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include defs
# dsfree --- return a block of storage to the available space list
subroutine dsfree (block)
pointer block
DS_DECL(Mem, 1)
pointer p0, p, q
integer n, junk
character con (10)
p0 = block - DS_OHEAD
n = Mem (p0 + DS_SIZE)
q = DS_AVAIL
repeat {
p = Mem (q + DS_LINK)
if (p == LAMBDA | p > p0)
break
q = p
}
if (q + Mem (q + DS_SIZE) > p0) {
call remark ("in dsfree: attempt to free unallocated block.")
call remark ("type 'c' to continue.")
junk = getlin (con, STDIN)
if (con (1) != LETC & con (1) != BIGC)
call endst
return # do not attempt to free the block
}
if (p0 + n == p & p != LAMBDA) {
n = n + Mem (p + DS_SIZE)
Mem (p0 + DS_LINK) = Mem (p + DS_LINK)
}
else
Mem (p0 + DS_LINK) = p
if (q + Mem (q + DS_SIZE) == p0) {
Mem (q + DS_SIZE) = Mem (q + DS_SIZE) + n
Mem (q + DS_LINK) = Mem (p0 + DS_LINK)
}
else {
Mem (q + DS_LINK) = p0
Mem (p0 + DS_SIZE) = n
}
return
end
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