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         MOV(mod3lo, acc)
  33
  34         AND(acc, 0x3) // acc = (mod3lo & 0x3)
  35         SR(mod3lo)
  36         SR(mod3lo) // (mod3lo >>  2)
  37         ADD(acc, mod3lo)
  38         MOV(mod3lo, acc)
  39
  40         AND(acc, 0x3) // acc = (mod3lo & 0x3)
  41         SR(mod3lo)
  42         SR(mod3lo) // (mod3lo >>  2)
  43         ADD(acc, mod3lo)
  44
  45         if (acc > 2) acc = acc - 3;
  46 }
  47
  48 void g(void){
  49         u8 notes_ix = acc & 0x7;
  50         if(3&i2)
  51                 notes_ix += 8;
  52         u8 result = ((i1<<8|i0)*notes[notes_ix])>>8;  // keep hi byte
  53         acc = result;
  54 }
  55 void main(void){
  56         CLEAR   (i0)
  57         CLEAR   (i1)
  58         CLEAR   (i2)
  59         for(;;) {
  60                 MOV     (acc, i2)// "mov mem,mem"
  61                 MOV     (n, acc)// does not exist
  62                 SL      (n)
  63                 SL      (n)
  64                 MOV     (acc, i1)
  65                 SWAP    (acc)
  66                 AND     (acc, 0xf)
  67                 SR      (acc)
  68                 SR      (acc)
  69                 OR      (n, acc)
  70
  71                 MOV     (acc, n)
  72                 CALL    (g)
  73                 SWAP    (acc)
  74                 AND     (acc, 0x1)
  75                 MOV     (sample, acc)
  76
  77                 MOV     (acc, i2)
  78                 SL      (acc)
  79                 SL      (acc)
  80                 SL      (acc)
  81                 MOV     (tmp_1, acc) // fresh tmp_1:
  82                 MOV     (acc, i1)
  83                 SWAP    (acc)
  84                 AND     (acc, 0xf)
  85                 SR      (acc)
  86                 OR      (acc, tmp_1) // tmp_1 done.
  87                 XOR     (acc, n)
  88                 CALL    (g)
  89                 SR      (acc)
  90                 AND     (acc, i2)
  91                 SR      (acc)
  92                 AND     (acc, 3)
  93                 ADD     (sample, acc)
  94
  95                 mod3hi = i2>>3;
  96                 mod3lo = i2<<5|i1>>3;
  97                 CALL    (mod3)
  98                 ADD     (acc, n)
  99                 CALL    (g)
 100                 SR      (acc)
 101                 SR      (acc)
 102                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 103                 MOV     (acc, i2)
 104                 // shift-divide by six
 105                 // note: i2 is max 0x78; so acc will <= 20. (breaks vor values >=128)
 106                 SR      (acc)
 107                 ADD     (acc, i2)
 108                 SR      (acc)
 109                 SR      (acc)
 110                 ADD     (acc, i2)
 111                 SR      (acc)
 112                 SR      (acc)
 113                 ADD     (acc, i2)
 114                 SR      (acc)
 115                 SR      (acc)
 116                 SR      (acc)
 117                 // end divide by six
 118                 AND     (acc, tmp_1) // acc restored from tmp_1
 119                 AND     (acc, 3)
 120                 ADD     (sample, acc)
 121
 122                 mod3hi = i2>>2;
 123                 mod3lo = i2<<6|i1>>2;
 124                 CALL    (mod3)
 125                 SUB     (acc, n)
 126                 SUB     (acc, 8)
 127                 NEG     (acc)
 128                 CALL    (g)
 129                 SR      (acc)
 130                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 131                 MOV     (acc, i2)
 132                 // shift-divide by ten
 133                 // note: i2 is max 0x78; so acc will <= 12.
 134                 INC     (i2)
 135                 SR      (acc)
 136                 ADD     (acc, i2)
 137                 SR      (acc)
 138                 SR      (acc)
 139                 SR      (acc)
 140                 ADD     (acc, i2)
 141                 SR      (acc)
 142                 ADD     (acc, i2)
 143                 SWAP    (acc)
 144                 DEC     (i2)
 145                 // end divide by ten
 146                 AND     (acc, tmp_1) // acc restored from tmp_1
 147                 AND     (acc, 3)
 148                 ADD     (sample, acc)
 149
 150                 MOV     (acc, sample)
 151                 SWAP    (acc)
 152                 putchar(acc);
 153
 154                 INC     (i0)
 155                 i1 += !i0; // ADDC i1
 156                 i2 += !i1 && !i0; // ADDC i2
 157         }
 158 }