1 | /* cpu_asm.S |
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2 | * |
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3 | * This file contains all assembly code for the Intel i386 IDT |
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4 | * manipulation. |
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5 | * |
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6 | * COPYRIGHT (c) 1998 valette@crf.canon.fr |
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7 | * |
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8 | * The license and distribution terms for this file may be |
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9 | * found in the file LICENSE in this distribution or at |
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10 | * http://www.rtems.com/license/LICENSE. |
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11 | * |
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12 | * $Id$ |
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13 | */ |
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14 | |
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15 | #include <rtems/asm.h> |
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16 | |
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17 | BEGIN_CODE |
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18 | /* |
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19 | * C callable function enabling to get easilly usable info from |
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20 | * the actual value of IDT register. |
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21 | * |
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22 | extern void i386_get_info_from_IDTR (interrupt_gate_descriptor** table, |
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23 | unsigned* limit); |
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24 | */ |
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25 | PUBLIC (i386_get_info_from_IDTR) |
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26 | PUBLIC (i386_set_IDTR) |
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27 | PUBLIC (i386_get_info_from_GDTR) |
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28 | PUBLIC (i386_set_GDTR) |
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29 | |
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30 | SYM (i386_get_info_from_IDTR): |
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31 | movl 4(esp), ecx /* get location where table address */ |
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32 | /* must be stored */ |
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33 | movl 8(esp), edx /* get location table size must be stored */ |
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34 | |
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35 | subl $6, esp /* let room to prepare 48 bit IDTR */ |
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36 | |
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37 | sidt (esp) /* get 48 bit IDTR value */ |
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38 | |
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39 | movl 2(esp), eax /* get base */ |
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40 | movl eax, (ecx) |
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41 | |
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42 | movzwl (esp), eax /* get limit */ |
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43 | movl eax, (edx) |
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44 | |
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45 | addl $6, esp /* restore %esp */ |
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46 | ret |
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47 | |
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48 | /* |
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49 | * C callable function enabling to change the value of IDT register. Must be called |
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50 | * with inmterrupt masked at processor level!!!. |
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51 | * |
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52 | extern void i386_set_IDTR (interrupt_gate_descriptor* table, |
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53 | unsigned limit); |
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54 | */ |
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55 | SYM (i386_set_IDTR): |
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56 | |
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57 | leal 4(esp), edx /* load in edx address of input */ |
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58 | /* parameter "table" */ |
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59 | |
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60 | movl (edx), eax /* load base into eax */ |
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61 | movl 4(edx), ecx /* load limit into ecx */ |
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62 | |
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63 | movw cx, (edx) /* prepare 48 bit pointer */ |
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64 | movl eax, 2(edx) |
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65 | |
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66 | lidt (edx) |
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67 | |
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68 | ret |
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69 | /* |
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70 | * |
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71 | * C callable function enabling to get easilly usable info from |
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72 | * the actual value of GDT register. |
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73 | extern void i386_get_info_from_GDTR (segment_descriptors** table, |
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74 | unsigned* limit); |
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75 | */ |
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76 | |
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77 | SYM (i386_get_info_from_GDTR): |
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78 | movl 4(esp), ecx /* get location where table address */ |
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79 | /* must be stored */ |
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80 | movl 8(esp), edx /* get location table size must be stored */ |
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81 | |
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82 | subl $6, esp /* let room to prepare 48 bit GDTR */ |
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83 | |
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84 | sgdt (esp) /* get 48 bit GDTR value */ |
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85 | |
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86 | movl 2(esp), eax /* get base */ |
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87 | movl eax, (ecx) |
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88 | |
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89 | movzwl (esp), eax /* get limit */ |
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90 | movl eax, (edx) |
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91 | |
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92 | addl $6, esp /* restore %esp */ |
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93 | ret |
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94 | |
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95 | /* |
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96 | * C callable function enabling to change the value of GDT register. |
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97 | * Must be called with interrupts masked at processor level!!!. |
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98 | * extern void i386_set_GDTR (segment_descriptors*, unsigned limit); |
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99 | */ |
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100 | SYM (i386_set_GDTR): |
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101 | |
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102 | leal 4(esp), edx /* load in edx address of input */ |
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103 | /* parameter "table" */ |
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104 | |
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105 | movl (edx), eax /* load base into eax */ |
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106 | movl 4(edx), ecx /* load limit into ecx */ |
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107 | |
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108 | movw cx, (edx) /* prepare 48 bit pointer */ |
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109 | movl eax, 2(edx) |
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110 | |
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111 | lgdt (edx) |
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112 | |
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113 | ret |
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114 | |
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115 | END_CODE |
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116 | |
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117 | END |
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