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.
  74
  75                 acc >>= 1;
  76                 acc += i2;
  77
  78                 acc >>= 1;
  79                 acc += 0;
  80
  81                 acc >>= 1;
  82                 acc += i2;
  83
  84                 acc >>= 1;
  85                 acc += 0;
  86
  87                 acc >>= 1;
  88                 acc += i2;
  89
  90                 acc >>= 1;
  91                 acc += 0;
  92
  93                 acc >>= 1;
  94                 acc >>= 1;
  95
  96                 // end divide by six
  97                 AND     (acc, tmp_1) // acc restored from tmp_1
  98                 AND     (acc, 3)
  99                 ADD     (sample, acc)
 100
 101                 MOV     (acc, n)
 102                 ADD     (acc, 8)
 103                 { u8 tmp3 = (i2<<6|i1>>2)%3;
 104                   SUB   (acc, tmp3)
 105                 } // tmp3
 106                 CALL    (g)
 107                 SR      (acc)
 108                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 109                 // shift-divide by ten
 110                 // note: i2 is max 0x78; so acc will <= 12.
 111                 acc = i2/10;//TODO
 112                 // end divide by ten
 113                 AND     (acc, tmp_1) // acc restored from tmp_1
 114                 AND     (acc, 3)
 115                 ADD     (sample, acc)
 116
 117                 MOV     (acc, sample)
 118                 SWAP    (acc)
 119                 putchar(acc);
 120
 121                 INC     (i0)
 122                 i1 += !i0; // ADDC i1
 123                 i2 += !i1 && !i0; // ADDC i2
 124         }
 125 }