reinetteII+.c

/*
 * Reinette II plus, a french Apple II emulator, using SDL2
 * and powered by puce6502 - a MOS 6502 cpu emulator by the same author
 * Last modified 21st of June 2021
 * Copyright (c) 2020 Arthur Ferreira
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */


#include <stdio.h>
#include <string.h>
#include <SDL2/SDL.h>

#include "puce6502.h"


// memory layout
#define RAMSIZE  0xC000
#define ROMSTART 0xD000
#define ROMSIZE  0x3000
uint8_t ram[RAMSIZE];   // 48K of ram in $000-$BFFF
uint8_t rom[ROMSIZE];   // 12K of rom in $D000-$FFFF

// language card
#define LGCSTART 0xD000
#define LGCSIZE  0x3000
#define BK2START 0xD000
#define BK2SIZE  0x1000
uint8_t lgc[LGCSIZE];   // Language Card 12K in $D000-$FFFF
uint8_t bk2[BK2SIZE];   // bank 2 of Language Card 4K in $D000-$DFFF

// disk ][ prom
#define SL6START 0xC600
#define SL6SIZE  0x0100
uint8_t sl6[SL6SIZE];   // P5A disk ][ prom in slot 6


//================================================================ SOFT SWITCHES

uint8_t KBD   = 0;                                                              // $C000, $C010 ascii value of keyboard input
bool TEXT  = true;                                                              // $C050 CLRTEXT  / $C051 SETTEXT
bool MIXED = false;                                                             // $C052 CLRMIXED / $C053 SETMIXED
bool PAGE2 = false;                                                             // $C054 PAGE2 off / $C055 PAGE2 on
bool HIRES = false;                                                             // $C056 GR       / $C057 HGR
bool LCWR  = true;                                                              // Language Card writable
bool LCRD  = false;                                                             // Language Card readable
bool LCBK2 = true;                                                              // Language Card bank 2 enabled
bool LCWFF = false;                                                             // Language Card pre-write flip flop


//====================================================================== PADDLES

uint8_t PB0 = 0;                                                                // $C061 Push Button 0 (bit 7) / Open Apple
uint8_t PB1 = 0;                                                                // $C062 Push Button 1 (bit 7) / Solid Apple
uint8_t PB2 = 0;                                                                // $C063 Push Button 2 (bit 7) / shift mod !!!
float GCP[2] = { 127.0f, 127.0f };                                              // GC Position ranging from 0 (left) to 255 right
float GCC[2] = { 0.0f };                                                        // $C064 (GC0) and $C065 (GC1) Countdowns
int GCD[2] = { 0 };                                                             // GC0 and GC1 Directions (left/down or right/up)
int GCA[2] = { 0 };                                                             // GC0 and GC1 Action (push or release)
uint8_t GCActionSpeed = 8;                                                      // Game Controller speed at which it goes to the edges
uint8_t GCReleaseSpeed = 8;                                                     // Game Controller speed at which it returns to center
long long int GCCrigger;                                                        // $C070 the tick at which the GCs were reseted

inline static void resetPaddles() {
	GCC[0] = GCP[0] * GCP[0];                                                     // initialize the countdown for both paddles
	GCC[1] = GCP[1] * GCP[1];                                                     // to the square of their actuall values (positions)
	GCCrigger = ticks;                                                            // records the time this was done
}

inline static uint8_t readPaddle(int pdl) {
	const float GCFreq = 6.6;                                                     // the speed at which the GC values decrease

	GCC[pdl] -= (ticks - GCCrigger) / GCFreq;                                     // decreases the countdown
	if (GCC[pdl] <= 0)                                                            // timeout
		return GCC[pdl] = 0;                                                        // returns 0
	return 0x80;                                                                  // not timeout, return something with the MSB set
}


//====================================================================== SPEAKER

#define audioBufferSize 4096                                                    // found to be large enought
Sint8 audioBuffer[2][audioBufferSize] = { 0 };                                  // see in main() for more details
SDL_AudioDeviceID audioDevice;
bool muted = false;                                                             // mute/unmute switch

static void playSound() {
	static long long int lastTick = 0LL;
	static bool SPKR = false;                                                     // $C030 Speaker toggle

	if (!muted) {
		SPKR = !SPKR;                                                               // toggle speaker state
		Uint32 length = (int)((double)(ticks - lastTick) / 10.65625f);              // 1023000Hz / 96000Hz = 10.65625
		lastTick = ticks;
		if (length > audioBufferSize) length = audioBufferSize;
		SDL_QueueAudio(audioDevice, audioBuffer[SPKR], length | 1);                 // | 1 TO HEAR HIGH FREQ SOUNDS
	}
}


//====================================================================== DISK ][

int curDrv = 0;                                                                 // Current Drive - only one can be enabled at a time

struct drive {
	char		 filename[400];                                                       // the full disk image pathname
	bool		 readOnly;                                                            // based on the image file attributes
	uint8_t	 data[232960];                                                        // nibblelized disk image
	bool		 motorOn;                                                             // motor status
	bool		 writeMode;                                                           // writes to file are not implemented
	uint8_t	 track;                                                               // current track position
	uint16_t nibble;                                                              // ptr to nibble under head position
} disk[2] = { 0 };                                                              // two disk ][ drive units


int insertFloppy(SDL_Window *wdo, char *filename, int drv) {

	FILE *f = fopen(filename, "rb");                                              // open file in read binary mode
	if (!f || fread(disk[drv].data, 1, 232960, f) != 232960)                      // load it into memory and check size
		return 0;
	fclose(f);

	sprintf(disk[drv].filename, "%s", filename);                                  // update disk filename record

	f = fopen(filename, "ab");                                                    // try to open the file in append binary mode
	if (f) {                                                                      // success, file is writable
		disk[drv].readOnly = false;                                                 // update the readOnly flag
		fclose(f);                                                                  // and close it untouched
	} else {
		disk[drv].readOnly = true;                                                  // f is NULL, no writable, no need to close it
	}
	char title[1000];                                                             // UPDATE WINDOW TITLE
	int i, a, b;

	i = a = 0;
	while (disk[0].filename[i] != 0)                                              // find start of filename for disk0
		if (disk[0].filename[i++] == '\\') a = i;
	i = b = 0;
	while (disk[1].filename[i] != 0)                                              // find start of filename for disk1
		if (disk[1].filename[i++] == '\\') b = i;

	sprintf(title, "Reinette ][+   D1: %s   D2: %s", disk[0].filename + a, disk[1].filename + b);
	SDL_SetWindowTitle(wdo, title);                                               // updates window title

	return 1;
}


int saveFloppy(int drive) {
	if (!disk[drive].filename[0]) return 0;                                       // no file loaded into drive
	if (disk[drive].readOnly) return 0;                                           // file is read only write no aptempted

	FILE *f = fopen(disk[drive].filename, "wb");
	if (!f) return 0;                                                             // could not open the file in write overide binary

	if (fwrite(disk[drive].data, 1, 232960, f) != 232960) {                       // failed to write the full file (disk full ?)
		fclose(f);                                                                  // release the ressource
		return 0;
	}
	fclose(f);                                                                    // success, release the ressource
	return 1;
}


void stepMotor(uint16_t address) {
	static bool phases[2][4] = { 0 };                                             // phases states (for both drives)
	static bool phasesB[2][4] = { 0 };                                            // phases states Before
	static bool phasesBB[2][4] = { 0 };                                           // phases states Before Before
	static int pIdx[2] = { 0 };                                                   // phase index (for both drives)
	static int pIdxB[2] = { 0 };                                                  // phase index Before
	static int halfTrackPos[2] = { 0 };

	address &= 7;
	int phase = address >> 1;

	phasesBB[curDrv][pIdxB[curDrv]] = phasesB[curDrv][pIdxB[curDrv]];
	phasesB[curDrv][pIdx[curDrv]]   = phases[curDrv][pIdx[curDrv]];
	pIdxB[curDrv] = pIdx[curDrv];
	pIdx[curDrv]  = phase;

	if (!(address & 1)) {                                                         // head not moving (PHASE x OFF)
		phases[curDrv][phase] = false;
		return;
	}

	if ((phasesBB[curDrv][(phase + 1) & 3]) && (--halfTrackPos[curDrv] < 0))      // head is moving in
		halfTrackPos[curDrv] = 0;

	if ((phasesBB[curDrv][(phase - 1) & 3]) && (++halfTrackPos[curDrv] > 140))    // head is moving out
		halfTrackPos[curDrv] = 140;

	phases[curDrv][phase] = true;                                                 // update track#
	disk[curDrv].track = (halfTrackPos[curDrv] + 1) / 2;
}


inline void setDrv(int drv) {
	disk[drv].motorOn = disk[!drv].motorOn || disk[drv].motorOn;                  // if any of the motors were ON
	disk[!drv].motorOn = false;                                                   // motor of the other drive is set to OFF
	curDrv = drv;                                                                 // set the current drive
}


//========================================== MEMORY MAPPED SOFT SWITCHES HANDLER
// this function is called from readMem and writeMem
// it complements both functions when address is in page $C0
uint8_t softSwitches(uint16_t address, uint8_t value, bool WRT) {
	static uint8_t dLatch = 0;                                                    // disk ][ I/O register

	switch (address) {
  	case 0xC000: return KBD;                                                    // KEYBOARD
  	case 0xC010: KBD &= 0x7F; return KBD;                                       // KBDSTROBE

  	case 0xC020:                                                                // TAPEOUT (shall we listen it ? - try SAVE from applesoft)
  	case 0xC030:                                                                // SPEAKER
  	case 0xC033: playSound(); break;                                            // apple invader uses $C033 to output sound !

  	case 0xC050: TEXT  = false; break;                                          // Graphics
  	case 0xC051: TEXT  = true;  break;                                          // Text
  	case 0xC052: MIXED = false; break;                                          // Mixed off
  	case 0xC053: MIXED = true;  break;                                          // Mixed on
  	case 0xC054: PAGE2 = false; break;                                          // PAGE2 off
  	case 0xC055: PAGE2 = true;  break;                                          // PAGE2 on
  	case 0xC056: HIRES = false; break;                                          // HiRes off
  	case 0xC057: HIRES = true;  break;                                          // HiRes on

  	case 0xC061: return PB0;                                                    // Push Button 0
  	case 0xC062: return PB1;                                                    // Push Button 1
  	case 0xC063: return PB2;                                                    // Push Button 2
  	case 0xC064: return readPaddle(0);                                          // Paddle 0
  	case 0xC065: return readPaddle(1);                                          // Paddle 1

  	case 0xC070: resetPaddles(); break;                                         // paddle timer RST

    case 0xC080:                                                                // LANGUAGE CARD :
  	case 0xC084: LCBK2 = 1; LCRD = 1; LCWR = 0;      LCWFF = 0;    break;       // LC2RD
  	case 0xC081:
  	case 0xC085: LCBK2 = 1; LCRD = 0; LCWR |= LCWFF; LCWFF = !WRT; break;       // LC2WR
  	case 0xC082:
  	case 0xC086: LCBK2 = 1; LCRD = 0; LCWR = 0;      LCWFF = 0;    break;       // ROMONLY2
  	case 0xC083:
  	case 0xC087: LCBK2 = 1; LCRD = 1; LCWR |= LCWFF; LCWFF = !WRT; break;       // LC2RW
  	case 0xC088:
  	case 0xC08C: LCBK2 = 0; LCRD = 1; LCWR = 0;      LCWFF = 0;    break;       // LC1RD
  	case 0xC089:
  	case 0xC08D: LCBK2 = 0; LCRD = 0; LCWR |= LCWFF; LCWFF = !WRT; break;       // LC1WR
  	case 0xC08A:
  	case 0xC08E: LCBK2 = 0; LCRD = 0; LCWR = 0;      LCWFF = 0;    break;       // ROMONLY1
  	case 0xC08B:
  	case 0xC08F: LCBK2 = 0; LCRD = 1; LCWR |= LCWFF; LCWFF = !WRT; break;       // LC1RW

		case 0xC0E0:
		case 0xC0E1:
		case 0xC0E2:
		case 0xC0E3:
		case 0xC0E4:
    case 0xC0E5:
		case 0xC0E6:
		case 0xC0E7: stepMotor(address); break;                                     // MOVE DRIVE HEAD

  	case 0xCFFF:
  	case 0xC0E8: disk[curDrv].motorOn = false; break;                           // MOTOROFF
  	case 0xC0E9: disk[curDrv].motorOn = true;  break;                           // MOTORON

  	case 0xC0EA: setDrv(0); break;                                              // DRIVE0EN
  	case 0xC0EB: setDrv(1); break;                                              // DRIVE1EN

  	case 0xC0EC:                                                                // Shift Data Latch
  		if (disk[curDrv].writeMode)                                               // writting
  			disk[curDrv].data[disk[curDrv].track*0x1A00+disk[curDrv].nibble]=dLatch;// good luck gcc
  		else                                                                      // reading
  			dLatch=disk[curDrv].data[disk[curDrv].track*0x1A00+disk[curDrv].nibble];// easy peasy
  		disk[curDrv].nibble = (disk[curDrv].nibble + 1) % 0x1A00;                 // turn floppy of 1 nibble
  		return dLatch;

  	case 0xC0ED: dLatch = value; break;                                         // Load Data Latch

  	case 0xC0EE:                                                                // latch for READ
  		disk[curDrv].writeMode = false;
  		return disk[curDrv].readOnly ? 0x80 : 0;                                  // check protection

  	case 0xC0EF: disk[curDrv].writeMode = true; break;                          // latch for WRITE
	}
	return ticks % 0xFF;                                                          // catch all, gives a 'floating' value
}


//======================================================================= MEMORY
// these two functions are imported into puce6502.c

uint8_t readMem(uint16_t address) {
	if (address < RAMSIZE)
		return ram[address];                                                        // RAM

	if (address >= ROMSTART) {
		if (!LCRD)
			return rom[address - ROMSTART];                                           // ROM

		if (LCBK2 && (address < 0xE000))
			return bk2[address - BK2START];                                           // BK2

		return lgc[address - LGCSTART];                                             // LC
	}

	if ((address & 0xFF00) == SL6START)
		return sl6[address - SL6START];                                             // disk][

	if ((address & 0xF000) == 0xC000)
		return softSwitches(address, 0, false);                                     // Soft Switches

	return ticks & 0xFF;                                                          // catch all, gives a 'floating' value
}


void writeMem(uint16_t address, uint8_t value) {
	if (address < RAMSIZE) {
		ram[address] = value;                                                       // RAM
		return;
	}

	if (LCWR && (address >= ROMSTART)) {
		if (LCBK2 && (address < 0xE000)) {
			bk2[address - BK2START] = value;                                          // BK2
			return;
		}
		lgc[address - LGCSTART] = value;                                            // LC
		return;
	}

	if ((address & 0xF000) == 0xC000) {
		softSwitches(address, value, true);                                         // Soft Switches
		return;
	}
}


//========================================================== PROGRAM ENTRY POINT

int main(int argc, char *argv[]) {


	//========================================================= SDL INITIALIZATION

	int zoom = 2;
	uint8_t tries = 0;                                                            // for disk ][ speed-up access
	SDL_Event event;
	SDL_bool running = true, paused = false, ctrl = false, shift = false, alt = false;

	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO) < 0) {
		printf("failed to initialize SDL2 : %s", SDL_GetError());
		return -1;
	}

	SDL_Window *wdo = SDL_CreateWindow("Reinette ][+", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 280 * zoom, 192 * zoom, SDL_WINDOW_OPENGL);
	SDL_Renderer *rdr = SDL_CreateRenderer(wdo, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
	SDL_SetRenderDrawBlendMode(rdr, SDL_BLENDMODE_NONE);                          // SDL_BLENDMODE_BLEND);
	SDL_EventState(SDL_DROPFILE, SDL_ENABLE);                                     // ask SDL2 to read dropfile events
	SDL_RenderSetScale(rdr, zoom, zoom);
	SDL_Surface *sshot;                                                           // used later for the screenshots


	//=================================================== SDL AUDIO INITIALIZATION

	SDL_AudioSpec desired = { 96000, AUDIO_S8, 1, 0, 4096, 0, 0, NULL, NULL };
	audioDevice = SDL_OpenAudioDevice(NULL, 0, &desired, NULL, SDL_FALSE);        // get the audio device ID
	SDL_PauseAudioDevice(audioDevice, muted);                                     // unmute it (muted is false)
	uint8_t volume = 4;

	for (int i = 0; i < audioBufferSize; i++) {                                   // two audio buffers,
		audioBuffer[true][i] = volume;                                              // one used when SPKR is true
		audioBuffer[false][i] = -volume;                                            // the other when SPKR is false
	}


	//===================================== VARIABLES USED IN THE VIDEO PRODUCTION

	int TextCache[24][40] = { 0 };
	int LoResCache[24][40] = { 0 };
	int HiResCache[192][40] = { 0 };                                              // check which Hi-Res 7 dots needs redraw
	uint8_t previousBit[192][40] = { 0 };                                         // the last bit value of the byte before.

	enum characterAttribute { A_NORMAL, A_INVERSE, A_FLASH } glyphAttr;           // character attribute in TEXT
	uint8_t flashCycle = 0;                                                       // TEXT cursor flashes at 2Hz

	SDL_Rect drvRect[2] = { { 272, 188, 4, 4 }, { 276, 188, 4, 4 } };             // disk drive status squares
	SDL_Rect pixelGR = { 0, 0, 7, 4 };                                            // a block in LoRes
	SDL_Rect dstRect = { 0, 0, 7, 8 };                                            // the dst character in rdr
	SDL_Rect charRects[128];                                                      // the src from the norm and rev textures
	for (int c = 0; c < 128; c++) {                                               // index of the array = ascii code
		charRects[c].x = 7 * c;
		charRects[c].y = 0;
		charRects[c].w = 7;
		charRects[c].h = 8;
	}

	const int color[16][3] = {                                                    // the 16 low res colors
		{ 0,   0,   0	  }, { 226, 57,  86  }, { 28,  116, 205 }, { 126, 110, 173 },
		{ 31,  129, 128 }, { 137, 130, 122 }, { 86,  168, 228 }, { 144, 178, 223 },
		{ 151, 88,  34	}, { 234, 108, 21  }, { 158, 151, 143 }, { 255, 206, 240 },
		{ 144, 192, 49	}, { 255, 253, 166 }, { 159, 210, 213 }, { 255, 255, 255 }
	};

	const int hcolor[16][3] = {                                                   // the high res colors (2 light levels)
		{ 0,   0,   0   }, { 144, 192, 49  }, { 126, 110, 173 }, { 255, 255, 255 },
		{ 0,   0,   0   }, { 234, 108, 21  }, { 86,  168, 228 }, { 255, 255, 255 },
		{ 0,   0,   0   }, { 63,  55,	 86  }, { 72,  96,  25	}, { 255, 255, 255 },
		{ 0,   0,   0   }, { 43,  84,	 114 }, { 117, 54,  10	}, { 255, 255, 255 }
	};

	const int offsetGR[24] = {                                                    // helper for TEXT and GR video generation
		0x0000, 0x0080, 0x0100, 0x0180, 0x0200, 0x0280, 0x0300, 0x0380,             // lines 0-7
		0x0028, 0x00A8, 0x0128, 0x01A8, 0x0228, 0x02A8, 0x0328, 0x03A8,             // lines 8-15
		0x0050, 0x00D0, 0x0150, 0x01D0, 0x0250, 0x02D0, 0x0350, 0x03D0              // lines 16-23
	};

	const int offsetHGR[192] = {                                                  // helper for HGR video generation
		0x0000, 0x0400, 0x0800, 0x0C00, 0x1000, 0x1400, 0x1800, 0x1C00,             // lines 0-7
		0x0080, 0x0480, 0x0880, 0x0C80, 0x1080, 0x1480, 0x1880, 0x1C80,             // lines 8-15
		0x0100, 0x0500, 0x0900, 0x0D00, 0x1100, 0x1500, 0x1900, 0x1D00,             // lines 16-23
		0x0180, 0x0580, 0x0980, 0x0D80, 0x1180, 0x1580, 0x1980, 0x1D80,
		0x0200, 0x0600, 0x0A00, 0x0E00, 0x1200, 0x1600, 0x1A00, 0x1E00,
		0x0280, 0x0680, 0x0A80, 0x0E80, 0x1280, 0x1680, 0x1A80, 0x1E80,
		0x0300, 0x0700, 0x0B00, 0x0F00, 0x1300, 0x1700, 0x1B00, 0x1F00,
		0x0380, 0x0780, 0x0B80, 0x0F80, 0x1380, 0x1780, 0x1B80, 0x1F80,
		0x0028, 0x0428, 0x0828, 0x0C28, 0x1028, 0x1428, 0x1828, 0x1C28,
		0x00A8, 0x04A8, 0x08A8, 0x0CA8, 0x10A8, 0x14A8, 0x18A8, 0x1CA8,
		0x0128, 0x0528, 0x0928, 0x0D28, 0x1128, 0x1528, 0x1928, 0x1D28,
		0x01A8, 0x05A8, 0x09A8, 0x0DA8, 0x11A8, 0x15A8, 0x19A8, 0x1DA8,
		0x0228, 0x0628, 0x0A28, 0x0E28, 0x1228, 0x1628, 0x1A28, 0x1E28,
		0x02A8, 0x06A8, 0x0AA8, 0x0EA8, 0x12A8, 0x16A8, 0x1AA8, 0x1EA8,
		0x0328, 0x0728, 0x0B28, 0x0F28, 0x1328, 0x1728, 0x1B28, 0x1F28,
		0x03A8, 0x07A8, 0x0BA8, 0x0FA8, 0x13A8, 0x17A8, 0x1BA8, 0x1FA8,
		0x0050, 0x0450, 0x0850, 0x0C50, 0x1050, 0x1450, 0x1850, 0x1C50,
		0x00D0, 0x04D0, 0x08D0, 0x0CD0, 0x10D0, 0x14D0, 0x18D0, 0x1CD0,
		0x0150, 0x0550, 0x0950, 0x0D50, 0x1150, 0x1550, 0x1950, 0x1D50,
		0x01D0, 0x05D0, 0x09D0, 0x0DD0, 0x11D0, 0x15D0, 0x19D0, 0x1DD0,
		0x0250, 0x0650, 0x0A50, 0x0E50, 0x1250, 0x1650, 0x1A50, 0x1E50,
		0x02D0, 0x06D0, 0x0AD0, 0x0ED0, 0x12D0, 0x16D0, 0x1AD0, 0x1ED0,             // lines 168-183
		0x0350, 0x0750, 0x0B50, 0x0F50, 0x1350, 0x1750, 0x1B50, 0x1F50,             // lines 176-183
		0x03D0, 0x07D0, 0x0BD0, 0x0FD0, 0x13D0, 0x17D0, 0x1BD0, 0x1FD0              // lines 184-191
	};


	//================================= LOAD NORMAL AND REVERSE CHARACTERS BITMAPS

	char workDir[1000];                                                           // find the working directory
	int workDirSize = 0, i = 0;
	while (argv[0][i] != '\0') {
		workDir[i] = argv[0][i];
		if (argv[0][++i] == '\\') workDirSize = i + 1;                              // find the last '/' if any
	}

	SDL_Surface *tmpSurface;
	workDir[workDirSize] = 0;
	tmpSurface = SDL_LoadBMP(strncat(workDir, "assets/font-normal.bmp", 23));     // load the normal font
	SDL_Texture *normCharTexture = SDL_CreateTextureFromSurface(rdr, tmpSurface);
	SDL_FreeSurface(tmpSurface);

	workDir[workDirSize] = 0;
	tmpSurface = SDL_LoadBMP(strncat(workDir, "assets/font-reverse.bmp", 24));    // load the reverse font
	SDL_Texture *revCharTexture = SDL_CreateTextureFromSurface(rdr, tmpSurface);
	SDL_FreeSurface(tmpSurface);


	//================================================================== LOAD ROMS

	workDir[workDirSize] = 0;
	FILE *f = fopen(strncat(workDir, "rom/appleII+.rom", 17), "rb");              // load the Apple II+ ROM
	if (!f) {
		SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Fatal error", "Could not locate appleII+.rom in the rom folder", NULL);
		return 1;                                                                   // exit
	}
	if (fread(rom, 1, ROMSIZE, f) != ROMSIZE) {                                   // the file is too small
		SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Fatal error", "appleII+.rom should be exactly 12 KB", NULL);
		return 1;                                                                   // exit
	}
	fclose(f);

	workDir[workDirSize] = 0;
	f = fopen(strncat(workDir, "rom/diskII.rom", 15), "rb");                      // load the P5A disk ][ PROM
	if (!f) {
		SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Fatal error", "Could not locate diskII.rom in the rom folder", NULL);
		return 1;                                                                   // exit
	}
	if (fread(sl6, 1, 256, f) != 256) {                                           // file too small
		SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Fatal error", "diskII.rom should be exactly 256 bytes", NULL);
		return 1;                                                                   // exit
	}
	fclose(f);


	//========================================================== VM INITIALIZATION

	if (argc > 1) insertFloppy(wdo, argv[1], 0);                                  // load floppy if provided at command line

	// reset the CPU
	puce6502RST();                                                                // reset the 6502

	// dirty hack, fix soon... if I understand why
	ram[0x4D] = 0xAA;   // Joust crashes if this memory location equals zero
	ram[0xD0] = 0xAA;   // Planetoids won't work if this memory location equals zero


	//================================================================== MAIN LOOP

	while (running) {

		if (!paused) {                                                              // the apple II is clocked at 1023000.0 Hhz
			puce6502Exec(17050);                                                      // execute instructions for 1/60 of a second
			while (disk[curDrv].motorOn && ++tries)                                   // until motor is off or i reaches 255+1=0
				puce6502Exec(5000);                                                     // speed up drive access artificially
		}


		//=============================================================== USER INPUT

		while (SDL_PollEvent(&event)) {
			alt   = SDL_GetModState() & KMOD_ALT   ? true : false;
			ctrl  = SDL_GetModState() & KMOD_CTRL  ? true : false;
			shift = SDL_GetModState() & KMOD_SHIFT ? true : false;
			PB0 = alt   ? 0xFF : 0x00;                                                // update push button 0
			PB1 = ctrl  ? 0xFF : 0x00;                                                // update push button 1
			PB2 = shift ? 0xFF : 0x00;                                                // update push button 2

			if (event.type == SDL_QUIT) running = false;                              // WM sent TERM signal

			// if (event.type == SDL_WINDOWEVENT) {                                      // pause if the window loses focus
			//   if (event.window.event == SDL_WINDOWEVENT_FOCUS_LOST)
			//     paused = true;
			//   else if (event.window.event == SDL_WINDOWEVENT_FOCUS_GAINED)
			//     paused = false;
			// }

			if (event.type == SDL_DROPFILE) {                                         // user dropped a file
				char *filename = event.drop.file;                                       // get full pathname
				if (!insertFloppy(wdo, filename, alt))                                  // if ALT is pressed : drv 1 else drv 0
					SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Load", "Not a valid nib file", NULL);
				SDL_free(filename);                                                     // free filename memory
				paused = false;                                                         // might already be the case

				if (!(alt || ctrl)) {                                                   // if ALT or CTRL were not pressed
					ram[0x3F4] = 0;                                                       // unset the Power-UP byte
					puce6502RST();                                                        // do a cold reset
					memset(ram, 0, sizeof(ram));
				}
			}

			if (event.type == SDL_KEYDOWN) {                                          // a key has been pressed
				switch (event.key.keysym.sym) {

				// EMULATOR CONTROLS :

				case SDLK_F1:                                                           // SAVES
					if (ctrl) {
						if (saveFloppy(0))
							SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_INFORMATION, "Save", "\nDisk 1 saved back to file\n", NULL);
						else
							SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Save", "\nTError while saving Disk 1\n", NULL);
					} else if (alt) {
						if (saveFloppy(1))
							SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_INFORMATION, "Save", "\nDisk 2 saved back to file\n", NULL);
						else
							SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Save", "\nError while saving Disk 2\n", NULL);
					} else {
						SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_WARNING, "Save", "CTRL-F1 to save D1\nALT-F1 to save D2\n", NULL);
					}
				break;


				case SDLK_F2: {                                                         // SCREENSHOTS
					sshot = SDL_GetWindowSurface(wdo);
					SDL_RenderReadPixels(rdr, NULL, SDL_GetWindowPixelFormat(wdo), sshot->pixels, sshot->pitch);
					workDir[workDirSize] = 0;
					int i = -1, a = 0, b = 0;
					while (disk[0].filename[++i] != '\0') {
						if (disk[0].filename[i] == '\\') a = i;
						if (disk[0].filename[i] == '.') b = i;
					}
					strncat(workDir, "screenshots\\", 14);
					if (a != b)
						strncat(workDir, disk[0].filename + a, b - a);
					else
						strncat(workDir, "no disk", 10);
					strncat(workDir, ".bmp", 5);
					SDL_SaveBMP(sshot, workDir);
					SDL_FreeSurface(sshot);
					}
				break;

				case SDLK_F3:                                                           // PASTE text from clipboard
					if (SDL_HasClipboardText()) {
						char *clipboardText = SDL_GetClipboardText();
						int c = 0;
						while (clipboardText[c]) {                                          // all chars until ascii NUL
							KBD = clipboardText[c++] | 0x80;                                  // set bit7
							if (KBD == 0x8A) KBD = 0x8D;                                      // translate Line Feed to Carriage Ret
							puce6502Exec(400000);                                             // give cpu (and applesoft) some cycles to process each char
						}
						SDL_free(clipboardText);                                            // release the ressource
					}
				break;

				case SDLK_F4:                                                           // VOLUME
					if (shift && (volume < 120)) volume++;                                // increase volume
					if (ctrl && (volume > 0)) volume--;                                   // decrease volume
					if (!ctrl && !shift) muted = !muted;                                  // toggle mute / unmute
					for (int i = 0; i < audioBufferSize; i++) {                           // update the audio buffers,
						audioBuffer[true][i] = volume;                                      // one used when SPKR is true
						audioBuffer[false][i] = -volume;                                    // the other when SPKR is false
					}
				break;

				case SDLK_F5:                                                           // JOYSTICK Release Speed
					if (shift && (GCReleaseSpeed < 127)) GCReleaseSpeed += 2;             // increase Release Speed
					if (ctrl && (GCReleaseSpeed > 1)) GCReleaseSpeed -= 2;                // decrease Release Speed
					if (!ctrl && !shift) GCReleaseSpeed = 8;                              // reset Release Speed to 8
				break;

				case SDLK_F6:                                                           // JOYSTICK Action Speed
					if (shift && (GCActionSpeed < 127)) GCActionSpeed += 2;               // increase Action Speed
					if (ctrl && (GCActionSpeed > 1)) GCActionSpeed -= 2;                  // decrease Action Speed
					if (!ctrl && !shift) GCActionSpeed = 8;                               // reset Action Speed to 8
				break;

				case SDLK_F7:                                                           // ZOOM
					if (shift && (zoom < 8)) zoom++;                                      // zoom in
					if (ctrl && (zoom > 1)) zoom--;                                       // zoom out
					if (!ctrl && !shift) zoom = 2;                                        // reset zoom to 2
					SDL_SetWindowSize(wdo, 280 * zoom, 192 * zoom);                       // update window size
					SDL_RenderSetScale(rdr, zoom, zoom);                                  // update renderer size
				break;

				case SDLK_F10: paused = !paused; break;                                  // toggle pause

				case SDLK_F11: puce6502RST(); break;                                    // simulate a reset

				case SDLK_F12:                                                          // help box
					SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_INFORMATION, "Help",
						  "\tReinette ][ plus v0.4.8\n"
							"\n"
              "ctrl F1\twrites the changes of the floppy in drive 0\n"
              "alt F1\twrites the changes of the floppy in drive 1\n"
              "\n"
							"F2\tsave a screenshot into the screenshots directory\n"
              "F3\tpaste text from clipboard\n"
              "\n"
							"F4\tmute / un-mute sound\n"
              "shift F4\tincrease volume\n"
              "ctrl F4\tdecrease volume\n"
              "\n"
							"F5\treset joystick release speed\n"
              "shift F5\tincrease joystick release speed\n"
              "crtl F5\tdecrease joystick release speed\n"
              "\n"
							"F6\treset joystick action speed\n"
              "shift F6\tincrease joystick action speed\n"
              "crtl F6\tdecrease joystick action speed\n"
              "\n"
							"F7\treset zoom to 2:1\n"
              "shift F7\tincrease zoom up to 8:1\n"
              "ctrl F7\tdecrease zoom down to 1:1\n"
							"\n"
              "F10\tpause / un-pause the emulator\n"
							"F11\treset\n"
              "\n"
							"F12\tthis help\n"
              "\n"
							"More information at github.com/ArthurFerreira2\n", NULL);
				break;

				// EMULATED KEYS :

				case SDLK_a:            KBD = ctrl ? 0x81: 0xC1;   break;               // a
				case SDLK_b:            KBD = ctrl ? 0x82: 0xC2;   break;               // b STX
				case SDLK_c:            KBD = ctrl ? 0x83: 0xC3;   break;               // c ETX
				case SDLK_d:            KBD = ctrl ? 0x84: 0xC4;   break;               // d EOT
				case SDLK_e:            KBD = ctrl ? 0x85: 0xC5;   break;               // e
				case SDLK_f:            KBD = ctrl ? 0x86: 0xC6;   break;               // f ACK
				case SDLK_g:            KBD = ctrl ? 0x87: 0xC7;   break;               // g BELL
				case SDLK_h:            KBD = ctrl ? 0x88: 0xC8;   break;               // h BS
				case SDLK_i:            KBD = ctrl ? 0x89: 0xC9;   break;               // i HTAB
				case SDLK_j:            KBD = ctrl ? 0x8A: 0xCA;   break;               // j LF
				case SDLK_k:            KBD = ctrl ? 0x8B: 0xCB;   break;               // k VTAB
				case SDLK_l:            KBD = ctrl ? 0x8C: 0xCC;   break;               // l FF
				case SDLK_m:            KBD = ctrl ? shift ? 0x9D: 0x8D: 0xCD; break;   // m CR ]
				case SDLK_n:            KBD = ctrl ? shift ? 0x9E: 0x8E: 0xCE; break;   // n ^
				case SDLK_o:            KBD = ctrl ? 0x8F: 0xCF;   break;               // o
				case SDLK_p:            KBD = ctrl ? shift ? 0x80: 0x90: 0xD0; break;   // p @
				case SDLK_q:            KBD = ctrl ? 0x91: 0xD1;   break;               // q
				case SDLK_r:            KBD = ctrl ? 0x92: 0xD2;   break;               // r
				case SDLK_s:            KBD = ctrl ? 0x93: 0xD3;   break;               // s ESC
				case SDLK_t:            KBD = ctrl ? 0x94: 0xD4;   break;               // t
				case SDLK_u:            KBD = ctrl ? 0x95: 0xD5;   break;               // u NAK
				case SDLK_v:            KBD = ctrl ? 0x96: 0xD6;   break;               // v
				case SDLK_w:            KBD = ctrl ? 0x97: 0xD7;   break;               // w
				case SDLK_x:            KBD = ctrl ? 0x98: 0xD8;   break;               // x CANCEL
				case SDLK_y:            KBD = ctrl ? 0x99: 0xD9;   break;               // y
				case SDLK_z:            KBD = ctrl ? 0x9A: 0xDA;   break;               // z
				case SDLK_LEFTBRACKET:  KBD = ctrl ? 0x9B: 0xDB;   break;               // [ {
				case SDLK_BACKSLASH:    KBD = ctrl ? 0x9C: 0xDC;   break;               // \ |
				case SDLK_RIGHTBRACKET: KBD = ctrl ? 0x9D: 0xDD;   break;               // ] }
				case SDLK_BACKSPACE:    KBD = ctrl ? 0xDF: 0x88;   break;               // BS
				case SDLK_0:            KBD = shift? 0xA9: 0xB0;   break;               // 0 )
				case SDLK_1:            KBD = shift? 0xA1: 0xB1;   break;               // 1 !
				case SDLK_2:            KBD = shift? 0xC0: 0xB2;   break;               // 2
				case SDLK_3:            KBD = shift? 0xA3: 0xB3;   break;               // 3 #
				case SDLK_4:            KBD = shift? 0xA4: 0xB4;   break;               // 4 $
				case SDLK_5:            KBD = shift? 0xA5: 0xB5;   break;               // 5 %
				case SDLK_6:            KBD = shift? 0xDE: 0xB6;   break;               // 6 ^
				case SDLK_7:            KBD = shift? 0xA6: 0xB7;   break;               // 7 &
				case SDLK_8:            KBD = shift? 0xAA: 0xB8;   break;               // 8 *
				case SDLK_9:            KBD = shift? 0xA8: 0xB9;   break;               // 9 (
				case SDLK_QUOTE:        KBD = shift? 0xA2: 0xA7;   break;               // ' "
				case SDLK_EQUALS:       KBD = shift? 0xAB: 0xBD;   break;               // = +
				case SDLK_SEMICOLON:    KBD = shift? 0xBA: 0xBB;   break;               // ; :
				case SDLK_COMMA:        KBD = shift? 0xBC: 0xAC;   break;               // , <
				case SDLK_PERIOD:       KBD = shift? 0xBE: 0xAE;   break;               // . >
				case SDLK_SLASH:        KBD = shift? 0xBF: 0xAF;   break;               // / ?
				case SDLK_MINUS:        KBD = shift? 0xDF: 0xAD;   break;               // - _
				case SDLK_BACKQUOTE:    KBD = shift? 0xFE: 0xE0;   break;               // ` ~
				case SDLK_LEFT:         KBD = 0x88;                break;               // BS
				case SDLK_RIGHT:        KBD = 0x95;                break;               // NAK
				case SDLK_SPACE:        KBD = 0xA0;                break;
				case SDLK_ESCAPE:       KBD = 0x9B;                break;               // ESC
				case SDLK_RETURN:       KBD = 0x8D;                break;               // CR

				// EMULATED JOYSTICK :

				case SDLK_KP_1:         GCD[0] = -1; GCA[0] = 1;   break;               // pdl0 <-
				case SDLK_KP_3:         GCD[0] = 1;  GCA[0] = 1;   break;               // pdl0 ->
				case SDLK_KP_5:         GCD[1] = -1; GCA[1] = 1;   break;               // pdl1 <-
				case SDLK_KP_2:         GCD[1] = 1;  GCA[1] = 1;   break;               // pdl1 ->
				}
			}

			if (event.type == SDL_KEYUP) {
				switch (event.key.keysym.sym) {
				case SDLK_KP_1:         GCD[0] = 1;  GCA[0] = 0;   break;               // pdl0 ->
				case SDLK_KP_3:         GCD[0] = -1; GCA[0] = 0;   break;               // pdl0 <-
				case SDLK_KP_5:         GCD[1] = 1;  GCA[1] = 0;   break;               // pdl1 ->
				case SDLK_KP_2:         GCD[1] = -1; GCA[1] = 0;   break;               // pdl1 <-
				}
			}
		}

		for (int pdl = 0; pdl < 2; pdl++) {                                         // update the two paddles positions
			if (GCA[pdl]) {                                                           // actively pushing the stick
				GCP[pdl] += GCD[pdl] * GCActionSpeed;
				if (GCP[pdl] > 255) GCP[pdl] = 255;
				if (GCP[pdl] < 0)   GCP[pdl] = 0;
			} else {                                                                  // the stick is return back to center
				GCP[pdl] += GCD[pdl] * GCReleaseSpeed;
				if (GCD[pdl] == 1  && GCP[pdl] > 127) GCP[pdl] = 127;
				if (GCD[pdl] == -1 && GCP[pdl] < 127) GCP[pdl] = 127;
			}
		}


		//============================================================= VIDEO OUTPUT

		// HIGH RES GRAPHICS
		if (!TEXT && HIRES) {
			uint16_t word;
			uint8_t bits[16], bit, pbit, colorSet, even;
			uint16_t vRamBase = 0x2000 + PAGE2 * 0x2000;
			uint8_t lastLine = MIXED ? 160 : 192;
			uint8_t colorIdx = 0;                                                     // to index the color arrays

			for (int line = 0; line < lastLine; line++) {                             // for every line
				for (int col = 0; col < 40; col += 2) {                                 // for every 7 horizontal dots
					int x = col * 7;
					even = 0;

					word = (uint16_t)(ram[vRamBase + offsetHGR[line] + col + 1]) << 8;    // store the two next bytes into 'word'
					word +=           ram[vRamBase + offsetHGR[line] + col];              // in reverse order

					if (HiResCache[line][col] != word || !flashCycle) {                   // check if this group of 7 dots need a redraw

						for (bit=0; bit < 16; bit++)                                        // store all bits 'word' into 'bits'
							bits[bit] = (word >> bit) & 1;
						colorSet = bits[7] * 4;                                             // select the right color set
						pbit = previousBit[line][col];                                      // the bit value of the left dot
						bit = 0;                                                            // starting at 1st bit of 1st byte

						while (bit < 15) {                                                  // until we reach bit7 of 2nd byte
							if (bit == 7) {                                                   // moving into the second byte
								colorSet = bits[15] * 4;                                        // update the color set
								bit++;                                                          // skip bit 7
							}
							colorIdx = even + colorSet + (bits[bit] << 1) + (pbit);
							SDL_SetRenderDrawColor(rdr, hcolor[colorIdx][0], hcolor[colorIdx][1], hcolor[colorIdx][2], SDL_ALPHA_OPAQUE);
							SDL_RenderDrawPoint(rdr, x++, line);
							pbit = bits[bit++];                                               // proceed to the next pixel
							even = even ? 0 : 8;                                              // one pixel every two is darker
						}

						HiResCache[line][col] = word;                                       // update the video cache
						if ((col < 37) && (previousBit[line][col + 2] != pbit)) {           // check color franging effect on the dot after
							previousBit[line][col + 2] = pbit;                                // set pbit and clear the
							HiResCache[line][col + 2] = -1;                                   // video cache for next dot
						}
					}                                                                     // if (HiResCache[line][col] ...
				}
			}
		}

		// lOW RES GRAPHICS
		else if (!TEXT) {                                                           // and not in HIRES
			uint16_t vRamBase = 0x400 + PAGE2 * 0x0400;
			uint8_t lastLine = MIXED ? 20 : 24;
			uint8_t glyph;                                                            // 2 blocks in GR
			uint8_t colorIdx = 0;                                                     // to index the color arrays

			for (int col = 0; col < 40; col++) {                                      // for each column
				pixelGR.x = col * 7;
				for (int line = 0; line < lastLine; line++) {                           // for each row
					pixelGR.y = line * 8;                                                 // first block

					glyph = ram[vRamBase + offsetGR[line] + col];                         // read video memory
					if (LoResCache[line][col] != glyph || !flashCycle) {
						LoResCache[line][col] = glyph;

						colorIdx = glyph & 0x0F;                                              // first nibble
						SDL_SetRenderDrawColor(rdr, color[colorIdx][0], color[colorIdx][1], color[colorIdx][2], SDL_ALPHA_OPAQUE);
						SDL_RenderFillRect(rdr, &pixelGR);

						pixelGR.y += 4;                                                       // second block
						colorIdx = (glyph & 0xF0) >> 4;                                       // second nibble
						SDL_SetRenderDrawColor(rdr, color[colorIdx][0], color[colorIdx][1], color[colorIdx][2], SDL_ALPHA_OPAQUE);
						SDL_RenderFillRect(rdr, &pixelGR);
					}
				}
			}
		}

		// TEXT 40 COLUMNS
		if (TEXT || MIXED) {                                                        // not Full Graphics
			uint16_t vRamBase = 0x400 +PAGE2 * 0x0400;
			uint8_t firstLine = TEXT ? 0 : 20;
			uint8_t glyph;                                                            // a TEXT character

			for (int col = 0; col < 40; col++) {                                      // for each column
				dstRect.x = col * 7;
				for (int line = firstLine; line < 24; line++) {                         // for each row
					dstRect.y = line * 8;

					glyph = ram[vRamBase + offsetGR[line] + col];                         // read video memory
					if (glyph > 0x7F) glyphAttr = A_NORMAL;                               // is NORMAL ?
					else if (glyph < 0x40) glyphAttr = A_INVERSE;                         // is INVERSE ?
					else glyphAttr = A_FLASH;                                             // it's FLASH !

					if (glyphAttr==A_FLASH || TextCache[line][col]!=glyph || !flashCycle){
						TextCache[line][col] = glyph;

						glyph &= 0x7F;                                                        // unset bit 7
						if (glyph > 0x5F) glyph &= 0x3F;                                      // shifts to match
						if (glyph < 0x20) glyph |= 0x40;                                      // the ASCII codes

						if (glyphAttr==A_NORMAL || (glyphAttr==A_FLASH && flashCycle<15))
							SDL_RenderCopy(rdr, normCharTexture, &charRects[glyph], &dstRect);
						else
							SDL_RenderCopy(rdr, revCharTexture, &charRects[glyph], &dstRect);
					}
				}
			}
		}


		//====================================================== DISPLAY DISK STATUS

		if (disk[curDrv].motorOn) {                                                 // drive is active
			if (disk[curDrv].writeMode)
				SDL_SetRenderDrawColor(rdr, 255, 0, 0, 85);                             // red for writes
			else
				SDL_SetRenderDrawColor(rdr, 0, 255, 0, 85);                             // green for reads
			SDL_RenderFillRect(rdr, &drvRect[curDrv]);                                // square actually
		}


		//========================================================= SDL RENDER FRAME

		if (++flashCycle == 30)                                                     // increase cursor flash cycle
			flashCycle = 0;                                                           // reset to zero every half second
		SDL_RenderPresent(rdr);                                                     // swap buffers
	}                                                                             // while (running)


	//================================================ RELEASE RESSOURSES AND EXIT

	SDL_AudioQuit();
	SDL_Quit();
	return 0;
}