mirror of https://github.com/nmlgc/ReC98.git
105 lines
1.6 KiB
NASM
105 lines
1.6 KiB
NASM
; master library - PC-9801
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;
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; Description:
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; グラフィック画面をハードウェア上スクロールする
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;
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; Function/Procedures:
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; void graph_scrollup( unsigned line ) ;
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;
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; Parameters:
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; line 上にずらすドット数( 0 〜 画面ライン数-1 )
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;
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; Returns:
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; none
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;
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; Binding Target:
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; Microsoft-C / Turbo-C / Turbo Pascal
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;
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; Running Target:
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; PC-9801V
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;
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; Requiring Resources:
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; CPU: 8086
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; GDC
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;
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; Notes:
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; lineが範囲外だと、line=0として振る舞います。
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;
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; Compiler/Assembler:
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; TASM 3.0
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; OPTASM 1.6
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;
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; Author:
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; 恋塚昭彦
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;
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; Revision History:
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; 93/ 2/ 4 Initial: grpscrol.asm
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; 93/ 5/11 [M0.16] GDC 5MHzの時に異常だった(^^; bugfix
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; 93/ 7/19 [M0.20] こんどはGDC 2.5MHzのときに…sz｡
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; 93/ 7/19 Initial: grpscrlu.asm/master.lib 0.20
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; 94/ 1/22 [M0.22] graph_VramZoom対応
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GDCSTATUS equ 0a0h
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GDCCMD equ 0a2h
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GDCPARAM equ 0a0h
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func GRAPH_SCROLLUP ; graph_scrollup() {
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push BP
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mov BP,SP
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; 引数
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@@line = (RETSIZE+1) * 2
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mov BX,[BP+@@line]
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mov DX,graph_VramLines
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sub BX,DX
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sbb AX,AX
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and BX,AX
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add BX,DX ; BX = min( BX, DX )
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sub DX,BX ; DX = graph_VramLines - BX
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mov BP,BX
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mov CX,graph_VramZoom
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shl BX,CL
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shl DX,CL
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mov CL,4
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@@WAITEMPTY:
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jmp $+2
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in AL,GDCSTATUS
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test AL,CL ; 4
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jz short @@WAITEMPTY
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mov AL,70h
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out GDCCMD,AL
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; adr1
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mov AX,BP
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shl AX,1
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shl AX,1
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add AX,BP ; AX = BP*5
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shl AX,1
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shl AX,1
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shl AX,1 ; *8 AX = BP*5*8 = BP*40
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call gdc_outpw
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; line1
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mov AX,DX
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shl AX,CL ; CL = 4
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or AH,CH
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call gdc_outpw
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; adr2
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xor AX,AX
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call gdc_outpw
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; line2
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mov AX,BX
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shl AX,CL ; CL = 4
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or AH,CH
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call gdc_outpw
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pop BP
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ret 2
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endfunc ; }
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