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 = (((i1&0x1f)<<8|i0)*t)>>8; //TODO
  77         RET //TODO: replace CALL/RET with IJMP?
  78 };
  79
  80 int main(void) {
  81         CLR     (zero)
  82         CLR     (i0)
  83         CLR     (i1)
  84         CLR     (i2)
  85         CLR     (i3)
  86         for (;;) {
  87                 MOV     (n, i2)
  88                 LSL     (n)
  89                 LSL     (n)
  90                 #define tmp _
  91                 MOV     (tmp, i1)
  92                 SWAP    (tmp)
  93                 ANDI    (tmp, 0x0f)
  94                 LSR     (tmp)
  95                 LSR     (tmp)
  96                 OR      (n, tmp)
  97                 #undef tmp
  98                 MOV     (s, i3)
  99                 ROR     (s)
 100                 ROR     (s)
 101                 ANDI    (s, 0x80)
 102                 #define tmp _
 103                 MOV     (tmp, i2)
 104                 LSR     (tmp)
 105                 OR      (s, tmp)
 106                 #undef tmp
 107
 108                 //voice 1:
 109                 MOV     (t, n)
 110                 RCALL   g();
 111                 SWAP    (t)
 112                 ANDI    (t, 0x0f)
 113                 ANDI    (t, 1)
 114                 MOV     (acc, t)
 115
 116                 //voice 2:
 117                 #define tmp _
 118                 MOV     (tmp, i2)
 119                 LSL     (tmp)
 120                 LSL     (tmp)
 121                 LSL     (tmp)
 122                 MOV     (t, i1)
 123                 SWAP    (t)
 124                 ANDI    (t, 0xf)
 125                 LSR     (t)
 126                 OR      (t, tmp)
 127                 #undef tmp
 128                 EOR     (t, n)
 129                 RCALL   g();
 130                 LSR     (t)
 131                 LSR     (t)
 132                 ANDI    (t, 3)
 133                 AND     (t, s)
 134                 ADD     (acc, t)
 135
 136                 //voice 3:
 137                 MOV     (Ml, i2)
 138                 SWAP    (Ml)
 139                 ANDI    (Ml, 0xf0)
 140                 LSL     (Ml)
 141                 #define tmp _
 142                 MOV     (tmp, i1)
 143                 LSR     (tmp)
 144                 LSR     (tmp)
 145                 LSR     (tmp)
 146                 OR      (Ml, tmp)
 147                 #undef tmp
 148                 MOV     (Mh, i3)
 149                 SWAP    (Mh)
 150                 ANDI    (Mh, 0xf0)
 151                 LSL     (Mh)
 152                 #define tmp _
 153                 MOV     (tmp, i2)
 154                 LSR     (tmp)
 155                 LSR     (tmp)
 156                 LSR     (tmp)
 157                 OR      (Mh, tmp)
 158                 #undef tmp
 159                 RCALL   mod3();
 160                 ADD     (t, n)
 161                 RCALL   g();
 162                 LSR     (t)
 163                 LSR     (t)
 164                 ANDI    (t, 3)
 165                 MOV     (x, s)
 166                 INC     (x)
 167                 #define tmp _
 168                 MOV     (tmp, x)
 169                 LSR     (tmp)
 170                 LSR     (tmp)
 171                 ADD     (tmp, x)
 172                 ROR     (tmp)
 173                 LSR     (tmp)
 174                 ADD     (tmp, x)
 175                 ROR     (tmp)
 176                 LSR     (tmp)
 177                 ADD     (tmp, x)
 178                 ROR     (tmp)
 179                 LSR     (tmp)
 180                 MOV     (x, tmp)
 181                 #undef tmp
 182                 AND     (t, x)
 183                 ADD     (acc, t)
 184
 185                 //voice 4:
 186                 MOV     (Ml, i2)
 187                 SWAP    (Ml)
 188                 ANDI    (Ml, 0xf0)
 189                 LSL     (Ml)
 190                 LSL     (Ml)
 191                 #define tmp _
 192                 MOV     (tmp, i1)
 193                 LSR     (tmp)
 194                 LSR     (tmp)
 195                 OR      (Ml, tmp)
 196                 #undef tmp
 197                 MOV     (Mh, i3)
 198                 SWAP    (Mh)
 199                 ANDI    (Mh, 0xf0)
 200                 LSL     (Mh)
 201                 LSL     (Mh)
 202                 #define tmp _
 203                 MOV     (tmp, i2)
 204                 LSR     (tmp)
 205                 LSR     (tmp)
 206                 OR      (Mh, tmp)
 207                 #undef tmp
 208                 RCALL   mod3();
 209                 SUB     (t, n)
 210                 NEG     (t)
 211                 SUBI    (t, -8)
 212                 RCALL   g();
 213                 LSR     (t)
 214                 ANDI    (t, 3)
 215                 MOV     (x, s)
 216                 INC     (x)
 217                 #define tmp _
 218                 MOV     (tmp, x)
 219                 LSR     (tmp)
 220                 ADD     (tmp, x)
 221                 ROR     (tmp)
 222                 LSR     (tmp)
 223                 LSR     (tmp)
 224                 ADD     (tmp, x)
 225                 ROR     (tmp)
 226                 ADD     (tmp, x)
 227                 ROR     (tmp)
 228                 LSR     (tmp)
 229                 LSR     (tmp)
 230                 MOV     (x, tmp)
 231                 #undef tmp
 232                 AND     (t, x)
 233                 ADD     (acc, t)
 234
 235                 putchar(acc<<4); //TODO
 236                 SUBI    (i0, -1)
 237                 ADC     (i1, zero, !i0)
 238                 ADC     (i2, zero, !i0&&!i1)
 239                 ADC     (i3, zero, !i0&&!i1&&!i2)
 240         }
 241 }