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/*
* librm: a library for interfacing to real-mode code
*
* Michael Brown <mbrown@fensystems.co.uk>
*
*/
#ifdef KEEP_IT_REAL
/* Build a null object under -DKEEP_IT_REAL */
#else
#include "stdint.h"
#include "stddef.h"
#include "string.h"
#include "librm.h"
/*
* This file provides functions for managing librm.
*
*/
/* Current location of librm in base memory */
char *installed_librm = librm;
/*
* Install librm to base memory
*
*/
void install_librm ( void *addr ) {
memcpy ( addr, librm, librm_size );
installed_librm = addr;
}
/*
* Increment lock count of librm
*
*/
void lock_librm ( void ) {
inst_librm_ref_count++;
}
/*
* Decrement lock count of librm
*
*/
void unlock_librm ( void ) {
#ifdef DEBUG_LIBRM
if ( inst_librm_ref_count == 0 ) {
printf ( "librm: ref count gone negative\n" );
lockup();
}
#endif
inst_librm_ref_count--;
}
/*
* Allocate space on the real-mode stack and copy data there.
*
*/
uint16_t copy_to_rm_stack ( void *data, size_t size ) {
#ifdef DEBUG_LIBRM
if ( inst_rm_stack.offset <= size ) {
printf ( "librm: out of space in RM stack\n" );
lockup();
}
#endif
inst_rm_stack.offset -= size;
copy_to_real ( inst_rm_stack.segment, inst_rm_stack.offset,
data, size );
return inst_rm_stack.offset;
};
/*
* Deallocate space on the real-mode stack, optionally copying back
* data.
*
*/
void remove_from_rm_stack ( void *data, size_t size ) {
if ( data ) {
copy_from_real ( data,
inst_rm_stack.segment, inst_rm_stack.offset,
size );
}
inst_rm_stack.offset += size;
};
#endif /* KEEP_IT_REAL */
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