vic6561.h

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/* Test-case for a very simple and inaccurate Commodore VIC-20 emulator using SDL2 library.
   Copyright (C)2016 LGB (Gábor Lénárt) <lgblgblgb@gmail.com>
 
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
 
#ifndef __LGB_VIC6561_H_INCLUDED
#define __LGB_VIC6561_H_INCLUDED
 
/* Defines the X ("dotpos") and Y ("scanline") parameters of the visible (emulated) screen area */
#define SCREEN_FIRST_VISIBLE_SCANLINE    28
#define SCREEN_LAST_VISIBLE_SCANLINE    311
#define SCREEN_FIRST_VISIBLE_DOTPOS      38
#define SCREEN_LAST_VISIBLE_DOTPOS      261
 
/* Usual (X/Y) origin of the screen (left bottom corner) if VIC-I X/Y origin registers are zero */
// maybe SCANLINE ORIGIN is 38 ... I guess :)
//#define SCREEN_ORIGIN_SCANLINE         38
//#define SCREEN_ORIGIN_DOTPOS           12
#define SCREEN_ORIGIN_SCANLINE            0
#define SCREEN_ORIGIN_DOTPOS             12
 
#define LAST_SCANLINE                   311
#define CYCLES_PER_SCANLINE              71
 
extern Uint32 vic_palette[16];                          // VIC palette with native SCREEN_FORMAT aware way. Must be initialized by the emulator
extern int scanline;                                    // scanline counter, must be maintained by the emulator, as increment, checking for all scanlines done, etc
 
extern Uint8 cpu_vic_reg_read ( int addr );
extern void cpu_vic_reg_write ( int addr, Uint8 data );
extern void vic_init ( Uint8 **lo8_pointers, Uint8 **hi4_pointers );
extern void vic_render_line ( void );
extern void vic_vsync ( int relock_texture );
 
 
#endif