[Openocd-svn] r2598 - trunk/src/target

[oharboe at B. <oh...@ma...>]

Author: oharboe
Date: 2009-08-20 09:15:46 +0200 (Thu, 20 Aug 2009)
New Revision: 2598

Modified:
   trunk/src/target/arm_disassembler.c
Log:
David Brownell <da...@pa...>More Thumb2 disassembly:

  ARMv7-M: A5.3.6 Load/store dual or exclusive, table branch

GCC will generate the table branch instructions, usually with inlined
tables that will confuse this disassembler.  LDREX and STREX are not
issued by GCC without inline assembly.

This means all Thumb2 instructions implemented by Cortex-M3 can now
be disassembled.  Cortex-A8 cores support more Thumb2 instructions,
but most of those aren't yet publicly documented.


Modified: trunk/src/target/arm_disassembler.c
===================================================================
--- trunk/src/target/arm_disassembler.c	2009-08-19 08:39:06 UTC (rev 2597)
+++ trunk/src/target/arm_disassembler.c	2009-08-20 07:15:46 UTC (rev 2598)
@@ -3007,6 +3007,133 @@
 	return ERROR_OK;
 }
 
+/* load/store dual or exclusive, table branch */
+static int t2ev_ldrex_strex(uint32_t opcode, uint32_t address,
+		arm_instruction_t *instruction, char *cp)
+{
+	unsigned op1op2 = (opcode >> 20) & 0x3;
+	unsigned op3 = (opcode >> 4) & 0xf;
+	char *mnemonic;
+	unsigned rn = (opcode >> 16) & 0xf;
+	unsigned rt = (opcode >> 12) & 0xf;
+	unsigned rd = (opcode >> 8) & 0xf;
+	unsigned imm = opcode & 0xff;
+	char *p1 = "";
+	char *p2 = "]";
+
+	op1op2 |= (opcode >> 21) & 0xc;
+	switch (op1op2) {
+	case 0:
+		mnemonic = "STREX";
+		goto strex;
+	case 1:
+		mnemonic = "LDREX";
+		goto ldrex;
+	case 2:
+	case 6:
+	case 8:
+	case 10:
+	case 12:
+	case 14:
+		mnemonic = "STRD";
+		goto immediate;
+	case 3:
+	case 7:
+	case 9:
+	case 11:
+	case 13:
+	case 15:
+		mnemonic = "LDRD";
+		if (rn == 15)
+			goto literal;
+		else
+			goto immediate;
+	case 4:
+		switch (op3) {
+		case 4:
+			mnemonic = "STREXB";
+			break;
+		case 5:
+			mnemonic = "STREXH";
+			break;
+		default:
+			return ERROR_INVALID_ARGUMENTS;
+		}
+		rd = opcode & 0xf;
+		imm = 0;
+		goto strex;
+	case 5:
+		switch (op3) {
+		case 0:
+			sprintf(cp, "TBB\t[r%u, r%u]", rn, imm & 0xf);
+			return ERROR_OK;
+		case 1:
+			sprintf(cp, "TBH\t[r%u, r%u, LSL #1]", rn, imm & 0xf);
+			return ERROR_OK;
+		case 4:
+			mnemonic = "LDREXB";
+			break;
+		case 5:
+			mnemonic = "LDREXH";
+			break;
+		default:
+			return ERROR_INVALID_ARGUMENTS;
+		}
+		imm = 0;
+		goto ldrex;
+	}
+	return ERROR_INVALID_ARGUMENTS;
+
+strex:
+	imm <<= 2;
+	if (imm)
+		sprintf(cp, "%s\tr%u, r%u, [r%u, #%u]\t; %#2.2x",
+				mnemonic, rd, rt, rn, imm, imm);
+	else
+		sprintf(cp, "%s\tr%u, r%u, [r%u]",
+				mnemonic, rd, rt, rn);
+	return ERROR_OK;
+
+ldrex:
+	imm <<= 2;
+	if (imm)
+		sprintf(cp, "%s\tr%u, [r%u, #%u]\t; %#2.2x",
+				mnemonic, rt, rn, imm, imm);
+	else
+		sprintf(cp, "%s\tr%u, [r%u]",
+				mnemonic, rt, rn);
+	return ERROR_OK;
+
+immediate:
+	/* two indexed modes will write back rn */
+	if (opcode & (1 << 21)) {
+		if (opcode & (1 << 24))	/* pre-indexed */
+			p2 = "]!";
+		else {			/* post-indexed */
+			p1 = "]";
+			p2 = "";
+		}
+	}
+
+	imm <<= 2;
+	sprintf(cp, "%s\tr%u, r%u, [r%u%s, #%s%u%s\t; %#2.2x",
+			mnemonic, rt, rd, rn, p1,
+			(opcode & (1 << 23)) ? "" : "-",
+			imm, p2, imm);
+	return ERROR_OK;
+
+literal:
+	address = thumb_alignpc4(address);
+	imm <<= 2;
+	if (opcode & (1 << 23))
+		address += imm;
+	else
+		address -= imm;
+	sprintf(cp, "%s\tr%u, r%u, %#8.8" PRIx32,
+			mnemonic, rt, rd, address);
+	return ERROR_OK;
+}
+
 static int t2ev_data_shift(uint32_t opcode, uint32_t address,
 		arm_instruction_t *instruction, char *cp)
 {
@@ -3677,6 +3804,10 @@
 	else if ((opcode & 0x1e400000) == 0x08000000)
 		retval = t2ev_ldm_stm(opcode, address, instruction, cp);
 
+	/* ARMv7-M: A5.3.6 Load/store dual or exclusive, table branch */
+	else if ((opcode & 0x1e400000) == 0x08400000)
+		retval = t2ev_ldrex_strex(opcode, address, instruction, cp);
+
 	/* ARMv7-M: A5.3.7 Load word */
 	else if ((opcode & 0x1f700000) == 0x18500000)
 		retval = t2ev_load_word(opcode, address, instruction, cp);
@@ -3711,11 +3842,14 @@
 	else if ((opcode & 0x1f800000) == 0x1b800000)
 		retval = t2ev_mul64_div(opcode, address, instruction, cp);
 
-	/* FIXME decode more 32-bit instructions */
-
 	if (retval == ERROR_OK)
 		return retval;
 
+	/*
+	 * Thumb2 also supports coprocessor, ThumbEE, and DSP/Media (SIMD)
+	 * instructions; not yet handled here.
+	 */
+
 	if (retval == ERROR_INVALID_ARGUMENTS) {
 		instruction->type = ARM_UNDEFINED_INSTRUCTION;
 		strcpy(cp, "UNDEFINED OPCODE");