# function gcd(a,b)
# {
#  while (true)
#    {
#     c = a-b
#     if (c > 0) a=c
#           else b=-c
#
#     if (c==0)
#           break;
#    }
#  return a;
# }
#
# proponowane wyrażenie watch
# c=0 a=1 b=2

	read 1          # r1 = a
	read 2          # r2 = b

while:	load 1          #
	sub  2          # r0 = c = a-b
	jgtz then
	jump else

then:	store 1         # a = c
	jump  endif

else:	store 2
	load =0
	sub   2
	store 2         # b = -c

endif:	jzero break     # c ?= 0
	jump  while

break:	write 1         # return a