Save/restore regs when reading/writing memory. Add SFR access.

The DPL and ACC registers are used by the memory access code,
so they need to be saved and restored. Stuff them up high in ram for now;
this should probably be fixed to pull them back to the host instead.

Special SFR access is required as not all SFRs are visible in the unified
address space.

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

2 files changed, 81 insertions, 2 deletions

diff --git a/lib/ccdbg-memory.c b/lib/ccdbg-memory.c
index 3406a1b1..d74726fb 100644
--- a/lib/ccdbg-memory.c
+++ b/lib/ccdbg-memory.c
@@ -23,9 +23,14 @@
  */
 
 static uint8_t	memory_init[] = {
+	2,	MOV_direct_A,		0x7f,
+	3,	MOV_direct1_direct2,	0x7e, SFR_DPL0,
+	3,	MOV_direct1_direct2,	0x7d, SFR_DPH0,
+	3,	MOV_direct1_direct2,	0x7c, SFR_DPL1,
+	3,	MOV_direct1_direct2,	0x7b, SFR_DPH1,
 	3,	MOV_DPTR_data16,	0,	0,
-#define HIGH_START	2
-#define LOW_START	3
+#define HIGH_START	21
+#define LOW_START	22
 	0,
 };
 
@@ -44,6 +49,15 @@ static uint8_t read8[] = {
 	0,
 };
 
+static uint8_t	memory_fini[] = {
+	2,	MOV_A_direct,		0x7f,
+	3,	MOV_direct1_direct2,	SFR_DPL0, 0x7e,
+	3,	MOV_direct1_direct2,	SFR_DPH0, 0x7d,
+	3,	MOV_direct1_direct2,	SFR_DPL1, 0x7c,
+	3,	MOV_direct1_direct2,	SFR_DPH1, 0x7b,
+	0,
+};
+
 uint8_t
 ccdbg_write_memory(struct ccdbg *dbg, uint16_t addr, uint8_t *bytes, int nbytes)
 {
@@ -64,6 +78,7 @@ ccdbg_write_memory(struct ccdbg *dbg, uint16_t addr, uint8_t *bytes, int nbytes)
 			nl = 0;
 		}
 	}
+	(void) ccdbg_execute(dbg, memory_fini);
 	if (nl)
 		ccdbg_debug(CC_DEBUG_MEMORY, "\n");
 	return 0;
@@ -88,6 +103,7 @@ ccdbg_read_memory(struct ccdbg *dbg, uint16_t addr, uint8_t *bytes, int nbytes)
 			nl = 0;
 		}
 	}
+	(void) ccdbg_execute(dbg, memory_fini);
 	if (nl)
 		ccdbg_debug(CC_DEBUG_MEMORY, "\n");
 	return 0;
@@ -118,3 +134,52 @@ ccdbg_read_hex_image(struct ccdbg *dbg, uint16_t address, uint16_t length)
 	ccdbg_read_memory(dbg, address, image->data, length);
 	return image;
 }
+
+static uint8_t sfr_init[] = {
+	2,	MOV_direct_A,		0x7f,
+	0,
+};
+
+static uint8_t sfr_fini[] = {
+	2,	MOV_A_direct,		0x7f,
+	0,
+};
+
+static uint8_t sfr_read[] = {
+	2,	MOV_A_direct,		0,
+#define SFR_READ_ADDR	2
+	0,
+};
+
+static uint8_t sfr_write[] = {
+	3,	MOV_direct_data,	0,	0,
+#define SFR_WRITE_ADDR	2
+#define SFR_WRITE_DATA	3
+	0,
+};
+
+uint8_t
+ccdbg_read_sfr(struct ccdbg *dbg, uint8_t addr, uint8_t *bytes, int nbytes)
+{
+	int	i;
+	(void) ccdbg_execute(dbg, sfr_init);
+	for (i = 0; i < nbytes; i++) {
+		sfr_read[SFR_READ_ADDR] = addr + i;
+		*bytes++ = ccdbg_execute(dbg, sfr_read);
+	}
+	(void) ccdbg_execute(dbg, sfr_fini);
+	return 0;
+}
+
+uint8_t
+ccdbg_write_sfr(struct ccdbg *dbg, uint8_t addr, uint8_t *bytes, int nbytes)
+{
+	int	i;
+	
+	for (i = 0; i < nbytes; i++) {
+		sfr_write[SFR_WRITE_ADDR] = addr + i;
+		sfr_write[SFR_WRITE_DATA] = *bytes++;
+		ccdbg_execute(dbg, sfr_write);
+	}
+	return 0;
+}
diff --git a/lib/ccdbg.h b/lib/ccdbg.h
index 834092b2..203b5aeb 100644
--- a/lib/ccdbg.h
+++ b/lib/ccdbg.h
@@ -44,6 +44,7 @@
 #define MOV_Rn_data(n)		(0x78 | (n))
 #define DJNZ_Rn_rel(n)		(0xd8 | (n))
 #define MOV_A_direct		0xe5
+#define MOV_direct1_direct2	0x85
 #define MOV_direct_A		0xf5
 #define MOV_DPTR_data16		0x90
 #define MOV_A_data		0x74
@@ -57,6 +58,13 @@
 /* 8051 special function registers
  */
 
+#define SFR_P0			0x80
+#define SFR_SP			0x81
+#define SFR_DPL0		0x82
+#define SFR_DPH0		0x83
+#define SFR_DPL1		0x84
+#define SFR_DPH1		0x85
+
 /* flash controller */
 #define FWT			0xAB
 #define FADDRL			0xAC
@@ -323,4 +331,10 @@ ccdbg_write_hex_image(struct ccdbg *dbg, struct hex_image *image, uint16_t offse
 struct hex_image *
 ccdbg_read_hex_image(struct ccdbg *dbg, uint16_t address, uint16_t length);
 
+uint8_t
+ccdbg_read_sfr(struct ccdbg *dbg, uint8_t addr, uint8_t *bytes, int nbytes);
+
+uint8_t
+ccdbg_write_sfr(struct ccdbg *dbg, uint8_t addr, uint8_t *bytes, int nbytes);
+
 #endif /* _CCDBG_H_ */