auto import from //depot/cupcake/@135843
diff --git a/emulator/qtools/armdis.cpp b/emulator/qtools/armdis.cpp
new file mode 100644
index 0000000..593f460
--- /dev/null
+++ b/emulator/qtools/armdis.cpp
@@ -0,0 +1,905 @@
+// Copyright 2006 The Android Open Source Project
+
+#include <stdio.h>
+#include <string.h>
+#include "armdis.h"
+#include "opcode.h"
+
+static char *cond_names[] = {
+    "eq",
+    "ne",
+    "cs",
+    "cc",
+    "mi",
+    "pl",
+    "vs",
+    "vc",
+    "hi",
+    "ls",
+    "ge",
+    "lt",
+    "gt",
+    "le",
+    "",
+    "RESERVED"
+};
+
+// Indexed by the shift type (bits 6-5)
+static const char *shift_names[] = {
+    "LSL",
+    "LSR",
+    "ASR",
+    "ROR"
+};
+
+static char* cond_to_str(int cond) {
+    return cond_names[cond];
+}
+
+char *Arm::disasm(uint32_t addr, uint32_t insn, char *result)
+{
+    static char   buf[80];
+    char          *ptr;
+
+    ptr = result ? result : buf;
+    Opcode opcode = decode(insn);
+    switch (opcode) {
+        case OP_INVALID:
+            sprintf(ptr, "Invalid");
+            return ptr;
+        case OP_UNDEFINED:
+            sprintf(ptr, "Undefined");
+            return ptr;
+        case OP_ADC:
+        case OP_ADD:
+        case OP_AND:
+        case OP_BIC:
+        case OP_CMN:
+        case OP_CMP:
+        case OP_EOR:
+        case OP_MOV:
+        case OP_MVN:
+        case OP_ORR:
+        case OP_RSB:
+        case OP_RSC:
+        case OP_SBC:
+        case OP_SUB:
+        case OP_TEQ:
+        case OP_TST:
+            return disasm_alu(opcode, insn, ptr);
+        case OP_B:
+        case OP_BL:
+            return disasm_branch(addr, opcode, insn, ptr);
+        case OP_BKPT:
+            return disasm_bkpt(insn, ptr);
+        case OP_BLX:
+            // not supported yet
+            break;
+        case OP_BX:
+            return disasm_bx(insn, ptr);
+        case OP_CDP:
+            sprintf(ptr, "cdp");
+            return ptr;
+        case OP_CLZ:
+            return disasm_clz(insn, ptr);
+        case OP_LDC:
+            sprintf(ptr, "ldc");
+            return ptr;
+        case OP_LDM:
+        case OP_STM:
+            return disasm_memblock(opcode, insn, ptr);
+        case OP_LDR:
+        case OP_LDRB:
+        case OP_LDRBT:
+        case OP_LDRT:
+        case OP_STR:
+        case OP_STRB:
+        case OP_STRBT:
+        case OP_STRT:
+            return disasm_mem(insn, ptr);
+        case OP_LDRH:
+        case OP_LDRSB:
+        case OP_LDRSH:
+        case OP_STRH:
+            return disasm_memhalf(insn, ptr);
+        case OP_MCR:
+        case OP_MRC:
+            return disasm_mcr(opcode, insn, ptr);
+        case OP_MLA:
+            return disasm_mla(opcode, insn, ptr);
+        case OP_MRS:
+            return disasm_mrs(insn, ptr);
+        case OP_MSR:
+            return disasm_msr(insn, ptr);
+        case OP_MUL:
+            return disasm_mul(opcode, insn, ptr);
+        case OP_PLD:
+            return disasm_pld(insn, ptr);
+        case OP_STC:
+            sprintf(ptr, "stc");
+            return ptr;
+        case OP_SWI:
+            return disasm_swi(insn, ptr);
+        case OP_SWP:
+        case OP_SWPB:
+            return disasm_swp(opcode, insn, ptr);
+        case OP_UMLAL:
+        case OP_UMULL:
+        case OP_SMLAL:
+        case OP_SMULL:
+            return disasm_umlal(opcode, insn, ptr);
+        default:
+            sprintf(ptr, "Error");
+            return ptr;
+    }
+    return NULL;
+}
+
+char *Arm::disasm_alu(Opcode opcode, uint32_t insn, char *ptr)
+{
+    static const uint8_t kNoOperand1 = 1;
+    static const uint8_t kNoDest = 2;
+    static const uint8_t kNoSbit = 4;
+
+    char rn_str[20];
+    char rd_str[20];
+    uint8_t flags = 0;
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t is_immed = (insn >> 25) & 0x1;
+    uint8_t bit_s = (insn >> 20) & 1;
+    uint8_t rn = (insn >> 16) & 0xf;
+    uint8_t rd = (insn >> 12) & 0xf;
+    uint8_t immed = insn & 0xff;
+
+    const char *opname = opcode_names[opcode];
+    switch (opcode) {
+        case OP_CMN:
+        case OP_CMP:
+        case OP_TEQ:
+        case OP_TST:
+            flags = kNoDest | kNoSbit;
+            break;
+        case OP_MOV:
+        case OP_MVN:
+            flags = kNoOperand1;
+            break;
+        default:
+            break;
+    }
+
+    // The "mov" instruction ignores the first operand (rn).
+    rn_str[0] = 0;
+    if ((flags & kNoOperand1) == 0) {
+        sprintf(rn_str, "r%d, ", rn);
+    }
+
+    // The following instructions do not write the result register (rd):
+    // tst, teq, cmp, cmn.
+    rd_str[0] = 0;
+    if ((flags & kNoDest) == 0) {
+        sprintf(rd_str, "r%d, ", rd);
+    }
+
+    char *sbit_str = "";
+    if (bit_s && !(flags & kNoSbit))
+        sbit_str = "s";
+
+    if (is_immed) {
+        sprintf(ptr, "%s%s%s\t%s%s#%u  ; 0x%x",
+                opname, cond_to_str(cond), sbit_str, rd_str, rn_str, immed, immed);
+        return ptr;
+    }
+
+    uint8_t shift_is_reg = (insn >> 4) & 1;
+    uint8_t rotate = (insn >> 8) & 0xf;
+    uint8_t rm = insn & 0xf;
+    uint8_t shift_type = (insn >> 5) & 0x3;
+    uint8_t rs = (insn >> 8) & 0xf;
+    uint8_t shift_amount = (insn >> 7) & 0x1f;
+    uint32_t rotated_val = immed;
+    uint8_t rotate2 = rotate << 1;
+    rotated_val = (rotated_val >> rotate2) | (rotated_val << (32 - rotate2));
+
+    if (!shift_is_reg && shift_type == 0 && shift_amount == 0) {
+        sprintf(ptr, "%s%s%s\t%s%sr%d",
+                opname, cond_to_str(cond), sbit_str, rd_str, rn_str, rm);
+        return ptr;
+    }
+
+    const char *shift_name = shift_names[shift_type];
+    if (shift_is_reg) {
+        sprintf(ptr, "%s%s%s\t%s%sr%d, %s r%d",
+                opname, cond_to_str(cond), sbit_str, rd_str, rn_str, rm,
+                shift_name, rs);
+        return ptr;
+    }
+    if (shift_amount == 0) {
+        if (shift_type == 3) {
+            sprintf(ptr, "%s%s%s\t%s%sr%d, RRX",
+                    opname, cond_to_str(cond), sbit_str, rd_str, rn_str, rm);
+            return ptr;
+        }
+        shift_amount = 32;
+    }
+    sprintf(ptr, "%s%s%s\t%s%sr%d, %s #%u",
+            opname, cond_to_str(cond), sbit_str, rd_str, rn_str, rm,
+            shift_name, shift_amount);
+    return ptr;
+}
+
+char *Arm::disasm_branch(uint32_t addr, Opcode opcode, uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint32_t offset = insn & 0xffffff;
+    // Sign-extend the 24-bit offset
+    if ((offset >> 23) & 1)
+        offset |= 0xff000000;
+
+    // Pre-compute the left-shift and the prefetch offset
+    offset <<= 2;
+    offset += 8;
+    addr += offset;
+    const char *opname = opcode_names[opcode];
+    sprintf(ptr, "%s%s\t0x%x", opname, cond_to_str(cond), addr);
+    return ptr;
+}
+
+char *Arm::disasm_bx(uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t rn = insn & 0xf;
+    sprintf(ptr, "bx%s\tr%d", cond_to_str(cond), rn);
+    return ptr;
+}
+
+char *Arm::disasm_bkpt(uint32_t insn, char *ptr)
+{
+    uint32_t immed = (((insn >> 8) & 0xfff) << 4) | (insn & 0xf);
+    sprintf(ptr, "bkpt\t#%d", immed);
+    return ptr;
+}
+
+char *Arm::disasm_clz(uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t rd = (insn >> 12) & 0xf;
+    uint8_t rm = insn & 0xf;
+    sprintf(ptr, "clz%s\tr%d, r%d", cond_to_str(cond), rd, rm);
+    return ptr;
+}
+
+char *Arm::disasm_memblock(Opcode opcode, uint32_t insn, char *ptr)
+{
+    char tmp_reg[10], tmp_list[80];
+
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t write_back = (insn >> 21) & 0x1;
+    uint8_t bit_s = (insn >> 22) & 0x1;
+    uint8_t is_up = (insn >> 23) & 0x1;
+    uint8_t is_pre = (insn >> 24) & 0x1;
+    uint8_t rn = (insn >> 16) & 0xf;
+    uint16_t reg_list = insn & 0xffff;
+
+    const char *opname = opcode_names[opcode];
+
+    char *bang = "";
+    if (write_back)
+        bang = "!";
+
+    char *carret = "";
+    if (bit_s)
+        carret = "^";
+
+    char *comma = "";
+    tmp_list[0] = 0;
+    for (int ii = 0; ii < 16; ++ii) {
+        if (reg_list & (1 << ii)) {
+            sprintf(tmp_reg, "%sr%d", comma, ii);
+            strcat(tmp_list, tmp_reg);
+            comma = ",";
+        }
+    }
+
+    char *addr_mode = "";
+    if (is_pre) {
+        if (is_up) {
+            addr_mode = "ib";
+        } else {
+            addr_mode = "db";
+        }
+    } else {
+        if (is_up) {
+            addr_mode = "ia";
+        } else {
+            addr_mode = "da";
+        }
+    }
+
+    sprintf(ptr, "%s%s%s\tr%d%s, {%s}%s",
+            opname, cond_to_str(cond), addr_mode, rn, bang, tmp_list, carret);
+    return ptr;
+}
+
+char *Arm::disasm_mem(uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t is_reg = (insn >> 25) & 0x1;
+    uint8_t is_load = (insn >> 20) & 0x1;
+    uint8_t write_back = (insn >> 21) & 0x1;
+    uint8_t is_byte = (insn >> 22) & 0x1;
+    uint8_t is_up = (insn >> 23) & 0x1;
+    uint8_t is_pre = (insn >> 24) & 0x1;
+    uint8_t rn = (insn >> 16) & 0xf;
+    uint8_t rd = (insn >> 12) & 0xf;
+    uint16_t offset = insn & 0xfff;
+
+    char *opname = "ldr";
+    if (!is_load)
+        opname = "str";
+
+    char *bang = "";
+    if (write_back)
+        bang = "!";
+
+    char *minus = "";
+    if (is_up == 0)
+        minus = "-";
+
+    char *byte = "";
+    if (is_byte)
+        byte = "b";
+
+    if (is_reg == 0) {
+        if (is_pre) {
+            if (offset == 0) {
+                sprintf(ptr, "%s%s%s\tr%d, [r%d]",
+                        opname, cond_to_str(cond), byte, rd, rn);
+            } else {
+                sprintf(ptr, "%s%s%s\tr%d, [r%d, #%s%u]%s",
+                        opname, cond_to_str(cond), byte, rd, rn, minus, offset, bang);
+            }
+        } else {
+            char *transfer = "";
+            if (write_back)
+                transfer = "t";
+            sprintf(ptr, "%s%s%s%s\tr%d, [r%d], #%s%u",
+                    opname, cond_to_str(cond), byte, transfer, rd, rn, minus, offset);
+        }
+        return ptr;
+    }
+
+    uint8_t rm = insn & 0xf;
+    uint8_t shift_type = (insn >> 5) & 0x3;
+    uint8_t shift_amount = (insn >> 7) & 0x1f;
+
+    const char *shift_name = shift_names[shift_type];
+
+    if (is_pre) {
+        if (shift_amount == 0) {
+            if (shift_type == 0) {
+                sprintf(ptr, "%s%s%s\tr%d, [r%d, %sr%d]%s",
+                        opname, cond_to_str(cond), byte, rd, rn, minus, rm, bang);
+                return ptr;
+            }
+            if (shift_type == 3) {
+                sprintf(ptr, "%s%s%s\tr%d, [r%d, %sr%d, RRX]%s",
+                        opname, cond_to_str(cond), byte, rd, rn, minus, rm, bang);
+                return ptr;
+            }
+            shift_amount = 32;
+        }
+        sprintf(ptr, "%s%s%s\tr%d, [r%d, %sr%d, %s #%u]%s",
+                opname, cond_to_str(cond), byte, rd, rn, minus, rm,
+                shift_name, shift_amount, bang);
+        return ptr;
+    }
+
+    char *transfer = "";
+    if (write_back)
+        transfer = "t";
+
+    if (shift_amount == 0) {
+        if (shift_type == 0) {
+            sprintf(ptr, "%s%s%s%s\tr%d, [r%d], %sr%d",
+                    opname, cond_to_str(cond), byte, transfer, rd, rn, minus, rm);
+            return ptr;
+        }
+        if (shift_type == 3) {
+            sprintf(ptr, "%s%s%s%s\tr%d, [r%d], %sr%d, RRX",
+                    opname, cond_to_str(cond), byte, transfer, rd, rn, minus, rm);
+            return ptr;
+        }
+        shift_amount = 32;
+    }
+
+    sprintf(ptr, "%s%s%s%s\tr%d, [r%d], %sr%d, %s #%u",
+            opname, cond_to_str(cond), byte, transfer, rd, rn, minus, rm,
+            shift_name, shift_amount);
+    return ptr;
+}
+
+char *Arm::disasm_memhalf(uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t is_load = (insn >> 20) & 0x1;
+    uint8_t write_back = (insn >> 21) & 0x1;
+    uint8_t is_immed = (insn >> 22) & 0x1;
+    uint8_t is_up = (insn >> 23) & 0x1;
+    uint8_t is_pre = (insn >> 24) & 0x1;
+    uint8_t rn = (insn >> 16) & 0xf;
+    uint8_t rd = (insn >> 12) & 0xf;
+    uint8_t bits_65 = (insn >> 5) & 0x3;
+    uint8_t rm = insn & 0xf;
+    uint8_t offset = (((insn >> 8) & 0xf) << 4) | (insn & 0xf);
+
+    char *opname = "ldr";
+    if (is_load == 0)
+        opname = "str";
+
+    char *width = "";
+    if (bits_65 == 1)
+        width = "h";
+    else if (bits_65 == 2)
+        width = "sb";
+    else
+        width = "sh";
+
+    char *bang = "";
+    if (write_back)
+        bang = "!";
+    char *minus = "";
+    if (is_up == 0)
+        minus = "-";
+
+    if (is_immed) {
+        if (is_pre) {
+            if (offset == 0) {
+                sprintf(ptr, "%s%sh\tr%d, [r%d]", opname, cond_to_str(cond), rd, rn);
+            } else {
+                sprintf(ptr, "%s%sh\tr%d, [r%d, #%s%u]%s",
+                        opname, cond_to_str(cond), rd, rn, minus, offset, bang);
+            }
+        } else {
+            sprintf(ptr, "%s%sh\tr%d, [r%d], #%s%u",
+                    opname, cond_to_str(cond), rd, rn, minus, offset);
+        }
+        return ptr;
+    }
+
+    if (is_pre) {
+        sprintf(ptr, "%s%sh\tr%d, [r%d, %sr%d]%s",
+                opname, cond_to_str(cond), rd, rn, minus, rm, bang);
+    } else {
+        sprintf(ptr, "%s%sh\tr%d, [r%d], %sr%d",
+                opname, cond_to_str(cond), rd, rn, minus, rm);
+    }
+    return ptr;
+}
+
+char *Arm::disasm_mcr(Opcode opcode, uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t crn = (insn >> 16) & 0xf;
+    uint8_t crd = (insn >> 12) & 0xf;
+    uint8_t cpnum = (insn >> 8) & 0xf;
+    uint8_t opcode2 = (insn >> 5) & 0x7;
+    uint8_t crm = insn & 0xf;
+
+    const char *opname = opcode_names[opcode];
+    sprintf(ptr, "%s%s\t%d, 0, r%d, cr%d, cr%d, {%d}",
+            opname, cond_to_str(cond), cpnum, crd, crn, crm, opcode2);
+    return ptr;
+}
+
+char *Arm::disasm_mla(Opcode opcode, uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t rd = (insn >> 16) & 0xf;
+    uint8_t rn = (insn >> 12) & 0xf;
+    uint8_t rs = (insn >> 8) & 0xf;
+    uint8_t rm = insn & 0xf;
+    uint8_t bit_s = (insn >> 20) & 1;
+
+    const char *opname = opcode_names[opcode];
+    sprintf(ptr, "%s%s%s\tr%d, r%d, r%d, r%d",
+            opname, cond_to_str(cond), bit_s ? "s" : "", rd, rm, rs, rn);
+    return ptr;
+}
+
+char *Arm::disasm_umlal(Opcode opcode, uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t rdhi = (insn >> 16) & 0xf;
+    uint8_t rdlo = (insn >> 12) & 0xf;
+    uint8_t rs = (insn >> 8) & 0xf;
+    uint8_t rm = insn & 0xf;
+    uint8_t bit_s = (insn >> 20) & 1;
+
+    const char *opname = opcode_names[opcode];
+    sprintf(ptr, "%s%s%s\tr%d, r%d, r%d, r%d",
+            opname, cond_to_str(cond), bit_s ? "s" : "", rdlo, rdhi, rm, rs);
+    return ptr;
+}
+
+char *Arm::disasm_mul(Opcode opcode, uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t rd = (insn >> 16) & 0xf;
+    uint8_t rs = (insn >> 8) & 0xf;
+    uint8_t rm = insn & 0xf;
+    uint8_t bit_s = (insn >> 20) & 1;
+
+    const char *opname = opcode_names[opcode];
+    sprintf(ptr, "%s%s%s\tr%d, r%d, r%d",
+            opname, cond_to_str(cond), bit_s ? "s" : "", rd, rm, rs);
+    return ptr;
+}
+
+char *Arm::disasm_mrs(uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t rd = (insn >> 12) & 0xf;
+    uint8_t ps = (insn >> 22) & 1;
+
+    sprintf(ptr, "mrs%s\tr%d, %s", cond_to_str(cond), rd, ps ? "spsr" : "cpsr");
+    return ptr;
+}
+
+char *Arm::disasm_msr(uint32_t insn, char *ptr)
+{
+    char flags[8];
+    int flag_index = 0;
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t is_immed = (insn >> 25) & 0x1;
+    uint8_t pd = (insn >> 22) & 1;
+    uint8_t mask = (insn >> 16) & 0xf;
+
+    if (mask & 1)
+        flags[flag_index++] = 'c';
+    if (mask & 2)
+        flags[flag_index++] = 'x';
+    if (mask & 4)
+        flags[flag_index++] = 's';
+    if (mask & 8)
+        flags[flag_index++] = 'f';
+    flags[flag_index] = 0;
+
+    if (is_immed) {
+        uint32_t immed = insn & 0xff;
+        uint8_t rotate = (insn >> 8) & 0xf;
+        uint8_t rotate2 = rotate << 1;
+        uint32_t rotated_val = (immed >> rotate2) | (immed << (32 - rotate2));
+        sprintf(ptr, "msr%s\t%s_%s, #0x%x",
+                cond_to_str(cond), pd ? "spsr" : "cpsr", flags, rotated_val);
+        return ptr;
+    }
+
+    uint8_t rm = insn & 0xf;
+
+    sprintf(ptr, "msr%s\t%s_%s, r%d",
+            cond_to_str(cond), pd ? "spsr" : "cpsr", flags, rm);
+    return ptr;
+}
+
+char *Arm::disasm_pld(uint32_t insn, char *ptr)
+{
+    uint8_t is_reg = (insn >> 25) & 0x1;
+    uint8_t is_up = (insn >> 23) & 0x1;
+    uint8_t rn = (insn >> 16) & 0xf;
+
+    char *minus = "";
+    if (is_up == 0)
+        minus = "-";
+
+    if (is_reg) {
+        uint8_t rm = insn & 0xf;
+        sprintf(ptr, "pld\t[r%d, %sr%d]", rn, minus, rm);
+        return ptr;
+    }
+
+    uint16_t offset = insn & 0xfff;
+    if (offset == 0) {
+        sprintf(ptr, "pld\t[r%d]", rn);
+    } else {
+        sprintf(ptr, "pld\t[r%d, #%s%u]", rn, minus, offset);
+    }
+    return ptr;
+}
+
+char *Arm::disasm_swi(uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint32_t sysnum = insn & 0x00ffffff;
+
+    sprintf(ptr, "swi%s 0x%x", cond_to_str(cond), sysnum);
+    return ptr;
+}
+
+char *Arm::disasm_swp(Opcode opcode, uint32_t insn, char *ptr)
+{
+    uint8_t cond = (insn >> 28) & 0xf;
+    uint8_t rn = (insn >> 16) & 0xf;
+    uint8_t rd = (insn >> 12) & 0xf;
+    uint8_t rm = insn & 0xf;
+
+    const char *opname = opcode_names[opcode];
+    sprintf(ptr, "%s%s\tr%d, r%d, [r%d]", opname, cond_to_str(cond), rd, rm, rn);
+    return ptr;
+}
+
+Opcode Arm::decode(uint32_t insn) {
+    uint32_t bits27_26 = (insn >> 26) & 0x3;
+    switch (bits27_26) {
+        case 0x0:
+            return decode00(insn);
+        case 0x1:
+            return decode01(insn);
+        case 0x2:
+            return decode10(insn);
+        case 0x3:
+            return decode11(insn);
+    }
+    return OP_INVALID;
+}
+
+Opcode Arm::decode00(uint32_t insn) {
+    uint8_t bit25 = (insn >> 25) & 0x1;
+    uint8_t bit4 = (insn >> 4) & 0x1;
+    if (bit25 == 0 && bit4 == 1) {
+        if ((insn & 0x0ffffff0) == 0x012fff10) {
+            // Bx instruction
+            return OP_BX;
+        }
+        if ((insn & 0x0ff000f0) == 0x01600010) {
+            // Clz instruction
+            return OP_CLZ;
+        }
+        if ((insn & 0xfff000f0) == 0xe1200070) {
+            // Bkpt instruction
+            return OP_BKPT;
+        }
+        uint32_t bits7_4 = (insn >> 4) & 0xf;
+        if (bits7_4 == 0x9) {
+            if ((insn & 0x0ff00ff0) == 0x01000090) {
+                // Swp instruction
+                uint8_t bit22 = (insn >> 22) & 0x1;
+                if (bit22)
+                    return OP_SWPB;
+                return OP_SWP;
+            }
+            // One of the multiply instructions
+            return decode_mul(insn);
+        }
+
+        uint8_t bit7 = (insn >> 7) & 0x1;
+        if (bit7 == 1) {
+            // One of the load/store halfword/byte instructions
+            return decode_ldrh(insn);
+        }
+    }
+
+    // One of the data processing instructions
+    return decode_alu(insn);
+}
+
+Opcode Arm::decode01(uint32_t insn) {
+    uint8_t is_reg = (insn >> 25) & 0x1;
+    uint8_t bit4 = (insn >> 4) & 0x1;
+    if (is_reg == 1 && bit4 == 1)
+        return OP_UNDEFINED;
+    uint8_t is_load = (insn >> 20) & 0x1;
+    uint8_t is_byte = (insn >> 22) & 0x1;
+    if ((insn & 0xfd70f000) == 0xf550f000) {
+        // Pre-load
+        return OP_PLD;
+    }
+    if (is_load) {
+        if (is_byte) {
+            // Load byte
+            return OP_LDRB;
+        }
+        // Load word
+        return OP_LDR;
+    }
+    if (is_byte) {
+        // Store byte
+        return OP_STRB;
+    }
+    // Store word
+    return OP_STR;
+}
+
+Opcode Arm::decode10(uint32_t insn) {
+    uint8_t bit25 = (insn >> 25) & 0x1;
+    if (bit25 == 0) {
+        // LDM/STM
+        uint8_t is_load = (insn >> 20) & 0x1;
+        if (is_load)
+            return OP_LDM;
+        return OP_STM;
+    }
+    // Branch or Branch with link
+    uint8_t is_link = (insn >> 24) & 1;
+    uint32_t offset = insn & 0xffffff;
+
+    // Sign-extend the 24-bit offset
+    if ((offset >> 23) & 1)
+        offset |= 0xff000000;
+
+    // Pre-compute the left-shift and the prefetch offset
+    offset <<= 2;
+    offset += 8;
+    if (is_link == 0)
+        return OP_B;
+    return OP_BL;
+}
+
+Opcode Arm::decode11(uint32_t insn) {
+    uint8_t bit25 = (insn >> 25) & 0x1;
+    if (bit25 == 0) {
+        // LDC, SDC
+        uint8_t is_load = (insn >> 20) & 0x1;
+        if (is_load) {
+            // LDC
+            return OP_LDC;
+        }
+        // STC
+        return OP_STC;
+    }
+
+    uint8_t bit24 = (insn >> 24) & 0x1;
+    if (bit24 == 0x1) {
+        // SWI
+        return OP_SWI;
+    }
+  
+    uint8_t bit4 = (insn >> 4) & 0x1;
+    uint8_t cpnum = (insn >> 8) & 0xf;
+
+    if (cpnum == 15) {
+        // Special case for coprocessor 15
+        uint8_t opcode = (insn >> 21) & 0x7;
+        if (bit4 == 0 || opcode != 0) {
+            // This is an unexpected bit pattern.  Create an undefined
+            // instruction in case this is ever executed.
+            return OP_UNDEFINED;
+        }
+
+        // MRC, MCR
+        uint8_t is_mrc = (insn >> 20) & 0x1;
+        if (is_mrc)
+            return OP_MRC;
+        return OP_MCR;
+    }
+
+    if (bit4 == 0) {
+        // CDP
+        return OP_CDP;
+    }
+    // MRC, MCR
+    uint8_t is_mrc = (insn >> 20) & 0x1;
+    if (is_mrc)
+        return OP_MRC;
+    return OP_MCR;
+}
+
+Opcode Arm::decode_mul(uint32_t insn) {
+    uint8_t bit24 = (insn >> 24) & 0x1;
+    if (bit24 != 0) {
+        // This is an unexpected bit pattern.  Create an undefined
+        // instruction in case this is ever executed.
+        return OP_UNDEFINED;
+    }
+    uint8_t bit23 = (insn >> 23) & 0x1;
+    uint8_t bit22_U = (insn >> 22) & 0x1;
+    uint8_t bit21_A = (insn >> 21) & 0x1;
+    if (bit23 == 0) {
+        // 32-bit multiply
+        if (bit22_U != 0) {
+            // This is an unexpected bit pattern.  Create an undefined
+            // instruction in case this is ever executed.
+            return OP_UNDEFINED;
+        }
+        if (bit21_A == 0)
+            return OP_MUL;
+        return OP_MLA;
+    }
+    // 64-bit multiply
+    if (bit22_U == 0) {
+        // Unsigned multiply long
+        if (bit21_A == 0)
+            return OP_UMULL;
+        return OP_UMLAL;
+    }
+    // Signed multiply long
+    if (bit21_A == 0)
+        return OP_SMULL;
+    return OP_SMLAL;
+}
+
+Opcode Arm::decode_ldrh(uint32_t insn) {
+    uint8_t is_load = (insn >> 20) & 0x1;
+    uint8_t bits_65 = (insn >> 5) & 0x3;
+    if (is_load) {
+        if (bits_65 == 0x1) {
+            // Load unsigned halfword
+            return OP_LDRH;
+        } else if (bits_65 == 0x2) {
+            // Load signed byte
+            return OP_LDRSB;
+        }
+        // Signed halfword
+        if (bits_65 != 0x3) {
+            // This is an unexpected bit pattern.  Create an undefined
+            // instruction in case this is ever executed.
+            return OP_UNDEFINED;
+        }
+        // Load signed halfword
+        return OP_LDRSH;
+    }
+    // Store halfword
+    if (bits_65 != 0x1) {
+        // This is an unexpected bit pattern.  Create an undefined
+        // instruction in case this is ever executed.
+        return OP_UNDEFINED;
+    }
+    // Store halfword
+    return OP_STRH;
+}
+
+Opcode Arm::decode_alu(uint32_t insn) {
+    uint8_t is_immed = (insn >> 25) & 0x1;
+    uint8_t opcode = (insn >> 21) & 0xf;
+    uint8_t bit_s = (insn >> 20) & 1;
+    uint8_t shift_is_reg = (insn >> 4) & 1;
+    uint8_t bit7 = (insn >> 7) & 1;
+    if (!is_immed && shift_is_reg && (bit7 != 0)) {
+        // This is an unexpected bit pattern.  Create an undefined
+        // instruction in case this is ever executed.
+        return OP_UNDEFINED;
+    }
+    switch (opcode) {
+        case 0x0:
+            return OP_AND;
+        case 0x1:
+            return OP_EOR;
+        case 0x2:
+            return OP_SUB;
+        case 0x3:
+            return OP_RSB;
+        case 0x4:
+            return OP_ADD;
+        case 0x5:
+            return OP_ADC;
+        case 0x6:
+            return OP_SBC;
+        case 0x7:
+            return OP_RSC;
+        case 0x8:
+            if (bit_s)
+                return OP_TST;
+            return OP_MRS;
+        case 0x9:
+            if (bit_s)
+                return OP_TEQ;
+            return OP_MSR;
+        case 0xa:
+            if (bit_s)
+                return OP_CMP;
+            return OP_MRS;
+        case 0xb:
+            if (bit_s)
+                return OP_CMN;
+            return OP_MSR;
+        case 0xc:
+            return OP_ORR;
+        case 0xd:
+            return OP_MOV;
+        case 0xe:
+            return OP_BIC;
+        case 0xf:
+            return OP_MVN;
+    }
+    // Unreachable
+    return OP_INVALID;
+}