#include <stdio.h>

typedef struct {
	unsigned char dat[0x100], ptr;
} Stack;

static unsigned int console_vector;
static unsigned char ram[0x10000], dev[0x100];
static Stack wst, rst;

/* I/O */

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

static void
emu_deo(const unsigned char port, const unsigned char 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;
	}
}

/* Unroll */

#define OPC(opc, A, B) {\
	case 0x00|opc: {const int _2=0,_r=0;A B;} break;\
	case 0x20|opc: {const int _2=1,_r=0;A B;} break;\
	case 0x40|opc: {const int _2=0,_r=1;A B;} break;\
	case 0x60|opc: {const int _2=1,_r=1;A B;} break;\
	case 0x80|opc: {const int _2=0,_r=0;int k=wst.ptr;A wst.ptr=k;B;} break;\
	case 0xa0|opc: {const int _2=1,_r=0;int k=wst.ptr;A wst.ptr=k;B;} break;\
	case 0xc0|opc: {const int _2=0,_r=1;int k=rst.ptr;A rst.ptr=k;B;} break;\
	case 0xe0|opc: {const int _2=1,_r=1;int k=rst.ptr;A rst.ptr=k;B;} break;\
}

/* Microcode */

#define REM if(_r) rst.ptr -= 1 + _2; else wst.ptr -= 1 + _2;
#define IMM(o) o = ram[pc] << 8 | ram[pc + 1], pc += 2;
#define MOV(x) { if(_2) pc = x; else pc += (signed char)x; }
#define DEC(s) s.dat[--s.ptr]
#define PO1(o) { if(_r) o = DEC(rst); else o = DEC(wst); }
#define PO2(o) { PO1(o) if(_r) o |= DEC(rst) << 8; else o |= DEC(wst) << 8; }
#define POx(o) { if(_2) PO2(o) else PO1(o) }
#define GOT(o) { if(_2) PO1(o[1]) PO1(o[0]) }
#define INC(s) s.dat[s.ptr++]
#define RP1(i) { if(_r) INC(wst) = i; else INC(rst) = i; }
#define PU1(i) { if(_r) INC(rst) = i; else INC(wst) = i; }
#define PUx(i) { if(_2) { c = (i); PU1(c >> 8) PU1(c) } else PU1(i) }
#define PUT(i) { PU1(i[0]) if(_2) PU1(i[1]) }
#define DEI(i,o) o[0] = emu_dei(i); if(_2) o[1] = emu_dei(i + 1); PUT(o)
#define DEO(i,j) emu_deo(i, j[0]); if(_2) emu_deo(i + 1, j[1]);
#define PEK(i,o,m) o[0] = ram[i]; if(_2) o[1] = ram[(i + 1) & m]; PUT(o)
#define POK(i,j,m) ram[i] = j[0]; if(_2) ram[(i + 1) & m] = j[1];

static unsigned int
uxn_eval(unsigned short pc)
{
	unsigned int a, b, c, x[2], y[2], z[2], step = 0x800000;
	while(step--) {
		switch(ram[pc++]) {
		/* BRK */ case 0x00: return 1;
		/* JCI */ case 0x20: IMM(c) if(DEC(wst)) pc += c; break;
		/* JMI */ case 0x40: IMM(c) pc += c; break;
		/* JSI */ case 0x60: IMM(c) INC(rst) = pc >> 8, INC(rst) = pc, pc += c; break;
		/* LI2 */ case 0xa0: INC(wst) = ram[pc++]; /* fall-through */
		/* LIT */ case 0x80: INC(wst) = ram[pc++]; break;
		/* L2r */ case 0xe0: INC(rst) = ram[pc++]; /* fall-through */
		/* LIr */ case 0xc0: INC(rst) = ram[pc++]; break;
		/* INC */ OPC(0x01,POx(a),PUx(a + 1))
		/* POP */ OPC(0x02,REM,{})
		/* NIP */ OPC(0x03,GOT(x) REM,PUT(x))
		/* SWP */ OPC(0x04,GOT(x) GOT(y),PUT(x) PUT(y))
		/* ROT */ OPC(0x05,GOT(x) GOT(y) GOT(z),PUT(y) PUT(x) PUT(z))
		/* DUP */ OPC(0x06,GOT(x),PUT(x) PUT(x))
		/* OVR */ OPC(0x07,GOT(x) GOT(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(a))
		/* JCN */ OPC(0x0d,POx(a) PO1(b),if(b) MOV(a))
		/* JSR */ OPC(0x0e,POx(a),RP1(pc >> 8) RP1(pc) MOV(a))
		/* STH */ OPC(0x0f,GOT(x),RP1(x[0]) if(_2) RP1(x[1]))
		/* LDZ */ OPC(0x10,PO1(a),PEK(a, x, 0xff))
		/* STZ */ OPC(0x11,PO1(a) GOT(y),POK(a, y, 0xff))
		/* LDR */ OPC(0x12,PO1(a),PEK(pc + (signed char)a, x, 0xffff))
		/* STR */ OPC(0x13,PO1(a) GOT(y),POK(pc + (signed char)a, y, 0xffff))
		/* LDA */ OPC(0x14,PO2(a),PEK(a, x, 0xffff))
		/* STA */ OPC(0x15,PO2(a) GOT(y),POK(a, y, 0xffff))
		/* DEI */ OPC(0x16,PO1(a),DEI(a, x))
		/* DEO */ OPC(0x17,PO1(a) GOT(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 && !dev[0x0f])
		uxn_eval(console_vector);
}

int
main(int argc, char **argv)
{
	FILE *f;
	if(argc < 2)
		fprintf(stdout, "usage: %s file.rom [args..]\n", argv[0]);
	else if(!(f = fopen(argv[1], "rb")))
		fprintf(stderr, "uxnmin: %s not found.\n", argv[1]);
	else {
		fread(&ram[0x0100], 0xff00, 1, f), fclose(f);
		dev[0x17] = argc > 2;
		if(uxn_eval(0x0100) && 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] && !feof(stdin))
				console_input(fgetc(stdin), 1);
			console_input(0, 4);
		}
	}
	return dev[0x0f] & 0x7f;
}