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Mohamed G. Gouda                                        CS 356
Summer      2007                                        Midterm 3 Solution
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1. (10 Points):

Statement S.0:

if b=1 -> up := true
[] b=0 -> up := false
fi; send chk(b) to p[i +n 1]

Statement S.1:

up := false

Statement S.2:

up := true; send chk(1) to p[1]

Statement S.3:

up := false; send chk(0) to p[1]

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2. (10 Points):

Statement RTMSG:

if i != x ^ j != 0 ^ up[prs[0]]  -> send data(x,y) to p[prs[0]]
[] i != x ^ j != 0 ^ ~up[prs[0]] -> {non reach.} skip
[] i != x ^ j = 0  ^ up[x,0]     -> send data(x,y) to p[x,0]
[] i != x ^ j = 0  ^ ~up[x,0]    -> {non reach.} skip
[] i  = x ^ j != y ^ up[prs[y]]  -> send data(x,y) to p[prs[y]]
[] i  = x ^ j != y ^ ~up[prs[y]] -> {non reach.} skip
[] i  = x ^ j = y                -> {arrived} skip
fi
 
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