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
  34         AND(acc, 0x3) // acc = (mod3lo & 0x3)
  35         SR(mod3lo)
  36         SR(mod3lo) // (mod3lo >>  2)
  37         ADD(acc, mod3lo)
  38         mod3lo = acc;
  39         //mod3lo = (mod3lo >>  2) + (mod3lo & 0x3);
  40         mod3lo = (mod3lo >>  2) + (mod3lo & 0x3);
  41         if (mod3lo > 2) mod3lo = mod3lo - 3;
  42         acc = mod3lo;
  43 }
  44
  45 void g(void){
  46         u8 notes_ix = acc & 0x7;
  47         if(3&i2)
  48                 notes_ix += 8;
  49         u8 result = ((i1<<8|i0)*notes[notes_ix])>>8;  // keep hi byte
  50         acc = result;
  51 }
  52 void main(void){
  53         CLEAR   (i0)
  54         CLEAR   (i1)
  55         CLEAR   (i2)
  56         for(;;) {
  57                 MOV     (acc, i2)// "mov mem,mem"
  58                 MOV     (n, acc)// does not exist
  59                 SL      (n)
  60                 SL      (n)
  61                 MOV     (acc, i1)
  62                 SWAP    (acc)
  63                 AND     (acc, 0xf)
  64                 SR      (acc)
  65                 SR      (acc)
  66                 OR      (n, acc)
  67
  68                 MOV     (acc, n)
  69                 CALL    (g)
  70                 SWAP    (acc)
  71                 AND     (acc, 0x1)
  72                 MOV     (sample, acc)
  73
  74                 MOV     (acc, i2)
  75                 SL      (acc)
  76                 SL      (acc)
  77                 SL      (acc)
  78                 MOV     (tmp_1, acc) // fresh tmp_1:
  79                 MOV     (acc, i1)
  80                 SWAP    (acc)
  81                 AND     (acc, 0xf)
  82                 SR      (acc)
  83                 OR      (acc, tmp_1) // tmp_1 done.
  84                 XOR     (acc, n)
  85                 CALL    (g)
  86                 SR      (acc)
  87                 AND     (acc, i2)
  88                 SR      (acc)
  89                 AND     (acc, 3)
  90                 ADD     (sample, acc)
  91
  92                 mod3hi = i2>>3;
  93                 mod3lo = i2<<5|i1>>3;
  94                 CALL    (mod3)
  95                 ADD     (acc, n)
  96                 CALL    (g)
  97                 SR      (acc)
  98                 SR      (acc)
  99                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 100                 MOV     (acc, i2)
 101                 // shift-divide by six
 102                 // note: i2 is max 0x78; so acc will <= 20. (breaks vor values >=128)
 103                 SR      (acc)
 104                 ADD     (acc, i2)
 105                 SR      (acc)
 106                 SR      (acc)
 107                 ADD     (acc, i2)
 108                 SR      (acc)
 109                 SR      (acc)
 110                 ADD     (acc, i2)
 111                 SR      (acc)
 112                 SR      (acc)
 113                 SR      (acc)
 114                 // end divide by six
 115                 AND     (acc, tmp_1) // acc restored from tmp_1
 116                 AND     (acc, 3)
 117                 ADD     (sample, acc)
 118
 119                 mod3hi = i2>>2;
 120                 mod3lo = i2<<6|i1>>2;
 121                 CALL    (mod3)
 122                 SUB     (acc, n)
 123                 SUB     (acc, 8)
 124                 NEG     (acc)
 125                 CALL    (g)
 126                 SR      (acc)
 127                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 128                 MOV     (acc, i2)
 129                 // shift-divide by ten
 130                 // note: i2 is max 0x78; so acc will <= 12.
 131                 INC     (i2)
 132                 SR      (acc)
 133                 ADD     (acc, i2)
 134                 SR      (acc)
 135                 SR      (acc)
 136                 SR      (acc)
 137                 ADD     (acc, i2)
 138                 SR      (acc)
 139                 ADD     (acc, i2)
 140                 SWAP    (acc)
 141                 DEC     (i2)
 142                 // end divide by ten
 143                 AND     (acc, tmp_1) // acc restored from tmp_1
 144                 AND     (acc, 3)
 145                 ADD     (sample, acc)
 146
 147                 MOV     (acc, sample)
 148                 SWAP    (acc)
 149                 putchar(acc);
 150
 151                 INC     (i0)
 152                 i1 += !i0; // ADDC i1
 153                 i2 += !i1 && !i0; // ADDC i2
 154         }
 155 }