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1882 | clevermous | 1 | /* special version for libc - uses %gs instead of %fs. Ignore comments */ |
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3 | /* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */ |
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4 | /* Copyright (c) 1995 DJ Delorie. Permission granted to use for any |
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5 | purpose, provided this copyright remains attached and unmodified. |
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6 | |||
7 | THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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8 | IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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9 | WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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10 | |||
11 | ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» |
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12 | º Far Pointer Simulation Functions º |
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13 | ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ |
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14 | |||
15 | This file attempts to make up for the lack of a "far" keyword in GCC. |
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16 | Although it doesn't provide access to far call APIs (like Windows), it |
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17 | does allow you to do far pointer data access without the overhead of |
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18 | movedata() or dosmemget/dosmemput(). |
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19 | |||
20 | You should *always* include this file when using these functions and |
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21 | compile with optimization enabled. They don't exist as normal functions |
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22 | in any library, and they compile down to only a few opcodes when used |
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23 | this way. They are almost as fast as native pointer operations, and |
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24 | about as fast as far pointers can get. |
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25 | |||
26 | If you don't use optimization, this file becomes prototypes for |
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27 | farptr.c, which generates real functions for these when not optimizing. |
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28 | When optimizing, farptr.c compiles to nothing. |
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29 | |||
30 | There are two types of functions here - standalone and invariant. The |
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31 | standalone functions take a selector and offset. These are used when |
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32 | you need only a few accesses, time isn't critical, or you don't know |
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33 | what's in the %gs register. The invariant ones don't take a selector, |
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34 | they only take an offset. These are used inside loops and in |
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35 | time-critical accesses where the selector doesn't change. To specify |
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36 | the selector, use the farsetsel() function. That selector is used for |
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37 | all farns*() functions until changed. You can use _fargetsel() if you |
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38 | want to temporary change the selector with _farsetsel() and restore |
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39 | it afterwards. |
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40 | |||
41 | The farpoke* and farpeek* take selectors. |
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42 | |||
43 | The farnspoke* and farnspeek* don't (note the `ns' for `no selector'). |
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44 | |||
45 | Warning: These routines all use the %gs register for their accesses. |
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46 | GCC normally uses only %ds and %es, and libc functions (movedata, |
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47 | dosmemget, dosmemput) use %gs. Still, you should be careful about |
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48 | assumptions concerning whether or not the value you put in %gs will be |
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49 | preserved across calls to other functions. If you guess wrong, your |
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50 | program will crash. Better safe than sorry. |
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51 | |||
52 | */ |
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53 | |||
54 | #ifndef __dj_include_sys_farptr_h_ |
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55 | #define __dj_include_sys_farptr_h_ |
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56 | |||
57 | #ifdef __cplusplus |
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58 | extern "C" { |
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59 | #endif |
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60 | |||
61 | #ifndef __dj_ENFORCE_ANSI_FREESTANDING |
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62 | |||
63 | #ifndef __STRICT_ANSI__ |
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64 | |||
65 | #ifndef _POSIX_SOURCE |
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66 | |||
67 | void _farpokeb(unsigned short, unsigned long, unsigned char); |
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68 | void _farpokew(unsigned short, unsigned long, unsigned short); |
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69 | void _farpokel(unsigned short, unsigned long, unsigned long); |
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70 | unsigned char _farpeekb(unsigned short, unsigned long); |
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71 | unsigned short _farpeekw(unsigned short, unsigned long); |
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72 | unsigned long _farpeekl(unsigned short, unsigned long); |
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73 | void _farsetsel(unsigned short); |
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74 | unsigned short _fargetsel(void); |
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75 | void _farnspokeb(unsigned long, unsigned char); |
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76 | void _farnspokew(unsigned long, unsigned short); |
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77 | void _farnspokel(unsigned long, unsigned long); |
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78 | unsigned char _farnspeekb(unsigned long); |
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79 | unsigned short _farnspeekw(unsigned long); |
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80 | unsigned long _farnspeekl(unsigned long); |
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81 | |||
82 | extern __inline__ void |
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83 | _farpokeb(unsigned short selector, |
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84 | unsigned long offset, |
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85 | unsigned char value) |
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86 | { |
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87 | __asm__ __volatile__ ("movw %w0,%%gs\n" |
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88 | " .byte 0x65 \n" |
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89 | " movb %b1,(%k2)" |
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90 | : |
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91 | : "rm" (selector), "qi" (value), "r" (offset)); |
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92 | } |
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93 | |||
94 | extern __inline__ void |
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95 | _farpokew(unsigned short selector, |
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96 | unsigned long offset, |
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97 | unsigned short value) |
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98 | { |
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99 | __asm__ __volatile__ ("movw %w0,%%gs \n" |
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100 | " .byte 0x65 \n" |
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101 | " movw %w1,(%k2)" |
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102 | : |
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103 | : "rm" (selector), "ri" (value), "r" (offset)); |
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104 | } |
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105 | |||
106 | extern __inline__ void |
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107 | _farpokel(unsigned short selector, |
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108 | unsigned long offset, |
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109 | unsigned long value) |
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110 | { |
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111 | __asm__ __volatile__ ("movw %w0,%%gs \n" |
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112 | " .byte 0x65 \n" |
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113 | " movl %k1,(%k2)" |
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114 | : |
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115 | : "rm" (selector), "ri" (value), "r" (offset)); |
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116 | } |
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117 | |||
118 | extern __inline__ unsigned char |
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119 | _farpeekb(unsigned short selector, |
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120 | unsigned long offset) |
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121 | { |
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122 | unsigned char result; |
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123 | __asm__ __volatile__ ("movw %w1,%%gs \n" |
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124 | " .byte 0x65 \n" |
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125 | " movb (%k2),%b0" |
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126 | : "=q" (result) |
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127 | : "rm" (selector), "r" (offset)); |
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128 | return result; |
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129 | } |
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130 | |||
131 | extern __inline__ unsigned short |
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132 | _farpeekw(unsigned short selector, |
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133 | unsigned long offset) |
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134 | { |
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135 | unsigned short result; |
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136 | __asm__ __volatile__ ("movw %w1, %%gs \n" |
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137 | " .byte 0x65 \n" |
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138 | " movw (%k2),%w0 \n" |
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139 | : "=r" (result) |
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140 | : "rm" (selector), "r" (offset)); |
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141 | return result; |
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142 | } |
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143 | |||
144 | extern __inline__ unsigned long |
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145 | _farpeekl(unsigned short selector, |
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146 | unsigned long offset) |
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147 | { |
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148 | unsigned long result; |
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149 | __asm__ __volatile__ ("movw %w1,%%gs\n" |
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150 | " .byte 0x65\n" |
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151 | " movl (%k2),%k0" |
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152 | : "=r" (result) |
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153 | : "rm" (selector), "r" (offset)); |
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154 | return result; |
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155 | } |
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156 | |||
157 | extern __inline__ void |
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158 | _farsetsel(unsigned short selector) |
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159 | { |
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160 | __asm__ __volatile__ ("movw %w0,%%gs" |
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161 | : |
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162 | : "rm" (selector)); |
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163 | } |
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164 | |||
165 | extern __inline__ unsigned short |
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166 | _fargetsel(void) |
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167 | { |
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168 | unsigned short selector; |
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169 | __asm__ __volatile__ ("movw %%gs,%w0 \n" |
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170 | : "=r" (selector) |
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171 | : ); |
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172 | return selector; |
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173 | } |
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174 | |||
175 | extern __inline__ void |
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176 | _farnspokeb(unsigned long offset, |
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177 | unsigned char value) |
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178 | { |
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179 | __asm__ __volatile__ (".byte 0x65\n" |
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180 | " movb %b0,(%k1)" |
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181 | : |
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182 | : "qi" (value), "r" (offset)); |
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183 | } |
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184 | |||
185 | extern __inline__ void |
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186 | _farnspokew(unsigned long offset, |
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187 | unsigned short value) |
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188 | { |
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189 | __asm__ __volatile__ (".byte 0x65\n" |
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190 | " movw %w0,(%k1)" |
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191 | : |
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192 | : "ri" (value), "r" (offset)); |
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193 | } |
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194 | |||
195 | extern __inline__ void |
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196 | _farnspokel(unsigned long offset, |
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197 | unsigned long value) |
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198 | { |
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199 | __asm__ __volatile__ (".byte 0x65\n" |
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200 | " movl %k0,(%k1)" |
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201 | : |
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202 | : "ri" (value), "r" (offset)); |
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203 | } |
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204 | |||
205 | extern __inline__ unsigned char |
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206 | _farnspeekb(unsigned long offset) |
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207 | { |
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208 | unsigned char result; |
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209 | __asm__ __volatile__ (".byte 0x65\n" |
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210 | " movb (%k1),%b0" |
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211 | : "=q" (result) |
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212 | : "r" (offset)); |
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213 | return result; |
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214 | } |
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215 | |||
216 | extern __inline__ unsigned short |
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217 | _farnspeekw(unsigned long offset) |
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218 | { |
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219 | unsigned short result; |
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220 | __asm__ __volatile__ (".byte 0x65\n" |
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221 | " movw (%k1),%w0" |
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222 | : "=r" (result) |
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223 | : "r" (offset)); |
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224 | return result; |
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225 | } |
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226 | |||
227 | extern __inline__ unsigned long |
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228 | _farnspeekl(unsigned long offset) |
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229 | { |
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230 | unsigned long result; |
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231 | __asm__ __volatile__ (".byte 0x65\n" |
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232 | " movl (%k1),%k0" |
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233 | : "=r" (result) |
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234 | : "r" (offset)); |
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235 | return result; |
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236 | } |
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237 | |||
238 | #endif /* !_POSIX_SOURCE */ |
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239 | #endif /* !__STRICT_ANSI__ */ |
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240 | #endif /* !__dj_ENFORCE_ANSI_FREESTANDING */ |
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241 | |||
242 | #ifndef __dj_ENFORCE_FUNCTION_CALLS |
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243 | #endif /* !__dj_ENFORCE_FUNCTION_CALLS */ |
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244 | |||
245 | #ifdef __cplusplus |
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246 | } |
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247 | #endif |
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248 | |||
249 | #endif /* !__dj_include_sys_farptr_h_ */ |