llcgrp.asm

Microsoft MS-DOS6.0 完整源代码

	TITLE	LLCGRP - Core GW-BASIC Graphics Interface
;***
; LLCGRP - Core GW-BASIC Graphics Interface
;
;	Copyright <C> 1986, Microsoft Corporation
;
;Purpose:
;	This module contains support for graphics functions required
;	by programs that may not use graphics drawing statements.
;	Some non-graphic statements (such as CLS) require some graphic
;	support.  Routines directly supporting only graphics drawing
;	statements are placed in LLAGRP to improve runtime granularity
;	and reduce the size of programs not directly using graphics.
;
;	Routines in this module are mode-independent in one or more of the
;	following ways:
;	    1) no device-dependent interaction,
;	    2) table driven through mode-dependent data vectors, or
;	    3) calls mode-dependent routines through function vectors.
;
;	Mode-dependent graphics functions and initializers for vectors
;	are segregated in separate modules for better granularity.
;
;******************************************************************************

	INCLUDE switch.inc	;switch file
	INCLUDE rmacros.inc

	USESEG	_BSS
	USESEG	_DATA
	USESEG	GR_TEXT 	

	INCLUDE seg.inc
	INCLUDE idmac.inc	
	INCLUDE grmac.inc	
	INCLUDE ibmunv.inc

sBegin	_BSS
;
;#***************************************************************************
; External variables
;#***************************************************************************
;
externW b$HugeDelta		;OS dependent selector increment
;
;#***************************************************************************
; Global variables
;#***************************************************************************
;
labelW	<PUBLIC,b$PenC>	;cursor "pen" is mask + attribute
globalB b$MaskC,,1		;  cursor mask byte
globalB b$AttrC,,1		;  each pixel in byte set to color attribute

labelD	<PUBLIC,b$AddrC>	;address of cursor in video memory
globalW b$OffC,,1		;  cursor address offset
globalW b$SegC,,1		;  cursor address segment

globalB b$PaintBorder,,1	;color attribute of PAINT border
globalB b$Tiling,,1		;tiling flag
globalW b$SaveCa,,1		;cursor values for first
globalB b$SaveCm,,1		;  non-border pixel during PAINT
globalB b$PlaneMask,,1 	;bit mask for Map Mask Reg for PUT

globalW b$Incr1,,1		;major axis update value for Line
globalW b$Incr2,,1		;minor axis update value for Line
globalW b$IncrY,,1		;change for Y movement for Line

globalW B$VTOFST,,1		;second row down from top of viewport
globalW B$VBOFST,,1		;bottom edge of viewport
globalW B$VLOFST,,1		;left edge of viewport and row 0
globalW B$VROFST,,1		;right edge of viewport and row 0
globalB B$VLMASK,,1		;corresponding mask for left edge
globalB B$VRMASK,,1		;corresponding mask for right edge
globalW B$LEOFST,,1		;left edge offset of viewport at current row
globalW B$REOFST,,1		;right edge offset of viewport at current row
globalB b$BorderColor,,1	;border color (overscan)
sEnd	_BSS			

sBegin	_DATA			
;
;#***************************************************************************
; Mode-dependent data and function vectors
;
; This data is filled by B$InitModeData from matching tables in the mode-
; dependent modules.  All are created using the same macro set to insure
; consistency in their structure and to provide a central point (the macros)
; for modifying that structure.  The "mEnd" macro actually builds the table.
; Specifying TRUE for its "def" (third) parameter causes it to also create
; PUBLIC names (prefixed with "b$") for each data item.  This also
; creates the GraphVectStart LABEL and GraphVectCnt ABSOLUTE used by
; B$InitModeData to reset the graphics function vectors for text modes.
;
; Refer to GRMAC.INC for more details on the actual structure and the
; variables provided.  To aid in the textual search for these names,
; omit the "b$" in the search.  This will locate all of the macro-generated
; sources for the data item in all the modules.  (e.g.: searching for
; "ScreenMode" instead of "b$ScreenMode" will find all of the "mScreenMode"
; macro invocations.)
;
;This data table is pre-initialized to resemble a 40-column (worst case)
;    text mode to account for its possible usage even before any screen mode
;    initialization takes place.  Function vectors are initialized to
;    B$ErrorReturn, which just sets the carry (as an error indication) and
;    returns.
;#***************************************************************************
;
mModeData	b$ModeData
mScreenMode	0
mBiosMode	0
mBurst		0
mScrWidth	40
mScrHeight	25
mHorzRes	320
mVertRes	200
mVideoBase	0B800H
mMaxAttr	15
mMaxColor	0
mPageSize	2		    ;page size in K
mCurrPSize	<(2*1024) shr 4>    ;page size in paragraphs
mMaxPage	0
mNullColor	7
mForeColor	7
mBackColor	0
mEgaWrMd	0
mInitPalette	0
mInitVgaPal	0
mAlphaDim	B$ErrorReturn
mSetMode	B$ErrorReturn
mSetPages	B$ErrorReturn
mPalReset	B$ErrorReturn
mPalPut 	B$ErrorReturn
mPalTrans	B$ErrorReturn
mPalSet 	B$ErrorReturn
mSetColor	B$ErrorReturn
mForeMapped	7
mBitsPerPixel	1
mPlanes 	1
mMapXYC 	B$ErrorReturn
mLeftC		B$ErrorReturn
mChkUpC 	B$ErrorReturn
mUpC		B$ErrorReturn
mChkDownC	B$ErrorReturn
mDownC		B$ErrorReturn
mSetAttr	B$ErrorReturn
mReadC		B$ErrorReturn
mSetC		B$ErrorReturn
mSetPixC	B$ErrorReturn
mSetPixFirstC	B$ErrorReturn
mSetPixLastC	B$ErrorReturn
mLineX		B$ErrorReturn
mLineY		B$ErrorReturn
mLineV		B$ErrorReturn
mPutAction	B$ErrorReturn
mNReadL 	B$ErrorReturn
mNWriteL	B$ErrorReturn
mNSetC		B$ErrorReturn
mPaintBound	B$ErrorReturn
mSetTile	B$ErrorReturn
mScanL		B$ErrorReturn
mScanR		B$ErrorReturn
mEnd		GraphDataLen,TextDataLen,TRUE
;
; End of table-initialized mode-dependent data
;
;#***************************************************************************
; Mode-dependent functions set-up and used by other mode-dependent functions
;	(see detailed descriptions below)
;#***************************************************************************
;
globalW b$PutVector,B$ErrorReturn,1	
;
;#***************************************************************************
; Mode-dependent variables are described in detail here
;#***************************************************************************
;

;***
;b$ScreenMode - Current Basic Screen Mode
;OEM-interface routine (variable)
;
;Purpose:
;	This variable contains the BASIC mode number of the current
;	screen mode.  This is the number as given in the SCREEN
;	statement, not the BIOS mode number.
;
;Allocated:
;	b$ScreenMode is a BYTE value allocated in _DATA by the OEM.
;
;Values:
;	This variable is initially set to 0 for a worst case scenario
;	when an error message has to be printed before the screen is
;	initialized.  After initialization, it may take on the value
;	of any legal screen mode (0-2, 7-13 if all possible modes are
;	supported).
;
;Initially Set:
;	b$ScreenMode is statically initialized to 0.
;
;Modified By:
;	This variable is only modified by the OEM-Dependent routines.
;	It should be updated when the screen is initialized, and when
;	a SCREEN statement is given.
;
;Used By:
;	This routine is used by the OEM-Dependent code to keep track
;	of which screen mode is current.  It is used by the OEM-Independent
;	Code to determine if a graphics mode is in effect.
;	(b$ScreenMode = 0 <=> non graphics mode)
;******************************************************************************

;
;#***************************************************************************
; Mode-dependent functions called indirectly are described in detail here
;#***************************************************************************
;

;*** 
; b$AlphaDim
;
;Purpose:
;	Validate the proposed text dimensions and establish mode-dependent
;	variables accordingly.	This routine may indicate that the
;	dimensions are invalid or unsupportable, or may request a change
;	in screen mode where the dimensions are supported.
;	NOTE:  No actual change in screen mode occurs until SetMode is called!
;
;Entry:
;	[BH] = number of lines
;	[BL] = number of columns
;
;Exit:
;	PSW.C = set if error
;	[AL] = -1 if dimensions set in current mode or error,
;	       otherwise AL is SCREEN mode to invoke for desired dimensions
;
;Uses:
;Exceptions:
;******************************************************************************

;
;*** 
; b$SetMode
;
;Purpose:
;	Set the screen mode according to the characteristics established
;	by previous calls to B$Screenx and b$AlphaDim
;
;Entry:
;Exit:
;Uses:
;Exceptions:
;******************************************************************************

;*** 
; b$SetPages
;
;Purpose:
;	Set the current active and visual pages and calculate page size
;	and video segment offsets.
;
;Entry:
;	[AL] = active page
;	[AH] = visual page
;
;Exit:
;Uses:
;Exceptions:
;******************************************************************************

;***
; b$PalReset - Reset PALETTE to default state.
;OEM-interface routine
;
;Purpose:
;	Reset the PALETTE to the initial, default colors.  This routine
;	is only called for the PALETTE command and when the screen modes
;	change (note: screen initialization is a mode change).
;
;	NOTE: b$PalReset is a variable through which the routine is
;	      indirectly called.
;
;Entry:
;	None
;
;Exit:
;	PSW.C is set to indicate an error.
;
;Uses:
;	Per convention
;
;Exceptions:
;	None.
;******************************************************************************

;***
; b$PalPut - Change palette entry
;OEM-interface routine
;
;Purpose:
;	Change palette entry with translation/verification.
;	A color value of negative one indicates that the associated
;	palette entry is not to be modified.
;
;	Before setting the palette, the color and attribute values
;	are verified as legal and translated, if necessary, to the
;	internal/hardware values.  Attribute values are seen by the
;	BASIC user as being contiguous, when in fact they may not
;	be.  Color values are similarly manipulated.
;
;	NOTE: b$PalPut is a variable through which the routine is
;	      indirectly called.
;
;Entry:
;	[DX:AX] = color
;	[BL]	= attribute
;
;Exit:
;	PSW.C reset indicates successful operation
;		set indicates PALETTE function call error
;
;Uses:
;	Per convention
;
;Exceptions:
;	None.
;******************************************************************************

;***
; b$PalTrans
;
;Purpose:
;	User supplied color and attribute values are verified as legal
;	and translated, if necessary, to internal/hardware values.
;	Attribute values are seen by the BASIC user as being contiguous
;	from 0 to b$MaxAttr, when in fact they may not be.  This
;	routine vector provides the opportunity for modes to map from the
;	user supplied attribute to that which is actually used as a pixel
;	value in video memory or as a palette index.
;	Color values are similarly disguised and may also be manipulated
;	in support of different monitors.
;
;	NOTE: b$PalTrans is a variable through which the routine is
;	      indirectly called.
;
;Entry:
;	[DX:AX] = internal color
;	[BL]	= internal attribute
;
;Exit:
;	PSW.C reset if entry OK
;	[DX:AX] = actual color
;	[BL]	= actual attribute
;
;Uses:
;Exceptions:
;******************************************************************************

;***
; b$PalSet - Set entire palette from an array
;OEM-interface routine
;
;Purpose:
;	Set the entire palette from an array specified by the user.  Each
;	element of the array is a color value for the attribute which is
;	the current index of the array.   A color value of
;	of -1 indicates the entry should be left alone.  All entries are
;	verified before any are set and are also translated, as needed.
;	Verification and Translation are discussed in b$PalTrans (a non
;	OEM interface routine) and b$PalPut.
;
;	Special consideration must be made for the number of bytes per
;	element in the array.  Also, if there are not enough elements in
;	the array to fill the palette, the return with PSW.C set for
;	an Illegal Function Call.
;
;	NOTE: b$PalSet is a variable through which the routine is
;	      indirectly called.
;
;Entry:
;	[AX]	= size of the array in elements
;	[ES:SI] = address of the array
;	[CX]	= size of each array element in bytes (2 or 4)
;
;Exit:
;	PSW.C set indicates function call error
;
;Uses:
;	Per convention
;
;Exceptions:
;	None.
;******************************************************************************

;***
; b$MapXYC - Map coordinates to graphics cursor
;OEM-interface routine
;
;Purpose:
;	Move the graphics cursor to the pixel specified by the given
;	coordinates.  Both coordinates will always be within the screen
;	boundaries and will already have been clipped to ensure that
;	they are within the viewport.
;
;	NOTE: b$MapXYC is a variable through which the routine is
;	      indirectly called.
;
;Entry:
;	[CX] = X coordinate
;	[DX] = Y coordinate
;
;Exit:
;	Graphics Cursor location updated.
;
;Uses:
;	Per convention
;
;Exceptions:
;	None.
;******************************************************************************
;Our Exit Condition:
;	   b$OffC, b$MaskC updated


;***
; b$LeftC - Move graphics cursor left a pixel
;OEM-interface routine
;
;Purpose:
;	Move graphics cursor left 1 pixel.  No test is made for
;	screen boundaries.
;
;	NOTE: b$LeftC is a variable through which the routine is
;	      indirectly called.
;
;Entry:
;	none
;
;Exit:
;	Graphics Cursor location updated.
;
;Uses:
;	Per convention
;
;Exceptions:
;	None
;******************************************************************************
;Our Exit Condition:
;	   b$OffC, b$MaskC updated

;***
; b$ChkUpC - Move graphics cursor up a pixel, checking for upper boundary
;OEM-interface routine
;
;Purpose:
;	This routine will move the graphics cursor up one pixel if it
;	would stay within the viewport boundaries.  If this move would
;	make it leave the viewport, then PSW.C is set upon the return
;	and no move is made.  The viewport boundaries are specified by
;	a previous call to B$MapVWC.  Note that there does not have
;	to be a separate check for screen boundaries, as the viewport
;	defaults to the screen boundary.
;
;	NOTE: b$ChkUpc is a variable through which the routine is
;	      indirectly called.
;
;Entry:
;	None.
;
;Exit:
;	PSW.C = set if original graphics cursor was on screen top edge.
;	PSW.C = reset if cursor could move.  Graphics Cursor location updated.
;
;Uses:
;	Per convention
;
;Exceptions:
;	None
;******************************************************************************
;Our Exit Condition:
;	   b$OffC, b$MaskC updated if cursor not on boundary.

;***
; b$UpC - Move graphics cursor up 1 pixel.
;OEM-interface routine
;
;Purpose:
;	Move graphics cursor up 1 pixel.  No test is made for
;	screen or viewport boundaries.