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; //MEM
  17 void mod3(void) {
  18         MOV(acc,mod3hi)
  19         ADD(mod3lo,acc) // mod3lo = hi+lo
  20         CLEAR(acc)
  21         ADDC0(acc) // mod3hi, 1bit
  22         SWAP(acc)
  23         MOV(mod3hi, acc)
  24
  25         mod3lo = mod3hi + (mod3lo>>4) + (mod3lo & 0xF);
  26         mod3lo = (mod3lo >>  2) + (mod3lo & 0x3);
  27         mod3lo = (mod3lo >>  2) + (mod3lo & 0x3);
  28         if (mod3lo > 2) mod3lo = mod3lo - 3;
  29         acc = mod3lo;
  30 }
  31
  32 void g(void){
  33         u8 notes_ix = acc & 0x7;
  34         if(3&i2)
  35                 notes_ix += 8;
  36         u8 result = ((i1<<8|i0)*notes[notes_ix])>>8;  // keep hi byte
  37         acc = result;
  38 }
  39 void main(void){
  40         CLEAR   (i0)
  41         CLEAR   (i1)
  42         CLEAR   (i2)
  43         for(;;) {
  44                 MOV     (acc, i2)// "mov mem,mem"
  45                 MOV     (n, acc)// does not exist
  46                 SL      (n)
  47                 SL      (n)
  48                 MOV     (acc, i1)
  49                 SWAP    (acc)
  50                 AND     (acc, 0xf)
  51                 SR      (acc)
  52                 SR      (acc)
  53                 OR      (n, acc)
  54
  55                 MOV     (acc, n)
  56                 CALL    (g)
  57                 SWAP    (acc)
  58                 AND     (acc, 0x1)
  59                 MOV     (sample, acc)
  60
  61                 MOV     (acc, i2)
  62                 SL      (acc)
  63                 SL      (acc)
  64                 SL      (acc)
  65                 MOV     (tmp_1, acc) // fresh tmp_1:
  66                 MOV     (acc, i1)
  67                 SWAP    (acc)
  68                 AND     (acc, 0xf)
  69                 SR      (acc)
  70                 OR      (acc, tmp_1) // tmp_1 done.
  71                 XOR     (acc, n)
  72                 CALL    (g)
  73                 SR      (acc)
  74                 AND     (acc, i2)
  75                 SR      (acc)
  76                 AND     (acc, 3)
  77                 ADD     (sample, acc)
  78
  79                 mod3hi = i2>>3;
  80                 mod3lo = i2<<5|i1>>3;
  81                 CALL    (mod3)
  82                 ADD     (acc, n)
  83                 CALL    (g)
  84                 SR      (acc)
  85                 SR      (acc)
  86                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
  87                 MOV     (acc, i2)
  88                 // shift-divide by six
  89                 // note: i2 is max 0x78; so acc will <= 20. (breaks vor values >=128)
  90                 SR      (acc)
  91                 ADD     (acc, i2)
  92                 SR      (acc)
  93                 SR      (acc)
  94                 ADD     (acc, i2)
  95                 SR      (acc)
  96                 SR      (acc)
  97                 ADD     (acc, i2)
  98                 SR      (acc)
  99                 SR      (acc)
 100                 SR      (acc)
 101                 // end divide by six
 102                 AND     (acc, tmp_1) // acc restored from tmp_1
 103                 AND     (acc, 3)
 104                 ADD     (sample, acc)
 105
 106                 mod3hi = i2>>2;
 107                 mod3lo = i2<<6|i1>>2;
 108                 CALL    (mod3)
 109                 SUB     (acc, n)
 110                 SUB     (acc, 8)
 111                 NEG     (acc)
 112                 CALL    (g)
 113                 SR      (acc)
 114                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 115                 MOV     (acc, i2)
 116                 // shift-divide by ten
 117                 // note: i2 is max 0x78; so acc will <= 12.
 118                 INC     (i2)
 119                 SR      (acc)
 120                 ADD     (acc, i2)
 121                 SR      (acc)
 122                 SR      (acc)
 123                 SR      (acc)
 124                 ADD     (acc, i2)
 125                 SR      (acc)
 126                 ADD     (acc, i2)
 127                 SWAP    (acc)
 128                 DEC     (i2)
 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 }