Thumb32 form branch disassembly.
Change-Id: I3a1af9164047b2d4ee1e215909e287be05a38bde
diff --git a/src/disassembler_arm.cc b/src/disassembler_arm.cc
index ae090a1..9a5ca75 100644
--- a/src/disassembler_arm.cc
+++ b/src/disassembler_arm.cc
@@ -708,8 +708,47 @@
}
break;
case 2:
- case 1: case 3:
+ if ((op2 & 0x38) == 0x38) {
+ if (op2 == 0x7F) {
+ opcode << "udf";
+ }
+ break;
+ }
+ // Else deliberate fall-through to B.
+ case 1: case 3: {
+ // B
+ // |111|11|1|0000|000000|11|1 |1|1 |10000000000|
+ // |5 3|21|0|9876|543 0|54|3 |2|1 |0 5 0|
+ // |---|--|-|----|------|--|--|-|--|-----------|
+ // |332|22|2|2222|221111|11|1 |1|1 |10000000000|
+ // |1 9|87|6|5 2|10 6|54|3 |2|1 |0 5 0|
+ // |---|--|-|----|------|--|--|-|--|-----------|
+ // |111|10|S|cond| imm6 |10|J1|0|J2| imm11 |
+ // |111|10|S| imm10 |10|J1|1|J2| imm11 |
+ uint32_t S = (instr >> 26) & 1;
+ uint32_t cond = (instr >> 22) & 0xF;
+ uint32_t J2 = (instr >> 11) & 1;
+ uint32_t form = (instr >> 12) & 1;
+ uint32_t J1 = (instr >> 13) & 1;
+ uint32_t imm10 = (instr >> 16) & 0x3FF;
+ uint32_t imm6 = (instr >> 16) & 0x3F;
+ uint32_t imm11 = instr & 0x7FF;
+ opcode << "b";
+ int32_t imm32;
+ if (form == 0) {
+ DumpCond(opcode, cond);
+ imm32 = (S << 20) | (J2 << 19) | (J1 << 18) | (imm6 << 12) | (imm11 << 1);
+ imm32 = (imm32 << 11) >> 11; // sign extend 21 bit immediate.
+ } else {
+ uint32_t I1 = ~(J1 ^ S);
+ uint32_t I2 = ~(J2 ^ S);
+ imm32 = (S << 24) | (I1 << 23) | (I2 << 22) | (imm10 << 12) | (imm11 << 1);
+ imm32 = (imm32 << 8) >> 8; // sign extend 24 bit immediate.
+ }
+ opcode << ".w";
+ DumpBranchTarget(args, instr_ptr + 4, imm32);
break;
+ }
case 4: case 6: case 5: case 7: {
// BL, BLX (immediate)
// |111|11|1|0000000000|11|1 |1|1 |10000000000|
