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PAGE ,132 ;AN000;
TITLE DOS - GRAPHICS Command - Interrupt 2FH Driver ;AN000;
;AN000;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;AN000;
;; DOS - GRAPHICS Command
;; (C) Copyright 1988 Microsoft
;; ;AN000;
;; File Name: GRINT2FH.ASM ;AN000;
;; ---------- ;AN000;
;; ;AN000;
;; Description: ;AN000;
;; ------------ ;AN000;
;; This file contains the Interrupt 2FH driver. ;AN000;
;; ;AN000;
;; Documentation Reference: ;AN000;
;; ------------------------ ;AN000;
;; OASIS High Level Design ;AN000;
;; OASIS GRAPHICS I1 Overview ;AN000;
;; ;AN000;
;; Procedures Contained in This File: ;AN000;
;; ---------------------------------- ;AN000;
;; INT_2FH_DRIVER - Interrupt 2FH driver ;AN000;
;; ;AN000;
;; Include Files Required: ;AN000;
;; ----------------------- ;AN000;
;; GRLOAD.EXT - Externals for profile load ;AN000;
;; GRCTRL.EXT - Externals for print screen control ;AN000;
;; GRPRINT.EXT - Externals for print modules ;AN000;
;; GRCPSD.EXT - Externals for COPY_SHARED_DATA module ;AN000;
;; ;AN000;
;; External Procedure References: ;AN000;
;; ------------------------------ ;AN000;
;; Calls next Int 2FH handler in the chain. ;AN000;
;; ;AN000;
;; Linkage Instructions: ;AN000;
;; -------------------- ;AN000;
;; Refer to GRAPHICS.ASM ;AN000;
;; ;AN000;
;; Change History: ;AN000;
;; --------------- ;AN000;
;; ;AN000;
;; ;AN000;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;AN000;
;; ;AN000;
;; ;AN000;
CODE SEGMENT PUBLIC 'CODE' ;; ;AN000;
ASSUME CS:CODE,DS:CODE ;; ;AN000;
;; ;AN000;
PUBLIC OLD_INT_2FH ;; ;AN000;
PUBLIC INT_2FH_DRIVER ;; ;AN000;
PUBLIC PRT_SCR_2FH_NUMBER ;; ;AN000;
PUBLIC RESIDENT_CODE_SEG ;; ;AN000;
PUBLIC SHARED_DATA_AREA_PTR ;; ;AN000;
;; ;AN000;
;; ;AN000;
.XLIST ;AN000;
INCLUDE STRUC.INC ;AN000;
INCLUDE GRINST.EXT ;AN000;
INCLUDE GRCTRL.EXT ;AN000;
INCLUDE GRCPSD.EXT ;AN000;
.LIST ;AN000;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;AN000;
;; ;AN000;
;; Module: INT_2FH_DRIVER ;AN000;
;; ;AN000;
;; Description: ;AN000;
;; Respond to GRAPHICS Int 2FH calls. ;AN000;
;; The following calls are handled: ;AN000;
;; ;AN000;
;; AL = 0 � Install Check ;AN000;
;; ;AN000;
;; Invoked By: ;AN000;
;; INT 2FH instruction. ;AN000;
;; ;AN000;
;; Modules Called: ;AN000;
;; Lower level INT 2FH handlers. ;AN000;
;; ;AN000;
;; Input Registers: ;AN000;
;; Install Check - AH=15H AL=0 ;AN000;
;; ;AN000;
;; ;AN000;
;; Output Registers: ;AN000;
;; Install Check: IF GRAPHICS installed ;AN000;
;; AH=FFH AL=FFH ;AN000;
;; ES : DI points to Shared Data Area ;AN000;
;; ELSE ;AN000;
;; AH=15H AL=0 ;AN000;
;; ;AN000;
;; Logic: ;AN000;
;; IF AH=15H THEN ;AN000;
;; IF AL=0 THEN ;AN000;
;; AH,AL := -1 ;AN000;
;; ES : DI := SHARED_DATA_AREA_PTR ;AN000;
;; ENDIF ;AN000;
;; IRET ;AN000;
;; ELSE ;AN000;
;; IF OLD_INT_2FH is a valid pointer THEN ;AN000;
;; Jump to Old Int 2FH ;AN000;
;; ELSE ;AN000;
;; IRET ;AN000;
;; ENDIF ;AN000;
;; ENDIF ;AN000;
;; ;AN000;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;AN000;
;AN000;
INT_2FH_DRIVER PROC NEAR ;AN000;
JMP INT_2FH ;AN000;
PRT_SCR_2FH_NUMBER EQU 15H ; 2FH Multiplex interrupt number ;AN000;
; assigned to Print Screen. ;AN000;
OLD_INT_2FH DD ? ; Pointer to next 2FH interrupt handler ;AN000;
RESIDENT_CODE_SEG DW ? ; Segment for installed stuff ;AN000;
SHARED_DATA_AREA_PTR DW ? ; Offset of the start of the ;AN000;
; Shared Data Area ;AN000;
;AN000;
INT_2FH: ;AN000;
;-------------------------------------------------------------------------------;AN000;
; Verify if the 2FH Interrupt call is for our interrupt handler: ;AN000;
;-------------------------------------------------------------------------------;AN000;
.IF <AH EQ PRT_SCR_2FH_NUMBER> AND;If 2FH call is for us ;AN000;
.IF <ZERO AL> ; and request is "Get install state" ;AN000;
.THEN ; then, ;AN000;
;-------------------------------------------------------------------------------;AN000;
; Yes: return results ;AN000;
;-------------------------------------------------------------------------------;AN000;
MOV DI,CS:SHARED_DATA_AREA_PTR ; ES:DI := Pointer to shared ;AN000;
PUSH CS:RESIDENT_CODE_SEG ; data area ;AN000;
POP ES ; ;AN000;
MOV AH,0FFH ; AL and AH := "We are installed" ;AN000;
MOV AL,AH ; ;AN000;
IRET ; Return to interrupted process ;AN000;
;-------------------------------------------------------------------------------;AN000;
; No, pass control to next 2FH interrupt handler: ;AN000;
;-------------------------------------------------------------------------------;AN000;
.ELSE ; else, this call is not for us: ;AN000;
.IF <<WORD PTR CS:OLD_INT_2FH> NE 0> AND ;if there is another ;AN000;
.IF <<WORD PTR CS:OLD_INT_2FH+2> NE 0> ; 2FH driver ;AN000;
.THEN ; below us then, ;AN000;
JMP CS:OLD_INT_2FH ; pass control to it ;AN000;
.ELSE ; else, there is nobody to pass ;AN000;
IRET ; control to, just return. ;AN000;
.ENDIF ; END If there is a driver below us.;AN000;
.ENDIF ; END If this call is for us. ;AN000;
INT_2FH_DRIVER ENDP ;AN000;
;AN000;
CODE ENDS ;AN000;
END ;AN000;
|
