1 | ; Project name : Assembly Library |
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2 | ; Description : Functions for system timer related operations. |
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3 | |
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4 | ; |
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5 | ; XTIDE Universal BIOS and Associated Tools |
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6 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team. |
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7 | ; |
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8 | ; This program is free software; you can redistribute it and/or modify |
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9 | ; it under the terms of the GNU General Public License as published by |
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10 | ; the Free Software Foundation; either version 2 of the License, or |
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11 | ; (at your option) any later version. |
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12 | ; |
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13 | ; This program is distributed in the hope that it will be useful, |
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14 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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16 | ; GNU General Public License for more details. |
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17 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html |
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18 | ; |
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19 | |
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20 | ; With a PIT input clock of 1193181.6666... Hz and a maximum |
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21 | ; 16 bit divisor of 65536 (if PIT programmed with 0) we get: |
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22 | ; |
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23 | ; Clock / Divisor = ~18.2065 ticks per second |
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24 | ; Clock * SecondsPerMinute / Divisor = ~1092 ticks per minute |
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25 | ; Clock * SecondsPerHour / Divisor = ~65543 ticks per hour |
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26 | ; |
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27 | ; Since 65543 can't fit in a 16 bit register we use the |
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28 | ; maximum possible instead and disregard the last ~8 ticks. |
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29 | |
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30 | TICKS_PER_HOUR EQU 65535 |
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31 | TICKS_PER_MINUTE EQU 1092 |
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32 | TICKS_PER_SECOND EQU 18 |
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33 | |
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34 | |
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35 | ; Section containing code |
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36 | SECTION .text |
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37 | |
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38 | ;-------------------------------------------------------------------- |
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39 | ; TimerTicks_GetHoursToAXandRemainderTicksToDXfromTicksInDXAX |
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40 | ; TimerTicks_GetMinutesToAXandRemainderTicksToDXfromTicksInDX |
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41 | ; TimerTicks_GetSecondsToAXandRemainderTicksToDXfromTicksInDX |
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42 | ; Parameters |
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43 | ; DX(:AX): Timer ticks to convert |
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44 | ; Returns: |
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45 | ; AX: Hours, minutes or seconds |
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46 | ; DX: Remainder ticks |
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47 | ; Corrupts registers: |
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48 | ; CX |
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49 | ;-------------------------------------------------------------------- |
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50 | %ifndef EXCLUDE_FROM_XUB |
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51 | %ifndef EXCLUDE_FROM_XTIDECFG |
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52 | ALIGN JUMP_ALIGN |
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53 | TimerTicks_GetHoursToAXandRemainderTicksToDXfromTicksInDXAX: |
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54 | mov cx, TICKS_PER_HOUR |
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55 | div cx ; Divide DX:AX by CX, Hours to AX, remainder ticks to DX |
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56 | ret |
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57 | %endif ; EXCLUDE_FROM_XTIDECFG |
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58 | |
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59 | ALIGN JUMP_ALIGN |
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60 | TimerTicks_GetMinutesToAXandRemainderTicksToDXfromTicksInDX: |
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61 | xor ax, ax |
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62 | xchg ax, dx ; Ticks now in DX:AX |
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63 | mov cx, TICKS_PER_MINUTE |
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64 | div cx ; Divide DX:AX by CX, Minutes to AX, remainder ticks to DX |
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65 | ret |
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66 | %endif ; EXCLUDE_FROM_XUB |
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67 | |
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68 | %ifndef EXCLUDE_FROM_XUB OR EXCLUDE_FROM_XTIDECFG |
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69 | ALIGN JUMP_ALIGN |
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70 | TimerTicks_GetSecondsToAXandRemainderTicksToDXfromTicksInDX: |
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71 | ; This procedure can handle at most 4607 ticks in DX (almost 256 seconds) |
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72 | ; More than 4607 ticks will generate a divide overflow exception! |
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73 | xchg ax, dx ; Ticks now in AX |
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74 | mov cl, TICKS_PER_SECOND |
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75 | div cl ; Divide AX by CL, Seconds to AL, remainder ticks to AH |
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76 | xor dx, dx |
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77 | xchg dl, ah ; Seconds in AX, remainder in DX |
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78 | ret |
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79 | %endif |
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80 | |
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81 | |
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82 | %ifdef EXCLUDE_FROM_XUB |
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83 | %ifndef MODULE_BOOT_MENU |
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84 | %define EXCLUDE |
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85 | %endif |
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86 | %endif |
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87 | ;-------------------------------------------------------------------- |
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88 | ; TimerTicks_GetSecondsToAXfromTicksInDX |
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89 | ; Parameters |
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90 | ; DX: Timer ticks to convert |
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91 | ; Returns: |
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92 | ; AX: Seconds |
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93 | ; Corrupts registers: |
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94 | ; DX |
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95 | ;-------------------------------------------------------------------- |
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96 | %ifndef EXCLUDE ; 1 of 3 |
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97 | ALIGN JUMP_ALIGN |
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98 | TimerTicks_GetSecondsToAXfromTicksInDX: |
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99 | mov ax, 3600 ; Approximately 65536 / (Clock / Divisor) |
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100 | mul dx |
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101 | xchg dx, ax |
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102 | ret |
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103 | %endif |
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104 | |
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105 | |
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106 | ;-------------------------------------------------------------------- |
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107 | ; First tick might take 0...54.9 ms and remaining ticks |
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108 | ; will occur at 54.9 ms intervals. Use delay of two (or more) ticks to |
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109 | ; ensure at least 54.9 ms timeout. |
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110 | ; |
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111 | ; TimerTicks_InitializeTimeoutFromAX |
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112 | ; Parameters: |
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113 | ; AX: Timeout ticks (54.9 ms) before timeout |
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114 | ; DS:BX: Ptr to timeout variable WORD |
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115 | ; Returns: |
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116 | ; [DS:BX]: Initialized for TimerTicks_SetCarryIfTimeoutFromDSBX |
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117 | ; Corrupts registers: |
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118 | ; AX |
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119 | ;-------------------------------------------------------------------- |
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120 | %ifndef EXCLUDE ; 2 of 3 |
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121 | ALIGN JUMP_ALIGN |
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122 | TimerTicks_InitializeTimeoutFromAX: |
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123 | mov [bx], ax ; Store timeout ticks |
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124 | call TimerTicks_ReadFromBdaToAX |
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125 | add [bx], ax ; [bx] now contains end time for timeout |
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126 | ret |
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127 | %endif |
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128 | |
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129 | |
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130 | ;-------------------------------------------------------------------- |
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131 | ; TimerTicks_GetTimeoutTicksLeftToAXfromDSBX |
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132 | ; Parameters: |
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133 | ; DS:BX: Ptr to timeout variable WORD |
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134 | ; Returns: |
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135 | ; AX: Number of ticks left before timeout |
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136 | ; CF: Set if timeout |
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137 | ; Cleared if time left |
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138 | ; Corrupts registers: |
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139 | ; Nothing |
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140 | ;-------------------------------------------------------------------- |
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141 | %ifndef EXCLUDE ; 3 of 3 |
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142 | ALIGN JUMP_ALIGN |
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143 | TimerTicks_GetTimeoutTicksLeftToAXfromDSBX: |
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144 | push dx |
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145 | mov dx, [bx] |
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146 | call TimerTicks_ReadFromBdaToAX |
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147 | xchg ax, dx |
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148 | sub ax, dx ; AX = End time - current time |
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149 | pop dx |
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150 | ret |
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151 | %endif |
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152 | |
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153 | %undef EXCLUDE |
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154 | |
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155 | |
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156 | ;-------------------------------------------------------------------- |
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157 | ; TimerTicks_GetElapsedToAXandResetDSBX |
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158 | ; Parameters |
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159 | ; DS:BX: Ptr to WORD containing previous reset time |
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160 | ; Returns: |
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161 | ; AX: 54.9 ms ticks elapsed since last reset |
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162 | ; [DS:BX]: Reset to latest time |
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163 | ; Corrupts registers: |
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164 | ; Nothing |
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165 | ;-------------------------------------------------------------------- |
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166 | %ifndef EXCLUDE_FROM_XUB OR EXCLUDE_FROM_XTIDECFG |
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167 | ALIGN JUMP_ALIGN |
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168 | TimerTicks_GetElapsedToAXandResetDSBX: |
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169 | call TimerTicks_ReadFromBdaToAX |
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170 | push ax |
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171 | sub ax, [bx] |
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172 | pop WORD [bx] ; Latest time to [DS:BX] |
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173 | ret |
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174 | %endif |
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175 | |
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176 | |
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177 | ;-------------------------------------------------------------------- |
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178 | ; TimerTicks_GetElapsedToAXfromDSBX |
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179 | ; Parameters |
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180 | ; DS:BX: Ptr to WORD containing previous update time |
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181 | ; Returns: |
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182 | ; AX: 54.9 ms ticks elapsed since initializing [DS:BX] |
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183 | ; Corrupts registers: |
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184 | ; Nothing |
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185 | ;-------------------------------------------------------------------- |
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186 | %ifndef EXCLUDE_FROM_XUB OR EXCLUDE_FROM_XTIDECFG |
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187 | ALIGN JUMP_ALIGN |
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188 | TimerTicks_GetElapsedToAXfromDSBX: |
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189 | call TimerTicks_ReadFromBdaToAX |
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190 | sub ax, [bx] |
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191 | ret |
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192 | %endif |
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193 | |
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194 | |
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195 | ;-------------------------------------------------------------------- |
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196 | ; TimerTicks_ReadFromBdaToAX |
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197 | ; Parameters |
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198 | ; Nothing |
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199 | ; Returns: |
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200 | ; AX: System time in 54.9 ms ticks |
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201 | ; Corrupts registers: |
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202 | ; Nothing |
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203 | ;-------------------------------------------------------------------- |
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204 | %ifdef EXCLUDE_FROM_XUB |
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205 | %ifndef MODULE_BOOT_MENU OR MODULE_HOTKEYS |
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206 | %define EXCLUDE |
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207 | %endif |
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208 | %endif |
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209 | |
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210 | %ifndef EXCLUDE |
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211 | ALIGN JUMP_ALIGN |
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212 | TimerTicks_ReadFromBdaToAX: |
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213 | push ds |
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214 | |
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215 | LOAD_BDA_SEGMENT_TO ds, ax |
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216 | mov ax, [BDA.dwTimerTicks] ; Read low WORD only |
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217 | |
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218 | pop ds |
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219 | ret |
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220 | %endif |
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221 | %undef EXCLUDE |
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