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         MOV(acc, mod3lo)
  26         SWAP(acc)
  27         AND(acc, 0xf) // (mod3lo>>4)
  28         XCH(mod3lo) // acc=mod3lo, mod3lo=mod3lo>>4
  29         AND(acc, 0xF) // acc=mod3lo&0xf, mod3lo=mod3lo>>4
  30         ADD(acc, mod3lo) // (mod3lo & 0xF)
  31         ADD(acc, mod3hi)
  32         mod3lo = acc;
  33         //mod3lo = mod3hi + (mod3lo>>4) + (mod3lo & 0xF);
  34         mod3lo = (mod3lo >>  2) + (mod3lo & 0x3);
  35         mod3lo = (mod3lo >>  2) + (mod3lo & 0x3);
  36         if (mod3lo > 2) mod3lo = mod3lo - 3;
  37         acc = mod3lo;
  38 }
  39
  40 void g(void){
  41         u8 notes_ix = acc & 0x7;
  42         if(3&i2)
  43                 notes_ix += 8;
  44         u8 result = ((i1<<8|i0)*notes[notes_ix])>>8;  // keep hi byte
  45         acc = result;
  46 }
  47 void main(void){
  48         CLEAR   (i0)
  49         CLEAR   (i1)
  50         CLEAR   (i2)
  51         for(;;) {
  52                 MOV     (acc, i2)// "mov mem,mem"
  53                 MOV     (n, acc)// does not exist
  54                 SL      (n)
  55                 SL      (n)
  56                 MOV     (acc, i1)
  57                 SWAP    (acc)
  58                 AND     (acc, 0xf)
  59                 SR      (acc)
  60                 SR      (acc)
  61                 OR      (n, acc)
  62
  63                 MOV     (acc, n)
  64                 CALL    (g)
  65                 SWAP    (acc)
  66                 AND     (acc, 0x1)
  67                 MOV     (sample, acc)
  68
  69                 MOV     (acc, i2)
  70                 SL      (acc)
  71                 SL      (acc)
  72                 SL      (acc)
  73                 MOV     (tmp_1, acc) // fresh tmp_1:
  74                 MOV     (acc, i1)
  75                 SWAP    (acc)
  76                 AND     (acc, 0xf)
  77                 SR      (acc)
  78                 OR      (acc, tmp_1) // tmp_1 done.
  79                 XOR     (acc, n)
  80                 CALL    (g)
  81                 SR      (acc)
  82                 AND     (acc, i2)
  83                 SR      (acc)
  84                 AND     (acc, 3)
  85                 ADD     (sample, acc)
  86
  87                 mod3hi = i2>>3;
  88                 mod3lo = i2<<5|i1>>3;
  89                 CALL    (mod3)
  90                 ADD     (acc, n)
  91                 CALL    (g)
  92                 SR      (acc)
  93                 SR      (acc)
  94                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
  95                 MOV     (acc, i2)
  96                 // shift-divide by six
  97                 // note: i2 is max 0x78; so acc will <= 20. (breaks vor values >=128)
  98                 SR      (acc)
  99                 ADD     (acc, i2)
 100                 SR      (acc)
 101                 SR      (acc)
 102                 ADD     (acc, i2)
 103                 SR      (acc)
 104                 SR      (acc)
 105                 ADD     (acc, i2)
 106                 SR      (acc)
 107                 SR      (acc)
 108                 SR      (acc)
 109                 // end divide by six
 110                 AND     (acc, tmp_1) // acc restored from tmp_1
 111                 AND     (acc, 3)
 112                 ADD     (sample, acc)
 113
 114                 mod3hi = i2>>2;
 115                 mod3lo = i2<<6|i1>>2;
 116                 CALL    (mod3)
 117                 SUB     (acc, n)
 118                 SUB     (acc, 8)
 119                 NEG     (acc)
 120                 CALL    (g)
 121                 SR      (acc)
 122                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 123                 MOV     (acc, i2)
 124                 // shift-divide by ten
 125                 // note: i2 is max 0x78; so acc will <= 12.
 126                 INC     (i2)
 127                 SR      (acc)
 128                 ADD     (acc, i2)
 129                 SR      (acc)
 130                 SR      (acc)
 131                 SR      (acc)
 132                 ADD     (acc, i2)
 133                 SR      (acc)
 134                 ADD     (acc, i2)
 135                 SWAP    (acc)
 136                 DEC     (i2)
 137                 // end divide by ten
 138                 AND     (acc, tmp_1) // acc restored from tmp_1
 139                 AND     (acc, 3)
 140                 ADD     (sample, acc)
 141
 142                 MOV     (acc, sample)
 143                 SWAP    (acc)
 144                 putchar(acc);
 145
 146                 INC     (i0)
 147                 i1 += !i0; // ADDC i1
 148                 i2 += !i1 && !i0; // ADDC i2
 149         }
 150 }