drivers/acpi/acpica/uthex.c

   1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
   2 /******************************************************************************
   3  *
   4  * Module Name: uthex -- Hex/ASCII support functions
   5  *
   6  * Copyright (C) 2000 - 2020, Intel Corp.
   7  *
   8  *****************************************************************************/
   9
  10 #include <acpi/acpi.h>
  11 #include "accommon.h"
  12
  13 #define _COMPONENT          ACPI_COMPILER
  14 ACPI_MODULE_NAME("uthex")
  15
  16 /* Hex to ASCII conversion table */
  17 static const char acpi_gbl_hex_to_ascii[] = {
  18         '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
  19             'E', 'F'
  20 };
  21
  22 /*******************************************************************************
  23  *
  24  * FUNCTION:    acpi_ut_hex_to_ascii_char
  25  *
  26  * PARAMETERS:  integer             - Contains the hex digit
  27  *              position            - bit position of the digit within the
  28  *                                    integer (multiple of 4)
  29  *
  30  * RETURN:      The converted Ascii character
  31  *
  32  * DESCRIPTION: Convert a hex digit to an Ascii character
  33  *
  34  ******************************************************************************/
  35
  36 char acpi_ut_hex_to_ascii_char(u64 integer, u32 position)
  37 {
  38         u64 index;
  39
  40         acpi_ut_short_shift_right(integer, position, &index);
  41         return (acpi_gbl_hex_to_ascii[index & 0xF]);
  42 }
  43
  44 /*******************************************************************************
  45  *
  46  * FUNCTION:    acpi_ut_ascii_to_hex_byte
  47  *
  48  * PARAMETERS:  two_ascii_chars             - Pointer to two ASCII characters
  49  *              return_byte                 - Where converted byte is returned
  50  *
  51  * RETURN:      Status and converted hex byte
  52  *
  53  * DESCRIPTION: Perform ascii-to-hex translation, exactly two ASCII characters
  54  *              to a single converted byte value.
  55  *
  56  ******************************************************************************/
  57
  58 acpi_status acpi_ut_ascii_to_hex_byte(char *two_ascii_chars, u8 *return_byte)
  59 {
  60
  61         /* Both ASCII characters must be valid hex digits */
  62
  63         if (!isxdigit((int)two_ascii_chars[0]) ||
  64             !isxdigit((int)two_ascii_chars[1])) {
  65                 return (AE_BAD_HEX_CONSTANT);
  66         }
  67
  68         *return_byte =
  69             acpi_ut_ascii_char_to_hex(two_ascii_chars[1]) |
  70             (acpi_ut_ascii_char_to_hex(two_ascii_chars[0]) << 4);
  71
  72         return (AE_OK);
  73 }
  74
  75 /*******************************************************************************
  76  *
  77  * FUNCTION:    acpi_ut_ascii_char_to_hex
  78  *
  79  * PARAMETERS:  hex_char                - Hex character in Ascii. Must be:
  80  *                                        0-9 or A-F or a-f
  81  *
  82  * RETURN:      The binary value of the ascii/hex character
  83  *
  84  * DESCRIPTION: Perform ascii-to-hex translation
  85  *
  86  ******************************************************************************/
  87
  88 u8 acpi_ut_ascii_char_to_hex(int hex_char)
  89 {
  90
  91         /* Values 0-9 */
  92
  93         if (hex_char <= '9') {
  94                 return ((u8)(hex_char - '0'));
  95         }
  96
  97         /* Upper case A-F */
  98
  99         if (hex_char <= 'F') {
 100                 return ((u8)(hex_char - 0x37));
 101         }
 102
 103         /* Lower case a-f */
 104
 105         return ((u8)(hex_char - 0x57));
 106 }