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ARM: disassemble two more v6+ instructions 

The SRS and RFE instructions speed exception entry/exit by
making it easy to save and restore PC and SPSR.  This handles
both ARM and Thumb2 encodings.

Fix minor PLD goofage; that "should never reach this point"
can't happen, so remove it.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
This commit is contained in:
David Brownell 2009-12-07 14:46:29 -08:00
parent efb93efd6f
commit 7936ab16da
1 changed files with 71 additions and 12 deletions
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83
src/target/arm_disassembler.c
View File

@ -106,6 +106,16 @@ static uint32_t ror(uint32_t value, int places)
return (value >> places) | (value << (32 - places));
}
static int evaluate_unknown(uint32_t opcode,
uint32_t address, struct arm_instruction *instruction)
{
instruction->type = ARM_UNDEFINED_INSTRUCTION;
snprintf(instruction->text, 128,
"0x%8.8" PRIx32 "\t0x%8.8" PRIx32
"\tUNDEFINED INSTRUCTION", address, opcode);
return ERROR_OK;
}
static int evaluate_pld(uint32_t opcode,
uint32_t address, struct arm_instruction *instruction)
{
@ -118,14 +128,50 @@ static int evaluate_pld(uint32_t opcode,
return ERROR_OK;
}
else
{
instruction->type = ARM_UNDEFINED_INSTRUCTION;
return ERROR_OK;
return evaluate_unknown(opcode, address, instruction);
}
static int evaluate_srs(uint32_t opcode,
uint32_t address, struct arm_instruction *instruction)
{
const char *wback = (opcode & (1 << 21)) ? "!" : "";
const char *mode;
switch ((opcode >> 23) & 0x3) {
case 0:
mode = "DA";
break;
case 1:
/* "IA" is default */
mode = "";
break;
case 2:
mode = "DB";
break;
case 3:
mode = "IB";
break;
}
LOG_ERROR("should never reach this point");
return -1;
switch (opcode & 0x0e500000) {
case 0x08400000:
snprintf(instruction->text, 128, "0x%8.8" PRIx32
"\t0x%8.8" PRIx32
"\tSRS%s\tSP%s, #%d",
address, opcode,
mode, wback, opcode & 0x1f);
break;
case 0x08100000:
snprintf(instruction->text, 128, "0x%8.8" PRIx32
"\t0x%8.8" PRIx32
"\tRFE%s\tr%d%s",
address, opcode,
mode, (opcode >> 16) & 0xf, wback);
break;
default:
return evaluate_unknown(opcode, address, instruction);
}
return ERROR_OK;
}
static int evaluate_swi(uint32_t opcode,
@ -1605,13 +1651,9 @@ int arm_evaluate_opcode(uint32_t opcode, uint32_t address, struct arm_instructio
if ((opcode & 0x08000000) == 0x00000000)
return evaluate_pld(opcode, address, instruction);
/* Undefined instruction */
/* Undefined instruction (or ARMv6+ SRS/RFE) */
if ((opcode & 0x0e000000) == 0x08000000)
{
instruction->type = ARM_UNDEFINED_INSTRUCTION;
snprintf(instruction->text, 128, "0x%8.8" PRIx32 "\t0x%8.8" PRIx32 "\tUNDEFINED INSTRUCTION", address, opcode);
return ERROR_OK;
}
return evaluate_srs(opcode, address, instruction);
/* Branch and branch with link and change to Thumb */
if ((opcode & 0x0e000000) == 0x0a000000)
@ -3414,11 +3456,28 @@ static int t2ev_ldm_stm(uint32_t opcode, uint32_t address,
int op = (opcode >> 22) & 0x6;
int t = (opcode >> 21) & 1;
unsigned registers = opcode & 0xffff;
char *mode = "";
if (opcode & (1 << 20))
op |= 1;
switch (op) {
case 0:
mode = "DB";
/* FALL THROUGH */
case 6:
sprintf(cp, "SRS%s\tsp%s, #%d", mode,
t ? "!" : "",
opcode & 0x1f);
return ERROR_OK;
case 1:
mode = "DB";
/* FALL THROUGH */
case 7:
sprintf(cp, "RFE%s\tr%d%s", mode,
(opcode >> 16) & 0xf,
t ? "!" : "");
return ERROR_OK;
case 2:
sprintf(cp, "STM.W\tr%d%s, ", rn, t ? "!" : "");
break;