static inline void copy_to_real_libkir ( uint16_t dest_seg, uint16_t dest_off,
void *src, size_t n ) {
- __asm__ ( "movw %4, %%es\n\t"
- "cld\n\t"
- "rep movsb\n\t"
- "pushw %%ds\n\t" /* restore %es */
- "popw %%es\n\t"
- : "=S" ( src ), "=D" ( dest_off ), "=c" ( n ) /* clobbered */
- : "S" ( src ), "r" ( dest_seg ), "D" ( dest_off ), "c" ( n )
- : "memory"
- );
+ __asm__ __volatile__ ( "movw %4, %%es\n\t"
+ "cld\n\t"
+ "rep movsb\n\t"
+ "pushw %%ds\n\t" /* restore %es */
+ "popw %%es\n\t"
+ : "=S" ( src ), "=D" ( dest_off ),
+ "=c" ( n ) /* clobbered */
+ : "S" ( src ), "r" ( dest_seg ),
+ "D" ( dest_off ), "c" ( n )
+ : "memory" );
}
static inline void copy_from_real_libkir ( void *dest,
uint16_t src_seg, uint16_t src_off,
size_t n ) {
- __asm__ ( "movw %%ax, %%ds\n\t"
- "cld\n\t"
- "rep movsb\n\t"
- "pushw %%es\n\t" /* restore %ds */
- "popw %%ds\n\t"
- : "=S" ( src_off ), "=D" ( dest ), "=c" ( n ) /* clobbered */
- : "a" ( src_seg ), "S" ( src_off ), "D" ( dest ), "c" ( n )
- : "memory"
- );
+ __asm__ __volatile__ ( "movw %%ax, %%ds\n\t"
+ "cld\n\t"
+ "rep movsb\n\t"
+ "pushw %%es\n\t" /* restore %ds */
+ "popw %%ds\n\t"
+ : "=S" ( src_off ), "=D" ( dest ),
+ "=c" ( n ) /* clobbered */
+ : "a" ( src_seg ), "S" ( src_off ),
+ "D" ( dest ), "c" ( n )
+ : "memory" );
}
#define copy_to_real copy_to_real_libkir
#define copy_from_real copy_from_real_libkir
#define BASEMEM_PARAMETER_INIT BASEMEM_PARAMETER_INIT_LIBKIR
#define BASEMEM_PARAMETER_DONE BASEMEM_PARAMETER_DONE_LIBKIR
+/* REAL_FRAGMENT: Declare and define a real-mode code fragment in
+ * .text16. We don't need this for REAL_EXEC, since we can just
+ * execute our real-mode code inline, but it's handy in case someone
+ * genuinely wants to create a block of code that can be copied to a
+ * specific location and then executed.
+ *
+ * Note that we put the code in the data segment, since otherwise we
+ * can't (easily) access it in order to copy it to its target
+ * location. We should never be calling any REAL_FRAGMENT routines
+ * directly anyway.
+ */
+#define REAL_FRAGMENT( name, asm_code_str ) \
+ extern void name ( void ); \
+ extern char name ## _size[]; \
+ __asm__ __volatile__ ( \
+ ".section \".data.text16\"\n\t" \
+ ".code16\n\t" \
+ ".arch i386\n\t" \
+ #name ":\n\t" \
+ asm_code_str "\n\t" \
+ "lret\n\t" \
+ #name "_end:\n\t" \
+ ".equ " #name "_size, " #name "_end - " #name "\n\t" \
+ ".code16gcc\n\t" \
+ ".previous\n\t" \
+ : : \
+ )
+#define FRAGMENT_SIZE( fragment ) ( (size_t) fragment ## _size )
+
/* REAL_CALL: call an external real-mode routine */
#define OUT_CONSTRAINTS(...) __VA_ARGS__
#define IN_CONSTRAINTS(...) "m" ( __routine ), ## __VA_ARGS__