#!./parrot
# Copyright (C) 2006-2009, Parrot Foundation.
# $Id: recursive-2.pir 45949 2010-04-24 01:14:23Z cotto $
#
# Ack by Leopold Toetsch
# Fib and Tak by Joshua Isom

# use less registers (leo)
# time ./parrot -Oc recursive-2.pir 11
# real 2.32 s   (AMD X2@2000)
# modified default value to n=3. Karl Forner


.sub main :main
    .param pmc argv
    .local int argc, n
    argc = argv
    n = 3
    unless argc == 2 goto argsok
    $S0 = argv[1]
    n = $S0
argsok:
    $P0 = getinterp
    $P0.'recursion_limit'(100000)

    .local pmc array
    array = new 'FixedFloatArray'
    array = 11

    dec n

    $I0 = n + 1
    $I1 = ack(3, $I0)
    array[0] = $I0
    array[1] = $I1

    $N0 = 28.0 + n
    array[2] = $N0
    $N0 = FibNum($N0)
    array[3] = $N0

    $I0 = n * 3
    $I1 = n * 2
    array[4] = $I0
    array[5] = $I1
    array[6] = n
    $I0 = TakInt($I0, $I1, n)
    array[7] = $I0

    $I0 = FibInt(3)
    array[8] = $I0

    $N0 = TakNum(3.0, 2.0, 1.0)
    array[9] = $N0

    $S0 = sprintf <<"END", array
Ack(3,%d): %d
Fib(%.1f): %.1f
Tak(%d,%d,%d): %d
Fib(3): %d
Tak(3.0,2.0,1.0): %.1f
END
    print $S0
.end

.sub ack
    .param int x
    .param int y
    unless x goto a1
    unless y goto a2
    dec y
    y = ack(x, y)
    dec x
    .tailcall ack(x, y)
a1:
    inc y
    .return (y)
a2:
    dec x
    .tailcall ack(x, 1)
.end

.sub FibInt
    .param int n
    unless n < 2 goto endif
    .return(1)
endif:
    .local int tmp
    tmp = n - 2
    $I0 = FibInt(tmp)
    tmp = n - 1
    $I1 = FibInt(tmp)
    $I0 += $I1
    .return($I0)
.end

.sub FibNum
    .param num n
    unless n < 2.0 goto endif
    .return(1.0)
endif:
    .local num tmp
    tmp = n - 2.0
    $N0 = FibNum(tmp)
    dec n
    n = FibNum(n)
    $N0 += n
    .return($N0)
.end

.sub TakNum
    .param num x
    .param num y
    .param num z
    unless y >= x goto endif
    .return(z)
endif:
    .local num tmp
    tmp = x - 1
    $N0 = TakNum(tmp, y, z)
    tmp = y - 1
    $N1 = TakNum(tmp, z, x)
    dec z
    z = TakNum(z, x, y)
    .tailcall TakNum($N0, $N1, z)
.end

.sub TakInt
    .param int x
    .param int y
    .param int z
    unless y >= x goto endif
    .return(z)
endif:
    .local int tmp
    tmp = x - 1
    $I0 = TakInt(tmp, y, z)
    tmp = y - 1
    tmp = TakInt(tmp, z, x)
    dec z
    z   = TakInt(z, x, y)
    .tailcall TakInt($I0, tmp, z)
.end


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#   mode: pir
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# End:
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