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  1. /******************************************************************************
  2.  *
  3.  * Module Name: exmisc - ACPI AML (p-code) execution - specific opcodes
  4.  *
  5.  *****************************************************************************/
  6.  
  7. /*
  8.  * Copyright (C) 2000 - 2015, Intel Corp.
  9.  * All rights reserved.
  10.  *
  11.  * Redistribution and use in source and binary forms, with or without
  12.  * modification, are permitted provided that the following conditions
  13.  * are met:
  14.  * 1. Redistributions of source code must retain the above copyright
  15.  *    notice, this list of conditions, and the following disclaimer,
  16.  *    without modification.
  17.  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18.  *    substantially similar to the "NO WARRANTY" disclaimer below
  19.  *    ("Disclaimer") and any redistribution must be conditioned upon
  20.  *    including a substantially similar Disclaimer requirement for further
  21.  *    binary redistribution.
  22.  * 3. Neither the names of the above-listed copyright holders nor the names
  23.  *    of any contributors may be used to endorse or promote products derived
  24.  *    from this software without specific prior written permission.
  25.  *
  26.  * Alternatively, this software may be distributed under the terms of the
  27.  * GNU General Public License ("GPL") version 2 as published by the Free
  28.  * Software Foundation.
  29.  *
  30.  * NO WARRANTY
  31.  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32.  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33.  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34.  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35.  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36.  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37.  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38.  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39.  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40.  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41.  * POSSIBILITY OF SUCH DAMAGES.
  42.  */
  43.  
  44. #include <acpi/acpi.h>
  45. #include "accommon.h"
  46. #include "acinterp.h"
  47. #include "amlcode.h"
  48. #include "amlresrc.h"
  49.  
  50. #define _COMPONENT          ACPI_EXECUTER
  51. ACPI_MODULE_NAME("exmisc")
  52.  
  53. /*******************************************************************************
  54.  *
  55.  * FUNCTION:    acpi_ex_get_object_reference
  56.  *
  57.  * PARAMETERS:  obj_desc            - Create a reference to this object
  58.  *              return_desc         - Where to store the reference
  59.  *              walk_state          - Current state
  60.  *
  61.  * RETURN:      Status
  62.  *
  63.  * DESCRIPTION: Obtain and return a "reference" to the target object
  64.  *              Common code for the ref_of_op and the cond_ref_of_op.
  65.  *
  66.  ******************************************************************************/
  67. acpi_status
  68. acpi_ex_get_object_reference(union acpi_operand_object *obj_desc,
  69.                              union acpi_operand_object **return_desc,
  70.                              struct acpi_walk_state *walk_state)
  71. {
  72.         union acpi_operand_object *reference_obj;
  73.         union acpi_operand_object *referenced_obj;
  74.  
  75.         ACPI_FUNCTION_TRACE_PTR(ex_get_object_reference, obj_desc);
  76.  
  77.         *return_desc = NULL;
  78.  
  79.         switch (ACPI_GET_DESCRIPTOR_TYPE(obj_desc)) {
  80.         case ACPI_DESC_TYPE_OPERAND:
  81.  
  82.                 if (obj_desc->common.type != ACPI_TYPE_LOCAL_REFERENCE) {
  83.                         return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
  84.                 }
  85.  
  86.                 /*
  87.                  * Must be a reference to a Local or Arg
  88.                  */
  89.                 switch (obj_desc->reference.class) {
  90.                 case ACPI_REFCLASS_LOCAL:
  91.                 case ACPI_REFCLASS_ARG:
  92.                 case ACPI_REFCLASS_DEBUG:
  93.  
  94.                         /* The referenced object is the pseudo-node for the local/arg */
  95.  
  96.                         referenced_obj = obj_desc->reference.object;
  97.                         break;
  98.  
  99.                 default:
  100.  
  101.                         ACPI_ERROR((AE_INFO, "Unknown Reference Class 0x%2.2X",
  102.                                     obj_desc->reference.class));
  103.                         return_ACPI_STATUS(AE_AML_INTERNAL);
  104.                 }
  105.                 break;
  106.  
  107.         case ACPI_DESC_TYPE_NAMED:
  108.                 /*
  109.                  * A named reference that has already been resolved to a Node
  110.                  */
  111.                 referenced_obj = obj_desc;
  112.                 break;
  113.  
  114.         default:
  115.  
  116.                 ACPI_ERROR((AE_INFO, "Invalid descriptor type 0x%X",
  117.                             ACPI_GET_DESCRIPTOR_TYPE(obj_desc)));
  118.                 return_ACPI_STATUS(AE_TYPE);
  119.         }
  120.  
  121.         /* Create a new reference object */
  122.  
  123.         reference_obj =
  124.             acpi_ut_create_internal_object(ACPI_TYPE_LOCAL_REFERENCE);
  125.         if (!reference_obj) {
  126.                 return_ACPI_STATUS(AE_NO_MEMORY);
  127.         }
  128.  
  129.         reference_obj->reference.class = ACPI_REFCLASS_REFOF;
  130.         reference_obj->reference.object = referenced_obj;
  131.         *return_desc = reference_obj;
  132.  
  133.         ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
  134.                           "Object %p Type [%s], returning Reference %p\n",
  135.                           obj_desc, acpi_ut_get_object_type_name(obj_desc),
  136.                           *return_desc));
  137.  
  138.         return_ACPI_STATUS(AE_OK);
  139. }
  140.  
  141. /*******************************************************************************
  142.  *
  143.  * FUNCTION:    acpi_ex_concat_template
  144.  *
  145.  * PARAMETERS:  operand0            - First source object
  146.  *              operand1            - Second source object
  147.  *              actual_return_desc  - Where to place the return object
  148.  *              walk_state          - Current walk state
  149.  *
  150.  * RETURN:      Status
  151.  *
  152.  * DESCRIPTION: Concatenate two resource templates
  153.  *
  154.  ******************************************************************************/
  155.  
  156. acpi_status
  157. acpi_ex_concat_template(union acpi_operand_object *operand0,
  158.                         union acpi_operand_object *operand1,
  159.                         union acpi_operand_object **actual_return_desc,
  160.                         struct acpi_walk_state *walk_state)
  161. {
  162.         acpi_status status;
  163.         union acpi_operand_object *return_desc;
  164.         u8 *new_buf;
  165.         u8 *end_tag;
  166.         acpi_size length0;
  167.         acpi_size length1;
  168.         acpi_size new_length;
  169.  
  170.         ACPI_FUNCTION_TRACE(ex_concat_template);
  171.  
  172.         /*
  173.          * Find the end_tag descriptor in each resource template.
  174.          * Note1: returned pointers point TO the end_tag, not past it.
  175.          * Note2: zero-length buffers are allowed; treated like one end_tag
  176.          */
  177.  
  178.         /* Get the length of the first resource template */
  179.  
  180.         status = acpi_ut_get_resource_end_tag(operand0, &end_tag);
  181.         if (ACPI_FAILURE(status)) {
  182.                 return_ACPI_STATUS(status);
  183.         }
  184.  
  185.         length0 = ACPI_PTR_DIFF(end_tag, operand0->buffer.pointer);
  186.  
  187.         /* Get the length of the second resource template */
  188.  
  189.         status = acpi_ut_get_resource_end_tag(operand1, &end_tag);
  190.         if (ACPI_FAILURE(status)) {
  191.                 return_ACPI_STATUS(status);
  192.         }
  193.  
  194.         length1 = ACPI_PTR_DIFF(end_tag, operand1->buffer.pointer);
  195.  
  196.         /* Combine both lengths, minimum size will be 2 for end_tag */
  197.  
  198.         new_length = length0 + length1 + sizeof(struct aml_resource_end_tag);
  199.  
  200.         /* Create a new buffer object for the result (with one end_tag) */
  201.  
  202.         return_desc = acpi_ut_create_buffer_object(new_length);
  203.         if (!return_desc) {
  204.                 return_ACPI_STATUS(AE_NO_MEMORY);
  205.         }
  206.  
  207.         /*
  208.          * Copy the templates to the new buffer, 0 first, then 1 follows. One
  209.          * end_tag descriptor is copied from Operand1.
  210.          */
  211.         new_buf = return_desc->buffer.pointer;
  212.         memcpy(new_buf, operand0->buffer.pointer, length0);
  213.         memcpy(new_buf + length0, operand1->buffer.pointer, length1);
  214.  
  215.         /* Insert end_tag and set the checksum to zero, means "ignore checksum" */
  216.  
  217.         new_buf[new_length - 1] = 0;
  218.         new_buf[new_length - 2] = ACPI_RESOURCE_NAME_END_TAG | 1;
  219.  
  220.         /* Return the completed resource template */
  221.  
  222.         *actual_return_desc = return_desc;
  223.         return_ACPI_STATUS(AE_OK);
  224. }
  225.  
  226. /*******************************************************************************
  227.  *
  228.  * FUNCTION:    acpi_ex_do_concatenate
  229.  *
  230.  * PARAMETERS:  operand0            - First source object
  231.  *              operand1            - Second source object
  232.  *              actual_return_desc  - Where to place the return object
  233.  *              walk_state          - Current walk state
  234.  *
  235.  * RETURN:      Status
  236.  *
  237.  * DESCRIPTION: Concatenate two objects OF THE SAME TYPE.
  238.  *
  239.  ******************************************************************************/
  240.  
  241. acpi_status
  242. acpi_ex_do_concatenate(union acpi_operand_object *operand0,
  243.                        union acpi_operand_object *operand1,
  244.                        union acpi_operand_object **actual_return_desc,
  245.                        struct acpi_walk_state *walk_state)
  246. {
  247.         union acpi_operand_object *local_operand1 = operand1;
  248.         union acpi_operand_object *return_desc;
  249.         char *new_buf;
  250.         acpi_status status;
  251.  
  252.         ACPI_FUNCTION_TRACE(ex_do_concatenate);
  253.  
  254.         /*
  255.          * Convert the second operand if necessary. The first operand
  256.          * determines the type of the second operand, (See the Data Types
  257.          * section of the ACPI specification.)  Both object types are
  258.          * guaranteed to be either Integer/String/Buffer by the operand
  259.          * resolution mechanism.
  260.          */
  261.         switch (operand0->common.type) {
  262.         case ACPI_TYPE_INTEGER:
  263.  
  264.                 status =
  265.                     acpi_ex_convert_to_integer(operand1, &local_operand1, 16);
  266.                 break;
  267.  
  268.         case ACPI_TYPE_STRING:
  269.  
  270.                 status = acpi_ex_convert_to_string(operand1, &local_operand1,
  271.                                                    ACPI_IMPLICIT_CONVERT_HEX);
  272.                 break;
  273.  
  274.         case ACPI_TYPE_BUFFER:
  275.  
  276.                 status = acpi_ex_convert_to_buffer(operand1, &local_operand1);
  277.                 break;
  278.  
  279.         default:
  280.  
  281.                 ACPI_ERROR((AE_INFO, "Invalid object type: 0x%X",
  282.                             operand0->common.type));
  283.                 status = AE_AML_INTERNAL;
  284.         }
  285.  
  286.         if (ACPI_FAILURE(status)) {
  287.                 goto cleanup;
  288.         }
  289.  
  290.         /*
  291.          * Both operands are now known to be the same object type
  292.          * (Both are Integer, String, or Buffer), and we can now perform the
  293.          * concatenation.
  294.          */
  295.  
  296.         /*
  297.          * There are three cases to handle:
  298.          *
  299.          * 1) Two Integers concatenated to produce a new Buffer
  300.          * 2) Two Strings concatenated to produce a new String
  301.          * 3) Two Buffers concatenated to produce a new Buffer
  302.          */
  303.         switch (operand0->common.type) {
  304.         case ACPI_TYPE_INTEGER:
  305.  
  306.                 /* Result of two Integers is a Buffer */
  307.                 /* Need enough buffer space for two integers */
  308.  
  309.                 return_desc = acpi_ut_create_buffer_object((acpi_size)
  310.                                                            ACPI_MUL_2
  311.                                                            (acpi_gbl_integer_byte_width));
  312.                 if (!return_desc) {
  313.                         status = AE_NO_MEMORY;
  314.                         goto cleanup;
  315.                 }
  316.  
  317.                 new_buf = (char *)return_desc->buffer.pointer;
  318.  
  319.                 /* Copy the first integer, LSB first */
  320.  
  321.                 memcpy(new_buf, &operand0->integer.value,
  322.                        acpi_gbl_integer_byte_width);
  323.  
  324.                 /* Copy the second integer (LSB first) after the first */
  325.  
  326.                 memcpy(new_buf + acpi_gbl_integer_byte_width,
  327.                        &local_operand1->integer.value,
  328.                        acpi_gbl_integer_byte_width);
  329.                 break;
  330.  
  331.         case ACPI_TYPE_STRING:
  332.  
  333.                 /* Result of two Strings is a String */
  334.  
  335.                 return_desc = acpi_ut_create_string_object(((acpi_size)
  336.                                                             operand0->string.
  337.                                                             length +
  338.                                                             local_operand1->
  339.                                                             string.length));
  340.                 if (!return_desc) {
  341.                         status = AE_NO_MEMORY;
  342.                         goto cleanup;
  343.                 }
  344.  
  345.                 new_buf = return_desc->string.pointer;
  346.  
  347.                 /* Concatenate the strings */
  348.  
  349.                 strcpy(new_buf, operand0->string.pointer);
  350.                 strcpy(new_buf + operand0->string.length,
  351.                        local_operand1->string.pointer);
  352.                 break;
  353.  
  354.         case ACPI_TYPE_BUFFER:
  355.  
  356.                 /* Result of two Buffers is a Buffer */
  357.  
  358.                 return_desc = acpi_ut_create_buffer_object(((acpi_size)
  359.                                                             operand0->buffer.
  360.                                                             length +
  361.                                                             local_operand1->
  362.                                                             buffer.length));
  363.                 if (!return_desc) {
  364.                         status = AE_NO_MEMORY;
  365.                         goto cleanup;
  366.                 }
  367.  
  368.                 new_buf = (char *)return_desc->buffer.pointer;
  369.  
  370.                 /* Concatenate the buffers */
  371.  
  372.                 memcpy(new_buf, operand0->buffer.pointer,
  373.                        operand0->buffer.length);
  374.                 memcpy(new_buf + operand0->buffer.length,
  375.                        local_operand1->buffer.pointer,
  376.                        local_operand1->buffer.length);
  377.                 break;
  378.  
  379.         default:
  380.  
  381.                 /* Invalid object type, should not happen here */
  382.  
  383.                 ACPI_ERROR((AE_INFO, "Invalid object type: 0x%X",
  384.                             operand0->common.type));
  385.                 status = AE_AML_INTERNAL;
  386.                 goto cleanup;
  387.         }
  388.  
  389.         *actual_return_desc = return_desc;
  390.  
  391. cleanup:
  392.         if (local_operand1 != operand1) {
  393.                 acpi_ut_remove_reference(local_operand1);
  394.         }
  395.         return_ACPI_STATUS(status);
  396. }
  397.  
  398. /*******************************************************************************
  399.  *
  400.  * FUNCTION:    acpi_ex_do_math_op
  401.  *
  402.  * PARAMETERS:  opcode              - AML opcode
  403.  *              integer0            - Integer operand #0
  404.  *              integer1            - Integer operand #1
  405.  *
  406.  * RETURN:      Integer result of the operation
  407.  *
  408.  * DESCRIPTION: Execute a math AML opcode. The purpose of having all of the
  409.  *              math functions here is to prevent a lot of pointer dereferencing
  410.  *              to obtain the operands.
  411.  *
  412.  ******************************************************************************/
  413.  
  414. u64 acpi_ex_do_math_op(u16 opcode, u64 integer0, u64 integer1)
  415. {
  416.  
  417.         ACPI_FUNCTION_ENTRY();
  418.  
  419.         switch (opcode) {
  420.         case AML_ADD_OP:        /* Add (Integer0, Integer1, Result) */
  421.  
  422.                 return (integer0 + integer1);
  423.  
  424.         case AML_BIT_AND_OP:    /* And (Integer0, Integer1, Result) */
  425.  
  426.                 return (integer0 & integer1);
  427.  
  428.         case AML_BIT_NAND_OP:   /* NAnd (Integer0, Integer1, Result) */
  429.  
  430.                 return (~(integer0 & integer1));
  431.  
  432.         case AML_BIT_OR_OP:     /* Or (Integer0, Integer1, Result) */
  433.  
  434.                 return (integer0 | integer1);
  435.  
  436.         case AML_BIT_NOR_OP:    /* NOr (Integer0, Integer1, Result) */
  437.  
  438.                 return (~(integer0 | integer1));
  439.  
  440.         case AML_BIT_XOR_OP:    /* XOr (Integer0, Integer1, Result) */
  441.  
  442.                 return (integer0 ^ integer1);
  443.  
  444.         case AML_MULTIPLY_OP:   /* Multiply (Integer0, Integer1, Result) */
  445.  
  446.                 return (integer0 * integer1);
  447.  
  448.         case AML_SHIFT_LEFT_OP: /* shift_left (Operand, shift_count, Result) */
  449.  
  450.                 /*
  451.                  * We need to check if the shiftcount is larger than the integer bit
  452.                  * width since the behavior of this is not well-defined in the C language.
  453.                  */
  454.                 if (integer1 >= acpi_gbl_integer_bit_width) {
  455.                         return (0);
  456.                 }
  457.                 return (integer0 << integer1);
  458.  
  459.         case AML_SHIFT_RIGHT_OP:        /* shift_right (Operand, shift_count, Result) */
  460.  
  461.                 /*
  462.                  * We need to check if the shiftcount is larger than the integer bit
  463.                  * width since the behavior of this is not well-defined in the C language.
  464.                  */
  465.                 if (integer1 >= acpi_gbl_integer_bit_width) {
  466.                         return (0);
  467.                 }
  468.                 return (integer0 >> integer1);
  469.  
  470.         case AML_SUBTRACT_OP:   /* Subtract (Integer0, Integer1, Result) */
  471.  
  472.                 return (integer0 - integer1);
  473.  
  474.         default:
  475.  
  476.                 return (0);
  477.         }
  478. }
  479.  
  480. /*******************************************************************************
  481.  *
  482.  * FUNCTION:    acpi_ex_do_logical_numeric_op
  483.  *
  484.  * PARAMETERS:  opcode              - AML opcode
  485.  *              integer0            - Integer operand #0
  486.  *              integer1            - Integer operand #1
  487.  *              logical_result      - TRUE/FALSE result of the operation
  488.  *
  489.  * RETURN:      Status
  490.  *
  491.  * DESCRIPTION: Execute a logical "Numeric" AML opcode. For these Numeric
  492.  *              operators (LAnd and LOr), both operands must be integers.
  493.  *
  494.  *              Note: cleanest machine code seems to be produced by the code
  495.  *              below, rather than using statements of the form:
  496.  *                  Result = (Integer0 && Integer1);
  497.  *
  498.  ******************************************************************************/
  499.  
  500. acpi_status
  501. acpi_ex_do_logical_numeric_op(u16 opcode,
  502.                               u64 integer0, u64 integer1, u8 *logical_result)
  503. {
  504.         acpi_status status = AE_OK;
  505.         u8 local_result = FALSE;
  506.  
  507.         ACPI_FUNCTION_TRACE(ex_do_logical_numeric_op);
  508.  
  509.         switch (opcode) {
  510.         case AML_LAND_OP:       /* LAnd (Integer0, Integer1) */
  511.  
  512.                 if (integer0 && integer1) {
  513.                         local_result = TRUE;
  514.                 }
  515.                 break;
  516.  
  517.         case AML_LOR_OP:        /* LOr (Integer0, Integer1) */
  518.  
  519.                 if (integer0 || integer1) {
  520.                         local_result = TRUE;
  521.                 }
  522.                 break;
  523.  
  524.         default:
  525.  
  526.                 status = AE_AML_INTERNAL;
  527.                 break;
  528.         }
  529.  
  530.         /* Return the logical result and status */
  531.  
  532.         *logical_result = local_result;
  533.         return_ACPI_STATUS(status);
  534. }
  535.  
  536. /*******************************************************************************
  537.  *
  538.  * FUNCTION:    acpi_ex_do_logical_op
  539.  *
  540.  * PARAMETERS:  opcode              - AML opcode
  541.  *              operand0            - operand #0
  542.  *              operand1            - operand #1
  543.  *              logical_result      - TRUE/FALSE result of the operation
  544.  *
  545.  * RETURN:      Status
  546.  *
  547.  * DESCRIPTION: Execute a logical AML opcode. The purpose of having all of the
  548.  *              functions here is to prevent a lot of pointer dereferencing
  549.  *              to obtain the operands and to simplify the generation of the
  550.  *              logical value. For the Numeric operators (LAnd and LOr), both
  551.  *              operands must be integers. For the other logical operators,
  552.  *              operands can be any combination of Integer/String/Buffer. The
  553.  *              first operand determines the type to which the second operand
  554.  *              will be converted.
  555.  *
  556.  *              Note: cleanest machine code seems to be produced by the code
  557.  *              below, rather than using statements of the form:
  558.  *                  Result = (Operand0 == Operand1);
  559.  *
  560.  ******************************************************************************/
  561.  
  562. acpi_status
  563. acpi_ex_do_logical_op(u16 opcode,
  564.                       union acpi_operand_object *operand0,
  565.                       union acpi_operand_object *operand1, u8 * logical_result)
  566. {
  567.         union acpi_operand_object *local_operand1 = operand1;
  568.         u64 integer0;
  569.         u64 integer1;
  570.         u32 length0;
  571.         u32 length1;
  572.         acpi_status status = AE_OK;
  573.         u8 local_result = FALSE;
  574.         int compare;
  575.  
  576.         ACPI_FUNCTION_TRACE(ex_do_logical_op);
  577.  
  578.         /*
  579.          * Convert the second operand if necessary. The first operand
  580.          * determines the type of the second operand, (See the Data Types
  581.          * section of the ACPI 3.0+ specification.)  Both object types are
  582.          * guaranteed to be either Integer/String/Buffer by the operand
  583.          * resolution mechanism.
  584.          */
  585.         switch (operand0->common.type) {
  586.         case ACPI_TYPE_INTEGER:
  587.  
  588.                 status =
  589.                     acpi_ex_convert_to_integer(operand1, &local_operand1, 16);
  590.                 break;
  591.  
  592.         case ACPI_TYPE_STRING:
  593.  
  594.                 status = acpi_ex_convert_to_string(operand1, &local_operand1,
  595.                                                    ACPI_IMPLICIT_CONVERT_HEX);
  596.                 break;
  597.  
  598.         case ACPI_TYPE_BUFFER:
  599.  
  600.                 status = acpi_ex_convert_to_buffer(operand1, &local_operand1);
  601.                 break;
  602.  
  603.         default:
  604.  
  605.                 status = AE_AML_INTERNAL;
  606.                 break;
  607.         }
  608.  
  609.         if (ACPI_FAILURE(status)) {
  610.                 goto cleanup;
  611.         }
  612.  
  613.         /*
  614.          * Two cases: 1) Both Integers, 2) Both Strings or Buffers
  615.          */
  616.         if (operand0->common.type == ACPI_TYPE_INTEGER) {
  617.                 /*
  618.                  * 1) Both operands are of type integer
  619.                  *    Note: local_operand1 may have changed above
  620.                  */
  621.                 integer0 = operand0->integer.value;
  622.                 integer1 = local_operand1->integer.value;
  623.  
  624.                 switch (opcode) {
  625.                 case AML_LEQUAL_OP:     /* LEqual (Operand0, Operand1) */
  626.  
  627.                         if (integer0 == integer1) {
  628.                                 local_result = TRUE;
  629.                         }
  630.                         break;
  631.  
  632.                 case AML_LGREATER_OP:   /* LGreater (Operand0, Operand1) */
  633.  
  634.                         if (integer0 > integer1) {
  635.                                 local_result = TRUE;
  636.                         }
  637.                         break;
  638.  
  639.                 case AML_LLESS_OP:      /* LLess (Operand0, Operand1) */
  640.  
  641.                         if (integer0 < integer1) {
  642.                                 local_result = TRUE;
  643.                         }
  644.                         break;
  645.  
  646.                 default:
  647.  
  648.                         status = AE_AML_INTERNAL;
  649.                         break;
  650.                 }
  651.         } else {
  652.                 /*
  653.                  * 2) Both operands are Strings or both are Buffers
  654.                  *    Note: Code below takes advantage of common Buffer/String
  655.                  *          object fields. local_operand1 may have changed above. Use
  656.                  *          memcmp to handle nulls in buffers.
  657.                  */
  658.                 length0 = operand0->buffer.length;
  659.                 length1 = local_operand1->buffer.length;
  660.  
  661.                 /* Lexicographic compare: compare the data bytes */
  662.  
  663.                 compare = memcmp(operand0->buffer.pointer,
  664.                                  local_operand1->buffer.pointer,
  665.                                  (length0 > length1) ? length1 : length0);
  666.  
  667.                 switch (opcode) {
  668.                 case AML_LEQUAL_OP:     /* LEqual (Operand0, Operand1) */
  669.  
  670.                         /* Length and all bytes must be equal */
  671.  
  672.                         if ((length0 == length1) && (compare == 0)) {
  673.  
  674.                                 /* Length and all bytes match ==> TRUE */
  675.  
  676.                                 local_result = TRUE;
  677.                         }
  678.                         break;
  679.  
  680.                 case AML_LGREATER_OP:   /* LGreater (Operand0, Operand1) */
  681.  
  682.                         if (compare > 0) {
  683.                                 local_result = TRUE;
  684.                                 goto cleanup;   /* TRUE */
  685.                         }
  686.                         if (compare < 0) {
  687.                                 goto cleanup;   /* FALSE */
  688.                         }
  689.  
  690.                         /* Bytes match (to shortest length), compare lengths */
  691.  
  692.                         if (length0 > length1) {
  693.                                 local_result = TRUE;
  694.                         }
  695.                         break;
  696.  
  697.                 case AML_LLESS_OP:      /* LLess (Operand0, Operand1) */
  698.  
  699.                         if (compare > 0) {
  700.                                 goto cleanup;   /* FALSE */
  701.                         }
  702.                         if (compare < 0) {
  703.                                 local_result = TRUE;
  704.                                 goto cleanup;   /* TRUE */
  705.                         }
  706.  
  707.                         /* Bytes match (to shortest length), compare lengths */
  708.  
  709.                         if (length0 < length1) {
  710.                                 local_result = TRUE;
  711.                         }
  712.                         break;
  713.  
  714.                 default:
  715.  
  716.                         status = AE_AML_INTERNAL;
  717.                         break;
  718.                 }
  719.         }
  720.  
  721. cleanup:
  722.  
  723.         /* New object was created if implicit conversion performed - delete */
  724.  
  725.         if (local_operand1 != operand1) {
  726.                 acpi_ut_remove_reference(local_operand1);
  727.         }
  728.  
  729.         /* Return the logical result and status */
  730.  
  731.         *logical_result = local_result;
  732.         return_ACPI_STATUS(status);
  733. }
  734.