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                 INC     (i2)
 102                 SR      (acc)
 103                 ADD     (acc, i2)
 104                 SR      (acc)
 105                 SR      (acc)
 106                 SR      (acc)
 107                 ADD     (acc, i2)
 108                 SR      (acc)
 109                 ADD     (acc, i2)
 110                 SWAP    (acc)
 111                 DEC     (i2)
 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 }