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42 | pj | 1 | /* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */ |
2 | /* Copyright (c) 1995 DJ Delorie. Permission granted to use for any |
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3 | purpose, provided this copyright remains attached and unmodified. |
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4 | |||
5 | THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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6 | IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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7 | WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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8 | |||
9 | ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» |
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10 | º Far Pointer Simulation Functions º |
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11 | ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ |
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12 | |||
13 | This file attempts to make up for the lack of a "far" keyword in GCC. |
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14 | Although it doesn't provide access to far call APIs (like Windows), it |
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15 | does allow you to do far pointer data access without the overhead of |
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16 | movedata() or dosmemget/dosmemput(). |
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17 | |||
18 | You should *always* include this file when using these functions and |
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19 | compile with optimization enabled. They don't exist as normal functions |
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20 | in any library, and they compile down to only a few opcodes when used |
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21 | this way. They are almost as fast as native pointer operations, and |
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22 | about as fast as far pointers can get. |
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23 | |||
24 | If you don't use optimization, this file becomes prototypes for |
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25 | farptr.c, which generates real functions for these when not optimizing. |
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26 | When optimizing, farptr.c compiles to nothing. |
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27 | |||
28 | There are two types of functions here - standalone and invariant. The |
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29 | standalone functions take a selector and offset. These are used when |
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30 | you need only a few accesses, time isn't critical, or you don't know |
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31 | what's in the %fs register. The invariant ones don't take a selector, |
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32 | they only take an offset. These are used inside loops and in |
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33 | time-critical accesses where the selector doesn't change. To specify |
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34 | the selector, use the farsetsel() function. That selector is used for |
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35 | all farns*() functions until changed. You can use _fargetsel() if you |
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36 | want to temporary change the selector with _farsetsel() and restore |
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37 | it afterwards. |
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38 | |||
39 | The farpoke* and farpeek* take selectors. |
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40 | |||
41 | The farnspoke* and farnspeek* don't (note the `ns' for `no selector'). |
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42 | |||
43 | Warning: These routines all use the %fs register for their accesses. |
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44 | GCC normally uses only %ds and %es, and libc functions (movedata, |
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45 | dosmemget, dosmemput) use %gs. Still, you should be careful about |
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46 | assumptions concerning whether or not the value you put in %fs will be |
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47 | preserved across calls to other functions. If you guess wrong, your |
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48 | program will crash. Better safe than sorry. |
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49 | |||
50 | */ |
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51 | |||
52 | #ifndef __dj_include_sys_farptr_h_ |
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53 | #define __dj_include_sys_farptr_h_ |
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54 | #ifdef __cplusplus |
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55 | extern "C" { |
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56 | #endif |
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57 | |||
58 | #ifndef __dj_ENFORCE_ANSI_FREESTANDING |
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59 | |||
60 | #ifndef __STRICT_ANSI__ |
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61 | |||
62 | #ifndef _POSIX_SOURCE |
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63 | |||
64 | void _farpokeb(unsigned short, unsigned long, unsigned char); |
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65 | void _farpokew(unsigned short, unsigned long, unsigned short); |
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66 | void _farpokel(unsigned short, unsigned long, unsigned long); |
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67 | unsigned char _farpeekb(unsigned short, unsigned long); |
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68 | unsigned short _farpeekw(unsigned short, unsigned long); |
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69 | unsigned long _farpeekl(unsigned short, unsigned long); |
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70 | void _farsetsel(unsigned short); |
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71 | unsigned short _fargetsel(void); |
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72 | void _farnspokeb(unsigned long, unsigned char); |
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73 | void _farnspokew(unsigned long, unsigned short); |
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74 | void _farnspokel(unsigned long, unsigned long); |
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75 | unsigned char _farnspeekb(unsigned long); |
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76 | unsigned short _farnspeekw(unsigned long); |
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77 | unsigned long _farnspeekl(unsigned long); |
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78 | |||
79 | extern __inline__ void |
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80 | _farpokeb(unsigned short selector, |
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81 | unsigned long offset, |
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82 | unsigned char value) |
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83 | { |
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84 | __asm__ __volatile__ ("movw %w0,%%fs\n" |
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85 | " .byte 0x64 \n" |
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86 | " movb %b1,%%fs:(%k2)" |
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87 | : |
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88 | : "rm" (selector), "qi" (value), "r" (offset)); |
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89 | } |
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90 | |||
91 | extern __inline__ void |
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92 | _farpokew(unsigned short selector, |
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93 | unsigned long offset, |
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94 | unsigned short value) |
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95 | { |
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96 | __asm__ __volatile__ ("movw %w0,%%fs \n" |
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97 | " .byte 0x64 \n" |
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98 | " movw %w1,(%k2)" |
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99 | : |
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100 | : "rm" (selector), "ri" (value), "r" (offset)); |
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101 | } |
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102 | |||
103 | extern __inline__ void |
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104 | _farpokel(unsigned short selector, |
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105 | unsigned long offset, |
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106 | unsigned long value) |
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107 | { |
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108 | __asm__ __volatile__ ("movw %w0,%%fs \n" |
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109 | " .byte 0x64 \n" |
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110 | " movl %k1,(%k2)" |
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111 | : |
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112 | : "rm" (selector), "ri" (value), "r" (offset)); |
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113 | } |
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114 | |||
115 | extern __inline__ unsigned char |
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116 | _farpeekb(unsigned short selector, |
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117 | unsigned long offset) |
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118 | { |
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119 | unsigned char result; |
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120 | __asm__ __volatile__ ("movw %w1,%%fs \n" |
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121 | " .byte 0x64 \n" |
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122 | " movb (%k2),%b0" |
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123 | : "=q" (result) |
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124 | : "rm" (selector), "r" (offset)); |
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125 | return result; |
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126 | } |
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127 | |||
128 | extern __inline__ unsigned short |
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129 | _farpeekw(unsigned short selector, |
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130 | unsigned long offset) |
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131 | { |
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132 | unsigned short result; |
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133 | __asm__ __volatile__ ("movw %w1, %%fs \n" |
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134 | " .byte 0x64 \n" |
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135 | " movw (%k2),%w0 \n" |
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136 | : "=r" (result) |
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137 | : "rm" (selector), "r" (offset)); |
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138 | return result; |
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139 | } |
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140 | |||
141 | extern __inline__ unsigned long |
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142 | _farpeekl(unsigned short selector, |
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143 | unsigned long offset) |
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144 | { |
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145 | unsigned long result; |
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146 | __asm__ __volatile__ ("movw %w1,%%fs\n" |
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147 | " .byte 0x64\n" |
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148 | " movl (%k2),%k0" |
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149 | : "=r" (result) |
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150 | : "rm" (selector), "r" (offset)); |
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151 | return result; |
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152 | } |
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153 | |||
154 | extern __inline__ void |
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155 | _farsetsel(unsigned short selector) |
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156 | { |
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157 | __asm__ __volatile__ ("movw %w0,%%fs" |
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158 | : |
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159 | : "rm" (selector)); |
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160 | } |
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161 | |||
162 | extern __inline__ unsigned short |
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163 | _fargetsel(void) |
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164 | { |
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165 | unsigned short selector; |
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166 | __asm__ __volatile__ ("movw %%fs,%w0 \n" |
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167 | : "=r" (selector) |
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168 | : ); |
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169 | return selector; |
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170 | } |
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171 | |||
172 | extern __inline__ void |
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173 | _farnspokeb(unsigned long offset, |
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174 | unsigned char value) |
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175 | { |
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176 | __asm__ __volatile__ (".byte 0x64\n" |
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177 | " movb %b0,(%k1)" |
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178 | : |
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179 | : "qi" (value), "r" (offset)); |
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180 | } |
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181 | |||
182 | extern __inline__ void |
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183 | _farnspokew(unsigned long offset, |
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184 | unsigned short value) |
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185 | { |
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186 | __asm__ __volatile__ (".byte 0x64\n" |
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187 | " movw %w0,(%k1)" |
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188 | : |
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189 | : "ri" (value), "r" (offset)); |
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190 | } |
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191 | |||
192 | extern __inline__ void |
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193 | _farnspokel(unsigned long offset, |
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194 | unsigned long value) |
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195 | { |
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196 | __asm__ __volatile__ (".byte 0x64\n" |
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197 | " movl %k0,(%k1)" |
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198 | : |
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199 | : "ri" (value), "r" (offset)); |
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200 | } |
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201 | |||
202 | extern __inline__ unsigned char |
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203 | _farnspeekb(unsigned long offset) |
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204 | { |
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205 | unsigned char result; |
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206 | __asm__ __volatile__ (".byte 0x64\n" |
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207 | " movb (%k1),%b0" |
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208 | : "=q" (result) |
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209 | : "r" (offset)); |
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210 | return result; |
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211 | } |
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212 | |||
213 | extern __inline__ unsigned short |
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214 | _farnspeekw(unsigned long offset) |
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215 | { |
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216 | unsigned short result; |
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217 | __asm__ __volatile__ (".byte 0x64\n" |
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218 | " movw (%k1),%w0" |
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219 | : "=r" (result) |
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220 | : "r" (offset)); |
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221 | return result; |
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222 | } |
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223 | |||
224 | extern __inline__ unsigned long |
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225 | _farnspeekl(unsigned long offset) |
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226 | { |
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227 | unsigned long result; |
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228 | __asm__ __volatile__ (".byte 0x64\n" |
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229 | " movl (%k1),%k0" |
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230 | : "=r" (result) |
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231 | : "r" (offset)); |
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232 | return result; |
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233 | } |
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234 | |||
235 | #endif /* !_POSIX_SOURCE */ |
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236 | #endif /* !__STRICT_ANSI__ */ |
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237 | #endif /* !__dj_ENFORCE_ANSI_FREESTANDING */ |
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238 | |||
239 | #ifndef __dj_ENFORCE_FUNCTION_CALLS |
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240 | #endif /* !__dj_ENFORCE_FUNCTION_CALLS */ |
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241 | |||
242 | #ifdef __cplusplus |
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243 | } |
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244 | #endif |
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245 | |||
246 | #endif /* !__dj_include_sys_farptr_h_ */ |