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         RET
  46 }
  47
  48 void g(void){
  49         // notes_ix_hi = always 0
  50         u8 notes_ix;//lo
  51         AND     (acc, 0x7)
  52         MOV     (notes_ix, acc)
  53         // test i2 & 3:
  54         MOV     (acc, i2)
  55         AND     (acc, 3)
  56         /*T0SN  FLAG.Z (0x00.0)*/       if(3&i2) {// skip if !(3&i0)
  57         SET1    (notes_ix, 3)           } // ix += 8 <=> ix |= 8
  58         IDXM    (acc, notes+notes_ix)
  59
  60         #define mul2 mod3hi
  61         #define mul1 mod3lo
  62         #define t tmp_1
  63         MOV     (t, acc)
  64         CLEAR   (mul2)
  65         CLEAR   (mul1)
  66         //1/8:
  67                 SR      (t)
  68                 /*T1SN  FLAG.C*/        if(!flag_c) {
  69                 goto    skip1;          }
  70                 MOV     (acc, i0)
  71                 ADD     (mul1, acc)
  72                 MOV     (acc, i1)
  73                 ADDC    (mul2, acc)
  74         skip1:  SR      (mul2)
  75                 SRC     (mul1)
  76         //2/8:
  77                 SR      (t)
  78         skip2:  SR      (mul2)
  79                 SRC     (mul1)
  80         //3/8:
  81                 SR      (t)
  82                 /*T1SN  FLAG.C*/        if(!flag_c) {
  83                 goto    skip3;          }
  84                 MOV     (acc, i0)
  85                 ADD     (mul1, acc)
  86                 MOV     (acc, i1)
  87                 ADDC    (mul2, acc)
  88         skip3:  SR      (mul2)
  89                 SRC     (mul1)
  90         //4/8:
  91                 SR      (t)
  92                 /*T1SN  FLAG.C*/        if(!flag_c) {
  93                 goto    skip4;          }
  94                 MOV     (acc, i0)
  95                 ADD     (mul1, acc)
  96                 MOV     (acc, i1)
  97                 ADDC    (mul2, acc)
  98         skip4:  SR      (mul2)
  99                 SRC     (mul1)
 100         //5/8:
 101                 SR      (t)
 102                 /*T1SN  FLAG.C*/        if(!flag_c) {
 103                 goto    skip5;          }
 104                 MOV     (acc, i0)
 105                 ADD     (mul1, acc)
 106                 MOV     (acc, i1)
 107                 ADDC    (mul2, acc)
 108         skip5:  SR      (mul2)
 109                 SRC     (mul1)
 110         //6/8:
 111                 SR      (t)
 112                 /*T1SN  FLAG.C*/        if(!flag_c) {
 113                 goto    skip6;          }
 114                 MOV     (acc, i0)
 115                 ADD     (mul1, acc)
 116         skip6:
 117                 SRC     (mul1)
 118         //7/8:
 119                 SR      (t)
 120                 /*T1SN  FLAG.C*/        if(!flag_c) {
 121                 goto    skip7;          }
 122                 MOV     (acc, i0)
 123                 ADD     (mul1, acc)
 124         skip7:
 125                 SRC     (mul1)
 126         //8/8:
 127                 SR      (t)
 128                 /*T1SN  FLAG.C*/        if(!flag_c) {
 129                 goto    skip8;          }
 130                 MOV     (acc, i0)
 131                 ADD     (mul1, acc)
 132         skip8:
 133                 SRC     (mul1)
 134
 135         MOV     (acc, mul1)
 136         RET
 137 }
 138 void main(void){
 139         CLEAR   (i0)
 140         CLEAR   (i1)
 141         CLEAR   (i2)
 142
 143         //rom is not mmapped; must load into ram first
 144         MOV     (acc, 0x84)
 145         MOV     (notes[0x0], acc)
 146         MOV     (notes[0x5], acc)
 147         MOV     (acc, 0x9d)
 148         MOV     (notes[0x1], acc)
 149         MOV     (notes[0x4], acc)
 150         MOV     (acc, 0xb0)
 151         MOV     (notes[0x2], acc)
 152         MOV     (notes[0xA], acc)
 153         MOV     (acc, 0x69)
 154         MOV     (notes[0x3], acc)
 155         MOV     (notes[0x6], acc)
 156         MOV     (notes[0xB], acc)
 157         MOV     (notes[0xE], acc)
 158         MOV     (acc, 0x58)
 159         MOV     (notes[0x7], acc)
 160         MOV     (notes[0xF], acc)
 161         MOV     (acc, 0x75)
 162         MOV     (notes[0x8], acc)
 163         MOV     (notes[0xD], acc)
 164         MOV     (acc, 0x8c)
 165         MOV     (notes[0x9], acc)
 166         MOV     (notes[0xC], acc)
 167
 168         for(;;) {
 169                 MOV     (acc, i2)// "mov mem,mem"
 170                 MOV     (n, acc)// does not exist
 171                 SL      (n)
 172                 SL      (n)
 173                 MOV     (acc, i1)
 174                 SWAP    (acc)
 175                 AND     (acc, 0xf)
 176                 SR      (acc)
 177                 SR      (acc)
 178                 OR      (n, acc)
 179
 180                 MOV     (acc, n)
 181                 CALL    (g)
 182                 SWAP    (acc)
 183                 AND     (acc, 0x1)
 184                 MOV     (sample, acc)
 185
 186                 MOV     (acc, i2)
 187                 SL      (acc)
 188                 SL      (acc)
 189                 SL      (acc)
 190                 MOV     (tmp_1, acc) // fresh tmp_1:
 191                 MOV     (acc, i1)
 192                 SWAP    (acc)
 193                 AND     (acc, 0xf)
 194                 SR      (acc)
 195                 OR      (acc, tmp_1) // tmp_1 done.
 196                 XOR     (acc, n)
 197                 CALL    (g)
 198                 SR      (acc)
 199                 AND     (acc, i2)
 200                 SR      (acc)
 201                 AND     (acc, 3)
 202                 ADD     (sample, acc)
 203
 204                 MOV     (acc, i2)
 205                 MOV     (mod3hi, acc)
 206                 SR      (mod3hi)
 207                 SR      (mod3hi)
 208                 SR      (mod3hi)
 209                 SWAP    (acc)
 210                 AND     (acc, 0xf0)
 211                 SL      (acc)
 212                 MOV     (mod3lo, acc)
 213                 MOV     (acc, i1)
 214                 SR      (acc)
 215                 SR      (acc)
 216                 SR      (acc)
 217                 OR      (mod3lo, acc)
 218                 CALL    (mod3)
 219                 ADD     (acc, n)
 220                 CALL    (g)
 221                 SR      (acc)
 222                 SR      (acc)
 223                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 224                 MOV     (acc, i2)
 225                 // shift-divide by six
 226                 // note: i2 is max 0x78; so acc will <= 20. (breaks vor values >=128)
 227                 SR      (acc)
 228                 ADD     (acc, i2)
 229                 SR      (acc)
 230                 SR      (acc)
 231                 ADD     (acc, i2)
 232                 SR      (acc)
 233                 SR      (acc)
 234                 ADD     (acc, i2)
 235                 SR      (acc)
 236                 SR      (acc)
 237                 SR      (acc)
 238                 // end divide by six
 239                 AND     (acc, tmp_1) // acc restored from tmp_1
 240                 AND     (acc, 3)
 241                 ADD     (sample, acc)
 242
 243                 MOV     (acc, i2)
 244                 MOV     (mod3hi, acc)
 245                 SR      (mod3hi)
 246                 SR      (mod3hi)
 247                 SWAP    (acc)
 248                 AND     (acc, 0xf0)
 249                 SL      (acc)
 250                 SL      (acc)
 251                 MOV     (mod3lo, acc)
 252                 MOV     (acc, i1)
 253                 SR      (acc)
 254                 SR      (acc)
 255                 OR      (mod3lo, acc)
 256                 CALL    (mod3)
 257                 SUB     (acc, n)
 258                 SUB     (acc, 8)
 259                 NEG     (acc)
 260                 CALL    (g)
 261                 SR      (acc)
 262                 MOV     (tmp_1, acc) // acc saved in tmp_1; fresh acc
 263                 MOV     (acc, i2)
 264                 // shift-divide by ten
 265                 // note: i2 is max 0x78; so acc will <= 12.
 266                 INC     (i2)
 267                 SR      (acc)
 268                 ADD     (acc, i2)
 269                 SR      (acc)
 270                 SR      (acc)
 271                 SR      (acc)
 272                 ADD     (acc, i2)
 273                 SR      (acc)
 274                 ADD     (acc, i2)
 275                 SWAP    (acc)
 276                 DEC     (i2)
 277                 // end divide by ten
 278                 AND     (acc, tmp_1) // acc restored from tmp_1
 279                 AND     (acc, 3)
 280                 ADD     (sample, acc)
 281
 282                 MOV     (acc, sample)
 283                 SWAP    (acc)
 284                 putchar(acc);
 285
 286                 INC     (i0)
 287                 /*ADDC  i1*/            i1 += !i0;
 288                 /*ADDC  i2*/            i2 += !i1 && !i0;
 289
 290                 if(i2 == 0x78) break;
 291         }
 292 }