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C02/lib6502/file6502.c
Curtis F Kaylor dee6b20bba Enhancements t file6502, run6502
2021-09-19 16:46:45 -04:00

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/* file6502.c - File I/O Command Processor for run6502.c */
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include <direct.h>
#include <dirent.h>
#include "error.h"
#include "lib6502.h"
#include "file6502.h"
typedef uint8_t byte;
typedef uint16_t word;
int debug;
byte *xmemory[16]; //Extended Memory
byte xmembank; //Extended Memory Current Bank
word xmemaddr; //Extended Memory Current Address
word smemaddr; //System Memory Address
#define STRLEN 128
#define STRSIZ STRLEN+1
/* DOS File Attributes */
#define _A_ARCH 0x20 //Archive. Set whenever the file is changed, and cleared by the BACKUP command.
#define _A_HIDDEN 0x02 //Hidden file. Not normally seen with the DIR command, unless the /AH option is used.
#define _A_RDONLY 0x01 //Read-only. File cannot be opened for writing.
#define _A_SUBDIR 0x10 //Subdirectory.
#define _A_SYSTEM 0x04 //System file. Not normally seen with the DIR command, unless the /AS option is used.
/* I/O Blocks for File I/O */
#define MAXIOB 15
#define TDIR 'D'
#define TFILE 'F'
typedef struct dirent dirent;
struct iocb
{
int opened; //Flag: file opened
char type; //Channel Type: TFILE, TDIR
char mode; //File Mode: 'R', 'W'
int recsize; //Record Size (0=None)
FILE *fp; //File Pointer
DIR *dp; //Directory Pointer
int errnum; //Last Error Number
char name[STRSIZ]; //File/Directory Name
};
static struct iocb iocbs[MAXIOB];
static char filename[STRSIZ]; //File name for open
static char filebuff[256]; //File I/O Buffer
static word fileaddr; //File Read/Write Address
static word fileindx; //File Record Size/Number
extern void setdebug(int dbg) {
debug = dbg;
}
static int save(M6502 *mpu, word address, unsigned length, const char *path)
{
FILE *file= 0;
int count= 0;
if (!(file= fopen(path, "wb")))
return 0;
while ((count= fwrite(mpu->memory + address, 1, length, file)))
{
address += count;
length -= count;
}
fclose(file);
return address;
}
static int load(M6502 *mpu, word address, const char *path)
{
FILE *file= 0;
int count= 0;
size_t max= 0x10000 - address;
if (!(file= fopen(path, "rb")))
return 0;
if (debug) fprintf(stderr, "loading %s\nstart address %04x\n", path, address);
while ((count= fread(mpu->memory + address, 1, max, file)) > 0)
{
address += count;
max -= count;
}
fclose(file);
if (debug) fprintf(stderr, "end address %04x\n", address);
return address;
}
int setiocb(int chan, int opened, char type, char mode, int recsize, FILE *fp, DIR *dp, char *name) {
iocbs[chan].opened = opened;
iocbs[chan].type = type;
iocbs[chan].mode = mode;
iocbs[chan].recsize = recsize;
iocbs[chan].fp = fp;
iocbs[chan].dp = dp;
iocbs[chan].errnum = 0;
strcpy(iocbs[chan].name, name);
return 0;
}
void initiocb(int chan) {
setiocb(chan, 0, ' ', ' ', 0, NULL, NULL, "");
if (debug) fprintf(stderr, "cleared iocb for channel %d\n", chan);
}
void initiocbs(void)
{
filename[0] = 0; //Set filename to ""
for (int chan=0; chan<=MAXIOB; chan++)
initiocb(chan);
}
/* Set Error Number and Error Message */
static int seterror(int chan, int errnum) {
if (debug) fprintf(stderr, "setting channel %d error to %d\n", chan, errnum);
iocbs[chan].errnum = errnum;
return errnum;
}
/* Set File Name */
static int setname(M6502 *mpu, word addr, char *name) {
int i;
if (debug) fprintf(stderr, "copying name from address $%04x\n", addr);
for (i=0; i<STRLEN; i++) {
char c = mpu->memory[addr + i & 0xFFFF];
if (c) name[i] = c;
else break;
}
name[i] = 0; //Terminate String
if (debug) fprintf(stderr, "copied %d characters\n", i);
return i;
}
/* Normalize Drive ID */
static char driveid(char drive) {
char id;
if (debug) fprintf(stderr, "normalizing drive $%02x\n", drive);
if (drive == 0 || strchr(" 0@", drive)) id = 0; //Default Drive
else id = toupper(drive);
if (debug) fprintf(stderr, "returning driveid $%02x\n", id);
return id;
}
/* Convert Drive ID to Drive Number *
* Args: driveid - Drive ID (A-Z) *
* Returns: Drive Number (1-126, *
* 0 for Default, or -errno */
static int driveno(char drvid) {
int id = driveid(drvid);
if (debug) fprintf(stderr, "converting drive id %02x\n", drvid);
if (id == 0 ) return 0;
if (id >='A' && id <='Z') return id - '@';
return -seterror(0, ENXIO); //No such device or address
}
/* Change Current Drive *
* Args: drivno - drive number (1-26) *
* Returns: Error (0=None) */
static int chgdrive(char drvno) {
if (debug) fprintf(stderr, "changing default drive to %d: ", drvno);
int r = _chdrive(drvno);
if (r) r = seterror(0, errno);
else if (debug) fprintf(stderr, "default drvno changed\n");
return r;
}
/* Build File Spec */
static int setspec(char *spec, char driveid, char* name, char* dflt) {
if (debug) fprintf(stderr, "building filespec for drive $%02x, name \"%s\"\n", driveid, name);
spec[0] = 0; //Set filespec to ""
int drive = driveno(driveid); if (drive < 0) return seterror(0, -drive);
for (int i = 0; i<STRLEN; i++) if (name[i] == '/') name[i] = '\\'; //Convert Slashes
if (strlen(name) == 0) {
strcpy(name, dflt);
if (debug) fprintf(stderr, "name changed to \"%s\"\n", name);
}
if (drive) {sprintf(spec, "%c:", drive); strncat(spec, name, STRLEN);}
else strncpy(spec, name, STRLEN);
return ENOERROR;
}
/* Find Unused IOCB */
static int uniocb(void) {
int chan;
for (chan=1; chan<=MAXIOB; chan++) {
if (iocbs[chan].opened == 0) break;
if (chan > MAXIOB) {chan = -24; break;}
}
return chan;
}
/* Validate Channel */
static int valchan(int chan, char valtype, FILE *fp) {
int errnum = 0; //Error (none)
if (debug) fprintf(stderr, "validating channel %d\n", chan);
if (chan == 0) {if (fp) iocbs[chan].fp = fp; else errnum = 9; }
else if (chan > MAXIOB) errnum = 44; //Channel number out of range
else if (iocbs[chan].opened == 0) errnum = 9; //Bad file descriptor
else if (iocbs[chan].type != valtype) {
if (debug) fprintf(stderr, "invalid channel type '%c'\n", iocbs[chan].type);
switch (iocbs[chan].type) {
case TDIR: errnum = EISDIR; //Is a directory
case TFILE: errnum = ENOTDIR; //Not a directory
default: errnum = EBADFD; //File descriptor in bad state
}
}
return errnum;
}
/* Write Buffer to Memory */
static int writemem(M6502 *mpu, char* buffer, int count) {
int i;
if (debug) fprintf(stderr, "writing to address %04x\n", fileaddr);
for (i = 0; i<count; i++)
mpu->memory[fileaddr+i] = buffer[i];
if (debug) fprintf(stderr, "wrote %d bytes\n", i);
return i;
}
/* Write String to Memory */
static int writestr(M6502 *mpu, char* buffer, int count) {
int i;
if (debug) fprintf(stderr, "writing '%s' to address %04x\n", buffer, fileaddr);
for (i = 0; i<count; i++) {
char c = buffer[i];
if (c == 0) break;
mpu->memory[fileaddr+i] = c;
}
mpu->memory[fileaddr+i] = 0; //Terminate String
if (debug) fprintf(stderr, "wrote %d characters\n", i);
return i;
}
/* Convert tm struct to readable time */
void strtm(char *s, tm *time) {
sprintf(s, "%d-%02d-%02d %02d:%02d:%02d",
time->tm_year+1900, time->tm_mon, time->tm_mday,
time->tm_hour, time->tm_min, time->tm_sec);
}
int copystring(char *b, char *s, int ofs) {
if (debug) fprintf(stderr, "copying string \"$s\" to buffer at offset %d\n", s, ofs);
for (int i = 0; i < STRLEN; i++) {
if (s[i]) b[ofs++] = s[i]; else break;
}
b[ofs++] = 0;
return ofs;
}
int copytime(char *b, tm *t, int ofs) {
char s[STRLEN]; strtm(s, t);
t->tm_mon = t->tm_mon + 1; //Adjust Zero-based Month
if (debug) fprintf(stderr, "copying timestamp %s to buffer at offset %d\n", s, ofs);
b[ofs++] = t->tm_year; b[ofs++] = t->tm_mon; b[ofs++] = t->tm_mday;
b[ofs++] = t->tm_hour; b[ofs++] = t->tm_min; b[ofs++] = t->tm_sec;
return ofs;
}
int copyword(char *b, word w, int ofs) {
if (debug) fprintf(stderr, "copying word %04x to buffer at offset %d\n", w, ofs);
b[ofs++] = w & 0xFF; b[ofs++] = w >> 8;
return ofs;
}
int copyattrs(char *b, int attr, int ofs) {
b[ofs++] = (attr & _A_ARCH) ? 0xFF : 00;
b[ofs++] = (attr & _A_HIDDEN) ? 0xFF : 00;
b[ofs++] = (attr & _A_RDONLY) ? 0xFF : 00;
b[ofs++] = (attr & _A_SUBDIR) ? 0xFF : 00;
b[ofs++] = (attr & _A_SYSTEM) ? 0xFF : 00;
return ofs;
}
/* Copy dirent to character array matching run6502.h02 *
* struct dirent { *
* struct {char arch, hidden, system, rdonly, subdir, system} attr *
* struct {char year, month, day, hour, minute, second;} time; *
* int size, char name[128];} */
int setentry(char *buffer, dirent *de) {
int offset = 0;
char ts[STRSIZ]; strtm(ts, de->d_time);
if (debug) fprintf(stderr, "copying entry \"%s\", attr=$%02x, size=%d, time=%s\n",
de->d_name, de->d_attr, de->d_size, ts);
offset = copyattrs(buffer, de->d_attr, offset);
offset = copytime(buffer, de->d_time, offset);
offset = copyword(buffer, de->d_size, offset);
offset = copystring(buffer, de->d_name, offset);
return offset;
}
/* Emulate fileio at addr */
extern int filecmd(M6502 *mpu, word addr, byte data) {
const char modes[8][4] = {"r", "rb", "w", "wb", "a", "ab", "a+", "ab+"};
const char ddesc[2][9] = {"creating", "removing"};
const char fdesc[2][10] = {"file", "directory"};
const char qdesc[2][7] = {"string", "line"};
int chan, e, i;
char c, d, m, n, t, mode[4];
char *buffer;
char filespec[STRSIZ], newspec[STRSIZ] ;
struct tm time;
dirent *de;
byte a = mpu->registers->a;
byte x = mpu->registers->x;
byte y = mpu->registers->y;
byte p = mpu->registers->p;
word yx = y << 8 | x;
if (debug) fprintf(stderr, "executing file command '%c' with options %02x,%02x,%02x\n", a, y, x, p);
switch (a) { //File I/O Command
case 'A': //Set filebuffer address - Y.X = address
if (p & 1) {
fileindx = yx;
if (debug) fprintf(stderr, "file index set to %04x\n", fileindx);
} else {
fileaddr = yx;
if (debug) fprintf(stderr, "file address set to %04x\n", fileaddr);
}
break;
//case 'B': //Unused
case 'C': //Close Channel - Y = channel, CC = File, CS = Directory
chan = y;
m = p & 1; t = (m) ? TDIR : TFILE;
if (debug) fprintf(stderr, "closing %s channel %d\n", fdesc[m], chan);
y = valchan(chan, t, NULL); if (y) break;
if (m) e = closedir(iocbs[chan].dp); else e = fclose(iocbs[chan].fp);
if (e) y = seterror(chan, errno); else initiocb(chan);
if (debug) fprintf(stderr, "channel closed\n");
break;
case 'D': //Read Directory - Y = Channel, CC = Entry, CS = Header
chan = y;
x = 0; //Return Value (Read Failed)
y = valchan(chan, TDIR, NULL); if (y) break;
if (p & 1) {
if (debug) fprintf(stderr, "retrieving directory name\n");
x = writestr(mpu, iocbs[chan].name, STRLEN);
} else {
if (debug) fprintf(stderr, "reading directory entry\n");
de = readdir(iocbs[chan].dp);
if (de) {x = setentry(filebuff, de); writemem(mpu, filebuff, x);}
else if (errno != 2) y = seterror(chan, errno);
}
break;
case 'E': //EOF - Y = channel
chan = y;
y = valchan(chan, TFILE, NULL); if (y) break;
y = feof(iocbs[chan].fp);
break;
case 'F': //Flush File - Y = Channel
chan = y;
y = valchan(chan, TFILE, NULL); if (y) break;
x = fflush(iocbs[chan].fp);
if (x) y = seterror(chan, errno);
break;
case 'G': //Get Character - Y = channel
chan = y;
x = 0; //Character read (none)
y = valchan(chan, TFILE, stdin); if (y) break;
c = fgetc(iocbs[chan].fp);
if (feof(iocbs[chan].fp)) {y = EOF; break;}
if (c == EOF) {y = seterror(chan, errno); break;}
x = c & 0xFF;
break;
case 'H': //Get String - Y = channel
chan = y;
x = 0; //Number of Characters read
y = valchan(chan, TFILE, stdin); if (y) break;
char *s = fgets(filebuff, STRLEN, iocbs[chan].fp);
if (s == NULL) {y = seterror(chan, errno); break;}
if (debug) fprintf(stderr, "read string '%s'\n", filebuff);
writestr(mpu, filebuff, STRLEN);
x = strlen(s); fprintf(stderr, "returning %d bytes read\n", x);
break;
case 'I': //Init File System
initiocbs(); //Initialize I/O Control Blocks
break;
case 'J': //Get/Put Word - Y = Channel, Carry Set = Put, Clear = Get
chan = y;
a = valchan(chan, TFILE, NULL); if (y) break;
if (p & 1) {
y = fileaddr >> 8; x = fileaddr & 0xFF;
e = fputc(x, iocbs[chan].fp);
if (e == EOF) {a = seterror(chan, errno); break;}
e = fputc(y, iocbs[chan].fp);
if (e == EOF) {a = seterror(chan, errno); break;}
} else {
c = fgetc(iocbs[chan].fp);
if (feof(iocbs[chan].fp)) {a = EOF; break;}
if (c == EOF) {a = seterror(chan, errno); break;}
x = c & 0xFF;
c = fgetc(iocbs[chan].fp);
if (feof(iocbs[chan].fp)) {a = EOF; break;}
if (c == EOF) {a = seterror(chan, errno); break;}
y = c & 0xFF;
}
break;
case 'K': //REMOVE - Delete File - Y,X = Filename
d = driveid(y);
y = setspec(filespec, d, filename, "."); if (y) break;
if (debug) fprintf(stderr, "removing file '%s'\n", filespec);
e = remove(filespec);
if (e) y=seterror(0, errno);
break;
case 'L': //Load file
//ALLOW SPECIFYING DRIVE ID
a = ENOERROR; //Error (none)
if (debug) fprintf(stderr, "loading file at %04h\n", fileaddr);
e = load(mpu, fileaddr, filename);
if (!e) {a = seterror(0, errno); break;}
y = e >> 8; x = e & 0xff;
break;
case 'M': //MOVE - Rename File - Y = Drive ID
d = driveid(y); //Not Implemented Yet
y = setspec(filespec, d, filename, "."); if (y) break;
y = setspec(newspec, d, filebuff, "."); if (y) break;
if (debug) fprintf(stderr, "renaming file \"%s\" to \"%s\"\n", filename, filebuff);
e = rename(filespec, newspec);
if (e) y=seterror(0, errno); else y=0;
break;
case 'N': //Set Name - Y,X = string address, CC = filename, CS = filebuff
m = p & 1;
if (m) {
x = setname(mpu, yx, filebuff); //Set filebuff and Return Length
if (debug) fprintf(stderr, "filebuff set to \"%s\"\n", filename);
} else {
x = setname(mpu, yx, filename); //Set filename and Return Length
if (debug) fprintf(stderr, "filename set to \"%s\"\n", filename);
}
break;
case 'O': //Open file/directory - Y = Drive#, X = Mode, CC = File, CS = Directory
if (p & 1) {
x = 0; //File channel (none)
d = driveid(y); //Normalize Drive ID
y = setspec(filespec, d, filename, "."); if (y) {seterror(0, y); break;}
chan = uniocb(); if (chan <0) {y = -chan; break;}
if (debug) fprintf(stderr, "opening directory '%s'\n", filespec, mode);
DIR *dp = opendir(filespec);
if (dp == NULL) { y = seterror(0, errno); break;}
if (debug) fprintf(stderr, "directory opened on channel %d\n", chan);
y = setiocb(chan, -1, TDIR, ' ', 0, NULL, dp, filespec); //Setup IOCB
if (y == 0) x = chan;
} else {
m = x >> 5 & 7; //Get Mode Index
x = 0; //File channel (none)
y = ENOERROR; //Error code (none)
strcpy(mode, modes[m]); //Set Mode from Mode Index
chan = uniocb(); if (chan <0) {y = seterror(0, -chan); break;}
if (debug) fprintf(stderr, "opening file '%s' with mode '%s'\n", filename, mode);
FILE *fp = fopen(filename, mode);
if (fp == NULL) { y = seterror(0, errno); break;}
if (debug) fprintf(stderr, "file opened on channel %d\n", chan);
i = (m > 5) ? fileindx : 0; //Set Records Size if Mode RECORD
y = setiocb(chan, -1, TFILE, mode[0], i, fp, NULL, filename); //Setup IOCB
if (y == 0) x = chan;
}
break;
case 'P': //Put character - Y = channel; X = character
chan = y;
c = x;
if (debug) fprintf(stderr, "writing '%c' to channel %d\n", c, chan);
x = 0xFF; //Character written (Error)
y = valchan(chan, TFILE, stdout); if (y) break;
e = fputc(c, iocbs[chan].fp);
if (e == EOF) {y = seterror(chan, errno); break;}
x = e & 0xFF;
break;
case 'Q': //Put String - Y = channel, Carry Set = putline
chan = y;
x = 0; //Number of characters written
y = valchan(chan, TFILE, stdout); if (y) break;
for (i = 0; i<128; i++) {
c = mpu->memory[fileaddr+i];
if (c) filebuff[i] = c;
else break;
}
filebuff[i] = 0;
if (debug) fprintf(stderr, "writing %s '%s'\n", qdesc[p&1], filebuff);
if (p & 1) strcat(filebuff, "\n");
e = fputs(filebuff, iocbs[chan].fp);
if (e == EOF) {y = seterror(chan, errno); break;}
x = strlen(filebuff);
break;
case 'R': //Read bytes - Y = channel, X=Number of Bytes
m = p & 1; //Set Mode: 0 = fread, 1 = fgetr
chan = y;
if (m) {
a = valchan(chan, TFILE, NULL); if (a) break;
if (debug) fprintf(stderr, "selecting record #%d\n", fileindx);
n = iocbs[chan].recsize;
i = fileindx * n;
if (debug) fprintf(stderr, "setting position to %d\n", i);
e = fseek(iocbs[chan].fp, i, SEEK_SET);
if (e) {a = seterror(chan, errno); break;}
} else {
y = valchan(chan, TFILE, NULL); if (y) break;
n = x;
}
if (debug) fprintf(stderr, "reading %d bytes\n", n);
x = fread(filebuff, 1, n, iocbs[chan].fp);
if (debug) fprintf(stderr, "read %d bytes\n", x);
e = ferror(iocbs[chan].fp);
if (e) {seterror(chan, errno); if (m) a = e; else y = e; break; }
writemem(mpu, filebuff, x);
if (m) {
fileindx++; y = fileindx >> 8; x = fileindx & 0xff;
if (debug) fprintf(stderr, "returning record #%d\n", fileindx);
}
break;
case 'S': //Save file Y,X = end address
//CHANGE INPUT PARAMETER TO DRIVE ID
a = ENOERROR; //Error (none)
if (debug) fprintf(stderr, "saving file from %04x to %04x\n", fileaddr, yx);
e = save(mpu, fileaddr, yx-fileaddr-1, filename);
if (!e) {a = seterror(0, errno); break;}
y = e >> 8; x = e & 0xff;
break;
//case 'T': //Unused
case 'U': //Get/Set Current Directory - Y = Drive/Disk ID, CC=Get. CS=Set
if (p & 1) { //Change Directory
d = driveid(y);
y = setspec(filespec, d, filename, "."); if (y) break;
if (debug) fprintf(stderr, "changing directory to \"%s\"\n", filespec);
if (_chdir(filespec)) {y = seterror(0, errno);}
} else { //Get Directory
x = 0; filename[0] = 0; //Clear filename, Set Length to 0
d = driveno(y); if (d < 0) {y=seterror(0, -d); break;}
e = _getdrive(); if (e == 0) {y=seterror(0, errno); break;}
if (d && e != d ) {y = chgdrive(d); if (y) break;}
if (debug) fprintf(stderr, "getting current working directory for drive %d\n", d);
if (_getcwd(filename, STRLEN) == NULL) y = seterror(0, errno);
else {
if (debug) fprintf(stderr, "current working directory ie \"%s\"\n", filename);
x = writestr(mpu, filename, STRLEN);
}
if (d && e != d ) {e = chgdrive(e); if (e) seterror(0, errno);}
}
break;
case 'V': //Get or Set Current Drive, Y=Drive, Carry=Get/Set
if (p & 1) {
if (debug) fprintf(stderr, "changing drive to %c\n", y+'@');
x = _chdrive(y); if (x) y=seterror(0, errno); else y=0;
} else {
x = _getdrive(); if (x) y=0; else y=seterror(0, errno);
if (debug) fprintf(stderr, "current drive is %c\n", x+'@');
}
break;
case 'W': //Write bytes - Y = channel, X = Number of Bytes
m = p & 1; //Set Mode: 0 = fread, 1 = fgetr
chan = y;
if (m) {
a = valchan(chan, TFILE, NULL); if (a) break;
if (debug) fprintf(stderr, "selecting record #%d\n", fileindx);
n = iocbs[chan].recsize;
i = fileindx * n;
if (debug) fprintf(stderr, "setting position to %d\n", i);
e = fseek(iocbs[chan].fp, i, SEEK_SET);
if (e) {a = seterror(chan, errno); break;}
i = ftell(iocbs[chan].fp);
if (debug) fprintf(stderr, "position set to %d\n", i);
} else {
y = valchan(chan, TFILE, NULL); if (y) break;
n = x;
}
for (i = 0; i<n; i++)
filebuff[i] = mpu->memory[fileaddr+i];
if (debug) fprintf(stderr, "writing %d bytes\n", n);
e = fwrite(filebuff, n, 1, iocbs[chan].fp);
if (debug) fprintf(stderr, "fwrite() returned %d\n", e);
if (e == 0) {e = seterror(chan, errno); if (m) a = e; else y = e; break; }
if (m) {
fileindx++; y = fileindx >> 8; x = fileindx & 0xff;
if (debug) fprintf(stderr, "returning record #%d\n", fileindx);
}
break;
case 'X': //Make/Remove Directory - Y = Drive ID, CC = RMDIR, CS = MKDIR
d = driveid(y);
m = p & 1;
y = setspec(filespec, d, filename, "."); if (y) break;
if (debug) fprintf(stderr, "%s directory '%s'\n", ddesc[m], filespec);
if (m) e = _rmdir(filespec);
else e = _mkdir(filespec);
if (e) y=seterror(0, errno);
break;
case 'Y': //Get Last Error: Y=chan
chan = y;
y = ENOERROR; //Set Error to None
x = 0xFF; //Set Result to Invalid
if (chan > MAXIOB) {y = 44; break;}
if (debug) fprintf(stderr, "getting last error for channel %d\n", chan);
x = iocbs[chan].errnum;
char *msg = strerror(x);
if (debug) fprintf(stderr, "retrieved error %d, '%s'\n", x, msg);
writestr(mpu, msg, STRLEN);
break;
case 'Z': //File Position: Y=chan, fileaddr = position, Carry = seek/tell
chan = y;
y = valchan(chan, TFILE, NULL); if (y) break;
if (p & 1) {
e = ftell(iocbs[chan].fp);
if (e < 0) {a = seterror(chan, errno);}
else {
if (debug) fprintf(stderr, "returning position %d\n", e);
a = ENOERROR;
}
y = e >> 8; x = e & 0xff;
} else {
if (fileindx == 0xFFFF) {i = 0; m = SEEK_END;}
else {i = fileindx, m = SEEK_SET;}
if (debug) fprintf(stderr, "seeking position %d\n", i);
e = fseek(iocbs[chan].fp, i, m);
if (e) y = seterror(chan, errno);
}
break;
default:
y = 22; //Error - invalid argument
}
if (debug) fprintf(stderr, "returning values %02x, %02x, %02x, %02x\n", a, y, x, p);
mpu->registers->a = a;
mpu->registers->x = x;
mpu->registers->y = y;
}
/* Emulate system command dispatch at addr */
extern int syscmd(M6502 *mpu, word addr, byte data) {
struct tm time;
dirent *de;
byte a = mpu->registers->a;
byte x = mpu->registers->x;
byte y = mpu->registers->y;
byte p = mpu->registers->p;
word yx = y << 8 | x;
if (debug) fprintf(stderr, "executing system command '%c' with options %02x,%02x,%02x\n", a, y, x, p);
switch(a) {
case 'C': //Get System Clock
if (debug) fprintf(stderr, "reading system clock\n");
clock_t clk = clock(); //Get System Clock
if (debug) fprintf(stderr, "system clock = %d ticks\n", clk);
int i = (clk / 50) & 0xFFFFFF; //Convert to 24-bit integer, 50 ticks per second
a = i >> 16; y = i >> 8; x = i; //with resolution of 50 ticks per second
if (debug) fprintf(stderr, "returning $%02x%02x%02x (%d)\n", a, y, x, clk);
break;
case 'T': //Get/Set Date and Time - YX = tm address; CC = Get, CS = Set
if (p & 1) {
y = 0xFF; //Return Error - Not Implemented
} else {
fileaddr = yx; //Set Struct Address
_getsystime(&time);
x = copytime(filebuff, &time, 0); //Convert time struct
writemem(mpu, filebuff, x); //Write to Memory
y = 0; //Return Error = None
}
break;
default:
y = 22; //Error - invalid argument
}
if (debug) fprintf(stderr, "returning values %02x, %02x, %02x, %02x\n", a, y, x, p);
mpu->registers->a = a;
mpu->registers->x = x;
mpu->registers->y = y;
}
/* Initialize Extended RAM */
extern void initxmem(void) {
for (int i=0; i<16; i++) xmemory[i] = (byte *) malloc(0x10000);
xmembank = 0;
xmemaddr = 0;
}
/* Increment Ext Memory Address and Page */
static void xmemnext() {
xmemaddr++;
if (xmemaddr > 0xFFFF) {xmembank++; xmemaddr = 0;}
if (xmembank > 0x0F) xmembank = 0;
}
/* Read/Write Extended Memory */
static byte readxmem(int inc) {
byte b = xmemory[xmembank][xmemaddr];
//if (debug) fprintf(stderr, "read byte %d from bank %02x address %04x\n", b, xmembank, xmemaddr);
if (inc) xmemnext();
return b;
}
static void writexmem(byte b, int inc) {
//if (debug) fprintf(stderr, "writing byte %d to bank %02x address %04x\n", b, xmembank, xmemaddr);
xmemory[xmembank][xmemaddr] = b;
if (inc) xmemnext();
}
/* Emulate extended memory command dispatch at addr */
extern int xmemcmd(M6502 *mpu, word addr, byte data) {
char mode[2][8] = {"reading", "writing"};
byte a = mpu->registers->a;
byte x = mpu->registers->x;
byte y = mpu->registers->y;
byte p = mpu->registers->p;
word yx = y << 8 | x;
byte cs = (p & 1);
if (debug) fprintf(stderr, "executing ext memory command '%c' with options %02x,%02x,%02x\n", a, y, x, p);
switch(a) {
case 'A': //Get/Set Address - YX = address, CC = get, CS = set
if (cs) {
xmemaddr = yx;
if (debug) fprintf(stderr, "set extended memory address to $%04x\n", xmemaddr);
} else {
if (debug) fprintf(stderr, "returning extended memory address $%04x\n", xmemaddr);
y = xmemaddr >> 8; x = xmemaddr & 0xFF;
}
break;
case 'B': //Get/Set Bank - X/A = bank, CC = get, CS = set
if (cs) {
xmembank = x & 0x0F;
if (debug) fprintf(stderr, "set extended memory bank to $%02x\n", xmembank);
} else {
if (debug) fprintf(stderr, "returning extended memory bank $%02x\n", xmembank);
a = xmembank;
}
break;
case 'C': //Read/Write Byte w/o Increment - X/A = Byte, CC = Read, CS = Write
if (cs) writexmem(x,0); else a = readxmem(0);
break;
case 'M': //Read/Write Bytes to RAM - YX = Byte Count, CC = Read, CS = Write
if (debug) fprintf(stderr, "%s %d bytes: %02x-%04x <-> %04x\n{", mode[cs], yx, xmembank, xmemaddr, smemaddr);
for (int i=0; i<yx; i++) {
if (cs) writexmem(mpu->memory[smemaddr], -1);
else mpu->memory[smemaddr] = readxmem(-1);
if (debug) {if (i) putc(',', stderr); fprintf(stderr, "%d", mpu->memory[smemaddr]);}
smemaddr++; if (smemaddr > 0xFFFF) smemaddr = 0;
}
if (debug) fprintf(stderr, "}\n");
a = xmembank; y = xmemaddr >> 8; x = xmemaddr & 0xFF;
break;
case 'N': //Read/Write Next Byte - X/A = Byte, CC = Read, CS = Write
if (cs) writexmem(x,-1); else a = readxmem(-1);
break;
case 'S': //Set System RAM Address - YX = address
smemaddr = yx;
if (debug) fprintf(stderr, "set system memory address to $%04x\n", smemaddr);
break;
case 'W': //Read/Write Next Word - YX = Word, CC = Read, CS = Write
if (cs) {writexmem(x,-1); writexmem(y,-1);}
else {x = readxmem(-1); y = readxmem(-1);}
break;
case 'X': //Read/Write Bytes to RAM - YX = Byte Count, CC = Read, CS = Write
if (debug) fprintf(stderr, "swapping %d bytes: %02x-%04x <-> %04x\n{", yx, xmembank, xmemaddr, smemaddr);
for (int i=0; i<yx; i++) {
byte temp = mpu->memory[smemaddr];
mpu->memory[smemaddr] = readxmem(-1);
writexmem(temp, -1);
smemaddr++; if (smemaddr > 0xFFFF) smemaddr = 0;
}
a = xmembank; y = xmemaddr >> 8; x = xmemaddr & 0xFF;
break;
default:
if (debug) fprintf(stderr, "invalid command '%x'\n", a);
}
if (debug) fprintf(stderr, "returning values %02x, %02x, %02x, %02x\n", a, y, x, p);
mpu->registers->a = a;
mpu->registers->x = x;
mpu->registers->y = y;
}
/* Read Keys Directly from Console, Eliminating getc() buffering */
extern int getkey(M6502 *mpu, word addr, byte data) {
int a = 0, y=0, x=0; //Initialize Key Press to None
int p = mpu->registers->p;
if (_kbhit()) {
y = _getch();
if (y == 0 || y == 0xE0) {
x = _getch(); //Get Extended Code
a = x | 0x80; //Convert to High ASCII
} else {
a = y;
}
}
if (a) p = p & 0xFD; else p = p | 0x02; //Set Z Flag
if (a > 127) p = p | 0x80; else p = p & 0x7F; //Set N Flag
mpu->registers->a = a;
mpu->registers->x = x;
mpu->registers->y = y;
mpu->registers->p = p;
}
/* Write Character Directly to Console, Eliminating putc() buffering */
extern int putcon(M6502 *mpu, word addr, byte data) {
byte a = mpu->registers->a;
switch (a) {
case 0xD6: a = _cputs("\e[2J"); break;
default: a = _putch(a);
}
mpu->registers->a = a;
}
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