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c BSWAP4 - Move bytes from array "a" to array "b", swapping the four bytes
c in each successive 4 byte group, i.e., 12345678 becomes 43218765.
subroutine bswap4 (a, aoff, b, boff, nbytes)
character*1 a(*), b(*), temp
integer aoff, boff, nbytes, i
integer aoff1, boff1, aoff2, boff2, aoff3, boff3
if (nbytes .le. 4) then
return
endif
aoff1 = aoff + 1
boff1 = boff + 1
aoff2 = aoff + 2
boff2 = boff + 2
aoff3 = aoff + 3
boff3 = boff + 3
do 10 i = 0, nbytes-3, 4
temp = a(aoff1+i)
b(boff1+i) = a(aoff2+i)
b(boff2+i) = temp
temp = a(aoff3+i)
b(boff3+i) = a(aoff+i)
b(boff+i) = temp
10 continue
end
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