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#include <pcap.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <sys/stat.h>
#if defined(unix) || defined(__unix__) || defined(__unix) || (defined(__APPLE__) && defined(__MACH__))
#include <unistd.h>
#include <termios.h>
int getch(void) { /* reads from keypress, doesn't echo */
struct termios oldattr, newattr;
int ch;
tcgetattr( STDIN_FILENO, &oldattr );
newattr = oldattr;
newattr.c_iflag &= ~( ICRNL );
newattr.c_lflag &= ~( ICANON | ECHO );
tcsetattr( STDIN_FILENO, TCSANOW, &newattr );
ch = getchar();
tcsetattr( STDIN_FILENO, TCSANOW, &oldattr );
// printf("%d\n", ch);
if(ch==0x1b) exit(0);
return ch==127 ? 8 : ch;
}
int putch(int c) { /* output character to sstdout & flush */
int res=putchar(c);
fflush(stdout);
return res;
}
#endif
int len = 0;
static pcap_t* handle = NULL;
static void pcapdev_init(void) {
char errbuf[PCAP_ERRBUF_SIZE];
pcap_if_t* devices;
if (pcap_findalldevs(&devices, errbuf) == -1) {
fprintf(stderr, "error pcap_findalldevs: %s\n", errbuf);
return;
}
pcap_if_t* device;
for(device = devices; device; device = device->next) {
if (device->description) {
printf(" (%s)\n", device->description);
}
else {
fprintf(stderr, "no device\n");
return;
}
}
device = devices->next->next;
if (NULL == (handle= pcap_open_live(device->name
, 65536, 1, 10 , errbuf))) {
fprintf(stderr, "\nUnable to open the adapter. %s is not supported by WinPcap\n");
pcap_freealldevs(devices);
return;
}
pcap_freealldevs(devices);
}
static unsigned short t;
static unsigned short s;
static unsigned short d[0x20]; /* data stack */
static unsigned short r[0x20]; /* return stack */
static unsigned short pc; /* program counter, counts cells */
static unsigned char dsp, rsp; /* point to top entry */
static unsigned short* memory; /* ram */
static int sx[4] = { 0, 1, -2, -1 }; /* 2-bit sign extension */
static void push(int v) // push v on the data stack
{
dsp = 0x1f & (dsp + 1);
d[dsp] = t;
t = v;
}
static int pop(void) // pop value from the data stack and return it
{
int v = t;
t = d[dsp];
dsp = 0x1f & (dsp - 1);
return v;
}
char eth_poll() {
const u_char* packet;
struct pcap_pkthdr* header;
int res = 0;
while (res == 0)
{
res = pcap_next_ex(handle, &header, &packet);
}
len = (int)header->len;
memcpy(&memory[0x2000], packet, len);
return len;
}
void eth_transmit(void) {
if ((pcap_sendpacket(handle, (char *)(&memory[0x2000]), len) == -1))
{
printf("sorry send error\n");
exit(1);
}
}
static void execute(int entrypoint)
{
int _pc, _t;
int insn = 0x4000 | entrypoint; // first insn: "call entrypoint"
pcapdev_init();
do {
_pc = pc + 1;
if (insn & 0x8000) { // literal
push(insn & 0x7fff);
} else {
int target = insn & 0x1fff;
switch (insn >> 13) {
case 0: // jump
_pc = target;
break;
case 1: // conditional jump
if (pop() == 0)
_pc = target;
break;
case 2: // call
rsp = 31 & (rsp + 1);
r[rsp] = _pc << 1;
_pc = target;
break;
case 3: // alu
if (insn & 0x1000) {/* r->pc */
_pc = r[rsp] >> 1;
}
s = d[dsp];
switch ((insn >> 8) & 0xf) {
case 0: _t = t; break; /* noop */
case 1: _t = s; break; /* copy */
case 2: _t = t+s; break; /* + */
case 3: _t = t&s; break; /* and */
case 4: _t = t|s; break; /* or */
case 5: _t = t^s; break; /* xor */
case 6: _t = ~t; break; /* invert */
case 7: _t = -(t==s); break; /* = */
case 8: _t = -((signed short)s < (signed short)t); break; /* < */
case 9: _t = s>>t; break; /* rshift */
case 0xa: _t = t-1; break; /* 1- */
case 0xb: _t = r[rsp]; break; /* r@ */
case 0xc: _t = (t==0xf008)?eth_poll():(t==0xf001)?1:(t==0xf000)?getch():memory[t>>1]; break; /* @ */
case 0xd: _t = s<<t; break; /* lshift */
case 0xe: _t = (rsp<<8) + dsp; break; /* dsp */
case 0xf: _t = -(s<t); break; /* u< */
}
dsp = 31 & (dsp + sx[insn & 3]); /* dstack+- */
rsp = 31 & (rsp + sx[(insn >> 2) & 3]); /* rstack+- */
if (insn & 0x80) /* t->s */
d[dsp] = t;
if (insn & 0x40) /* t->r */
r[rsp] = t;
if (insn & 0x20) /* s->[t] */
(t==0xf008)?eth_transmit(): (t==0xf002)?(rsp=0):(t==0xf000)?putch(s):(memory[t>>1]=s); /* ! */
t = _t;
break;
}
}
pc = _pc;
insn = memory[pc];
} while (1);
}
/* end of cpu */
/* start of i/o demo */
int main(int argc , char *argv[])
{
unsigned short m[0x4000]; /* 32kb or RAM */
FILE *f = fopen("j1.bin", "rb");
fread(m, 0x2000, sizeof(m[0]), f); /* 0kb - 16kb data and code */
fclose(f);
if (argc>1) { // program name is counted as one
struct stat st;
f = fopen(argv[1], "r");
stat(argv[1], &st);
(&m[0x2000])[0] = st.st_size; /* 16kb - 32kb memory mapped i/o */
fread(&m[0x2001], 0x2000, sizeof(m[0]), f);
fclose(f);
}
memory = m;
execute(0x00);
return 0;
}
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