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 x;
u8 t;
u8 o;
+u8 _;
+#define Mh o //mod3 vars
+#define Ml t // -"-
+//http://homepage.divms.uiowa.edu/~jones/bcd/mod.shtml
+void mod3(void) {
+ // mod3(Mh.Ml) -> t
+ #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)
+ MOV (tmp, Ml)
+ LSR (tmp)
+ LSR (tmp)
+ ANDI (Ml, 0x03)
+ ADD (Ml, tmp)
+ MOV (tmp, Ml)
+ LSR (tmp)
+ LSR (tmp)
+ ANDI (Ml, 0x03)
+ ADD (Ml, tmp)
+ CPI (Ml, 3)
+ BRPL (skip)
+ SUBI (Ml, 3)
+ skip:;
+ RET
+ #undef tmp
+}
void g(void) {
- // g(i, x, t, o) -> t
- u8 tmp;
+ // g(i, t) -> t
+ // tempvars: `x` and `_`
+ #define tmp _
ANDI (t, 0x07)
MOV (tmp, i2)
ANDI (tmp, 3)
TST (tmp)
+ #undef tmp
BREQ (skip)
SUBI (t, -8)
skip:
t = data[t];
- t = (((i1&0x1f)<<8|i0)*t)>>8 >> o;
- AND (t, x)
- ANDI (t, 3)
- RET
+ /*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
+ RET //TODO: CALL/RET is expensive; store PC in register and RJMP, then JRMP back
};
int main(void) {
#undef tmp
//voice 1:
- LDI (x, 1)
MOV (t, n)
LDI (o, 4)
RCALL g();
+ t >>= o; //NOTE: o == {1, 2, 4}
+ ANDI (t, 3)
+ ANDI (t, 1)
MOV (acc, t)
//voice 2:
- MOV (x, s)
#define tmp o
MOV (tmp, i2)
LSL (tmp)
EOR (t, n)
LDI (o, 2)
RCALL g();
+ t >>= o; //NOTE: o == {1, 2, 4}
+ ANDI (t, 3)
+ AND (t, s)
ADD (acc, t)
//voice 3:
+ MOV (Ml, i2)
+ SWAP (Ml)
+ ANDI (Ml, 0xf0)
+ LSL (Ml)
+ #define tmp Mh
+ MOV (tmp, i1)
+ LSR (tmp)
+ LSR (tmp)
+ LSR (tmp)
+ OR (Ml, tmp)
+ #undef tmp
+ MOV (Mh, i3)
+ SWAP (Mh)
+ ANDI (Mh, 0xf0)
+ LSL (Mh)
+ #define tmp _
+ MOV (tmp, i2)
+ LSR (tmp)
+ LSR (tmp)
+ LSR (tmp)
+ OR (Mh, tmp)
+ #undef tmp
+ RCALL mod3();
+ ADD (t, n)
+ LDI (o, 2)
+ RCALL g();
+ t >>= o; //NOTE: o == {1, 2, 4}
+ ANDI (t, 3)
MOV (x, s)
INC (x)
#define tmp o
- //NOTE: we only need 1 bit of the upper byte. instead of using a u16 and LSR'ing,
- //we can use a u8 for sum and use ROR (which shifts the carry in)
- CLR (tmp)
- ADD (tmp, x)
- ROR (tmp)
- //nop
+ MOV (tmp, x)
+ LSR (tmp)
LSR (tmp)
ADD (tmp, x)
ROR (tmp)
- //nop
LSR (tmp)
ADD (tmp, x)
ROR (tmp)
- //nop
LSR (tmp)
ADD (tmp, x)
ROR (tmp)
- //nop
LSR (tmp)
- x = tmp;
+ MOV (x, tmp)
#undef tmp
- t = ((i3&0x01)<<13 | i2<<5 | i1>>3) % 3;
- ADD (t, n)
- LDI (o, 2)
- RCALL g();
+ AND (t, x)
ADD (acc, t)
//voice 4:
- MOV (x, s)
- INC (x)
- #define tmp o
- unsigned short sum = 0; //XXX
- sum += x;
- sum >>= 1;
- sum += x;
- sum >>= 1;
- //nop
- sum >>= 1;
- //nop
- sum >>= 1;
- sum += x;
- sum >>= 1;
- sum += x;
- sum >>= 1;
- //nop
- sum >>= 1;
- //nop
- sum >>= 1;
- x = sum;
+ MOV (Ml, i2)
+ SWAP (Ml)
+ ANDI (Ml, 0xf0)
+ LSL (Ml)
+ LSL (Ml)
+ #define tmp Mh
+ MOV (tmp, i1)
+ LSR (tmp)
+ LSR (tmp)
+ OR (Ml, tmp)
#undef tmp
- t = ((i3&0x01)<<14 | i2<<6 | i1>>2) % 3;
+ MOV (Mh, i3)
+ SWAP (Mh)
+ ANDI (Mh, 0xf0)
+ LSL (Mh)
+ LSL (Mh)
+ #define tmp _
+ MOV (tmp, i2)
+ LSR (tmp)
+ LSR (tmp)
+ OR (Mh, tmp)
+ #undef tmp
+ RCALL mod3();
SUB (t, n)
NEG (t)
SUBI (t, -8)
LDI (o, 1)
RCALL g();
+ t >>= o; //NOTE: o == {1, 2, 4}
+ ANDI (t, 3)
+ 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
+ AND (t, x)
ADD (acc, t)
- putchar(acc<<4);
- #define tmp acc
- LDI (tmp, 0)
+ putchar(acc<<4); //TODO
SUBI (i0, -1)
- ADC (i1, tmp, !i0)
- ADC (i2, tmp, !i0&&!i1)
- ADC (i3, tmp, !i0&&!i1&&!i2)
- #undef tmp
+ ADC (i1, zero, !i0)
+ ADC (i2, zero, !i0&&!i1)
+ ADC (i3, zero, !i0&&!i1&&!i2)
}
}
git://git.gir.st / Chiptunes.git / blobdiff