bsv.c

   1 #include <stdio.h>
   2 #include "fakeasm.h"
   3 typedef unsigned char u8;
   4
   5 u8 i0, i1, i2; //MEM
   6 u8 n; //MEM
   7 u8 sample; //MEM
   8 u8 tmp_1; //MEM
   9 u8 acc; //ACC
  10
  11 u8 notes[] = {
  12         0x84, 0x9d, 0xb0, 0x69, 0x9d, 0x84, 0x69, 0x58,
  13         0x75, 0x8c, 0xb0, 0x69, 0x8c, 0x75, 0x69, 0x58
  14 };
  15
  16 u8 mod3hi, mod3lo;
  17 void mod3(void) {
  18         acc = (mod3hi<<8|mod3lo) % 3;
  19 }
  20
  21 void g(void){
  22         u8 notes_ix = acc & 0x7;
  23         if(3&i2)
  24                 notes_ix += 8;
  25         u8 result = ((i1<<8|i0)*notes[notes_ix])>>8;  // keep hi byte
  26         acc = result;
  27 }
  28 void main(void){
  29         CLEAR   (i0)
  30         CLEAR   (i1)
  31         CLEAR   (i2)
  32         for(;;) {
  33                 MOV     (acc, i2)// "mov mem,mem"
  34                 MOV     (n, acc)// does not exist
  35                 SL      (n)
  36                 SL      (n)
  37                 MOV     (acc, i1)
  38                 SWAP    (acc)
  39                 AND     (acc, 0xf)
  40                 SR      (acc)
  41                 SR      (acc)
  42                 OR      (n, acc)
  43
  44                 MOV     (acc, n)
  45                 CALL    (g)
  46                 SWAP    (acc)
  47                 AND     (acc, 0x1)
  48                 MOV     (sample, acc)
  49
  50                 MOV     (acc, i2)
  51                 SL      (acc)
  52                 SL      (acc)
  53                 SL      (acc)
  54                 MOV     (tmp_1, acc) // fresh tmp_1:
  55                 MOV     (acc, i1)
  56                 SWAP    (acc)
  57                 AND     (acc, 0xf)
  58                 SR      (acc)
  59                 OR      (acc, tmp_1) // tmp_1 done.
  60                 XOR     (acc, n)
  61                 CALL    (g)
  62                 SR      (acc)
  63                 AND     (acc, i2)
  64                 SR      (acc)
  65                 AND     (acc, 3)
  66                 ADD     (sample, acc)
  67
  68                 mod3hi = i2>>3;
  69                 mod3lo = i2<<5|i1>>3;
  70                 mod3();
  71                 ADD     (acc, n)
  72                 CALL    (g)
  73                 SR      (acc)
  74                 SR      (acc)
  75                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
  76                 MOV     (acc, i2)
  77                 // shift-divide by six
  78                 // note: i2 is max 0x78; so acc will <= 20. (breaks vor values >=128)
  79                 SR      (acc)
  80                 ADD     (acc, i2)
  81                 SR      (acc)
  82                 SR      (acc)
  83                 ADD     (acc, i2)
  84                 SR      (acc)
  85                 SR      (acc)
  86                 ADD     (acc, i2)
  87                 SR      (acc)
  88                 SR      (acc)
  89                 SR      (acc)
  90                 // end divide by six
  91                 AND     (acc, tmp_1) // acc restored from tmp_1
  92                 AND     (acc, 3)
  93                 ADD     (sample, acc)
  94
  95                 mod3hi = i2>>2;
  96                 mod3lo = i2<<6|i1>>2;
  97                 mod3();
  98                 acc -= n;
  99                 acc -= 8;
 100                 acc *= -1; //NEG acc
 101                 CALL    (g)
 102                 SR      (acc)
 103                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 104                 MOV     (acc, i2)
 105                 // shift-divide by ten
 106                 // note: i2 is max 0x78; so acc will <= 12.
 107                 INC     (i2)
 108                 SR      (acc)
 109                 ADD     (acc, i2)
 110                 SR      (acc)
 111                 SR      (acc)
 112                 SR      (acc)
 113                 ADD     (acc, i2)
 114                 SR      (acc)
 115                 ADD     (acc, i2)
 116                 SWAP    (acc)
 117                 DEC     (i2)
 118                 // end divide by ten
 119                 AND     (acc, tmp_1) // acc restored from tmp_1
 120                 AND     (acc, 3)
 121                 ADD     (sample, acc)
 122
 123                 MOV     (acc, sample)
 124                 SWAP    (acc)
 125                 putchar(acc);
 126
 127                 INC     (i0)
 128                 i1 += !i0; // ADDC i1
 129                 i2 += !i1 && !i0; // ADDC i2
 130         }
 131 }