src/arch/i386/include/libkir.h

   1 #ifndef LIBKIR_H
   2 #define LIBKIR_H
   3
   4 #include "realmode.h"
   5
   6 #ifndef ASSEMBLY
   7
   8 /*
   9  * Full API documentation for these functions is in realmode.h.
  10  *
  11  */
  12
  13 /* Copy to/from base memory */
  14
  15 static inline void copy_to_real_libkir ( uint16_t dest_seg, uint16_t dest_off,
  16                                          void *src, size_t n ) {
  17         __asm__ ( "movw %4, %%es\n\t"
  18                   "cld\n\t"
  19                   "rep movsb\n\t"
  20                   "pushw %%ds\n\t" /* restore %es */
  21                   "popw %%es\n\t"
  22                   : "=S" ( src ), "=D" ( dest_off ), "=c" ( n ) /* clobbered */
  23                   : "S" ( src ), "r" ( dest_seg ), "D" ( dest_off ), "c" ( n )
  24                   : "memory"
  25                   );
  26 }
  27
  28 static inline void copy_from_real_libkir ( void *dest,
  29                                            uint16_t src_seg, uint16_t src_off,
  30                                            size_t n ) {
  31         __asm__ ( "movw %%ax, %%ds\n\t"
  32                   "cld\n\t"
  33                   "rep movsb\n\t"
  34                   "pushw %%es\n\t" /* restore %ds */
  35                   "popw %%ds\n\t"
  36                   : "=S" ( src_off ), "=D" ( dest ), "=c" ( n ) /* clobbered */
  37                   : "a" ( src_seg ), "S" ( src_off ), "D" ( dest ), "c" ( n )
  38                   : "memory"
  39                   );
  40 }
  41 #define copy_to_real copy_to_real_libkir
  42 #define copy_from_real copy_from_real_libkir
  43
  44 /*
  45  * Transfer individual values to/from base memory.  There may well be
  46  * a neater way to do this.  We have two versions: one for constant
  47  * offsets (where the mov instruction must be of the form "mov
  48  * %es:123, %xx") and one for non-constant offsets (where the mov
  49  * instruction must be of the form "mov %es:(%xx), %yx".  If it's
  50  * possible to incorporate both forms into one __asm__ instruction, I
  51  * don't know how to do it.
  52  *
  53  * Ideally, the mov instruction should be "mov%z0"; the "%z0" is meant
  54  * to expand to either "b", "w" or "l" depending on the size of
  55  * operand 0.  This would remove the (minor) ambiguity in the mov
  56  * instruction.  However, gcc on at least my system barfs with an
  57  * "internal compiler error" when confronted with %z0.
  58  *
  59  */
  60
  61 #define put_real_kir_const_off( var, seg, off )                              \
  62         __asm__ ( "movw %w1, %%es\n\t"                                       \
  63                   "mov %0, %%es:%c2\n\t"                                     \
  64                   "pushw %%ds\n\t" /* restore %es */                         \
  65                   "popw %%es\n\t"                                            \
  66                   :                                                          \
  67                   : "r,r" ( var ), "rm,rm" ( seg ), "i,!r" ( off )           \
  68                   )
  69
  70 #define put_real_kir_nonconst_off( var, seg, off )                           \
  71         __asm__ ( "movw %w1, %%es\n\t"                                       \
  72                   "mov %0, %%es:(%2)\n\t"                                    \
  73                   "pushw %%ds\n\t" /* restore %es */                         \
  74                   "popw %%es\n\t"                                            \
  75                   :                                                          \
  76                   : "r" ( var ), "rm" ( seg ), "r" ( off )                   \
  77                   )
  78
  79 #define put_real_kir( var, seg, off )                                        \
  80         do {                                                                 \
  81           if ( __builtin_constant_p ( off ) )                                \
  82                   put_real_kir_const_off ( var, seg, off );                  \
  83           else                                                               \
  84                   put_real_kir_nonconst_off ( var, seg, off );               \
  85         } while ( 0 )
  86
  87 #define get_real_kir_const_off( var, seg, off )                              \
  88         __asm__ ( "movw %w1, %%es\n\t"                                       \
  89                   "mov %%es:%c2, %0\n\t"                                     \
  90                   "pushw %%ds\n\t" /* restore %es */                         \
  91                   "popw %%es\n\t"                                            \
  92                   : "=r,r" ( var )                                           \
  93                   : "rm,rm" ( seg ), "i,!r" ( off )                          \
  94                   )
  95
  96 #define get_real_kir_nonconst_off( var, seg, off )                           \
  97         __asm__ ( "movw %w1, %%es\n\t"                                       \
  98                   "mov %%es:(%2), %0\n\t"                                    \
  99                   "pushw %%ds\n\t" /* restore %es */                         \
 100                   "popw %%es\n\t"                                            \
 101                   : "=r" ( var )                                             \
 102                   : "rm" ( seg ), "r" ( off )                                \
 103                   )
 104
 105 #define get_real_kir( var, seg, off )                                        \
 106         do {                                                                 \
 107           if ( __builtin_constant_p ( off ) )                                \
 108                   get_real_kir_const_off ( var, seg, off );                  \
 109           else                                                               \
 110                   get_real_kir_nonconst_off ( var, seg, off );               \
 111         } while ( 0 )
 112
 113 #define put_real put_real_kir
 114 #define get_real get_real_kir
 115
 116 /* Place/remove parameter on real-mode stack in a way that's
 117  * compatible with libkir
 118  */
 119 #define BASEMEM_PARAMETER_INIT_LIBKIR( param ) \
 120         ( ( uint16_t ) ( ( uint32_t ) & ( param ) ) )
 121 #define BASEMEM_PARAMETER_DONE_LIBKIR( param )
 122 #define BASEMEM_PARAMETER_INIT BASEMEM_PARAMETER_INIT_LIBKIR
 123 #define BASEMEM_PARAMETER_DONE BASEMEM_PARAMETER_DONE_LIBKIR
 124
 125 /* REAL_CALL: call an external real-mode routine */
 126 #define OUT_CONSTRAINTS(...) __VA_ARGS__
 127 #define IN_CONSTRAINTS(...) "m" ( __routine ), ## __VA_ARGS__
 128 #define CLOBBER(...) __VA_ARGS__
 129 #define REAL_CALL( routine, num_out_constraints, out_constraints,            \
 130                    in_constraints, clobber )                                 \
 131         do {                                                                 \
 132                 segoff_t __routine = routine;                                \
 133                 __asm__ __volatile__ (                                       \
 134                         "pushl %" #num_out_constraints "\n\t"                \
 135                         ".code16\n\t"                                        \
 136                         "pushw %%gs\n\t"        /* preserve segs */          \
 137                         "pushw %%fs\n\t"                                     \
 138                         "pushw %%es\n\t"                                     \
 139                         "pushw %%ds\n\t"                                     \
 140                         "pushw %%cs\n\t"        /* lcall to routine */       \
 141                         "call 1f\n\t"                                        \
 142                         "jmp 2f\n\t"                                         \
 143                         "\n1:\n\t"                                           \
 144                         "addr32 pushl 12(%%esp)\n\t"                         \
 145                         "lret\n\t"                                           \
 146                         "\n2:\n\t"                                           \
 147                         "popw %%ds\n\t"         /* restore segs */           \
 148                         "popw %%es\n\t"                                      \
 149                         "popw %%fs\n\t"                                      \
 150                         "popw %%gs\n\t"                                      \
 151                         "addw $4, %%sp\n\t"                                  \
 152                         ".code16gcc\n\t"                                     \
 153                         : out_constraints : in_constraints : clobber         \
 154                 );                                                           \
 155         } while ( 0 )
 156
 157 /* REAL_EXEC: execute some inline assembly code in a way that matches
 158  * the interface of librm
 159  */
 160
 161 #define IN_CONSTRAINTS_NO_ROUTINE( routine, ... ) __VA_ARGS__
 162 #define REAL_EXEC( name, asm_code_str, num_out_constraints, out_constraints, \
 163                    in_constraints, clobber )                                 \
 164         __asm__ __volatile__ (                                               \
 165                 ".code16\n\t"                                                \
 166                 "pushw %%gs\n\t"                                             \
 167                 "pushw %%fs\n\t"                                             \
 168                 "pushw %%es\n\t"                                             \
 169                 "pushw %%ds\n\t"                                             \
 170                 "\n" #name ":\n\t"                                           \
 171                 asm_code_str                                                 \
 172                 "popw %%ds\n\t"                                              \
 173                 "popw %%es\n\t"                                              \
 174                 "popw %%fs\n\t"                                              \
 175                 "popw %%gs\n\t"                                              \
 176                 ".code16gcc\n\t"                                             \
 177                 : out_constraints                                            \
 178                 : IN_CONSTRAINTS_NO_ROUTINE ( in_constraints )               \
 179                 : clobber                                                    \
 180                 );
 181
 182 #endif /* ASSEMBLY */
 183
 184 #endif /* LIBKIR_H */