(a)
// Assume R==0 on entry
// Fill message buffer
for( int i=0; i<n; i++)
   M[i] = ...;
// Signal that message is ready.
R = 1;

(b)
// Assume R==0 on entry
// Wait for signal from sender
while( R==0 )
   continue
// Read the message
for( int i=0; i<n; i++ )
    ... = M[i];

Example 1: (a) Code for sending a message; (b) code for receiving a message. Code assumes sequential consistency.