openpower/isafunctions/bcd.mdwn

   1 # B.1 BCD-to-DPD Translation; B.2 DPD-to-BCD Translation
   2
   3 The following describes conversions between 3-digit BCD and 10-bit DPD formats.
   4
   5 <!-- Power ISA Book I Version 3.0C Section B.1 page 795 -->
   6
   7     def BCD_TO_DPD( BCD ):
   8         a <- BCD[0]
   9         b <- BCD[1]
  10         c <- BCD[2]
  11         d <- BCD[3]
  12         e <- BCD[4]
  13         f <- BCD[5]
  14         g <- BCD[6]
  15         h <- BCD[7]
  16         i <- BCD[8]
  17         j <- BCD[9]
  18         k <- BCD[10]
  19         m <- BCD[11]
  20
  21         p <- ((f & a & i & ¬e) | (j & a & ¬i) | (b & ¬a))
  22         q <- ((g & a & i & ¬e) | (k & a & ¬i) | (c & ¬a))
  23         r <- d
  24
  25         s <- ((j & ¬a & e & ¬i) | (f & ¬i & ¬e) |
  26             (f & ¬a & ¬e) | (e & i))
  27         t <- ((k & ¬a & e & ¬i) | (g & ¬i & ¬e) |
  28             (g & ¬a & ¬e) | (a & i))
  29
  30         u <- h
  31
  32         v <- (a | e | i)
  33
  34         w <- ((¬e & j & ¬i) | (e & i) | a)
  35         x <- ((¬a & k & ¬i) | (a & i) | e)
  36         y <- m
  37
  38         return (p || q || r || s || t || u || v || w || x || y)
  39
  40 <!-- Power ISA Book I Version 3.0C Section B.2 page 795 -->
  41
  42     def DPD_TO_BCD(DPD):
  43         p <- DPD[0]
  44         q <- DPD[1]
  45         r <- DPD[2]
  46         s <- DPD[3]
  47         t <- DPD[4]
  48         u <- DPD[5]
  49         v <- DPD[6]
  50         w <- DPD[7]
  51         x <- DPD[8]
  52         y <- DPD[9]
  53
  54         a <- ((¬s & v & w) | (t & v & w & s) | (v & w & ¬x))
  55         b <- ((p & s & x & ¬t) | (p & ¬w) | (p & ¬v))
  56         c <- ((q & s & x & ¬t) | (q & ¬w) | (q & ¬v))
  57         d <- r
  58
  59         e <- ((v & ¬w & x) | (s & v & w & x) |
  60             (¬t & v & x & w))
  61         f <- ((p & t & v & w & x & ¬s) | (s & ¬x & v) |
  62             (s & ¬v))
  63         g <- ((q & t & w & v & x & ¬s) | (t & ¬x & v) |
  64             (t & ¬v))
  65         h <- u
  66
  67         i <- ((t & v & w & x) | (s & v & w & x) |
  68             (v & ¬w & ¬x))
  69         j <- ((p & ¬s & ¬t & w & v) | (s & v & ¬w & x) |
  70             (p & w & ¬x & v) | (w & ¬v))
  71         k <- ((q & ¬s & ¬t & v & w) | (t & v & ¬w & x) |
  72             (q & v & w & ¬x) | (x & ¬v))
  73         m <- y
  74
  75         return (a || b || c || d || e || f || g || h || i || j || k || m)