data/Basic1/hardware-posix.h

/*
 *
 * $Id: hardware-posix.h,v 1.7 2023/07/16 14:17:08 stefan Exp stefan $
 *
 *	Stefan's basic interpreter 
 *
 *	Playing around with frugal programming. See the licence file on 
 *	https://github.com/slviajero/tinybasic for copyright/left.
 *	(GNU GENERAL PUBLIC LICENSE, Version 3, 29 June 2007)
 *
 *	Author: Stefan Lenz, [email protected]
 *
 *	Hardware definition file coming with basic.c aka TinybasicArduino.ino
 *
 *	Link to some of the POSIX OS features to mimic a microcontroller platform
 *	See hardware-arduino for more details on the interface.
 *
 *	Supported: filesystem, real time clock, (serial) I/O on the text console
 *	Not supported: radio, wire, SPI, MQTT
 *
 *	Partially supported: Wiring library on Raspberry PI
 *
 */

#if ! defined(ARDUINO) && ! defined(__HARDWAREH__)
#define __HARDWAREH__ 

/* 
 * Hardware flags of the POSIX systems 
 * POSIXTERMINAL, POSIXVT52TOANSI: ensure compatibility of BASIC programs  
 * 	control characters of BASIC are translated to ANSI, bringing the Aruino 
 * 	VT52 commands to POSIX
 * POSIXSIGNALS: enables signal handling of ^C interrupting programs
 * POSIXNONBLOCKING: non blocking I/O to handle GET and the BREAKCHAR 
 * 	tricky on DOS, not very portable, experimental, use signals instead
 * POSIXFRAMEBUFFER: directly draw to the frame buffer of Raspberry PI
 * 	only tested on this platform
 * POSIXWIRE: simple Raspberry PI wire code
 * POSIXMQTT: analogous to ARDUINOMQTT, send and receive MQTT messages (unfinished)
 * POSIXWIRING: use the (deprectated) wiring code for gpio on Raspberry Pi
 * POSIXPIGPIO: use the pigpio library on a Raspberry PI 
 */

#define POSIXTERMINAL
#define POSIXVT52TOANSI
#define POSIXSIGNALS
#undef POSIXNONBLOCKING
#undef POSIXFRAMEBUFFER
#undef POSIXWIRE
#undef POSIXMQTT
#undef POSIXWIRING
#undef POSIXPIGPIO

/* simulates SPI RAM, only test code, keep undefed if you don't want to do something special */
#undef SPIRAMSIMULATOR

/* use a serial port as printer interface - unfinished - similar to Arduino */
#define ARDUINOPRT

/* used pins and other parameters */

/* set this is you want pin 4 on low interrupting the interpreter */
/* #define BREAKPIN 4 */
#undef BREAKPIN

/* the SIGNAL the interpreters listens to for interrupt */
#define BREAKSIGNAL SIGINT

/* in case of non blocking IO turn on background tasks */
#ifdef POSIXNONBLOCKING
#define BASICBGTASK
#endif

/* frame buffer health check - currently only supported on Raspberry */ 
#ifndef RASPPI
#undef POSIXFRAMEBUFFER
#endif

/* wire parameters for Raspberry*/
#define POSIXI2CBUS 1

/* Wiring Code, which library to use */
#ifdef POSIXWIRING
#include <wiringPi.h>
#endif

#ifdef POSIXPIGPIO
#include <pigpiod_if2.h>
#undef POSIXWIRING
static int pigpio_pi = 0;
#endif

/* 
 * the system type and system capabilities
 */

#if defined(MSDOS)
const char bsystype = SYSTYPE_MSDOS
#elif defined(RASPPI)
const char bsystype = SYSTYPE_PASPPI
#elif defined(MINGW)
const char bsystype = SYSTYPE_MINGW
#else
const char bsystype = SYSTYPE_POSIX;
#endif

/* 
 * Arduino default serial baudrate and serial flags for the 
 * two supported serial interfaces. Set to 0 on POSIX OSes 
 */
const int serial_baudrate = 0;
const int serial1_baudrate = 0;
char sendcr = 0;
short blockmode = 0;

/*  handling time, remember when we started, needed in millis() */
struct timeb start_time;
void timeinit() { ftime(&start_time); }

/* starting wiring for raspberry */
void wiringbegin() {
#ifdef POSIXWIRING
	wiringPiSetup();
#endif
#ifdef POSIXPIGPIO
	pigpio_pi=pigpio_start("localhost","8888");
	printf("** GPIO started with result %d\n", pigpio_pi);
	printf("** pigpio version %d.\n", get_pigpio_version(pigpio_pi));
	printf("** Hardware revision %d.\n", get_hardware_revision(pigpio_pi));
#endif
}

/*
 * signal handling 
 */
#ifdef POSIXSIGNALS
#include <signal.h>
mem_t breaksignal = 0;

/* simple signal handler */
void signalhandler(int sig){
	breaksignal=1;
	signal(BREAKSIGNAL, signalhandler);
}

/* activate signal handling */
void signalon() {
	signal(BREAKSIGNAL, signalhandler);
}

/* deactivate signal handling unused and not yet done*/
void signaloff() {}

#endif

/*
 * helper functions OS, heuristic on how much memory is 
 * available in BASIC
 */
long freememorysize() {
#ifdef MSDOS
	return 48000;
#else
	return 65536;
#endif  
}

long freeRam() {
	return freememorysize();
}

/* 
 * the sleep and restart functions
 */
void restartsystem() { exit(0);}
void activatesleep(long t) {}

/* 
 * start the SPI bus 
 */
void spibegin() {}


/*
 * DISPLAY driver code section, the hardware models define a set of 
 * of functions and definitions needed for the display driver. These are 
 *
 * dsp_rows, dsp_columns: size of the display
 * dspbegin(), dspprintchar(c, col, row), dspclear()
 * 
 * All displays which have this functions can be used with the 
 * generic display driver below.
 * 
 * Graphics displays need to implement the functions 
 * 
 * rgbcolor(), vgacolor()
 * plot(), line(), rect(), frect(), circle(), fcircle() 
 * 
 * Color is currently either 24 bit or 4 bit 16 color vga.
 */
const int dsp_rows=0;
const int dsp_columns=0;
void dspsetupdatemode(char c) {}
void dspwrite(char c){}
void dspbegin() {}
int dspstat(char c) {return 0; }
char dspwaitonscroll() { return 0; }
char dspactive() {return 0; }
void dspsetscrollmode(char c, short l) {}
void dspsetcursor(short c, short r) {}

#ifndef POSIXFRAMEBUFFER
/* these are the graphics commands */
void rgbcolor(int r, int g, int b) {}
void vgacolor(short c) {}
void plot(int x, int y) {}
void line(int x0, int y0, int x1, int y1)   {}
void rect(int x0, int y0, int x1, int y1)   {}
void frect(int x0, int y0, int x1, int y1)  {}
void circle(int x0, int y0, int r) {}
void fcircle(int x0, int y0, int r) {}

/* stubs for the vga code part analogous to ESP32 */
void vgabegin(){}
void vgawrite(char c){}
#else
/* 
 * This is the first draft of the linux framebuffer code 
 * currently very raw, works only if the framebuffer is 24 bit 
 * very few checks, all kind of stuff can go wrong here.
 * 
 * Main ideas and some part of the code came from this
 * article https://www.mikrocontroller.net/topic/379335
 * by Andy W.
 * 
 * Bresenham's algorithm came from the Wikipedia article 
 * and this very comprehensive discussion
 * http://members.chello.at/~easyfilter/bresenham.html
 * by Alois Zingl from the Vienna Technikum. I also recommend
 * his thesis: http://members.chello.at/%7Eeasyfilter/Bresenham.pdf
 * 
 */
#include <sys/fcntl.h>
#include <sys/ioctl.h>
#include <linux/fb.h>
#include <sys/mman.h>
#include <string.h>

/* 'global' variables to store screen info */
char *framemem = 0;
int framedesc = 0;

/* info from the frame buffer itself */
struct fb_var_screeninfo vinfo;
struct fb_fix_screeninfo finfo;
struct fb_var_screeninfo orig_vinfo;

/* the color variable of the frame buffer */
long framecolor = 0xffffff;
int  framevgacolor = 0x0f;
long framescreensize = 0;
int framecolordepth = 0;

/* prepare the framebuffer device */
void vgabegin() {

/* see if we can open the framebuffer device */
	framedesc = open("/dev/fb0", O_RDWR);
	if (!framedesc) {
		printf("** error opening frame buffer \n");
		return;
	} 

/* now get the variable info of the screen */
	if (ioctl(framedesc, FBIOGET_VSCREENINFO, &vinfo)) {
		printf("** error reading screen information \n");
		return;
	}
	printf("** detected screen %dx%d, %dbpp \n", vinfo.xres, vinfo.yres, vinfo.bits_per_pixel);

/* BASIC currently does 24 bit color only */
	memcpy(&orig_vinfo, &vinfo, sizeof(struct fb_var_screeninfo)); 
/*
	vinfo.bits_per_pixel = 24; 
	if (ioctl(framedesc, FBIOPUT_VSCREENINFO, &vinfo)) {
		printf("** error setting variable information \n");
		return;
	}
*/

/* how much color have we got */
	framecolordepth = vinfo.bits_per_pixel;

/* get the fixed information of the screen */
	if (ioctl(framedesc, FBIOGET_FSCREENINFO, &finfo)) {
		printf("Error reading fixed information.\n");
		return;
	}

/* now ready to memory map the screen - evil, we assume 24 bit without checking */

	framescreensize = (framecolordepth/8) * vinfo.xres * vinfo.yres;  
	framemem = (char*)mmap(0, framescreensize, PROT_READ | PROT_WRITE, MAP_SHARED, framedesc, 0);
	if ((int)framemem == -1) {
		printf("** error failed to mmap.\n");
		framemem=0;
		return;
	}

/* if all went well we have valid non -1 framemem and can continue */
}

/* this function does not exist in the ESP32 world because we don't care there */
void vgaend() {
	if ((int)framemem) munmap(framemem, framescreensize); 
	if (ioctl(framedesc, FBIOPUT_VSCREENINFO, &orig_vinfo)) {
		printf("** error re-setting variable information \n");
	}
	close(framedesc);
}

/* set the color variable depending on the color depth*/
void rgbcolor(int r, int g, int b) {
	switch (framecolordepth/8) {
	case 4:
		framecolor = (((long)r << 16) & 0x00ff0000) | (((long)g << 8) & 0x0000ff00) | ((long)b & 0x000000ff); /* untested */
		break;
	case 3:
		framecolor = (((long)r << 16) & 0x00ff0000) | (((long)g << 8) & 0x0000ff00) | ((long)b & 0x000000ff);
		break;
	case 2:
		framecolor = ((long) (r & 0xff) >> 3) << 10 | ((long) (g & 0xff) >> 2) << 6 | ((long) (b & 0xff) >> 3); /* untested */
		break;
	case 1:
		framecolor = ((long) (r & 0xff) >> 5) << 5 | ((long) (g & 0xff) >> 5) << 2 | ((long) (b & 0xff) >> 6); /* untested */
		break;
	}
}

/* this is taken from the Arduino TFT code */
void vgacolor(short c) {
  short base=128;
  framevgacolor=c;
  if (c==8) { rgbcolor(64, 64, 64); return; }
  if (c>8) base=255;
  rgbcolor(base*(c&1), base*((c&2)/2), base*((c&4)/4));  
}

/* plot directly into the framebuffer */
void plot(int x, int y) {
	unsigned long pix_offset;

/* is everything in range, no error here */
	if (x < 0 || y < 0 || x >= vinfo.xres || y >= vinfo.yres) return; 

/* find the memory location */
	pix_offset = (framecolordepth/8) * x + y * finfo.line_length;

	if (pix_offset < 0 || pix_offset+ (framecolordepth/8-1) > framescreensize) return;

/* write to the buffer */
	switch (framecolordepth/8) {
	case 4:
		*((char*)(framemem + pix_offset  )) = (unsigned char)(framecolor         & 0x000000ff);
		*((char*)(framemem + pix_offset+1)) = (unsigned char)((framecolor >>  8) & 0x000000ff);
		*((char*)(framemem + pix_offset+3)) = (unsigned char)((framecolor >> 16) & 0x000000ff);
		break;
	case 3:
		*((char*)(framemem + pix_offset  )) = (unsigned char)(framecolor         & 0x000000ff);
		*((char*)(framemem + pix_offset+1)) = (unsigned char)((framecolor >>  8) & 0x000000ff);
		*((char*)(framemem + pix_offset+2)) = (unsigned char)((framecolor >> 16) & 0x000000ff);
		break;
	case 2:
		*((char*)(framemem + pix_offset  )) = (unsigned char)((framecolor & 0x1f) + (((framecolor >> 5) & 0x03) << 6));
		*((char*)(framemem + pix_offset+1)) = (unsigned char)((framecolor >> 7) & 0xff);
		break;
	case 1:
		*((char*)(framemem + pix_offset  )) = (unsigned char)(framecolor         & 0x000000ff);
		break;
	}

}

/* Bresenham's algorith from Wikipedia */
void line(int x0, int y0, int x1, int y1) {
	int dx, dy, sx, sy;
	int error, e2;
	
	dx=abs(x0-x1);
	sx=x0 < x1 ? 1 : -1;
	dy=-abs(y1-y0);
	sy=y0 < y1 ? 1 : -1;
	error=dx+dy;

	while(1) {
		plot(x0, y0);
		if (x0 == x1 && y0 == y1) break;
		e2=2*error;
		if (e2 > dy) {
			if (x0 == x1) break;
			error=error+dy;
			x0=x0+sx;
		}
		if (e2 <= dx) {
			if (y0 == y1) break;
			error=error+dx;
			y0=y0+sy;
		}
	}
}

/* rects could also be drawn with hline and vline */
void rect(int x0, int y0, int x1, int y1) {
	line(x0, y0, x1, y0);
	line(x1, y0, x1, y1);
	line(x1, y1, x0, y1);
	line(x0, y1, x0, y0); 
}

/* filled rect, also just using line right now */
void frect(int x0, int y0, int x1, int y1) {
	int dx, sx;
	int x;
	sx=x0 < x1 ? 1 : -1;
	for(x=x0; x != x1; x=x+sx) line(x, y0, x, y1);
}

/* Bresenham for circles, based on Alois Zingl's work */
void circle(int x0, int y0, int r) {
	int x, y, err;
	x=-r;
	y=0; 
	err=2-2*r;
	do {
		plot(x0-x, y0+y);
		plot(x0-y, y0-x);
		plot(x0+x, y0-y);
		plot(x0+y, y0+x);
		r=err;
		if (r <= y) err+=++y*2+1;
		if (r > x || err > y) err+=++x*2+1;
	} while (x < 0);
}

/* for filled circles draw lines instead of points */
void fcircle(int x0, int y0, int r) {
	int x, y, err;
	x=-r;
	y=0; 
	err=2-2*r;
	do {
		line(x0-x, y0+y, x0+x, y0+y);
		line(x0+x, y0-y, x0-x, y0-y);
		r=err;
		if (r <= y) err+=++y*2+1;
		if (r > x || err > y) err+=++x*2+1;
	} while (x < 0);
}

/* not needed really, now, later yes ;-) */
void vgawrite(char c) {}
#endif

/* 
 * Keyboard code stubs
 * keyboards can implement 
 * 	kbdbegin()
 * they need to provide
 * 	kbdavailable(), kbdread(), kbdcheckch()
 * the later is for interrupting running BASIC code
 */
void kbdbegin() {}
int kbdstat(char c) {return 0; }
char kbdavailable(){ return 0;}
char kbdread() { return 0;}
char kbdcheckch() { return 0;}

/* vt52 code stubs - unused here - needed for basic.c */
mem_t vt52avail() {return 0;}
char vt52read() { return 0; }

/* Display driver would be here, together with vt52 */

/* 
 * Real Time clock code 
 */
#define HASCLOCK

void rtcbegin() {}

short rtcget(short i) {
	struct timeb thetime;
	struct tm *ltime;
	ftime(&thetime);
	ltime=localtime(&thetime.time);
	switch (i) {
		case 0: 
			return ltime->tm_sec;
		case 1:
			return ltime->tm_min;
		case 2:
			return ltime->tm_hour;
		case 3:
			return ltime->tm_wday;
		case 4:
			return ltime->tm_mday;
		case 5:
			return ltime->tm_mon+1;
		case 6:
			return ltime->tm_year-100;
		default:
			return 0;
	}
}

void rtcset(uint8_t i, short v) {}


/* 
 * Wifi and MQTT code 
 */
#ifndef POSIXMQTT
void netbegin() {}
char netconnected() { return 0; }
void mqttbegin() {}
int mqttstat(char c) {return 0; }
int  mqttstate() {return -1;}
void mqttsubscribe(char *t) {}
void mqttsettopic(char *t) {}
void mqttouts(char *m, short l) {}
void mqttins(char *b, short nb) { z.a=0; };
char mqttinch() {return 0;};
#else 
/* we use mosquitto */
#include <mosquitto.h>
/* we assume to be on the network */
void netbegin() {}
char netconnected() { return 1; }
/* the mqtt code */
void mqttbegin() {}
int mqttstat(char c) {return 0; }
int  mqttstate() {return -1;}
void mqttsubscribe(char *t) {}
void mqttsettopic(char *t) {}
void mqttouts(char *m, short l) {}
void mqttins(char *b, short nb) { z.a=0; };
char mqttinch() {return 0;};
#endif

/* 
 *	EEPROM handling, these function enable the @E array and 
 *	loading and saving to EEPROM with the "!" mechanism
 *	a filesystem based dummy
 */ 
signed char eeprom[EEPROMSIZE];
void ebegin(){ 
	int i;
	FILE* efile;
	for (i=0; i<EEPROMSIZE; i++) eeprom[i]=-1;
	efile=fopen("eeprom.dat", "r");
	if (efile) fread(eeprom, EEPROMSIZE, 1, efile);
}

void eflush(){
	FILE* efile;
	efile=fopen("eeprom.dat", "w");
	if (efile) fwrite(eeprom, EEPROMSIZE, 1, efile);
	fclose(efile);
}

address_t elength() { return EEPROMSIZE; }
void eupdate(address_t a, mem_t c) { if (a>=0 && a<EEPROMSIZE) eeprom[a]=c; }
mem_t eread(address_t a) { if (a>=0 && a<EEPROMSIZE) return eeprom[a]; else return -1;  }

/* 
 *	the wrappers of the arduino io functions, to avoid 
 */	
#if !defined(POSIXWIRING) && !defined(POSIXPIGPIO)
void aread(){ pop(); push(0); }
void dread(){ pop(); push(0); }
void awrite(address_t p, address_t v){}
void dwrite(address_t p, address_t v){}
void pinm(address_t p, address_t m){}
#endif

#ifdef POSIXWIRING
void aread(){ push(analogRead(pop())); }
void dread(){ push(digitalRead(pop())); }


void awrite(address_t p, address_t v){
	if (v >= 0 && v<256) analogWrite(p, v);
	else error(EORANGE);
}

void dwrite(address_t p, address_t v){
	if (v == 0) digitalWrite(p, LOW);
	else if (v == 1) digitalWrite(p, HIGH);
	else error(EORANGE);
}

/* pin Modes without range check, values in wiringPi are different from Arduino*/
void pinm(address_t p, address_t m){
	if (m>=0) pinMode(p, m);
	else error(EORANGE); 
}
#endif

/* the pigpio library */
#ifdef POSIXPIGPIO


void aread(){ pop(); push(0); }


void dread(){ 
	push(gpio_read(pigpio_pi, pop()));
}

void awrite(address_t p, address_t v){
	set_PWM_dutycycle(pigpio_pi, p, v);
}


void dwrite(address_t p, address_t v){
	gpio_write(pigpio_pi, p, v);
}

void pinm(address_t p, address_t m){
	set_mode(pigpio_pi, p, m);
}
#endif

/* we need to do millis by hand except for RASPPI with wiring */
#if !defined(POSIXWIRING)
unsigned long millis() { 
	struct timeb thetime;
	ftime(&thetime);
	return (thetime.time-start_time.time)*1000+(thetime.millitm-start_time.millitm);
}
#endif

void bpulsein() { pop(); pop(); pop(); push(0); }
void bpulseout(short a) { while (a--) pop(); }
void btone(short a) { pop(); pop(); if (a == 3) pop(); }

/* the POSIX code has no yield as it runs on an OS */
void yieldfunction() {}

void longyieldfunction() {
#ifdef BASICBGTASK
/* polling for the BREAKCHAR */
#ifdef POSIXNONBLOCKING
	if (checkch() == BREAKCHAR) breakcondition=1;
#endif
#endif
}

void yieldschedule() {}

/* 
 *	The file system driver - all methods needed to support BASIC fs access
 *	MSDOS to be done 
 *
 * file system code is a wrapper around the POSIX API
 */
void fsbegin(char v) {}
#define FILESYSTEMDRIVER
FILE* ifile;
FILE* ofile;
#ifndef MSDOS
DIR* root;
struct dirent* file; 
#else
void* root;
void* file;
#endif 

/* POSIX OSes always have filesystems */
int fsstat(char c) {return 1; }

/*
 *	File I/O function on an Arduino
 * 
 * filewrite(), fileread(), fileavailable() as byte access
 * open and close is handled separately by (i/o)file(open/close)
 * only one file can be open for write and read at the same time
 */
void filewrite(char c) { 
	if (ofile) 
		fputc(c, ofile); 
	else 
		ert=1;
}

char fileread(){
	char c;
	if (ifile) c=fgetc(ifile); else { ert=1; return 0; }
	if (cheof(c)) ert=-1;
	return c;
}

char ifileopen(const char* filename){
	ifile=fopen(filename, "r");
	// return (int) ifile;
	return ifile!=0;
}

void ifileclose(){
	if (ifile) fclose(ifile);
	ifile=0;	
}

char ofileopen(char* filename, const char* m){
	ofile=fopen(filename, m);
	// return (int) ofile; 
	return ofile!=0;
}

void ofileclose(){ 
	if (ofile) fclose(ofile); 
	ofile=0;
}

int fileavailable(){ return !feof(ifile); }

/*
 * directory handling for the catalog function
 * these methods are needed for a walkthtrough of 
 * one directory
 *
 * rootopen()
 * while rootnextfile()
 * 	if rootisfile() print rootfilename() rootfilesize()
 *	rootfileclose()
 * rootclose()
 */
#ifdef MSDOS
#include <dos.h>
#include <dir.h>
struct ffblk *bffblk; 
#endif

void rootopen() {
#ifndef MSDOS
	root=opendir ("./");
#else 
	(void) findfirst("*.*", bffblk, 0);
#endif
}

int rootnextfile() {
#ifndef MSDOS
  file = readdir(root);
  return (file != 0);
#else 
  return (findnext(bffblk) == 0);
#endif
}

int rootisfile() {
#if !defined(MSDOS) && !defined(MINGW)
  return (file->d_type == DT_REG);
#else
  return 1;
#endif
}

const char* rootfilename() { 
#ifndef MSDOS
  return (file->d_name);
#else
  return (bffblk->ff_name);
#endif  
}

long rootfilesize() { 
#ifndef MSDOS
	return 0;
#else
	return (bffblk->ff_fsize);
#endif
}

void rootfileclose() {}
void rootclose(){
#ifndef MSDOS
  (void) closedir(root);
#endif  
}

/*
 * remove method for files
 */
void removefile(char *filename) {
	remove(filename);
}

/*
 * formatting for fdisk of the internal filesystems
 */
void formatdisk(short i) {
	outsc("Format not implemented on this platform\n");
}

/*
 * Primary serial code, if NONBLOCKING is set, 
 * platform dependent I/O is used. This means that 
 * UNIXes use fcntl() to implement a serialcheckch
 * and MSDOS as well als WIndows use kbhit(). 
 * This serves only to interrupt programs with 
 * BREAKCHAR at the moment. 
 */
#ifdef POSIXNONBLOCKING
#if !defined(MSDOS) && !defined(MINGW)
#include <fcntl.h>

/* we need to poll the serial port in non blocking mode 
		this slows it down so that we don't block an entire core 
		read speed here is one character per millisecond which
		is 8000 baud, no one can type that fast but tedious when
		from stdin */
/*
void freecpu() {
	struct timespec intervall;
	struct timespec rtmp;
	intervall.tv_sec=0;
	intervall.tv_nsec=1000000;
	nanosleep(&intervall, &rtmp);
}
*/

/* for non blocking I/O try to modify the stdin file descriptor */
void serialbegin() {
/* we keep I/O mostly blocking here */
/*
 fcntl(0, F_SETFL, fcntl(0, F_GETFL) | O_NONBLOCK);
*/
}

/* get and unget the character in a non blocking way */
short serialcheckch(){ 
 	fcntl(0, F_SETFL, fcntl(0, F_GETFL) | O_NONBLOCK);
	int ch=getchar();
	ungetc(ch, stdin);
	fcntl(0, F_SETFL, fcntl(0, F_GETFL) & ~O_NONBLOCK);
	return ch;
}

/* check EOF, don't use feof()) here */
short serialavailable() { 
 if (cheof(serialcheckch())) return 0; else return 1;
}

/* two versions of serialread */
char serialread() { 
	char ch;
/* blocking to let the OS handle the wait - this means: no call to byield() in interaction */
	ch=getchar();
	return ch;
/* this is the code that waits - calls byield() often just like on the Arduino */
/*
	while (cheof(serialcheckch())) { byield(); freecpu(); }
	return getchar(); 
*/
}

/* flushes the serial code in non blocking mode */
void serialflush() {
	fcntl(0, F_SETFL, fcntl(0, F_GETFL) | O_NONBLOCK);
	while (!cheof(getchar()));
	fcntl(0, F_SETFL, fcntl(0, F_GETFL) & ~O_NONBLOCK);
}
#else
/* the non blocking MSDOS and MINGW code */
#include <conio.h>
/* we go way back in time here and do it like DOS did it */ 
void serialbegin(){}

/* we go through the terminal on read */
char serialread() { 
	return getchar();
}

/* check if a key is hit, get it and return it */
short serialcheckch(){ 
	if (kbhit()) return getch();
}

/* simple version */
short serialavailable() {
	return 1;
}

/* simple version */
void serialflush() { }
#endif
#else 
/* the blocking code only uses puchar and getchar */
void serialbegin(){}
char serialread() { return getchar(); }
short serialcheckch(){ return 1; }
short serialavailable() { return 1; }
void serialflush() {}
#endif

int serialstat(char c) {
	if (c == 0) return 1;
	if (c == 1) return serial_baudrate;
	return 0;
}

/* send the CSI sequence to start with ANSI */
void sendcsi() {
	putchar(27); putchar('['); /* CSI */
}

/* the vt52 state engine */
#ifdef POSIXVT52TOANSI
#include <stdlib.h>
mem_t dspesc = 0;
mem_t vt52s = 0;
int cursory = 0;
mem_t vt52active = 1;

/* something little */
uint8_t vt52number(char c) {
	uint8_t b=c;
	if (b>31) return b-32; else return 0;
}

/* set the cursor */
void dspsetcursory(int i) {
	cursory=i;
}

/* remember the position */
void dspsetcursorx(int i) {
	sendcsi();
	printf("%d;%dH", abs(cursory)+1, abs(i)+1);
}

/* set colors, vga here */
void dspsetfgcolor(int co) {
	sendcsi();
	if (co < 8) {
		putchar('3');
	} else {
		putchar('9');
		co=co-8;
	}
	putchar('0'+co);
	putchar('m');
}

void dspsetbgcolor(int co) {
	sendcsi();
	if (co < 8) {
		putchar('4');
	} else {
		putchar('1'); putchar('0');
		co=co-8;
	}
	putchar('0'+co);
	putchar('m');
}

/* vt52 state engine, a smaller version of the Arduino code*/
void dspvt52(char* c){
  
/* reading and processing multi byte commands */
  switch (vt52s) {
    case 'Y':
      if (dspesc == 2) { 
        dspsetcursory(vt52number(*c));
        dspesc=1; 
        *c=0;
        return;
      }
      if (dspesc == 1) { 
        dspsetcursorx(vt52number(*c)); 
        *c=0; 
      }
      vt52s=0; 
      break;
    case 'b':
      dspsetfgcolor(vt52number(*c));
      *c=0;
      vt52s=0;
      break;
    case 'c':
      dspsetbgcolor(vt52number(*c));
      *c=0;
      vt52s=0;
      break;
  }
 
/* commands of the terminal in text mode */
  switch (*c) {
    case 'v': /* GEMDOS / TOS extension enable wrap */
      break;
    case 'w': /* GEMDOS / TOS extension disable wrap */
      break;
    case '^': /* Printer extensions - print on */
      break;
    case '_': /* Printer extensions - print off */
      break;
    case 'W': /* Printer extensions - print without display on */
      break;
    case 'X': /* Printer extensions - print without display off */
      break;
    case 'V': /* Printer extensions - print cursor line */
      break;
    case ']': /* Printer extension - print screen */
      break;
    case 'F': /* enter graphics mode */
      break;
    case 'G': /* exit graphics mode */
      break;
    case 'Z': // Ident 
      break;
    case '=': // alternate keypad on 
    case '>': // alternate keypad off 
      break;
    case 'b': // GEMDOS / TOS extension text color 
    case 'c': // GEMDOS / TOS extension background color 
      vt52s=*c;
      dspesc=1;
      *c=0;
      return;
    case 'e': // GEMDOS / TOS extension enable cursor
      break;
    case 'f': // GEMDOS / TOS extension disable cursor 
      break;
    case 'p': // GEMDOS / TOS extension reverse video 
      break;
    case 'q': // GEMDOS / TOS extension normal video 
      break;
    case 'A': // cursor up
    	sendcsi();
    	putchar('A');
      break;
    case 'B': // cursor down 
    	sendcsi();
    	putchar('B');
      break;
    case 'C': // cursor right 
    	sendcsi();
    	putchar('C');
      break; 
    case 'D': // cursor left 
    	sendcsi();
    	putchar('D');
      break;
    case 'E': // GEMDOS / TOS extension clear screen 
    	*c=12; 
    	dspesc=0;
      return;
    case 'H': // cursor home 
    	*c=2;
    	dspesc=0;
      return;  
    case 'Y': // Set cursor position 
      vt52s='Y';
      dspesc=2;
      *c=0;
      return;
    case 'J': // clear to end of screen 
    	sendcsi();
    	putchar('J');
      break;
    case 'd': // GEMDOS / TOS extension clear to start of screen 
    	sendcsi();
    	putchar('1'); putchar('J');
      break;
    case 'K': // clear to the end of line
    	sendcsi();
    	putchar('K');
      break;
    case 'l': // GEMDOS / TOS extension clear line 
    	sendcsi();
    	putchar('2'); putchar('K');
      break;
    case 'o': // GEMDOS / TOS extension clear to start of line
    	sendcsi();
    	putchar('1'); putchar('K');
      break;
    case 'k': // GEMDOS / TOS extension restore cursor
      break;
    case 'j': // GEMDOS / TOS extension save cursor
      break;
    case 'I': // reverse line feed
    	putchar(27);
    	putchar('M');
      break;
    case 'L': // Insert line
      break;
    case 'M': // Delete line - questionable 
    	sendcsi();
    	putchar('2'); putchar('K');
      break;
  }
  dspesc=0;
  *c=0;
}
#endif

void serialwrite(char c) { 

/* the vt52 state engine */
#ifdef POSIXVT52TOANSI
  if (dspesc) { 
    dspvt52(&c); 
    if (c == 0) return;
  }

/* ESC is caught here and we only listen to VT52 not to ANSI */
  if (c == 27 && vt52active) {
  	dspesc=1;
  	return;
  }
#endif

/* this is the character translation routine to convert the Arduino 
	style characters 12 for CLS and 2 for HOME to ANSI, makes 
	BASIC programs more compatible */
#ifdef POSIXTERMINAL
	switch (c) {
/* form feed is clear screen - compatibility with Arduino code */
		case 12:
			sendcsi();
			putchar('2'); putchar('J');
/* home sequence in the arduino code */
		case 2: 
			sendcsi();
			putchar('H');
			return;
	}
#endif

/* finally send the plain character */	
	putchar(c);
}


/*
 * reading from the console with inch 
 * this mixes interpreter levels as inch is used here 
 * this code needs to go to the main interpreter section after 
 * thorough rewrite
 */
void consins(char *b, short nb) {
	char c;
	
	z.a=1;
	while(z.a < nb) {
		c=inch();
		if (c == '\r') c=inch();
		if (c == '\n' || cheof(c)) { /* terminal character is either newline or EOF */
			break;
		} else {
			b[z.a++]=c;
		} 
	}
	b[z.a]=0x00;
	z.a--;
	b[0]=(unsigned char)z.a;
}

/* 
 * handling the second serial interface - only done on Mac so far 
 * test code
 * 
 * Tried to learn from https://www.pololu.com/docs/0J73/15.5
 *
 */
#ifdef ARDUINOPRT
#include <fcntl.h>
#if !defined(MSDOS) && !defined(MINGW)
#include <termios.h>
#endif

/* the file name of the printer port */
int prtfile;

/* the buffer to read one character */
char prtbuf = 0;


void prtbegin() {}

char prtopen(char* filename, int mode) {
#if !defined(MSDOS) && !defined(MINGW)

/* try to open the device file */
	prtfile=open(filename, O_RDWR | O_NOCTTY);
	if (prtfile == -1) {
		perror(filename);
		return 0;
	} 

/* get rid of garbage */
	tcflush(prtfile, TCIOFLUSH);

/* configure the device */
	struct termios opt;
	(void) tcgetattr(prtfile, &opt);


/* raw terminal settings
  opt.c_iflag &= ~(INLCR | IGNCR | ICRNL | IXON | IXOFF);
  opt.c_oflag &= ~(ONLCR | OCRNL);
  opt.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
*/

/* timeout settings on read 100ms, read every character */
  opt.c_cc[VTIME] = 1;
  opt.c_cc[VMIN] = 0;

/* set the baudrate */
  switch (mode) {
  	case 9600: 
			cfsetospeed(&opt, B9600);
			break;
		default:
			cfsetospeed(&opt, B9600);
			break;
  }
  cfsetispeed(&opt, cfgetospeed(&opt));

/* set the termin attributes */
  tcsetattr(prtfile, TCSANOW, &opt);
#endif

	return 1;
}

void prtclose() {
	if (prtfile) close(prtfile);
}

int prtstat(char c) {return 1; }
void prtset(int s) {}

/* write the characters byte by byte */
void prtwrite(char c) {
	int i=write(prtfile, &c, 1);
	if (i != 1) ert=1;
}

/* read just one byte, map no bytes to EOF = -1 */
char prtread() {
	char c;

/* something in the buffer? return it! */
	if (prtbuf) {
		c=prtbuf;
		prtbuf=0;
	} else {
/* try to read */
		int i=read(prtfile, &c, 1);
		if (i < 0) {
			ert=1;
			return 0;
		} 
		if (i == 0) return -1;
	}
	return c;
}

/* not yet implemented */
short prtcheckch(){ 
	if (!prtbuf) { /* try to read */
		int i=read(prtfile, &prtbuf, 1);
		if (i <= 0) prtbuf=0;
	}
	return prtbuf; 
}

short prtavailable(){ 
	return prtcheckch()!=0; 
}

#else
void prtbegin() {}
int prtstat(char c) {return 0; }
void prtset(int s) {}
void prtwrite(char c) {}
char prtread() {return 0;}
short prtcheckch(){ return 0; }
short prtavailable(){ return 0; }
#endif


/* 
 * The wire code 
 */ 
#if defined(POSIXWIRE) && defined(POSIXPIGPIO)
#define HASWIRE
uint8_t wire_slaveid = 0;

/* open the wire connection in pigpio */
void wirebegin() {
}

/* we return the handle here, inconsistent with the Arduino code */
int wirestat(char c) {
	return 1; 
}

void wireopen(char s, char m) {
	if (m == 0) {
		wire_slaveid=s;
	} else if ( m == 1 ) { 
		outsc("** wire slave mode not implemented"); outcr();
	} else 
		error(EORANGE);
}


/* read a number of bytes, depending on the string length */
void wireins(char *b, uint8_t l) {
	int handle;

	handle=i2c_open(pigpio_pi, POSIXI2CBUS, wire_slaveid, 0);
	if (handle < 0) { 
		printf("** wire handle %d returned \n", handle);
		ert=1; 
	}

	z.a=i2c_read_device(pigpio_pi, handle, b+1, l);

	if (z.a < 0) {
		ert=-1;
		z.a=0;
	} 
	b[0]=z.a;

	i2c_close(pigpio_pi, handle);
}



void wireouts(char *b, uint8_t l) {
	int handle;

	handle=i2c_open(pigpio_pi, POSIXI2CBUS, wire_slaveid, 0);
	if (handle < 0) { 
		printf("** wire handle %d returned \n", handle);
		ert=1; 
	}

	if (i2c_write_device(pigpio_pi, handle, b, l) < 0) ert=-1;

	i2c_close(pigpio_pi, handle);
}

short wireavailable() { return 1; }

/* the register access functions */
short wirereadbyte(short port) { 
	int res, handle;
	handle=i2c_open(pigpio_pi, POSIXI2CBUS, port, 0);
	if (handle < 0) { 
		printf("** wire handle %d returned \n", handle);
		ert=1; 
		return -1; 
	}
	
	res=i2c_read_byte(pigpio_pi, handle);
	i2c_close(pigpio_pi, handle);
	return res; 
}

/* use the simple wire byte function */ 
void wirewritebyte(short port, short data) { 
	int res, handle;
	handle=i2c_open(pigpio_pi, POSIXI2CBUS, port, 0);
	if (handle < 0) { ert=1; return; }
	
	ert=i2c_write_byte(pigpio_pi, handle, data);

	i2c_close(pigpio_pi, handle);
}


/* this code used the write byte function twice */
/*
void wirewriteword(short port, short data1, short data2) { 
	int res, handle;
	handle=i2c_open(pigpio_pi, POSIXI2CBUS, port, 0);
	if (handle < 0) { ert=1; return; }
	
	ert=i2c_write_byte(pigpio_pi, handle, data1);
	ert+=i2c_write_byte(pigpio_pi, handle, data2);

	i2c_close(pigpio_pi, handle);
}
*/

/* use the raw access function in a buffer */
void wirewriteword(short port, short data1, short data2) { 
	int res, handle;
	mem_t buf[2];

	handle=i2c_open(pigpio_pi, POSIXI2CBUS, port, 0);
	if (handle < 0) { ert=1; return; }

	buf[0]=data1;
	buf[1]=data2;

	if (i2c_write_device(pigpio_pi, handle, buf, 2) <0 ) ert=-1;

	i2c_close(pigpio_pi, handle);
}

#else
void wirebegin() {}
int wirestat(char c) {return 0; }
void wireopen(char s, char m) {}
void wireins(char *b, uint8_t l) { b[0]=0; z.a=0; }
void wireouts(char *b, uint8_t l) {}
short wireavailable() { return 1; }
short wirereadbyte(short port) { return 0; }
void wirewritebyte(short port, short data) { return; }
void wirewriteword(short port, short data1, short data2) { return; }
#endif

/* 
 *	Read from the radio interface, radio is always block 
 *	oriented. 
 */
int radiostat(char c) {return 0; }
void radioset(int s) {}
void radioins(char *b, short nb) { b[0]=0; b[1]=0; z.a=0; }
void radioouts(char *b, short l) {}
void iradioopen(char *filename) {}
void oradioopen(char *filename) {}
short radioavailable() { return 0; }

/* Arduino sensors */
void sensorbegin() {}
number_t sensorread(short s, short v) {return 0;};

/*
 * Experimental code to simulate 64kb SPI SRAM modules
 * 
 * currently used to test the string code of the mem 
 * interface
 *
 */

#ifdef SPIRAMSIMULATOR
#define USEMEMINTERFACE

static mem_t* spiram;

/* the RAM begin method sets the RAM to byte mode */
address_t spirambegin() {
  spiram=(mem_t*)malloc(65536);
  if (maxnum>32767) return 65534; else return 32766;  
}

/* the simple unbuffered byte write, with a cast to signed char */
void spiramrawwrite(address_t a, mem_t c) {spiram[a]=c;}

/* the simple unbuffered byte read, with a cast to signed char */
mem_t spiramrawread(address_t a) {return spiram[a];}

/* the buffers calls, also only simulated here */

void spiram_rwbufferwrite(address_t a, mem_t c) {spiram[a]=c;}

mem_t spiram_rwbufferread(address_t a) {return spiram[a];}

mem_t spiram_robufferread(address_t a) {return spiram[a];}

/* to handle strings in SPIRAM situations two more buffers are needed 
 * they store intermediate results of string operations. The buffersize 
 * limits the maximum string length indepents of how big strings are set
 */
#define SPIRAMSBSIZE 128
char spistrbuf1[SPIRAMSBSIZE];
char spistrbuf2[SPIRAMSBSIZE];
#endif

/* stub for events */
#ifdef HASEVENTS
mem_t enableevent(mem_t pin) {
	int i;
  if ((i=eventindex(pin))<0) return 0; 
  else {
  	eventlist[i].enabled=1; 
  	return 1;
  }
}
void disableevent(mem_t pin) {}
#endif


#endif