foo.c

   1 #include <stdio.h>
   2 #include "fakeasm.h"
   3 typedef unsigned char u8;
   4
   5 u8 data[] = {
   6         0x84, 0x9d, 0xb0, 0x69, 0x9d, 0x84, 0x69, 0x58,
   7         0x75, 0x8c, 0xb0, 0x69, 0x8c, 0x75, 0x69, 0x58
   8 };
   9 u8 zero;        //r16
  10 u8 acc;         //r17
  11 u8 i0;          //r18
  12 u8 i1;          //r19
  13 u8 i2;          //r20
  14 u8 i3;          //r21
  15 u8 n;           //r22
  16 u8 s;           //r23
  17 u8 _;           //r24
  18                 //r25
  19 u8 t;/*==Ml*/   //r26 (Xlo)
  20 u8 x;/*==Mh*/   //r27 (Xhi)
  21                 //r28
  22                 //r29
  23 /*fakestack_l*/ //r30 (Zlo)
  24 /*fakestack_h*/ //r31 (Zhi)
  25 #define Mh x //mod3 vars
  26 #define Ml t // -"-
  27 //http://homepage.divms.uiowa.edu/~jones/bcd/mod.shtml
  28 void mod3(void) {
  29         // mod3(Mh.Ml) -> t
  30         #define tmp _
  31         ADD     (Ml, Mh)
  32         CLR     (Mh)
  33         ADC     (Mh, zero, carry) //Mh only holds the carry bit
  34         MOV     (tmp, Ml)
  35         SWAP    (tmp)
  36         ANDI    (tmp, 0x0f)
  37         SWAP    (Mh)
  38         OR      (tmp, Mh)
  39         ANDI    (Ml, 0x0f)
  40         ADD     (Ml, tmp)
  41         MOV     (tmp, Ml)
  42         LSR     (tmp)
  43         LSR     (tmp)
  44         ANDI    (Ml, 0x03)
  45         ADD     (Ml, tmp)
  46         MOV     (tmp, Ml)
  47         LSR     (tmp)
  48         LSR     (tmp)
  49         ANDI    (Ml, 0x03)
  50         ADD     (Ml, tmp)
  51         CPI     (Ml, 3)
  52         BRPL    (skip)
  53         SUBI    (Ml, 3)
  54         skip:;
  55         RET
  56         #undef tmp
  57 }
  58 void g(void) {
  59         // g(i, t) -> t
  60         // tempvars: `x` and `_`
  61         #define tmp _
  62         ANDI    (t, 0x07)
  63         MOV     (tmp, i2)
  64         ANDI    (tmp, 3)
  65         TST     (tmp)
  66         #undef tmp
  67         BREQ    (skip)
  68         SUBI    (t, -8)
  69         skip:
  70         t = data[t];
  71         /*MOV X_hi==x, data_hi
  72           MOV X_lo==t, data_lo
  73           ADD X_lo, t
  74           ADC X_hi, zero
  75           LD  t, X         */
  76         t &= 0xfd; //hint
  77         t = (((i1&0x1f)<<8|i0)*t)>>8; //TODO
  78         t &= 0x1e; //hint
  79         RET //TODO: replace CALL/RET with IJMP?
  80 };
  81
  82 int main(void) {
  83         CLR     (zero)
  84         CLR     (i0)
  85         CLR     (i1)
  86         CLR     (i2)
  87         CLR     (i3)
  88         for (;;) {
  89                 MOV     (n, i2)
  90                 LSL     (n)
  91                 LSL     (n)
  92                 #define tmp _
  93                 MOV     (tmp, i1)
  94                 SWAP    (tmp)
  95                 ANDI    (tmp, 0x0f)
  96                 LSR     (tmp)
  97                 LSR     (tmp)
  98                 OR      (n, tmp)
  99                 #undef tmp
 100                 MOV     (s, i3)
 101                 ROR     (s)
 102                 ROR     (s)
 103                 ANDI    (s, 0x80)
 104                 #define tmp _
 105                 MOV     (tmp, i2)
 106                 LSR     (tmp)
 107                 OR      (s, tmp)
 108                 #undef tmp
 109
 110                 //voice 1:
 111                 MOV     (t, n)
 112                 RCALL   g();
 113                 SWAP    (t)
 114                 ANDI    (t, 0x0f)
 115                 ANDI    (t, 1)
 116                 MOV     (acc, t)
 117
 118                 //voice 2:
 119                 #define tmp _
 120                 MOV     (tmp, i2)
 121                 LSL     (tmp)
 122                 LSL     (tmp)
 123                 LSL     (tmp)
 124                 MOV     (t, i1)
 125                 SWAP    (t)
 126                 ANDI    (t, 0xf)
 127                 LSR     (t)
 128                 OR      (t, tmp)
 129                 #undef tmp
 130                 EOR     (t, n)
 131                 RCALL   g();
 132                 LSR     (t)
 133                 LSR     (t)
 134                 ANDI    (t, 3)
 135                 AND     (t, s)
 136                 ADD     (acc, t)
 137
 138                 //voice 3:
 139                 MOV     (Ml, i2)
 140                 SWAP    (Ml)
 141                 ANDI    (Ml, 0xf0)
 142                 LSL     (Ml)
 143                 #define tmp _
 144                 MOV     (tmp, i1)
 145                 LSR     (tmp)
 146                 LSR     (tmp)
 147                 LSR     (tmp)
 148                 OR      (Ml, tmp)
 149                 #undef tmp
 150                 MOV     (Mh, i3)
 151                 SWAP    (Mh)
 152                 ANDI    (Mh, 0xf0)
 153                 LSL     (Mh)
 154                 #define tmp _
 155                 MOV     (tmp, i2)
 156                 LSR     (tmp)
 157                 LSR     (tmp)
 158                 LSR     (tmp)
 159                 OR      (Mh, tmp)
 160                 #undef tmp
 161                 RCALL   mod3();
 162                 ADD     (t, n)
 163                 RCALL   g();
 164                 LSR     (t)
 165                 LSR     (t)
 166                 ANDI    (t, 3)
 167                 MOV     (x, s)
 168                 INC     (x)
 169                 #define tmp _
 170                 MOV     (tmp, x)
 171                 LSR     (tmp)
 172                 LSR     (tmp)
 173                 ADD     (tmp, x)
 174                 ROR     (tmp)
 175                 LSR     (tmp)
 176                 ADD     (tmp, x)
 177                 ROR     (tmp)
 178                 LSR     (tmp)
 179                 ADD     (tmp, x)
 180                 ROR     (tmp)
 181                 LSR     (tmp)
 182                 MOV     (x, tmp)
 183                 #undef tmp
 184                 AND     (t, x)
 185                 ADD     (acc, t)
 186
 187                 //voice 4:
 188                 MOV     (Ml, i2)
 189                 SWAP    (Ml)
 190                 ANDI    (Ml, 0xf0)
 191                 LSL     (Ml)
 192                 LSL     (Ml)
 193                 #define tmp _
 194                 MOV     (tmp, i1)
 195                 LSR     (tmp)
 196                 LSR     (tmp)
 197                 OR      (Ml, tmp)
 198                 #undef tmp
 199                 MOV     (Mh, i3)
 200                 SWAP    (Mh)
 201                 ANDI    (Mh, 0xf0)
 202                 LSL     (Mh)
 203                 LSL     (Mh)
 204                 #define tmp _
 205                 MOV     (tmp, i2)
 206                 LSR     (tmp)
 207                 LSR     (tmp)
 208                 OR      (Mh, tmp)
 209                 #undef tmp
 210                 RCALL   mod3();
 211                 SUB     (t, n)
 212                 NEG     (t)
 213                 SUBI    (t, -8)
 214                 RCALL   g();
 215                 LSR     (t)
 216                 ANDI    (t, 3)
 217                 MOV     (x, s)
 218                 INC     (x)
 219                 #define tmp _
 220                 MOV     (tmp, x)
 221                 LSR     (tmp)
 222                 ADD     (tmp, x)
 223                 ROR     (tmp)
 224                 LSR     (tmp)
 225                 LSR     (tmp)
 226                 ADD     (tmp, x)
 227                 ROR     (tmp)
 228                 ADD     (tmp, x)
 229                 ROR     (tmp)
 230                 LSR     (tmp)
 231                 LSR     (tmp)
 232                 MOV     (x, tmp)
 233                 #undef tmp
 234                 AND     (t, x)
 235                 ADD     (acc, t)
 236
 237                 putchar(acc<<4); //TODO
 238                 SUBI    (i0, -1)
 239                 ADC     (i1, zero, !i0)
 240                 ADC     (i2, zero, !i0&&!i1)
 241                 ADC     (i3, zero, !i0&&!i1&&!i2)
 242         }
 243 }