#include <stdio.h>

typedef unsigned char Uint8;
typedef unsigned short Uint16;

static unsigned int console_vector;
static Uint8 ram[0x10000], dev[0x100], ptr[2], stk[2][0x100];

static Uint8
emu_dei(const Uint8 port)
{
	return dev[port];
}

static void
emu_deo(const Uint8 port, const Uint8 value)
{
	dev[port] = value;
	switch(port) {
	case 0x11: console_vector = dev[0x10] << 8 | value; return;
	case 0x18: fputc(value, stdout); return;
	case 0x19: fputc(value, stderr); return;
	}
}

#define REM *p -= 1 + _2;
#define DEC s[--(*p)]
#define INC s[(*p)++]
#define MOV { if(_2) pc = a; else pc += (signed char)a; }
#define JMP(x) { c = ram[pc] << 8, c |= ram[pc + 1]; pc += x + 2; }
#define STK(m) Uint8 *s = stk[m], *p = &ptr[m];
#define PO1(o) o = DEC;
#define PO2(o) { PO1(o) o |= DEC << 8; }
#define POx(o) { PO1(o) if(_2) o |= DEC << 8; }
#define POt(o) if(_2) PO1(o[1]) PO1(o[0])
#define PU1(i) INC = i;
#define PU2(i) PU1(i >> 8) PU1(i)
#define PUx(i) c = (i); if(_2) PU1(c >> 8) PU1(c)
#define PUt(i) PU1(i[0]) if(_2) PU1(i[1])
#define PUr(i) stk[!_r][ptr[!_r]++] = i;
#define DEO(o,r) emu_deo(o, r[0]); if(_2) emu_deo(o + 1, r[1]);
#define DEI(i,r) r[0] = emu_dei(i); if(_2) r[1] = emu_dei(i + 1);
#define POK(o,r,m) ram[o] = r[0]; if(_2) ram[(o + 1) & m] = r[1];
#define PEK(i,r,m) r[0] = ram[i]; if(_2) r[1] = ram[(i + 1) & m];

#define OPC(opc, A, B) {\
	case 0x00|opc: {const int _2=0,_r=0;STK(_r)A B} goto step;\
	case 0x20|opc: {const int _2=1,_r=0;STK(_r)A B} goto step;\
	case 0x40|opc: {const int _2=0,_r=1;STK(_r)A B} goto step;\
	case 0x60|opc: {const int _2=1,_r=1;STK(_r)A B} goto step;\
	case 0x80|opc: {const int _2=0,_r=0;STK(_r)int k=*p; A *p=k;B} goto step;\
	case 0xa0|opc: {const int _2=1,_r=0;STK(_r)int k=*p; A *p=k;B} goto step;\
	case 0xc0|opc: {const int _2=0,_r=1;STK(_r)int k=*p; A *p=k;B} goto step;\
	case 0xe0|opc: {const int _2=1,_r=1;STK(_r)int k=*p; A *p=k;B} goto step;}

static unsigned int
uxn_eval(Uint16 pc)
{
	Uint16 a, b, c, x[2], y[2], z[2];
step:
	switch(ram[pc++]) {
	/* BRK */ case 0x00: return 1;
	/* JCI */ case 0x20: if(stk[0][--ptr[0]]) JMP(c) else pc += 2; goto step;
	/* JMI */ case 0x40: JMP(c) goto step;
	/* JSI */ case 0x60: { STK(1) JMP(0) PU2(pc) pc += c; } goto step;
	/* LI2 */ case 0xa0: { STK(0) INC = ram[pc++]; INC = ram[pc++]; } goto step;
	/* LIT */ case 0x80: { stk[0][ptr[0]++] = ram[pc++]; } goto step;
	/* L2r */ case 0xe0: { STK(1) INC = ram[pc++]; INC = ram[pc++]; } goto step;
	/* LIr */ case 0xc0: { stk[1][ptr[1]++] = ram[pc++]; } goto step;
	/* INC */ OPC(0x01,POx(a),PUx(a + 1))
	/* POP */ OPC(0x02,REM,(void)s;)
	/* NIP */ OPC(0x03,POt(x) REM,PUt(x))
	/* SWP */ OPC(0x04,POt(x) POt(y),PUt(x) PUt(y))
	/* ROT */ OPC(0x05,POt(x) POt(y) POt(z),PUt(y) PUt(x) PUt(z))
	/* DUP */ OPC(0x06,POt(x),PUt(x) PUt(x))
	/* OVR */ OPC(0x07,POt(x) POt(y),PUt(y) PUt(x) PUt(y))
	/* EQU */ OPC(0x08,POx(a) POx(b),PU1(b == a))
	/* NEQ */ OPC(0x09,POx(a) POx(b),PU1(b != a))
	/* GTH */ OPC(0x0a,POx(a) POx(b),PU1(b > a))
	/* LTH */ OPC(0x0b,POx(a) POx(b),PU1(b < a))
	/* JMP */ OPC(0x0c,POx(a),MOV)
	/* JCN */ OPC(0x0d,POx(a) PO1(b),if(b) MOV)
	/* JSR */ OPC(0x0e,POx(a),PUr(pc >> 8) PUr(pc) MOV)
	/* STH */ OPC(0x0f,POt(x),PUr(x[0]) if(_2) PUr(x[1]))
	/* LDZ */ OPC(0x10,PO1(a),PEK(a, x, 0xff) PUt(x))
	/* STZ */ OPC(0x11,PO1(a) POt(y),POK(a, y, 0xff))
	/* LDR */ OPC(0x12,PO1(a),PEK(pc + (signed char)a, x, 0xffff) PUt(x))
	/* STR */ OPC(0x13,PO1(a) POt(y),POK(pc + (signed char)a, y, 0xffff))
	/* LDA */ OPC(0x14,PO2(a),PEK(a, x, 0xffff) PUt(x))
	/* STA */ OPC(0x15,PO2(a) POt(y),POK(a, y, 0xffff))
	/* DEI */ OPC(0x16,PO1(a),DEI(a, x) PUt(x))
	/* DEO */ OPC(0x17,PO1(a) POt(y),DEO(a, y))
	/* ADD */ OPC(0x18,POx(a) POx(b),PUx(b + a))
	/* SUB */ OPC(0x19,POx(a) POx(b),PUx(b - a))
	/* MUL */ OPC(0x1a,POx(a) POx(b),PUx(b * a))
	/* DIV */ OPC(0x1b,POx(a) POx(b),PUx(a ? b / a : 0))
	/* AND */ OPC(0x1c,POx(a) POx(b),PUx(b & a))
	/* ORA */ OPC(0x1d,POx(a) POx(b),PUx(b | a))
	/* EOR */ OPC(0x1e,POx(a) POx(b),PUx(b ^ a))
	/* SFT */ OPC(0x1f,PO1(a) POx(b),PUx(b >> (a & 0xf) << (a >> 4)))
	}
	return 0;
}

static void
console_input(int c, unsigned int type)
{
	dev[0x12] = c, dev[0x17] = type;
	if(console_vector)
		uxn_eval(console_vector);
}

int
main(int argc, char **argv)
{
	FILE *f;
	if(argc < 2)
		return fprintf(stdout, "usage: %s file.rom [args..]\n", argv[0]);
	else if(!(f = fopen(argv[1], "rb")))
		return fprintf(stderr, "%s: %s not found.\n", argv[0], argv[1]);
	fread(&ram[0x100], 0xff00, 1, f), fclose(f);
	dev[0x17] = argc > 2;
	if(uxn_eval(0x100) && console_vector) {
		int i = 2;
		for(; i < argc; i++) {
			char c, *p = argv[i];
			while(!dev[0x0f] && (c = *p++))
				console_input(c, 2);
			console_input(0, 3 + (i == argc - 1));
		}
		while(!dev[0x0f]) {
			char c = fgetc(stdin);
			if(feof(stdin)) break;
			console_input(c, 1);
		}
		console_input(0, 4);
	}
	return dev[0x0f] & 0x7f;
}