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; //zero register
  10 u8 i0;
  11 u8 i1;
  12 u8 i2;
  13 u8 i3;
  14 u8 x;
  15 u8 t;
  16 u8 o;
  17 u8 _;
  18 #define Mh o //mod3 vars
  19 #define Ml t // -"-
  20 void mod3(void) { //avail: t, o _
  21 //http://homepage.divms.uiowa.edu/~jones/bcd/mod.shtml
  22     unsigned short a = ((Mh) + (Ml)) &0x1ff;
  23         Mh = a>>8; //1 bit
  24         Ml = a;
  25     Ml = (Mh<<4|Ml>>4) + (Ml & 0xF);
  26     Ml = (Ml >>  2) + (Ml & 0x3);
  27     Ml = (Ml >>  2) + (Ml & 0x3);
  28     if (Ml > 2) Ml = Ml - 3;
  29 }
  30 void g(void) {
  31         // g(i, x, t, o) -> t
  32         #define tmp _
  33         ANDI    (t, 0x07)
  34         MOV     (tmp, i2)
  35         ANDI    (tmp, 3)
  36         TST     (tmp)
  37         #undef tmp
  38         BREQ    (skip)
  39         SUBI    (t, -8)
  40         skip:
  41         t = data[t];
  42         /*MOV X_hi==_, data_hi
  43           MOV X_lo==t, data_lo
  44           ADD X_lo, t
  45           ADC X_hi, zero
  46           LD  t, X         */
  47         t = (((i1&0x1f)<<8|i0)*t)>>8; //TODO
  48         t >>= o; //NOTE: o == {1, 2, 4}
  49         AND     (t, x)
  50         ANDI    (t, 3)
  51         RET
  52 };
  53
  54 int main(void) {
  55         u8 n;
  56         u8 s;
  57         u8 acc;
  58         //TODO: clear all vars/registers
  59         for (;;) {
  60                 MOV     (n, i2)
  61                 LSL     (n)
  62                 LSL     (n)
  63                 #define tmp acc
  64                 MOV     (tmp, i1)
  65                 SWAP    (tmp)
  66                 ANDI    (tmp, 0x0f)
  67                 LSR     (tmp)
  68                 LSR     (tmp)
  69                 OR      (n, tmp)
  70                 #undef tmp
  71                 MOV     (s, i3)
  72                 ROR     (s)
  73                 ROR     (s)
  74                 ANDI    (s, 0x80)
  75                 #define tmp acc
  76                 MOV     (tmp, i2)
  77                 LSR     (tmp)
  78                 OR      (s, tmp)
  79                 #undef tmp
  80
  81                 //voice 1:
  82                 LDI     (x, 1)
  83                 MOV     (t, n)
  84                 LDI     (o, 4)
  85                 RCALL   g();
  86                 MOV     (acc, t)
  87
  88                 //voice 2:
  89                 MOV     (x, s)
  90                 #define tmp o
  91                 MOV     (tmp, i2)
  92                 LSL     (tmp)
  93                 LSL     (tmp)
  94                 LSL     (tmp)
  95                 MOV     (t, i1)
  96                 SWAP    (t)
  97                 ANDI    (t, 0xf)
  98                 LSR     (t)
  99                 OR      (t, tmp)
 100                 #undef tmp
 101                 EOR     (t, n)
 102                 LDI     (o, 2)
 103                 RCALL   g();
 104                 ADD     (acc, t)
 105
 106                 //voice 3:
 107                 MOV     (x, s)
 108                 INC     (x)
 109                 #define tmp o
 110                 MOV     (tmp, x)
 111                 LSR     (tmp)
 112                 LSR     (tmp)
 113                 ADD     (tmp, x)
 114                 ROR     (tmp)
 115                 LSR     (tmp)
 116                 ADD     (tmp, x)
 117                 ROR     (tmp)
 118                 LSR     (tmp)
 119                 ADD     (tmp, x)
 120                 ROR     (tmp)
 121                 LSR     (tmp)
 122                 MOV     (x, tmp)
 123                 #undef tmp
 124                 Ml = i2<<5 | i1>>3;
 125                 Mh = i3<<5 | i2>>3;
 126                 RCALL   mod3();
 127                 ADD     (t, n)
 128                 LDI     (o, 2)
 129                 RCALL   g();
 130                 ADD     (acc, t)
 131
 132                 //voice 4:
 133                 MOV     (x, s)
 134                 INC     (x)
 135                 #define tmp o
 136                 MOV     (tmp, x)
 137                 LSR     (tmp)
 138                 ADD     (tmp, x)
 139                 ROR     (tmp)
 140                 LSR     (tmp)
 141                 LSR     (tmp)
 142                 ADD     (tmp, x)
 143                 ROR     (tmp)
 144                 ADD     (tmp, x)
 145                 ROR     (tmp)
 146                 LSR     (tmp)
 147                 LSR     (tmp)
 148                 MOV     (x, tmp)
 149                 #undef tmp
 150                 Ml = i2<<6 | i1>>2;
 151                 Mh = i3<<6 | i2>>2;
 152                 RCALL   mod3();
 153                 SUB     (t, n)
 154                 NEG     (t)
 155                 SUBI    (t, -8)
 156                 LDI     (o, 1)
 157                 RCALL   g();
 158                 ADD     (acc, t)
 159
 160                 putchar(acc<<4); //TODO
 161                 SUBI    (i0, -1)
 162                 ADC     (i1, zero, !i0)
 163                 ADC     (i2, zero, !i0&&!i1)
 164                 ADC     (i3, zero, !i0&&!i1&&!i2)
 165         }
 166 }