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/*

 * Copyright (c) 2008 Jiri Svoboda

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - 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.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.

 */

/** @addtogroup debug

 * @{

 */

/** @file

 */

#include <stdio.h>

#include <stdlib.h>

#include <assert.h>

#include <sys/types.h>

#include <errno.h>

#include <udebug.h>

#include "../../../cons.h"

#include "../../../main.h"

#include "../../../breakpoint.h"

#include "../../../include/arch.h"

#include "../../../include/arch/arch.h"

#include "../../../genarch/idec/idec.h"

static istate_t istate;

typedef enum {

    /* Branch */

    OP_B,

    OP_BL,

    OP_BLX1,

    OP_BLX2,

    OP_BX,

    OP_MOV_PC_LR

} op_t;

typedef struct {

    uint32_t mask;

    uint32_t value;

    op_t op;

} instr_desc_t;

static instr_desc_t decoding_table[] = {

    /* Unconditional branch (link) and exchange */

    { 0xfe000000, 0xfa000000, OP_BLX1 },

    { 0x0ffffff0, 0x012fff30, OP_BLX2 },

    { 0x0ffffff0, 0x012fff10, OP_BX },

    /*

     * Order is significant here, as the condition code for B, BL

     * (the top 4 bits) must not be 0xf, which is caught by BLX, BX

     */

    /* Branch (and link) */

    { 0x0f000000, 0x0a000000, OP_B },

    { 0x0f000000, 0x0b000000, OP_BL },

    /* mov pc, lr */

    { 0xffffffff, 0xe1a0f00e, OP_MOV_PC_LR },

    { 0, 0, -1 }

};

/** Sign-extend a value to 32 bits.

 *

 * @param val   A signed value (of limited width)

 * @param bits  Bit-width of value.

 * @return The value extended to a 32-bit signed integer.

 */

#define EXTS(val, bits) ((int32_t)(val) << (32 - (bits)) >> (32 - (bits)))

void arch_dthread_initialize(dthread_t *dt)

{

    dt->arch.singlestep = false;

    bstore_initialize(&dt->arch.cur);

    bstore_initialize(&dt->arch.next[0]);

    bstore_initialize(&dt->arch.next[1]);

}

int arch_breakpoint_set(breakpoint_t *b)

{

    int rc;

    rc = idec_breakpoint_set(b);

    if (rc != 0) return rc;

    return 0;

}

int arch_breakpoint_remove(breakpoint_t *b)

{

    return idec_breakpoint_remove(b);

}

static int islot_read(uintptr_t addr, uint32_t *instr)

{

    int rc;

    rc = udebug_mem_read(app_phone, instr, addr, sizeof(uint32_t));

    if (rc != EOK) {

        cons_printf("Error reading memory address 0x%zx\n", addr);

    }

    return rc;

}

static int get_reg(dthread_t *dt, int reg_no, uint32_t *value)

{

    int rc;

    cons_printf("get_reg...\n");

    if (reg_no == 0) {

        *value = 0;

        return 0;

    }

    rc = udebug_regs_read(app_phone, dt->hash, &istate);

    if (rc < 0) return rc;

    switch (reg_no) {

    case 0: *value = istate.r0; break;

    case 1: *value = istate.r1; break;

    case 2: *value = istate.r2; break;

    case 3: *value = istate.r3; break;

    case 4: *value = istate.r4; break;

    case 5: *value = istate.r5; break;

    case 6: *value = istate.r6; break;

    case 7: *value = istate.r7; break;

    case 8: *value = istate.r8; break;

    case 9: *value = istate.r9; break;

    case 10: *value = istate.r10; break;

    case 11: *value = istate.r11; break;

    case 12: *value = istate.r12; break;

    case 13: *value = istate.sp; break;

    case 14: *value = istate.lr; break;

    case 15: *value = istate.pc; break;

    }

    printf("get_reg ok (0x%08x)\n", *value);

    return 0;

}

static op_t instr_decode(uint32_t instr)

{

    instr_desc_t *idesc;

    idesc = &decoding_table[0];

    while (idesc->op >= 0) {

        if ((instr & idesc->mask) == idesc->value)

            return idesc->op;

        ++idesc;

    }

    return -1;

}

/** Get address of the instruction that will be executed after the current one.

 *

 * Assumptions: addr == PC, *addr is not covered by a BREAK.

 *

 * @param dt        Dthread on which to operate.

 * @param addr      Address of an instruction.

 * @param buffer    Buffer for storing up to 2 addresses.

 * @return      Number of stored addresses or negative error code.

 */

int get_next_addr(dthread_t *dt, uintptr_t addr, uintptr_t *buffer)

{

    uint32_t instr;

    int32_t imm, h;

    uint32_t regv;

    op_t op;

    int rc;

    int n;

    rc = islot_read(addr, &instr);

    if (rc != 0) return rc;

    op = instr_decode(instr);

    switch (op) {

    /* Branch (and link) */

    case OP_B:

    case OP_BL:

        /* imm is a 24-bit signed integer */

        imm = EXTS(instr & 0x00ffffff, 24);

        buffer[0] = (addr + 8) + (imm << 2);

        buffer[1] = addr + 4;

        n = 2;

        break;

    /* Unconditional branch, link and exchange */

    case OP_BLX1:

        /* imm is a 24-bit signed integer */

        imm = EXTS(instr & 0x00ffffff, 24);

        h = (instr & 0x01000000) ? 1 : 0;

        buffer[0] = (addr + 8) + (imm << 2) + (h << 1);

        n = 1;

        break;

    case OP_BLX2:

    case OP_BX:

        /* BLX (2), BX */

        rc = get_reg(dt, instr & 0xf, &regv);

        if (rc != 0) return rc;

        buffer[0] = regv & ~0x1;

        buffer[1] = addr + 4;

        n = 2;

        break;

    case OP_MOV_PC_LR:

        /* mov pc, lr - this is typically used as 'return' */

        rc = get_reg(dt, 14 /* lr */, &regv);

        if (rc != 0) return rc;

        buffer[0] = regv & ~0x1;

        printf("mov pc, lr ---> 0x%x\n", buffer[0]);

        n = 1;

        break;

    /* TODO: handle general case of instructions writing r15(pc) */

    default:

        /* Regular instruction */  

        buffer[0] = addr + 4;

        n = 1;

        break;

    }

    return n;

}

void arch_event_breakpoint(thash_t thread_hash)

{

    idec_event_breakpoint(thread_hash);

}

void arch_event_trap(dthread_t *dt)

{

    /* Unused */

    (void)dt;

}

void arch_dump_regs(thash_t thash)

{

    /* TODO */

}

void arch_singlestep(dthread_t *dt)

{

    idec_singlestep(dt);

}

/** @}

 */