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 void g(void){
  17         u8 notes_ix = acc & 0x7;
  18         if(3&i2)
  19                 notes_ix += 8;
  20         u8 result = ((i1<<8|i0)*notes[notes_ix])>>8;  // keep hi byte
  21         acc = result;
  22 }
  23 void main(void){
  24         CLEAR   (i0)
  25         CLEAR   (i1)
  26         CLEAR   (i2)
  27         for(;;) {
  28                 MOV     (acc, i2)// "mov mem,mem"
  29                 MOV     (n, acc)// does not exist
  30                 SL      (n)
  31                 SL      (n)
  32                 MOV     (acc, i1)
  33                 SWAP    (acc)
  34                 AND     (acc, 0xf)
  35                 SR      (acc)
  36                 SR      (acc)
  37                 OR      (n, acc)
  38
  39                 MOV     (acc, n)
  40                 CALL    (g)
  41                 SWAP    (acc)
  42                 AND     (acc, 0x1)
  43                 MOV     (sample, acc)
  44
  45                 MOV     (acc, i2)
  46                 SL      (acc)
  47                 SL      (acc)
  48                 SL      (acc)
  49                 MOV     (tmp_1, acc) // fresh tmp_1:
  50                 MOV     (acc, i1)
  51                 SWAP    (acc)
  52                 AND     (acc, 0xf)
  53                 SR      (acc)
  54                 OR      (acc, tmp_1) // tmp_1 done.
  55                 XOR     (acc, n)
  56                 CALL    (g)
  57                 SR      (acc)
  58                 AND     (acc, i2)
  59                 SR      (acc)
  60                 AND     (acc, 3)
  61                 ADD     (sample, acc)
  62
  63                 { u8 tmp2 = (i2<<5|i1>>3)%3;//TODO
  64                 MOV     (acc, tmp2)
  65                 ADD     (acc, n)
  66                 CALL    (g)
  67                 } //tmp2
  68                 SR      (acc)
  69                 SR      (acc)
  70                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
  71                 MOV     (acc, i2)
  72                 // shift-divide by six
  73                 // note: i2 is max 0x78; so acc will <= 20. (breaks vor values >=128)
  74                 SR      (acc)
  75                 ADD     (acc, i2)
  76                 SR      (acc)
  77                 SR      (acc)
  78                 ADD     (acc, i2)
  79                 SR      (acc)
  80                 SR      (acc)
  81                 ADD     (acc, i2)
  82                 SR      (acc)
  83                 SR      (acc)
  84                 SR      (acc)
  85                 // end divide by six
  86                 AND     (acc, tmp_1) // acc restored from tmp_1
  87                 AND     (acc, 3)
  88                 ADD     (sample, acc)
  89
  90                 MOV     (acc, n)
  91                 ADD     (acc, 8)
  92                 { u8 tmp3 = (i2<<6|i1>>2)%3;
  93                   SUB   (acc, tmp3)
  94                 } // tmp3
  95                 CALL    (g)
  96                 SR      (acc)
  97                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
  98                 MOV     (acc, i2)
  99                 // shift-divide by ten
 100                 // note: i2 is max 0x78; so acc will <= 12.
 101                 i2++;
 102                 acc >>= 1;
 103                 acc += i2;
 104
 105                 acc >>= 1;
 106                 acc += 0;
 107
 108                 acc >>= 1;
 109                 acc += 0;
 110
 111                 acc >>= 1;
 112                 acc += i2;
 113
 114                 acc >>= 1;
 115                 acc += i2;
 116
 117                 acc >>= 1;
 118                 acc += 0;
 119
 120                 acc >>= 1;
 121                 acc += 0;
 122
 123                 acc >>= 1;
 124                 acc += 0;
 125
 126                 acc >>= 1;
 127                 i2--;
 128
 129                 // end divide by ten
 130                 AND     (acc, tmp_1) // acc restored from tmp_1
 131                 AND     (acc, 3)
 132                 ADD     (sample, acc)
 133
 134                 MOV     (acc, sample)
 135                 SWAP    (acc)
 136                 putchar(acc);
 137
 138                 INC     (i0)
 139                 i1 += !i0; // ADDC i1
 140                 i2 += !i1 && !i0; // ADDC i2
 141         }
 142 }