;	私製ライブラリ・グラフィック篇
;	(c) MATSUUCHI Ryosuke in Dec,1992
;
;	gpoint.asm
;
;	1992. 8. 3(Mon)
;	1992.12.28(Sun)


		public	gpoint,_gpoint
		extrn	__AddVramBase_edi	:near
		extrn	__SetVramSeg		:near
		extrn	__AddVramBase_ebx	:near
		extrn	__AddVramBase_esi	:near

		include	grplib.inc
		
		assume	cs:cseg, ds:dseg



dseg segment dword 'DATA'

col		dd	0

dseg ends



cseg segment dword 'CODE'

;---------------------------------------------------------------
;	_gpoint : 点の色の読み出し
;		in  EAX : x
;		    EBX : y
;		out EAX : 色
;
;	int gpoint(int x,int y);
;---------------------------------------------------------------

		align 4



gpoint		proc
		push	ebx
		pushfd
		mov	eax,[esp+8+4]
		mov	ebx,[esp+8+8]
		call	_gpoint
		popfd
		pop	ebx
		ret
gpoint		endp



_gpoint		proc
		pushad
		push	es
		mov	ecx,[_nowscrmod]
		cmp	ecx,3
		jl	#end
		cmp	ecx,5
		jge	#0
		call	gpoint_16
		jmp	#end
#0:		cmp	ecx,9
		jge	#1
		call	gpoint_32a
		jmp	#end
#1:		cmp	ecx,12
		jge	#2
		call	gpoint_32b
		jmp	#end
#2:		cmp	ecx,15
		jge	#3
		call	gpoint_256
		jmp	#end
#3:		cmp	ecx,19
		jge	#end
		call	gpoint_32c
#end:		pop	es
		popad
		mov	eax,[col]
		ret
_gpoint		endp



pageadr		macro
		call	__AddVramBase_edi
		endm



gpoint_16	proc
	;edi ← アドレス
		mov	esi,eax
		and	esi,0fff8h
		shr	esi,1
		mov	edi,ebx
		shl	edi,9
		add	edi,esi
		pageadr
	;点の色の読み出し
		call	__SetVramSeg
		mov	edx,es:[edi]	;edx ← DW データ
		mov	ecx,eax		;ecx ← (x % 8) * 4
		and	ecx,7
		lea	ecx,[ecx*4]
		shr	edx,cl		;edx のうち必要なニブルを取り出す
		and	edx,0fh
		mov	[col],edx
		ret
gpoint_16	endp



gpoint_32a	proc
	;edi ← アドレス
		mov	edi,ebx
		shl	edi,9
		add	edi,eax
		add	edi,eax
		pageadr
	;点の色の読み出し
		call	__SetVramSeg
		mov	dx,es:[edi]
		and	edx,7fffh
		mov	[col],edx
		ret
gpoint_32a	endp



gpoint_32b	proc
	;edi ← アドレス
		mov	edi,ebx
		shl	edi,10
		add	edi,eax
		add	edi,eax
		pageadr
	;点の色の読み出し
		call	__SetVramSeg
		mov	dx,es:[edi]
		and	edx,7fffh
		mov	[col],edx
		ret
gpoint_32b	endp


gpoint_256	proc
;★まだ作ってないよん
		ret
gpoint_256	endp


gpoint_32c	proc
	;edi ← アドレス
		mov	edi,ebx
		shl	edi,10
		add	edi,eax
		add	edi,eax
		pageadr
	;点の色の読み出し
		call	__SetVramSeg
		mov	dx,es:[edi]
		and	edx,7fffh
		mov	[col],edx
		ret
gpoint_32c	endp



cseg ends

end