void aml_append(Aml *parent_ctx, Aml *child)
{
    GArray *buf = build_alloc_array();
    build_append_array(buf, child->buf);

    switch (child->block_flags) {
    case AML_OPCODE:
        build_append_byte(parent_ctx->buf, child->op);
        break;
    case AML_EXT_PACKAGE:
        build_extop_package(buf, child->op);
        break;
    case AML_PACKAGE:
        build_package(buf, child->op);
        break;
    case AML_RES_TEMPLATE:
        build_append_byte(buf, 0x79); /* EndTag */
        /*
         * checksum operations are treated as succeeded if checksum
         * field is zero. [ACPI Spec 1.0b, 6.4.2.8 End Tag]
         */
        build_append_byte(buf, 0);
        /* fall through, to pack resources in buffer */
    case AML_BUFFER:
        build_buffer(buf, child->op);
        break;
    case AML_NO_OPCODE:
        break;
    default:
        assert(0);
        break;
    }
    build_append_array(parent_ctx->buf, buf);
    build_free_array(buf);
}

/* ACPI 1.0b: 16.2.6.3 Debug Objects Encoding: DebugObj */
Aml *aml_debug(void)
{
    Aml *var = aml_alloc();
    build_append_byte(var->buf, 0x5B); /* ExtOpPrefix */
    build_append_byte(var->buf, 0x31); /* DebugOp */
    return var;
}

static void build_append_value(GArray *table, uint32_t value, int size)
{
    uint8_t prefix;
    int i;

    switch (size) {
    case 1:
        prefix = 0x0A; /* BytePrefix */
        break;
    case 2:
        prefix = 0x0B; /* WordPrefix */
        break;
    case 4:
        prefix = 0x0C; /* DWordPrefix */
        break;
    default:
        assert(0);
        return;
    }
    build_append_byte(table, prefix);
    for (i = 0; i < size; ++i) {
        build_append_byte(table, value & 0xFF);
        value = value >> 8;
    }
}

/*
 * ACPI 2.0b: 16.2.3.6.4.3  Unicode Macro (Convert Ascii String To Unicode)
 */
Aml *aml_unicode(const char *str)
{
    int i = 0;
    Aml *var = aml_bundle(0x11 /* BufferOp */, AML_BUFFER);

    do {
        build_append_byte(var->buf, str[i]);
        build_append_byte(var->buf, 0);
        i++;
    } while (i <= strlen(str));

    return var;
}

static void build_append_int(GArray *table, uint32_t value)
{
    if (value == 0x00) {
        build_append_byte(table, 0x00); /* ZeroOp */
    } else if (value == 0x01) {
        build_append_byte(table, 0x01); /* OneOp */
    } else if (value <= 0xFF) {
        build_append_value(table, value, 1);
    } else if (value <= 0xFFFFF) {
        build_append_value(table, value, 2);
    } else {
        build_append_value(table, value, 4);
    }
}

/* ACPI 2.0a: 17.2.4.4 Type 2 Opcodes Encoding: DefToInteger */
Aml *aml_to_integer(Aml *arg)
{
    Aml *var = aml_opcode(0x99 /* ToIntegerOp */);
    aml_append(var, arg);
    build_append_byte(var->buf, 0x00 /* NullNameOp */);
    return var;
}

/* ACPI 1.0b: 16.2.5.2 Named Objects Encoding: DefField */
Aml *aml_field(const char *name, AmlFieldFlags flags)
{
    Aml *var = aml_bundle(0x81 /* FieldOp */, AML_EXT_PACKAGE);
    build_append_namestring(var->buf, "%s", name);
    build_append_byte(var->buf, flags);
    return var;
}

/* ACPI 1.0b: 16.2.5.4 Type 2 Opcodes Encoding: DefAnd */
Aml *aml_and(Aml *arg1, Aml *arg2)
{
    Aml *var = aml_opcode(0x7B /* AndOp */);
    aml_append(var, arg1);
    aml_append(var, arg2);
    build_append_byte(var->buf, 0x00 /* NullNameOp */);
    return var;
}

static GArray *build_alloc_method(const char *name, uint8_t arg_count)
{
    GArray *method = build_alloc_array();

    build_append_nameseg(method, "%s", name);
    build_append_byte(method, arg_count); /* MethodFlags: ArgCount */

    return method;
}

void build_append_int_noprefix(GArray *table, uint64_t value, int size)
{
    int i;

    for (i = 0; i < size; ++i) {
        build_append_byte(table, value & 0xFF);
        value = value >> 8;
    }
}

/*
 * Build NAME(XXXX, 0x00000000) where 0x00000000 is encoded as a dword,
 * and return the offset to 0x00000000 for runtime patching.
 *
 * Warning: runtime patching is best avoided. Only use this as
 * a replacement for DataTableRegion (for guests that don't
 * support it).
 */
int
build_append_named_dword(GArray *array, const char *name_format, ...)
{
    int offset;
    va_list ap;

    build_append_byte(array, 0x08); /* NameOp */
    va_start(ap, name_format);
    build_append_namestringv(array, name_format, ap);
    va_end(ap);

    build_append_byte(array, 0x0C); /* DWordPrefix */

    offset = array->len;
    build_append_int_noprefix(array, 0x00000000, 4);
    assert(array->len == offset + 4);

    return offset;
}

static void build_append_notify_target_ifequal(GArray *method,
                                               GArray *target_name,
                                               uint32_t value, int size)
{
    GArray *notify = build_alloc_array();
    uint8_t op = 0xA0; /* IfOp */

    build_append_byte(notify, 0x93); /* LEqualOp */
    build_append_byte(notify, 0x68); /* Arg0Op */
    build_append_value(notify, value, size);
    build_append_byte(notify, 0x86); /* NotifyOp */
    build_append_array(notify, target_name);
    build_append_byte(notify, 0x69); /* Arg1Op */

    /* Pack it up */
    build_package(notify, op, 1);

    build_append_array(method, notify);

    build_free_array(notify);
}