From 8b89224c6e206dcfa2d8bae10dcfb8251b3cb333 Mon Sep 17 00:00:00 2001
From: zwelch <zwelch@b42882b7-edfa-0310-969c-e2dbd0fdcd60>
Date: Wed, 15 Jul 2009 23:48:11 +0000
Subject: David Brownell <david-b@pacbell.net>:
Make the Thumb2 disassembler handle a bunch of 32-bit instructions:
A5.3.4 Branches and miscellaneous control
Note that this shifts some responsabililty out of helper functions,
making the code and layout simpler for 32-bit decoders: they only
need to know how to format the instruction and its parameters.
Also, technical note: with this patch, Thumb1 decoders could now
call the Thumb2 decoder if they wanted to get nicer treatment of
the exiting 32-bit B/BLX instructions.
git-svn-id: svn://svn.berlios.de/openocd/trunk@2532 b42882b7-edfa-0310-969c-e2dbd0fdcd60
---
src/target/arm_disassembler.c | 267 +++++++++++++++++++++++++++++++++++++++++-
1 file changed, 263 insertions(+), 4 deletions(-)
(limited to 'src/target')
diff --git a/src/target/arm_disassembler.c b/src/target/arm_disassembler.c
index 4d134213..69d5de87 100644
--- a/src/target/arm_disassembler.c
+++ b/src/target/arm_disassembler.c
@@ -2292,6 +2292,247 @@ int thumb_evaluate_opcode(uint16_t opcode, uint32_t address, arm_instruction_t *
return -1;
}
+static int t2ev_b_bl(uint32_t opcode, uint32_t address,
+ arm_instruction_t *instruction, char *cp)
+{
+ unsigned offset;
+ unsigned b21 = 1 << 21;
+ unsigned b22 = 1 << 22;
+
+ /* instead of combining two smaller 16-bit branch instructions,
+ * Thumb2 uses only one larger 32-bit instruction.
+ */
+ offset = opcode & 0x7ff;
+ offset |= (opcode & 0x03ff0000) >> 5;
+ if (opcode & (1 << 26)) {
+ offset |= 0xff << 23;
+ if ((opcode & (1 << 11)) == 0)
+ b21 = 0;
+ if ((opcode & (1 << 13)) == 0)
+ b22 = 0;
+ } else {
+ if (opcode & (1 << 11))
+ b21 = 0;
+ if (opcode & (1 << 13))
+ b22 = 0;
+ }
+ offset |= b21;
+ offset |= b22;
+
+
+ address += 4;
+ address += offset << 1;
+
+ instruction->type = (opcode & (1 << 14)) ? ARM_BL : ARM_B;
+ instruction->info.b_bl_bx_blx.reg_operand = -1;
+ instruction->info.b_bl_bx_blx.target_address = address;
+ sprintf(cp, "%s\t%#8.8" PRIx32,
+ (opcode & (1 << 14)) ? "BL" : "B.W",
+ address);
+
+ return ERROR_OK;
+}
+
+static int t2ev_cond_b(uint32_t opcode, uint32_t address,
+ arm_instruction_t *instruction, char *cp)
+{
+ unsigned offset;
+ unsigned b17 = 1 << 17;
+ unsigned b18 = 1 << 18;
+ unsigned cond = (opcode >> 22) & 0x0f;
+
+ offset = opcode & 0x7ff;
+ offset |= (opcode & 0x003f0000) >> 5;
+ if (opcode & (1 << 26)) {
+ offset |= 0xffff << 19;
+ if ((opcode & (1 << 11)) == 0)
+ b17 = 0;
+ if ((opcode & (1 << 13)) == 0)
+ b18 = 0;
+ } else {
+ if (opcode & (1 << 11))
+ b17 = 0;
+ if (opcode & (1 << 13))
+ b18 = 0;
+ }
+ offset |= b17;
+ offset |= b18;
+
+ address += 4;
+ address += offset << 1;
+
+ instruction->type = ARM_B;
+ instruction->info.b_bl_bx_blx.reg_operand = -1;
+ instruction->info.b_bl_bx_blx.target_address = address;
+ sprintf(cp, "B%s.W\t%#8.8" PRIx32,
+ arm_condition_strings[cond],
+ address);
+
+ return ERROR_OK;
+}
+
+static const char *special_name(int number)
+{
+ char *special = "(RESERVED)";
+
+ switch (number) {
+ case 0:
+ special = "apsr";
+ break;
+ case 1:
+ special = "iapsr";
+ break;
+ case 2:
+ special = "eapsr";
+ break;
+ case 3:
+ special = "xpsr";
+ break;
+ case 5:
+ special = "ipsr";
+ break;
+ case 6:
+ special = "epsr";
+ break;
+ case 7:
+ special = "iepsr";
+ break;
+ case 8:
+ special = "msp";
+ break;
+ case 9:
+ special = "psp";
+ break;
+ case 16:
+ special = "primask";
+ break;
+ case 17:
+ special = "basepri";
+ break;
+ case 18:
+ special = "basepri_max";
+ break;
+ case 19:
+ special = "faultmask";
+ break;
+ case 20:
+ special = "control";
+ break;
+ }
+ return special;
+}
+
+static int t2ev_hint(uint32_t opcode, uint32_t address,
+ arm_instruction_t *instruction, char *cp)
+{
+ const char *mnemonic;
+
+ if (opcode & 0x0700) {
+ instruction->type = ARM_UNDEFINED_INSTRUCTION;
+ strcpy(cp, "UNDEFINED");
+ return ERROR_OK;
+ }
+
+ if (opcode & 0x00f0) {
+ sprintf(cp, "DBG\t#%d", opcode & 0xf);
+ return ERROR_OK;
+ }
+
+ switch (opcode & 0x0f) {
+ case 0:
+ mnemonic = "NOP.W";
+ break;
+ case 1:
+ mnemonic = "YIELD.W";
+ break;
+ case 2:
+ mnemonic = "WFE.W";
+ break;
+ case 3:
+ mnemonic = "WFI.W";
+ break;
+ case 4:
+ mnemonic = "SEV.W";
+ break;
+ default:
+ mnemonic = "HINT.W (UNRECOGNIZED)";
+ break;
+ }
+ strcpy(cp, mnemonic);
+ return ERROR_OK;
+}
+
+static int t2ev_misc(uint32_t opcode, uint32_t address,
+ arm_instruction_t *instruction, char *cp)
+{
+ const char *mnemonic;
+
+ switch ((opcode >> 4) & 0x0f) {
+ case 2:
+ mnemonic = "CLREX";
+ break;
+ case 4:
+ mnemonic = "DSB";
+ break;
+ case 5:
+ mnemonic = "DMB";
+ break;
+ case 6:
+ mnemonic = "ISB";
+ break;
+ default:
+ return ERROR_INVALID_ARGUMENTS;
+ }
+ strcpy(cp, mnemonic);
+ return ERROR_OK;
+}
+
+static int t2ev_b_misc(uint32_t opcode, uint32_t address,
+ arm_instruction_t *instruction, char *cp)
+{
+ /* permanently undefined */
+ if ((opcode & 0x07f07000) == 0x07f02000) {
+ instruction->type = ARM_UNDEFINED_INSTRUCTION;
+ strcpy(cp, "UNDEFINED");
+ return ERROR_OK;
+ }
+
+ switch ((opcode >> 12) & 0x5) {
+ case 0x1:
+ case 0x5:
+ return t2ev_b_bl(opcode, address, instruction, cp);
+ case 0x4:
+ goto undef;
+ case 0:
+ if (((opcode >> 23) & 0x07) == 0x07)
+ return t2ev_cond_b(opcode, address, instruction, cp);
+ if (opcode & (1 << 26))
+ goto undef;
+ break;
+ }
+
+ switch ((opcode >> 20) & 0x7f) {
+ case 0x38:
+ case 0x39:
+ sprintf(cp, "MSR\t%s, r%d", special_name(opcode & 0xff),
+ (opcode >> 16) & 0x0f);
+ return ERROR_OK;
+ case 0x3a:
+ return t2ev_hint(opcode, address, instruction, cp);
+ case 0x3b:
+ return t2ev_misc(opcode, address, instruction, cp);
+ case 0x3e:
+ case 0x3f:
+ sprintf(cp, "MRS\tr%d, %s", (opcode >> 16) & 0x0f,
+ special_name(opcode & 0xff));
+ return ERROR_OK;
+ }
+
+undef:
+ return ERROR_INVALID_ARGUMENTS;
+}
+
+
/*
* REVISIT for Thumb2 instructions, instruction->type and friends aren't
* always set. That means eventual arm_simulate_step() support for Thumb2
@@ -2302,6 +2543,7 @@ int thumb2_opcode(target_t *target, uint32_t address, arm_instruction_t *instruc
int retval;
uint16_t op;
uint32_t opcode;
+ char *cp;
/* clear low bit ... it's set on function pointers */
address &= ~1;
@@ -2332,13 +2574,30 @@ int thumb2_opcode(target_t *target, uint32_t address, arm_instruction_t *instruc
return thumb_evaluate_opcode(op, address, instruction);
}
- /* FIXME decode the 32-bit instructions */
+ snprintf(instruction->text, 128,
+ "0x%8.8" PRIx32 " 0x%8.8" PRIx32 "\t",
+ address, opcode);
+ cp = strchr(instruction->text, 0);
+ retval = ERROR_FAIL;
+
+ /* ARMv7-M: A5.3.4 Branches and miscellaneous control */
+ if ((opcode & 0x18008000) == 0x10008000)
+ retval = t2ev_b_misc(opcode, address, instruction, cp);
+
+ /* FIXME decode more 32-bit instructions */
+
+ if (retval == ERROR_OK)
+ return retval;
+
+ if (retval == ERROR_INVALID_ARGUMENTS) {
+ instruction->type = ARM_UNDEFINED_INSTRUCTION;
+ strcpy(cp, "UNDEFINED OPCODE");
+ return ERROR_OK;
+ }
LOG_DEBUG("Can't decode 32-bit Thumb2 yet (opcode=%08x)", opcode);
- snprintf(instruction->text, 128,
- "0x%8.8" PRIx32 " 0x%8.8x\t... 32-bit Thumb2 ...",
- address, opcode);
+ strcpy(cp, "(32-bit Thumb2 ...)");
return ERROR_OK;
}
--
cgit v1.2.3