Subversion Repositories Shiroi

/*
 * Troy's TMS9918 Emulator - Utility / helper functions
 *
 * Copyright (c) 2022 Troy Schrapel
 *
 * This code is licensed under the MIT license
 *
 * https://github.com/visrealm/vrEmuTms9918
 *
 */

#include "tms9918util.h"

#ifndef WIN32
#undef VR_EMU_TMS9918_DLLEXPORT
#define VR_EMU_TMS9918_DLLEXPORT
#endif

#undef VR_EMU_TMS9918_DLLEXPORT_CONST
#define VR_EMU_TMS9918_DLLEXPORT_CONST

#define LAST_SPRITE_YPOS 0xD0

/* tms9918 palette */
VR_EMU_TMS9918_DLLEXPORT_CONST uint32_t vrEmuTms9918Palette[] = {
    0x00000000, /* transparent */
    0x000000ff, /* black */
    0x21c942ff, /* medium green */
    0x5edc78ff, /* light green */
    0x5455edff, /* dark blue */
    0x7d75fcff, /* light blue */
    0xd3524dff, /* dark red */
    0x43ebf6ff, /* cyan */
    0xfd5554ff, /* medium red */
    0xff7978ff, /* light red */
    0xd3c153ff, /* dark yellow */
    0xe5ce80ff, /* light yellow */
    0x21b03cff, /* dark green */
    0xc95bbaff, /* magenta */
    0xccccccff, /* grey */
    0xffffffff  /* white */
};

static void clearTmsRam(VrEmuTms9918* tms9918) {
        vrEmuTms9918SetAddressWrite(tms9918, 0x0000);
        vrEmuTms9918WriteByteRpt(tms9918, 0x00, 0x4000);

        vrEmuTms9918SetAddressWrite(tms9918, TMS_DEFAULT_VRAM_SPRITE_ATTR_ADDRESS);
        for(int i = 0; i < 32; ++i) {
                vrEmuTms9918WriteData(tms9918, LAST_SPRITE_YPOS);
                vrEmuTms9918WriteData(tms9918, 0);
                vrEmuTms9918WriteData(tms9918, 0);
                vrEmuTms9918WriteData(tms9918, 0);
        }
}

VR_EMU_TMS9918_DLLEXPORT
void vrEmuTms9918InitialiseGfxI(VrEmuTms9918* tms9918) {
        vrEmuTms9918WriteRegisterValue(tms9918, TMS_REG_0, TMS_R0_EXT_VDP_DISABLE | TMS_R0_MODE_GRAPHICS_I);
        vrEmuTms9918WriteRegisterValue(tms9918, TMS_REG_1, TMS_R1_RAM_16K | TMS_R1_MODE_GRAPHICS_I | TMS_R1_RAM_16K | TMS_R1_DISP_ACTIVE | TMS_R1_INT_ENABLE);
        vrEmuTms9918SetNameTableAddr(tms9918, TMS_DEFAULT_VRAM_NAME_ADDRESS);
        vrEmuTms9918SetColorTableAddr(tms9918, TMS_DEFAULT_VRAM_COLOR_ADDRESS);
        vrEmuTms9918SetPatternTableAddr(tms9918, TMS_DEFAULT_VRAM_PATT_ADDRESS);
        vrEmuTms9918SetSpriteAttrTableAddr(tms9918, TMS_DEFAULT_VRAM_SPRITE_ATTR_ADDRESS);
        vrEmuTms9918SetSpritePattTableAddr(tms9918, TMS_DEFAULT_VRAM_SPRITE_PATT_ADDRESS);
        vrEmuTms9918SetFgBgColor(tms9918, TMS_BLACK, TMS_CYAN);

        clearTmsRam(tms9918);
}

VR_EMU_TMS9918_DLLEXPORT
void vrEmuTms9918InitialiseGfxII(VrEmuTms9918* tms9918) {
        vrEmuTms9918WriteRegisterValue(tms9918, TMS_REG_0, TMS_R0_EXT_VDP_DISABLE | TMS_R0_MODE_GRAPHICS_II);
        vrEmuTms9918WriteRegisterValue(tms9918, TMS_REG_1, TMS_R1_RAM_16K | TMS_R1_MODE_GRAPHICS_II | TMS_R1_RAM_16K | TMS_R1_DISP_ACTIVE | TMS_R1_INT_ENABLE);
        vrEmuTms9918SetNameTableAddr(tms9918, TMS_DEFAULT_VRAM_NAME_ADDRESS);

        /* in Graphics II, Registers 3 and 4 work differently
         *
         * reg3 - Color table
         *   0x7f = 0x0000
         *   0xff = 0x2000
         *
         * reg4 - Pattern table
         *  0x03 = 0x0000
         *  0x07 = 0x2000
         */

        vrEmuTms9918WriteRegisterValue(tms9918, TMS_REG_COLOR_TABLE, 0x7f);
        vrEmuTms9918WriteRegisterValue(tms9918, TMS_REG_PATTERN_TABLE, 0x07);

        vrEmuTms9918SetSpriteAttrTableAddr(tms9918, TMS_DEFAULT_VRAM_SPRITE_ATTR_ADDRESS);
        vrEmuTms9918SetSpritePattTableAddr(tms9918, TMS_DEFAULT_VRAM_SPRITE_PATT_ADDRESS);
        vrEmuTms9918SetFgBgColor(tms9918, TMS_BLACK, TMS_CYAN);

        clearTmsRam(tms9918);

        vrEmuTms9918SetAddressWrite(tms9918, TMS_DEFAULT_VRAM_NAME_ADDRESS);
        for(int i = 0; i < 768; ++i) {
                vrEmuTms9918WriteData(tms9918, i & 0xff);
        }
}