbg-state.c
new file mode 100644
index 00000000..9aca8d2e
--- /dev/null
+++ b/lib/ccdbg-state.c
@@ -0,0 +1,128 @@
+/*
+ * 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"
+
+static uint8_t save_acc[] = {
+	1,	NOP,
+	0
+};
+
+static uint8_t save_sfr[] = {
+	2,	MOV_A_direct,	0,
+#define SAVE_SFR_ADDR	2
+	0,
+};
+
+struct sfr_state {
+	uint8_t		address;
+	uint16_t	mask;
+	char		*name;
+};
+
+static struct sfr_state	sfrs[CC_STATE_NSFR] = {
+	{ SFR_DPL0,	CC_STATE_DP,	"dpl0" },
+	{ SFR_DPH0,	CC_STATE_DP,	"dph0" },
+	{ SFR_DPL1,	CC_STATE_DP,	"dpl1" },
+	{ SFR_DPH1,	CC_STATE_DP,	"dph1" },
+	{ PSW(0),	CC_STATE_PSW,	"psw"  },
+};
+
+uint8_t
+ccdbg_state_save(struct ccdbg *dbg, struct ccstate *state, unsigned int mask)
+{
+	int	i;
+
+	mask |= CC_STATE_ACC;
+	if (mask & CC_STATE_ACC)
+		state->acc = ccdbg_execute(dbg, save_acc);
+	for (i = 0; i < CC_STATE_NSFR; i++) {
+		if (sfrs[i].mask & mask) {
+			save_sfr[SAVE_SFR_ADDR] = sfrs[i].address;
+			state->sfr[i] = ccdbg_execute(dbg, save_sfr);
+		}
+	}
+	state->mask = mask;
+	return 0;
+}
+
+static uint8_t restore_sfr[] = {
+	3,	MOV_direct_data,	0,	0,
+#define RESTORE_SFR_ADDR	2
+#define RESTORE_SFR_DATA	3
+	0
+};
+
+static uint8_t restore_acc[] = {
+	2,	MOV_A_data,	0,
+#define RESTORE_ACC_DATA	2
+	0
+};
+
+uint8_t
+ccdbg_state_restore(struct ccdbg *dbg, struct ccstate *state)
+{
+	int i;
+	for (i = CC_STATE_NSFR - 1; i >= 0; i--) {
+		if (sfrs[i].mask & state->mask) {
+			restore_sfr[RESTORE_SFR_ADDR] = sfrs[i].address;
+			restore_sfr[RESTORE_SFR_DATA] = state->sfr[i];
+			ccdbg_execute(dbg, restore_sfr);
+		}
+	}
+	if (state->mask & CC_STATE_ACC) {
+		restore_acc[RESTORE_ACC_DATA] = state->acc;
+		ccdbg_execute(dbg, restore_acc);
+	}
+	state->mask = 0;
+	return 0;
+}
+
+static void
+ccdbg_state_replace(uint16_t sfr_addr, uint8_t sfr, char *name,
+		    uint16_t addr, uint8_t *bytes, int nbytes)
+{
+	sfr_addr += 0xdf00;
+
+	if (addr <= sfr_addr && sfr_addr < addr + nbytes) {
+		fprintf(stderr, "replacing %s at 0x%04x - read 0x%02x saved 0x%02x\n",
+			name, sfr_addr, bytes[sfr_addr - addr], sfr);
+		bytes[sfr_addr - addr] = sfr;
+	}
+}
+
+void
+ccdbg_state_replace_xmem(struct ccdbg *dbg, struct ccstate *state,
+			 uint16_t addr, uint8_t *bytes, int nbytes)
+{
+	int i;
+	if (state->mask & CC_STATE_ACC)
+		ccdbg_state_replace(ACC(0), state->acc, "acc",
+				    addr, bytes, nbytes);
+	for (i = 0; i < CC_STATE_NSFR; i++)
+		if (state->mask & sfrs[i].mask)
+			ccdbg_state_replace(sfrs[i].address, state->sfr[i],
+					    sfrs[i].name, addr, bytes, nbytes);
+}
+
+void
+ccdbg_state_replace_sfr(struct ccdbg *dbg, struct ccstate *state,
+			uint8_t addr, uint8_t *bytes, int nbytes)
+{
+	ccdbg_state_replace_xmem(dbg, state, (uint16_t) addr + 0xdf00, bytes, nbytes);
+}