/*  $NetBSD: db_disasm.c,v 1.19 2007/02/28 04:21:53 thorpej Exp $   */

/*-
 * Copyright (c) 1991, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ralph Campbell.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *  from: @(#)kadb.c    8.1 (Berkeley) 6/10/93
 */

#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <sys/cdefs.h>
#include <sys/types.h>

#include <android/log.h>

#include "mips_opcode.h"

#define __unused __attribute__((__unused__))

static char *sprintf_buffer;
static int sprintf_buf_len;

typedef uint64_t db_addr_t;
static void db_printf(const char* fmt, ...);

static const char * const op_name[64] = {
/* 0 */ "spec", "bcond", "j", "jal", "beq", "bne", "blez", "bgtz",
/* 8 */ "pop10", "addiu", "slti", "sltiu", "andi", "ori", "xori", "aui",
/*16 */ "cop0", "cop1", "cop2", "?", "?", "?", "pop26", "pop27",
/*24 */ "pop30", "daddiu", "?", "?", "?", "daui", "msa", "op37",
/*32 */ "lb", "lh", "?",  "lw", "lbu", "lhu", "?", "lwu",
/*40 */ "sb", "sh", "?", "sw", "?", "?", "?", "?",
/*48 */ "?", "lwc1", "bc", "?", "?",  "ldc1", "pop66", "ld",
/*56 */ "?", "swc1", "balc", "pcrel", "?", "sdc1", "pop76", "sd"
};

static const char * const spec_name[64] = {
/* 0 */ "sll", "?", "srl", "sra", "sllv", "?", "srlv", "srav",
/* 8 */ "?", "jalr", "?", "?", "syscall", "break", "sdbpp", "sync",
/*16 */ "clz", "clo", "dclz", "dclo", "dsllv", "dlsa", "dsrlv", "dsrav",
/*24 */ "sop30", "sop31", "sop32", "sop33", "sop34", "sop35", "sop36", "sop37",
/*32 */ "add", "addu", "sub", "subu", "and", "or", "xor", "nor",
/*40 */ "?", "?", "slt", "sltu", "dadd", "daddu", "dsub", "dsubu",
/*48 */ "tge", "tgeu", "tlt", "tltu", "teq", "seleqz", "tne", "selnez",
/*56 */ "dsll", "?", "dsrl", "dsra", "dsll32", "?", "dsrl32", "dsra32"
};

static const char * const bcond_name[32] = {
/* 0 */ "bltz", "bgez", "?", "?", "?", "?", "dahi", "?",
/* 8 */ "?", "?", "?", "?", "?", "?", "?", "?",
/*16 */ "nal", "bal", "?", "?", "?", "?", "?", "sigrie",
/*24 */ "?", "?", "?", "?", "?", "?", "dati", "synci",
};

static const char * const cop1_name[64] = {
/* 0 */ "fadd",  "fsub", "fmpy", "fdiv", "fsqrt","fabs", "fmov", "fneg",
/* 8 */ "fop08","fop09","fop0a","fop0b","fop0c","fop0d","fop0e","fop0f",
/*16 */ "fop10","fop11","fop12","fop13","fop14","fop15","fop16","fop17",
/*24 */ "fop18","fop19","fop1a","fop1b","fop1c","fop1d","fop1e","fop1f",
/*32 */ "fcvts","fcvtd","fcvte","fop23","fcvtw","fop25","fop26","fop27",
/*40 */ "fop28","fop29","fop2a","fop2b","fop2c","fop2d","fop2e","fop2f",
/*48 */ "fcmp.f","fcmp.un","fcmp.eq","fcmp.ueq","fcmp.olt","fcmp.ult",
    "fcmp.ole","fcmp.ule",
/*56 */ "fcmp.sf","fcmp.ngle","fcmp.seq","fcmp.ngl","fcmp.lt","fcmp.nge",
    "fcmp.le","fcmp.ngt"
};

static const char * const fmt_name[16] = {
    "s",    "d",    "e",    "fmt3",
    "w",    "fmt5", "fmt6", "fmt7",
    "fmt8", "fmt9", "fmta", "fmtb",
    "fmtc", "fmtd", "fmte", "fmtf"
};

static char * const mips_reg_name[32] = {
    "zero", "at",   "v0",   "v1",   "a0",   "a1",   "a2",   "a3",
    "a4",   "a5",   "a6",   "a7",   "t0",   "t1",   "t2",   "t3",
    "s0",   "s1",   "s2",   "s3",   "s4",   "s5",   "s6",   "s7",
    "t8",   "t9",   "k0",   "k1",   "gp",   "sp",   "s8",   "ra"
};

static char * alt_arm_reg_name[32] = {  // hacked names for comparison with ARM code
    "zero", "at",   "r0",   "r1",   "r2",   "r3",   "r4",   "r5",
    "r6",   "r7",   "r8",   "r9",   "r10",  "r11",  "r12",  "r13",
    "r14",  "r15",  "at2",  "cmp",  "s4",   "s5",   "s6",   "s7",
    "t8",   "t9",   "k0",   "k1",   "gp",   "sp",   "s8",   "ra"
};

static char * const * reg_name =  &mips_reg_name[0];

static const char * const c0_opname[64] = {
    "c0op00","tlbr",  "tlbwi", "c0op03","c0op04","c0op05","tlbwr", "c0op07",
    "tlbp",  "c0op11","c0op12","c0op13","c0op14","c0op15","c0op16","c0op17",
    "rfe",   "c0op21","c0op22","c0op23","c0op24","c0op25","c0op26","c0op27",
    "eret",  "c0op31","c0op32","c0op33","c0op34","c0op35","c0op36","c0op37",
    "c0op40","c0op41","c0op42","c0op43","c0op44","c0op45","c0op46","c0op47",
    "c0op50","c0op51","c0op52","c0op53","c0op54","c0op55","c0op56","c0op57",
    "c0op60","c0op61","c0op62","c0op63","c0op64","c0op65","c0op66","c0op67",
    "c0op70","c0op71","c0op72","c0op73","c0op74","c0op75","c0op77","c0op77",
};

static const char * const c0_reg[32] = {
    "index",    "random",   "tlblo0",  "tlblo1",
    "context",  "pagemask", "wired",   "cp0r7",
    "badvaddr", "count",    "tlbhi",   "compare",
    "status",   "cause",    "epc",     "prid",
    "config",   "lladdr",   "watchlo", "watchhi",
    "xcontext", "cp0r21",   "cp0r22",  "debug",
    "depc",     "perfcnt",  "ecc",     "cacheerr",
    "taglo",    "taghi",    "errepc",  "desave"
};

static void print_addr(db_addr_t);
db_addr_t mips_disassem(db_addr_t loc, char *di_buffer, int alt_dis_format);


/*
 * Disassemble instruction 'insn' nominally at 'loc'.
 * 'loc' may in fact contain a breakpoint instruction.
 */
static db_addr_t
db_disasm_insn(int insn, db_addr_t loc, bool altfmt __unused)
{
    bool bdslot = false;
    InstFmt i;

    i.word = insn;

    switch (i.JType.op) {
    case OP_SPECIAL:
        if (i.word == 0) {
            db_printf("nop");
            break;
        }
        if (i.word == 0x0080) {
            db_printf("NIY");
            break;
        }
        if (i.word == 0x00c0) {
            db_printf("NOT IMPL");
            break;
        }
        /* Special cases --------------------------------------------------
         * "addu" is a "move" only in 32-bit mode.  What's the correct
         * answer - never decode addu/daddu as "move"?
         */
        if ( (i.RType.func == OP_ADDU && i.RType.rt == 0)  ||
             (i.RType.func == OP_OR   && i.RType.rt == 0) ) {
            db_printf("move\t%s,%s",
                reg_name[i.RType.rd],
                reg_name[i.RType.rs]);
            break;
        }

        if (i.RType.func == OP_SRL && (i.RType.rs & 1) == 1) {
            db_printf("rotr\t%s,%s,%d", reg_name[i.RType.rd],
                reg_name[i.RType.rt], i.RType.shamt);
            break;
        }
        if (i.RType.func == OP_SRLV && (i.RType.shamt & 1) == 1) {
            db_printf("rotrv\t%s,%s,%s", reg_name[i.RType.rd],
                reg_name[i.RType.rt], reg_name[i.RType.rs]);
            break;
        }

        if (i.RType.func == OP_SOP30) {
            if (i.RType.shamt == OP_MUL) {
                db_printf("mul");
            } else if (i.RType.shamt == OP_MUH) {
                db_printf("muh");
            }
            db_printf("\t%s,%s,%s", reg_name[i.RType.rd],
                reg_name[i.RType.rs], reg_name[i.RType.rt]);
            break;
        }
        if (i.RType.func == OP_SOP31) {
            if (i.RType.shamt == OP_MUL) {
                db_printf("mulu");
            } else if (i.RType.shamt == OP_MUH) {
                db_printf("muhu");
            }
            db_printf("\t%s,%s,%s", reg_name[i.RType.rd],
                reg_name[i.RType.rs], reg_name[i.RType.rt]);
            break;
        }

        if (i.RType.func == OP_JALR && i.RType.rd == 0) {
            db_printf("jr\t%s", reg_name[i.RType.rs]);
            bdslot = true;
            break;
        }

        db_printf("%s", spec_name[i.RType.func]);
        switch (i.RType.func) {
        case OP_SLL:
        case OP_SRL:
        case OP_SRA:
        case OP_DSLL:

        case OP_DSRL:
        case OP_DSRA:
        case OP_DSLL32:
        case OP_DSRL32:
        case OP_DSRA32:
            db_printf("\t%s,%s,%d",
                reg_name[i.RType.rd],
                reg_name[i.RType.rt],
                i.RType.shamt);
            break;

        case OP_SLLV:
        case OP_SRLV:
        case OP_SRAV:
        case OP_DSLLV:
        case OP_DSRLV:
        case OP_DSRAV:
            db_printf("\t%s,%s,%s",
                reg_name[i.RType.rd],
                reg_name[i.RType.rt],
                reg_name[i.RType.rs]);
            break;

        case OP_CLZ:
        case OP_CLO:
        case OP_DCLZ:
        case OP_DCLO:
            db_printf("\t%s,%s",
                reg_name[i.RType.rd],
                reg_name[i.RType.rs]);
            break;

        case OP_JALR:
            db_printf("\t");
            if (i.RType.rd != 31) {
                db_printf("%s,", reg_name[i.RType.rd]);
            }
            db_printf("%s", reg_name[i.RType.rs]);
            bdslot = true;
            break;

        case OP_SYSCALL:
        case OP_SYNC:
            break;

        case OP_BREAK:
            db_printf("\t%d", (i.RType.rs << 5) | i.RType.rt);
            break;

        default:
            db_printf("\t%s,%s,%s",
                reg_name[i.RType.rd],
                reg_name[i.RType.rs],
                reg_name[i.RType.rt]);
        }
        break;

    case OP_SPECIAL3:
        if (i.RType.func == OP_EXT)
            db_printf("ext\t%s,%s,%d,%d",
                    reg_name[i.RType.rt],
                    reg_name[i.RType.rs],
                    i.RType.shamt,
                    i.RType.rd+1);
        else if (i.RType.func == OP_DEXT)
            db_printf("dext\t%s,%s,%d,%d",
                    reg_name[i.RType.rt],
                    reg_name[i.RType.rs],
                    i.RType.shamt,
                    i.RType.rd+1);
        else if (i.RType.func == OP_DEXTM)
            db_printf("dextm\t%s,%s,%d,%d",
                    reg_name[i.RType.rt],
                    reg_name[i.RType.rs],
                    i.RType.shamt,
                    i.RType.rd+33);
        else if (i.RType.func == OP_DEXTU)
            db_printf("dextu\t%s,%s,%d,%d",
                    reg_name[i.RType.rt],
                    reg_name[i.RType.rs],
                    i.RType.shamt+32,
                    i.RType.rd+1);
        else if (i.RType.func == OP_INS)
            db_printf("ins\t%s,%s,%d,%d",
                    reg_name[i.RType.rt],
                    reg_name[i.RType.rs],
                    i.RType.shamt,
                    i.RType.rd-i.RType.shamt+1);
        else if (i.RType.func == OP_DINS)
            db_printf("dins\t%s,%s,%d,%d",
                    reg_name[i.RType.rt],
                    reg_name[i.RType.rs],
                    i.RType.shamt,
                    i.RType.rd-i.RType.shamt+1);
        else if (i.RType.func == OP_DINSM)
            db_printf("dinsm\t%s,%s,%d,%d",
                    reg_name[i.RType.rt],
                    reg_name[i.RType.rs],
                    i.RType.shamt,
                    i.RType.rd-i.RType.shamt+33);
        else if (i.RType.func == OP_DINSU)
            db_printf("dinsu\t%s,%s,%d,%d",
                    reg_name[i.RType.rt],
                    reg_name[i.RType.rs],
                    i.RType.shamt+32,
                    i.RType.rd-i.RType.shamt+1);
        else if (i.RType.func == OP_BSHFL && i.RType.shamt == OP_WSBH)
            db_printf("wsbh\t%s,%s",
                reg_name[i.RType.rd],
                reg_name[i.RType.rt]);
        else if (i.RType.func == OP_BSHFL && i.RType.shamt == OP_SEB)
            db_printf("seb\t%s,%s",
                reg_name[i.RType.rd],
                reg_name[i.RType.rt]);
        else if (i.RType.func == OP_BSHFL && i.RType.shamt == OP_SEH)
            db_printf("seh\t%s,%s",
                reg_name[i.RType.rd],
                reg_name[i.RType.rt]);
        else if (i.RType.func == OP_RDHWR)
            db_printf("rdhwr\t%s,%s",
                reg_name[i.RType.rd],
                reg_name[i.RType.rt]);
        else
            db_printf("Unknown");
        break;

    case OP_BCOND:
        db_printf("%s\t%s,", bcond_name[i.IType.rt],
            reg_name[i.IType.rs]);
        goto pr_displ;

    case OP_BLEZ:
    case OP_BGTZ:
        db_printf("%s\t%s,", op_name[i.IType.op],
            reg_name[i.IType.rs]);
        goto pr_displ;

    case OP_BEQ:
        if (i.IType.rs == 0 && i.IType.rt == 0) {
            db_printf("b\t");
            goto pr_displ;
        }
        /* FALLTHROUGH */
    case OP_BNE:
        db_printf("%s\t%s,%s,", op_name[i.IType.op],
            reg_name[i.IType.rs],
            reg_name[i.IType.rt]);
    pr_displ:
        print_addr(loc + 4 + ((short)i.IType.imm << 2));
        bdslot = true;
        break;

    case OP_COP0:
        switch (i.RType.rs) {
        case OP_BCx:
        case OP_BCy:

            db_printf("bc0%c\t",
                "ft"[i.RType.rt & COPz_BC_TF_MASK]);
            goto pr_displ;

        case OP_MT:
            db_printf("mtc0\t%s,%s",
                reg_name[i.RType.rt],
                c0_reg[i.RType.rd]);
            break;

        case OP_DMT:
            db_printf("dmtc0\t%s,%s",
                reg_name[i.RType.rt],
                c0_reg[i.RType.rd]);
            break;

        case OP_MF:
            db_printf("mfc0\t%s,%s",
                reg_name[i.RType.rt],
                c0_reg[i.RType.rd]);
            break;

        case OP_DMF:
            db_printf("dmfc0\t%s,%s",
                reg_name[i.RType.rt],
                c0_reg[i.RType.rd]);
            break;

        default:
            db_printf("%s", c0_opname[i.FRType.func]);
        }
        break;

    case OP_COP1:
        switch (i.RType.rs) {
        case OP_BCx:
        case OP_BCy:
            db_printf("bc1%c\t",
                "ft"[i.RType.rt & COPz_BC_TF_MASK]);
            goto pr_displ;

        case OP_MT:
            db_printf("mtc1\t%s,f%d",
                reg_name[i.RType.rt],
                i.RType.rd);
            break;

        case OP_MF:
            db_printf("mfc1\t%s,f%d",
                reg_name[i.RType.rt],
                i.RType.rd);
            break;

        case OP_CT:
            db_printf("ctc1\t%s,f%d",
                reg_name[i.RType.rt],
                i.RType.rd);
            break;

        case OP_CF:
            db_printf("cfc1\t%s,f%d",
                reg_name[i.RType.rt],
                i.RType.rd);
            break;

        default:
            db_printf("%s.%s\tf%d,f%d,f%d",
                cop1_name[i.FRType.func],
                fmt_name[i.FRType.fmt],
                i.FRType.fd, i.FRType.fs, i.FRType.ft);
        }
        break;

    case OP_J:
    case OP_JAL:
        db_printf("%s\t", op_name[i.JType.op]);
        print_addr((loc & 0xFFFFFFFFF0000000) | (i.JType.target << 2));
        bdslot = true;
        break;

    case OP_LWC1:
    case OP_SWC1:
        db_printf("%s\tf%d,", op_name[i.IType.op],
            i.IType.rt);
        goto loadstore;

    case OP_LB:
    case OP_LH:
    case OP_LW:
    case OP_LD:
    case OP_LBU:
    case OP_LHU:
    case OP_LWU:
    case OP_SB:
    case OP_SH:
    case OP_SW:
    case OP_SD:
        db_printf("%s\t%s,", op_name[i.IType.op],
            reg_name[i.IType.rt]);
    loadstore:
        db_printf("%d(%s)", (short)i.IType.imm,
            reg_name[i.IType.rs]);
        break;

    case OP_ORI:
    case OP_XORI:
        if (i.IType.rs == 0) {
            db_printf("li\t%s,0x%x",
                reg_name[i.IType.rt],
                i.IType.imm);
            break;
        }
        /* FALLTHROUGH */
    case OP_ANDI:
        db_printf("%s\t%s,%s,0x%x", op_name[i.IType.op],
            reg_name[i.IType.rt],
            reg_name[i.IType.rs],
            i.IType.imm);
        break;

    case OP_AUI:
        if (i.IType.rs == 0) {
            db_printf("lui\t%s,0x%x", reg_name[i.IType.rt],
                i.IType.imm);
        } else {
            db_printf("%s\t%s,%s,%d", op_name[i.IType.op],
            reg_name[i.IType.rt], reg_name[i.IType.rs],
            (short)i.IType.imm);
        }
        break;

    case OP_ADDIU:
    case OP_DADDIU:
        if (i.IType.rs == 0) {
            db_printf("li\t%s,%d",
                reg_name[i.IType.rt],
                (short)i.IType.imm);
            break;
        }
        /* FALLTHROUGH */
    default:
        db_printf("%s\t%s,%s,%d", op_name[i.IType.op],
            reg_name[i.IType.rt],
            reg_name[i.IType.rs],
            (short)i.IType.imm);
    }
    // db_printf("\n");
    // if (bdslot) {
    //     db_printf("   bd: ");
    //     mips_disassem(loc+4);
    //     return (loc + 8);
    // }
    return (loc + 4);
}

static void
print_addr(db_addr_t loc)
{
    db_printf("0x%08lx", loc);
}

static void db_printf(const char* fmt, ...)
{
    int cnt;
    va_list argp;
    va_start(argp, fmt);
    if (sprintf_buffer) {
        cnt = vsnprintf(sprintf_buffer, sprintf_buf_len, fmt, argp);
        sprintf_buffer += cnt;
        sprintf_buf_len -= cnt;
    } else {
        vprintf(fmt, argp);
    }
    va_end(argp);
}

/*
 * Disassemble instruction at 'loc'.
 * Return address of start of next instruction.
 * Since this function is used by 'examine' and by 'step'
 * "next instruction" does NOT mean the next instruction to
 * be executed but the 'linear' next instruction.
 */
db_addr_t
mips_disassem(db_addr_t loc, char *di_buffer, int alt_dis_format)
{
    u_int32_t instr;

    if (alt_dis_format) {   // use ARM register names for disassembly
        reg_name = &alt_arm_reg_name[0];
    }

    sprintf_buffer = di_buffer;     // quick 'n' dirty printf() vs sprintf()
    sprintf_buf_len = 39;           // should be passed in

    instr =  *(u_int32_t *)loc;
    return (db_disasm_insn(instr, loc, false));
}