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425 | victor | 1 | $Revision: 425 $ |
1 | ha | 2 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
3 | ;; ;; |
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4 | ;; QUEUE.INC ;; |
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5 | ;; ;; |
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6 | ;; Buffer queue management for Menuet OS TCP/IP Stack ;; |
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7 | ;; ;; |
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8 | ;; Version 0.3 29 August 2002 ;; |
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9 | ;; ;; |
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10 | ;; Copyright 2002 Mike Hibbett, mikeh@oceanfree.net ;; |
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11 | ;; ;; |
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12 | ;; See file COPYING for details ;; |
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13 | ;; ;; |
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14 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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15 | |||
16 | |||
17 | ;******************************************************************* |
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18 | ; Interface |
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19 | ; |
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20 | ; queueInit Configures the queues to empty |
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21 | ; dequeue Removes a buffer pointer from a queue |
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22 | ; queue Inserts a buffer pointer into a queue |
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23 | ; freeBuff Adds the buffer pointer to the list of free buffers |
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24 | ; queueSize Returns the number of entries in a queue |
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25 | ; |
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26 | ; The various defines for queue names can be found in stack.inc |
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27 | ; |
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28 | ;******************************************************************* |
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29 | |||
30 | |||
31 | ;*************************************************************************** |
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32 | ; Function |
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33 | ; freeBuff |
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34 | ; |
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35 | ; Description |
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36 | ; Adds a buffer number to the beginning of the free list. |
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37 | ; buffer number in eax ( ms word zeroed ) |
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38 | ; all other registers preserved |
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39 | ; This always works, so no error returned |
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40 | ;*************************************************************************** |
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41 | freeBuff: |
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42 | push ebx |
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43 | push ecx |
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44 | mov ebx, EMPTY_QUEUE |
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45 | shl ebx, 1 |
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46 | add ebx, queues |
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47 | cli ; Ensure that another process does not interfer |
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48 | movzx ecx, word [ebx] |
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49 | mov [ebx], ax |
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50 | shl eax, 1 |
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51 | add eax, queueList |
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52 | mov [eax], cx |
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53 | sti |
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54 | pop ecx |
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55 | pop ebx |
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56 | |||
57 | ret |
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58 | |||
59 | |||
60 | ;*************************************************************************** |
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61 | ; Function |
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62 | ; queueSize |
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63 | ; |
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64 | ; Description |
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65 | ; Counts the number of entries in a queue |
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66 | ; queue number in ebx ( ms word zeroed ) |
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67 | ; Queue size returned in eax |
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68 | ; This always works, so no error returned |
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69 | ;*************************************************************************** |
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70 | queueSize: |
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71 | xor eax, eax |
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72 | shl ebx, 1 |
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73 | add ebx, queues |
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74 | movzx ecx, word [ebx] |
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75 | cmp cx, NO_BUFFER |
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76 | je qs_exit |
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77 | |||
78 | qs_001: |
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79 | inc eax |
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80 | shl ecx, 1 |
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81 | add ecx, queueList |
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82 | movzx ecx, word [ecx] |
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83 | cmp cx, NO_BUFFER |
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84 | je qs_exit |
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85 | jmp qs_001 |
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86 | |||
87 | qs_exit: |
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88 | ret |
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89 | |||
90 | |||
91 | ;*************************************************************************** |
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92 | ; Function |
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93 | ; queue |
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94 | ; |
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95 | ; Description |
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96 | ; Adds a buffer number to the *end* of a queue |
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97 | ; This is quite quick because these queues will be short |
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98 | ; queue number in eax ( ms word zeroed ) |
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99 | ; buffer number in ebx ( ms word zeroed ) |
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100 | ; all other registers preserved |
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101 | ; This always works, so no error returned |
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102 | ;*************************************************************************** |
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103 | queue: |
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104 | push ebx |
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105 | shl ebx, 1 |
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106 | add ebx, queueList ; eax now holds address of queue entry |
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107 | mov [ebx], word NO_BUFFER ; This buffer will be the last |
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108 | |||
109 | cli |
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110 | shl eax, 1 |
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111 | add eax, queues ; eax now holds address of queue |
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112 | movzx ebx, word [eax] |
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113 | |||
114 | cmp bx, NO_BUFFER |
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115 | jne qu_001 |
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116 | |||
117 | pop ebx |
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118 | ; The list is empty, so add this to the head |
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119 | mov [eax], bx |
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120 | jmp qu_exit |
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121 | |||
122 | qu_001: |
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123 | ; Find the last entry |
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124 | shl ebx, 1 |
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125 | add ebx, queueList |
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126 | mov eax, ebx |
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127 | movzx ebx, word [ebx] |
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128 | cmp bx, NO_BUFFER |
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129 | jne qu_001 |
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130 | |||
131 | mov ebx, eax |
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132 | pop eax |
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133 | mov [ebx], ax |
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134 | |||
135 | qu_exit: |
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136 | sti |
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137 | ret |
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138 | |||
139 | |||
140 | |||
141 | ;*************************************************************************** |
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142 | ; Function |
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143 | ; dequeue |
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144 | ; |
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145 | ; Description |
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146 | ; removes a buffer number from the head of a queue |
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147 | ; This is fast, as it unlinks the first entry in the list |
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148 | ; queue number in eax ( ms word zeroed ) |
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149 | ; buffer number returned in eax ( ms word zeroed ) |
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150 | ; all other registers preserved |
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151 | ; |
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152 | ;*************************************************************************** |
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153 | dequeue: |
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154 | push ebx |
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155 | shl eax, 1 |
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156 | add eax, queues ; eax now holds address of queue |
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157 | mov ebx, eax |
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158 | cli |
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159 | movzx eax, word [eax] |
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160 | cmp ax, NO_BUFFER |
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161 | je dq_exit |
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162 | push eax |
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163 | shl eax, 1 |
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164 | add eax, queueList ; eax now holds address of queue entry |
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165 | mov ax, [eax] |
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166 | mov [ebx], ax |
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167 | pop eax |
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168 | |||
169 | dq_exit: |
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170 | sti |
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171 | pop ebx |
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172 | ret |
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173 | |||
174 | |||
175 | ;*************************************************************************** |
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176 | ; Function |
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177 | ; queueInit |
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178 | ; |
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179 | ; Description |
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180 | ; Initialises the queues to empty, and creates the free queue |
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181 | ; list. |
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182 | ; |
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183 | ;*************************************************************************** |
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184 | queueInit: |
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185 | mov esi, queues |
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186 | mov ecx, NUMQUEUES |
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187 | mov ax, NO_BUFFER |
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188 | |||
189 | qi001: |
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190 | mov [esi], ax |
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191 | inc esi |
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192 | inc esi |
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193 | loop qi001 |
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194 | |||
195 | mov esi, queues + ( 2 * EMPTY_QUEUE ) |
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196 | |||
197 | ; Initialise empty queue list |
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198 | |||
199 | xor ax, ax |
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200 | mov [esi], ax |
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201 | |||
202 | mov ecx, NUMQUEUEENTRIES - 1 |
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203 | mov esi, queueList |
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204 | |||
205 | qi002: |
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206 | inc ax |
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207 | mov [esi], ax |
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208 | inc esi |
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209 | inc esi |
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210 | loop qi002 |
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211 | |||
212 | mov ax, NO_BUFFER |
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213 | mov [esi], ax |
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214 | |||
215 | ret |