bsv.c

   1 #include <stdio.h>
   2 #include "fakeasm.h"
   3 typedef unsigned char u8;
   4
   5 u8 notes[16]; //MEM
   6 u8 i0, i1, i2; //MEM
   7 u8 n; //MEM
   8 u8 sample; //MEM
   9 u8 tmp_1; //MEM
  10 u8 acc; //ACC
  11
  12 u8 mod3hi, mod3lo; //MEM
  13 //todo: can mod3hi be aliased to tmp_1?
  14 void mod3(void) {
  15         MOV     (acc,mod3hi)
  16         ADD     (mod3lo,acc) // mod3lo = hi+lo
  17         CLEAR   (acc)
  18         ADDC0   (acc) // mod3hi, 1bit
  19         SWAP    (acc)
  20         MOV     (mod3hi, acc)
  21
  22         MOV     (acc, mod3lo)
  23         SWAP    (acc)
  24         AND     (acc, 0xf) // (mod3lo>>4)
  25         XCH     (mod3lo) // acc=mod3lo, mod3lo=mod3lo>>4
  26         AND     (acc, 0xF) // acc=mod3lo&0xf, mod3lo=mod3lo>>4
  27         ADD     (acc, mod3lo) // (mod3lo & 0xF)
  28         ADD     (acc, mod3hi)
  29         MOV     (mod3lo, acc)
  30
  31         AND     (acc, 0x3) // acc = (mod3lo & 0x3)
  32         SR      (mod3lo)
  33         SR      (mod3lo) // (mod3lo >>  2)
  34         ADD     (acc, mod3lo)
  35         MOV     (mod3lo, acc)
  36
  37         AND     (acc, 0x3) // acc = (mod3lo & 0x3)
  38         SR      (mod3lo)
  39         SR      (mod3lo) // (mod3lo >>  2)
  40         ADD     (acc, mod3lo)
  41
  42         SUB     (acc,3)
  43         /*T0SN  FLAG.C (0x00.1)*/       if (flag_c){ // skip if carry clear
  44         ADD (acc,3)                     }
  45 }
  46
  47 void g(void){
  48         // notes_ix_hi = always 0
  49         u8 notes_ix;//lo
  50         AND     (acc, 0x7)
  51         MOV     (notes_ix, acc)
  52         // test i2 & 3:
  53         MOV     (acc, i2)
  54         AND     (acc, 3)
  55         /*T0SN  FLAG.Z (0x00.0)*/       if(3&i2) {// skip if !(3&i0)
  56         SET1    (notes_ix, 3)           }
  57         /*IDXM  acc, notes_ix*/         acc = notes[notes_ix];
  58         u8 result = ((i1<<8|i0)*acc)>>8;  // keep hi byte
  59         acc = result;
  60 }
  61 void main(void){
  62         CLEAR   (i0)
  63         CLEAR   (i1)
  64         CLEAR   (i2)
  65
  66         //rom is not mmapped; must load into ram first
  67         MOV     (acc, 0x84)
  68         MOV     (notes[0x0], acc)
  69         MOV     (notes[0x5], acc)
  70         MOV     (acc, 0x9d)
  71         MOV     (notes[0x1], acc)
  72         MOV     (notes[0x4], acc)
  73         MOV     (acc, 0xb0)
  74         MOV     (notes[0x2], acc)
  75         MOV     (notes[0xA], acc)
  76         MOV     (acc, 0x69)
  77         MOV     (notes[0x3], acc)
  78         MOV     (notes[0x6], acc)
  79         MOV     (notes[0xB], acc)
  80         MOV     (notes[0xE], acc)
  81         MOV     (acc, 0x58)
  82         MOV     (notes[0x7], acc)
  83         MOV     (notes[0xF], acc)
  84         MOV     (acc, 0x75)
  85         MOV     (notes[0x8], acc)
  86         MOV     (notes[0xD], acc)
  87         MOV     (acc, 0x8c)
  88         MOV     (notes[0x9], acc)
  89         MOV     (notes[0xC], acc)
  90
  91         for(;;) {
  92                 MOV     (acc, i2)// "mov mem,mem"
  93                 MOV     (n, acc)// does not exist
  94                 SL      (n)
  95                 SL      (n)
  96                 MOV     (acc, i1)
  97                 SWAP    (acc)
  98                 AND     (acc, 0xf)
  99                 SR      (acc)
 100                 SR      (acc)
 101                 OR      (n, acc)
 102
 103                 MOV     (acc, n)
 104                 CALL    (g)
 105                 SWAP    (acc)
 106                 AND     (acc, 0x1)
 107                 MOV     (sample, acc)
 108
 109                 MOV     (acc, i2)
 110                 SL      (acc)
 111                 SL      (acc)
 112                 SL      (acc)
 113                 MOV     (tmp_1, acc) // fresh tmp_1:
 114                 MOV     (acc, i1)
 115                 SWAP    (acc)
 116                 AND     (acc, 0xf)
 117                 SR      (acc)
 118                 OR      (acc, tmp_1) // tmp_1 done.
 119                 XOR     (acc, n)
 120                 CALL    (g)
 121                 SR      (acc)
 122                 AND     (acc, i2)
 123                 SR      (acc)
 124                 AND     (acc, 3)
 125                 ADD     (sample, acc)
 126
 127                 MOV     (acc, i2)
 128                 MOV     (mod3hi, acc)
 129                 SR      (mod3hi)
 130                 SR      (mod3hi)
 131                 SR      (mod3hi)
 132                 SWAP    (acc)
 133                 AND     (acc, 0xf0)
 134                 SL      (acc)
 135                 MOV     (mod3lo, acc)
 136                 MOV     (acc, i1)
 137                 SR      (acc)
 138                 SR      (acc)
 139                 SR      (acc)
 140                 OR      (mod3lo, acc)
 141                 CALL    (mod3)
 142                 ADD     (acc, n)
 143                 CALL    (g)
 144                 SR      (acc)
 145                 SR      (acc)
 146                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 147                 MOV     (acc, i2)
 148                 // shift-divide by six
 149                 // note: i2 is max 0x78; so acc will <= 20. (breaks vor values >=128)
 150                 SR      (acc)
 151                 ADD     (acc, i2)
 152                 SR      (acc)
 153                 SR      (acc)
 154                 ADD     (acc, i2)
 155                 SR      (acc)
 156                 SR      (acc)
 157                 ADD     (acc, i2)
 158                 SR      (acc)
 159                 SR      (acc)
 160                 SR      (acc)
 161                 // end divide by six
 162                 AND     (acc, tmp_1) // acc restored from tmp_1
 163                 AND     (acc, 3)
 164                 ADD     (sample, acc)
 165
 166                 MOV     (acc, i2)
 167                 MOV     (mod3hi, acc)
 168                 SR      (mod3hi)
 169                 SR      (mod3hi)
 170                 SWAP    (acc)
 171                 AND     (acc, 0xf0)
 172                 SL      (acc)
 173                 SL      (acc)
 174                 MOV     (mod3lo, acc)
 175                 MOV     (acc, i1)
 176                 SR      (acc)
 177                 SR      (acc)
 178                 OR      (mod3lo, acc)
 179                 CALL    (mod3)
 180                 SUB     (acc, n)
 181                 SUB     (acc, 8)
 182                 NEG     (acc)
 183                 CALL    (g)
 184                 SR      (acc)
 185                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 186                 MOV     (acc, i2)
 187                 // shift-divide by ten
 188                 // note: i2 is max 0x78; so acc will <= 12.
 189                 INC     (i2)
 190                 SR      (acc)
 191                 ADD     (acc, i2)
 192                 SR      (acc)
 193                 SR      (acc)
 194                 SR      (acc)
 195                 ADD     (acc, i2)
 196                 SR      (acc)
 197                 ADD     (acc, i2)
 198                 SWAP    (acc)
 199                 DEC     (i2)
 200                 // end divide by ten
 201                 AND     (acc, tmp_1) // acc restored from tmp_1
 202                 AND     (acc, 3)
 203                 ADD     (sample, acc)
 204
 205                 MOV     (acc, sample)
 206                 SWAP    (acc)
 207                 putchar(acc);
 208
 209                 INC     (i0)
 210                 /*ADDC  i1*/            i1 += !i0;
 211                 /*ADDC  i2*/            i2 += !i1 && !i0;
 212
 213                 if(i2 == 0x78) break;
 214         }
 215 }