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