home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
The World of Computer Software
/
The World of Computer Software.iso
/
em-xmkit.zip
/
EMM15_C.ASM
< prev
next >
Wrap
Assembly Source File
|
1989-11-29
|
6KB
|
111 lines
;-----------------------------------------------------------------------------;
; MODULE NAME: EMM15_C.ASM ;
; ;
; FUNCTION NAME: get_set_context ;
; ;
; DESCRIPTION: This function simultaneously saves a current mapping ;
; context and restores a previous mapping context for all ;
; mappable memory regions (both conventional and ;
; expanded). First, it copies the contents of the ;
; mapping hardware from each expanded memory board into a ;
; destination structure. (The application must pass a ;
; pointer to the destination structure.) Then the ;
; function copies the contents of a source structure ;
; into the mapping hardware on each of the expanded ;
; memory boards. (The application must pass a pointer to ;
; the source structure.) ;
; ;
; Use this function instead of save_context & ;
; restore_context if you need to save or restore the ;
; mapping context but don't want (or have) to use a ;
; handle. ;
; ;
; PASSED: &dest_context: ;
; is a far pointer to the destination structure of the ;
; mapping context to be saved. ;
; ;
; &source_context: ;
; is a far pointer to the source structure of the ;
; mapping context to be restored. ;
; The structure member is described here: ;
; ;
; source_context.reserved: ;
; is a character array which is reserved for use by ;
; the memory manager. In this instance it contains ;
; the data for the mapping hardware state. ;
; ;
; RETURNED: status: ;
; is the status EMM returns from the call. All other ;
; returned results are valid only if the status ;
; returned is zero. Otherwise they are undefined. ;
; ;
; dest_context: ;
; is a structure containing the state of all the ;
; mapping hardware on all boards in the system. It ;
; also contains any additional information necessary ;
; to restore the boards to their original state when ;
; the program invokes a set_context or get_set_context ;
; function. ;
; The structure member is described here: ;
; ;
; dest_context.reserved: ;
; is a character array which is reserved for use by ;
; the memory manager. In this instance it contains ;
; the data for the mapping hardware state. ;
; ;
; C USE CONVENTION: unsigned int status; ;
; CONTEXT_STRUCT dest_context; ;
; CONTEXT_STRUCT source_context; ;
; ;
; status = get_set_context (&dest_context, ;
; &source_context); ;
;-----------------------------------------------------------------------------;
.XLIST
PAGE 60,132
IFDEF SMALL
.MODEL SMALL, C
ENDIF
IFDEF MEDIUM
.MODEL MEDIUM, C
ENDIF
IFDEF LARGE
.MODEL LARGE, C
ENDIF
IFDEF COMPACT
.MODEL COMPACT, C
ENDIF
IFDEF HUGE
.MODEL HUGE, C
ENDIF
INCLUDE emmlib.equ
INCLUDE emmlib.str
INCLUDE emmlib.mac
.LIST
.CODE
get_set_context PROC \
USES DS SI DI, \
ptr_dest_context:FAR PTR BYTE, \
ptr_source_context:FAR PTR BYTE
;---------------------------------------------------------------------;
; do; ;
; . get current & set new memory mapping context from/to EMM; ;
;---------------------------------------------------------------------;
MOVE AX, get_and_set_page_map_fcn
MOVE ES:DI, ptr_dest_context
MOVE DS:SI, ptr_source_context
INT EMM_int
;---------------------------------------------------------------------;
; . return (EMM status); ;
; end; ;
;---------------------------------------------------------------------;
RET_EMM_STAT AH
get_set_context ENDP
END