#include <stdio.h>

typedef signed char Sint8;
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 OPC(opc, A, B) {\
	case 0x00|opc: {const Uint8 d=0,r=0;A B} break;\
	case 0x20|opc: {const Uint8 d=1,r=0;A B} break;\
	case 0x40|opc: {const Uint8 d=0,r=1;A B} break;\
	case 0x60|opc: {const Uint8 d=1,r=1;A B} break;\
	case 0x80|opc: {const Uint8 d=0,r=0,k=ptr[0];A ptr[0]=k;B} break;\
	case 0xa0|opc: {const Uint8 d=1,r=0,k=ptr[0];A ptr[0]=k;B} break;\
	case 0xc0|opc: {const Uint8 d=0,r=1,k=ptr[1];A ptr[1]=k;B} break;\
	case 0xe0|opc: {const Uint8 d=1,r=1,k=ptr[1];A ptr[1]=k;B} break;}
#define DEC(m) stk[m][--ptr[m]]
#define INC(m) stk[m][ptr[m]++]
#define IMM a = ram[pc++] << 8, a |= ram[pc++];
#define MOV pc = d ? (Uint16)a : pc + (Sint8)a;
#define POx(o,m) o = DEC(r); if(m) o |= DEC(r) << 8;
#define PUx(i,m,s) if(m) c = (i), INC(s) = c >> 8, INC(s) = c; else INC(s) = i;
#define GOT(o) if(d) o[1] = DEC(r); o[0] = DEC(r);
#define PUT(i,s) INC(s) = i[0]; if(d) INC(s) = i[1];
#define DEO(o,v) emu_deo(o, v[0]); if(d) emu_deo(o + 1, v[1]);
#define DEI(i,v) v[0] = emu_dei(i); if(d) v[1] = emu_dei(i + 1); PUT(v,r)
#define POK(o,v,m) ram[o] = v[0]; if(d) ram[(o + 1) & m] = v[1];
#define PEK(i,v,m) v[0] = ram[i]; if(d) v[1] = ram[(i + 1) & m]; PUT(v,r)

static unsigned int
uxn_eval(Uint16 pc)
{
	Uint16 a, b, c, x[2], y[2], z[2];
	for(;;)
	switch(ram[pc++]) {
	/* BRK */ case 0x00: return 1;
	/* JCI */ case 0x20: if(DEC(0)) { IMM pc += a; } else pc += 2; break;
	/* JMI */ case 0x40: IMM pc += a; break;
	/* JSI */ case 0x60: IMM PUx(pc, 1, 1) pc += a; break;
	/* LI2 */ case 0xa0: INC(0) = ram[pc++]; /* fall-through */
	/* LIT */ case 0x80: INC(0) = ram[pc++]; break;
	/* L2r */ case 0xe0: INC(1) = ram[pc++]; /* fall-through */
	/* LIr */ case 0xc0: INC(1) = ram[pc++]; break;
	/* INC */ OPC(0x01,POx(a,d),PUx(a + 1,d,r))
	/* POP */ OPC(0x02,ptr[r] -= 1 + d;,{})
	/* NIP */ OPC(0x03,GOT(x) ptr[r] -= 1 + d;,PUT(x,r))
	/* SWP */ OPC(0x04,GOT(x) GOT(y),PUT(x,r) PUT(y,r))
	/* ROT */ OPC(0x05,GOT(x) GOT(y) GOT(z),PUT(y,r) PUT(x,r) PUT(z,r))
	/* DUP */ OPC(0x06,GOT(x),PUT(x,r) PUT(x,r))
	/* OVR */ OPC(0x07,GOT(x) GOT(y),PUT(y,r) PUT(x,r) PUT(y,r))
	/* EQU */ OPC(0x08,POx(a,d) POx(b,d),PUx(b == a,0,r))
	/* NEQ */ OPC(0x09,POx(a,d) POx(b,d),PUx(b != a,0,r))
	/* GTH */ OPC(0x0a,POx(a,d) POx(b,d),PUx(b > a,0,r))
	/* LTH */ OPC(0x0b,POx(a,d) POx(b,d),PUx(b < a,0,r))
	/* JMP */ OPC(0x0c,POx(a,d),MOV)
	/* JCN */ OPC(0x0d,POx(a,d) POx(b,0),if(b) MOV)
	/* JSR */ OPC(0x0e,POx(a,d),PUx(pc,1,!r) MOV)
	/* STH */ OPC(0x0f,GOT(x),PUT(x,!r))
	/* LDZ */ OPC(0x10,POx(a,0),PEK(a, x, 0xff))
	/* STZ */ OPC(0x11,POx(a,0) GOT(y),POK(a, y, 0xff))
	/* LDR */ OPC(0x12,POx(a,0),PEK(pc + (Sint8)a, x, 0xffff))
	/* STR */ OPC(0x13,POx(a,0) GOT(y),POK(pc + (Sint8)a, y, 0xffff))
	/* LDA */ OPC(0x14,POx(a,1),PEK(a, x, 0xffff))
	/* STA */ OPC(0x15,POx(a,1) GOT(y),POK(a, y, 0xffff))
	/* DEI */ OPC(0x16,POx(a,0),DEI(a, x))
	/* DEO */ OPC(0x17,POx(a,0) GOT(y),DEO(a, y))
	/* ADD */ OPC(0x18,POx(a,d) POx(b,d),PUx(b + a, d,r))
	/* SUB */ OPC(0x19,POx(a,d) POx(b,d),PUx(b - a, d,r))
	/* MUL */ OPC(0x1a,POx(a,d) POx(b,d),PUx(b * a, d,r))
	/* DIV */ OPC(0x1b,POx(a,d) POx(b,d),PUx(a ? b / a : 0, d,r))
	/* AND */ OPC(0x1c,POx(a,d) POx(b,d),PUx(b & a, d,r))
	/* ORA */ OPC(0x1d,POx(a,d) POx(b,d),PUx(b | a, d,r))
	/* EOR */ OPC(0x1e,POx(a,d) POx(b,d),PUx(b ^ a, d,r))
	/* SFT */ OPC(0x1f,POx(a,0) POx(b,d),PUx(b >> (a & 0xf) << (a >> 4), d,r))
	} 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('\n', 3 + (i == argc - 1));
		}
		while(!dev[0x0f]) {
			char c = fgetc(stdin);
			if(feof(stdin)) break;
			console_input(c, 1);
		}
		console_input('\n', 4);
	}
	return dev[0x0f] & 0x7f;
}