new version

[Chiptunes.git] / foo.c

#include <stdio.h>
#include "fakeasm.h"
typedef unsigned char u8;

u8 data[] = {   
	0x84, 0x9d, 0xb0, 0x69, 0x9d, 0x84, 0x69, 0x58,
	0x75, 0x8c, 0xb0, 0x69, 0x8c, 0x75, 0x69, 0x58
};
u8 zero; //zero register
u8 i0;
u8 i1;
u8 i2;
u8 i3;
u8 x;
u8 t;
u8 o;
u8 _;
#define Mh o //mod3 vars
#define Ml t // -"-
void mod3(void) { //avail: t, o _
//http://homepage.divms.uiowa.edu/~jones/bcd/mod.shtml
    #define tmp _
	ADD	(Ml, Mh)
	CLR	(Mh)
	ADC	(Mh, zero, carry) //Mh only holds the carry bit
	MOV	(tmp, Ml)
	SWAP	(tmp)
	ANDI	(tmp, 0x0f)
	SWAP	(Mh)
	OR	(tmp, Mh)
	ANDI	(Ml, 0x0f)
	ADD	(Ml, tmp) //discard tmp
    Ml = (Ml >>  2) + (Ml & 0x3);
    Ml = (Ml >>  2) + (Ml & 0x3);
    if (Ml > 2) Ml = Ml - 3;
    #undef tmp
}
void g(void) {
	// g(i, x, t, o) -> t
	#define tmp _
	ANDI	(t, 0x07)
	MOV	(tmp, i2)
	ANDI	(tmp, 3)
	TST	(tmp)
	#undef tmp
	BREQ	(skip)
	SUBI	(t, -8)
	skip:
	t = data[t];
	/*MOV X_hi==_, data_hi
	  MOV X_lo==t, data_lo
	  ADD X_lo, t
	  ADC X_hi, zero
	  LD  t, X         */
	t = (((i1&0x1f)<<8|i0)*t)>>8; //TODO
	t >>= o; //NOTE: o == {1, 2, 4}
	AND	(t, x)
	ANDI	(t, 3)
	RET
};

int main(void) {
	u8 n;
	u8 s;
	u8 acc;
	//TODO: clear all vars/registers
	for (;;) {
		MOV	(n, i2)
		LSL	(n)
		LSL	(n)
		#define tmp acc
		MOV	(tmp, i1)
		SWAP	(tmp)
		ANDI	(tmp, 0x0f)
		LSR	(tmp)
		LSR	(tmp)
		OR	(n, tmp)
		#undef tmp
		MOV	(s, i3)
		ROR	(s)
		ROR	(s)
		ANDI	(s, 0x80)
		#define tmp acc
		MOV	(tmp, i2)
		LSR	(tmp)
		OR	(s, tmp)
		#undef tmp

		//voice 1:
		LDI	(x, 1)
		MOV	(t, n)
		LDI	(o, 4)
		RCALL	g();
		MOV	(acc, t)

		//voice 2:
		MOV	(x, s)
		#define tmp o
		MOV	(tmp, i2)
		LSL	(tmp)
		LSL	(tmp)
		LSL	(tmp)
		MOV	(t, i1)
		SWAP	(t)
		ANDI	(t, 0xf)
		LSR	(t)
		OR	(t, tmp)
		#undef tmp
		EOR	(t, n)
		LDI	(o, 2)
		RCALL	g();
		ADD	(acc, t)

		//voice 3:
		MOV	(x, s)
		INC	(x)
		#define tmp o
		MOV	(tmp, x)
		LSR	(tmp)
		LSR	(tmp)
		ADD	(tmp, x)
		ROR	(tmp)
		LSR	(tmp)
		ADD	(tmp, x)
		ROR	(tmp)
		LSR	(tmp)
		ADD	(tmp, x)
		ROR	(tmp)
		LSR	(tmp)
                MOV	(x, tmp)
		#undef tmp
		Ml = i2<<5 | i1>>3;
		Mh = i3<<5 | i2>>3;
		RCALL	mod3();
		ADD	(t, n)
		LDI	(o, 2)
		RCALL	g();
		ADD	(acc, t)

		//voice 4:
		MOV	(x, s)
		INC	(x)
		#define tmp o
                MOV	(tmp, x)
		LSR	(tmp)
                ADD	(tmp, x)
		ROR	(tmp)
		LSR	(tmp)
		LSR	(tmp)
                ADD	(tmp, x)
		ROR	(tmp)
                ADD	(tmp, x)
		ROR	(tmp)
		LSR	(tmp)
		LSR	(tmp)
                MOV	(x, tmp)
		#undef tmp
		Ml = i2<<6 | i1>>2;
		Mh = i3<<6 | i2>>2;
		RCALL	mod3();
		SUB	(t, n)
		NEG	(t)
		SUBI	(t, -8)
		LDI	(o, 1)
		RCALL	g();
		ADD	(acc, t)

		putchar(acc<<4); //TODO
		SUBI	(i0, -1)
		ADC	(i1, zero, !i0)
		ADC	(i2, zero, !i0&&!i1)
		ADC	(i3, zero, !i0&&!i1&&!i2)
	}
}