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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <syserr.h>
include <mach.h>
include "fmio.h"
# FMIO_EXTEND -- Allocate new pages in the datafile. Allocate the new pages
# and modify the in-core page table and lfile pagemap accordingly. The PTI is
# not modified, allocating new pages to store the page table itself, until
# fm_sync is called. The page number of the first page allocated is returned
# as the function value (a contiguous sequence of pages will be allocated).
int procedure fmio_extend (fm, lfile, npages)
pointer fm #I FMIO descriptor
int lfile #I lfile getting the new pages
int npages #I number of pages to add
pointer pt, pm, lf
int npte_perpage, npti
int inc, np, p1, p2, l1, l2, i
int krealloc()
begin
# Extend the global page table.
p1 = FM_PTNPTE(fm) + 1
p2 = p1 + npages - 1
# Make sure we have enough page table index entries for the new pages.
if (lfile != PT_LFILE) {
npte_perpage = FM_SZBPAGE(fm) / (SZB_CHAR*SZ_SHORT)
np = p2 + FM_PTILEN(fm)
npti = (np + npte_perpage-1) / npte_perpage
if (npti > FM_PTILEN(fm)) {
call fmio_posterr (fm, SYS_FMPTIOVFL, FM_DFNAME(fm))
return (ERR)
}
}
# Increase the size of the in-core page table if necessary.
if (p2 > FM_PTLEN(fm)) {
inc = FM_SZBPAGE(fm) / (SZ_SHORT * SZB_CHAR)
FM_PTLEN(fm) = ((p2 + inc-1) / inc) * inc
if (krealloc (FM_PTABLE(fm), FM_PTLEN(fm), TY_SHORT) == ERR)
return (ERR)
}
# Add the pages to the global page table.
FM_PTNPTE(fm) = p2
pt = FM_PTABLE(fm)
do i = p1, p2
Mems[pt+i-1] = lfile
lf = FM_FTABLE(fm) + lfile * LEN_FTE
pm = LF_PAGEMAP(lf)
# Extend the lfile page table if the lfile is active.
if (pm != NULL) {
l1 = LF_NPAGES(lf) + 1
l2 = l1 + npages - 1
# Increase the size of the lfile pagemap if necessary.
if (l2 > LF_PMLEN(lf)) {
LF_PMLEN(lf) = (l2 + INC_PMLEN-1) / INC_PMLEN * INC_PMLEN
if (krealloc (LF_PAGEMAP(lf), LF_PMLEN(lf), TY_INT) == ERR)
return (ERR)
pm = LF_PAGEMAP(lf)
}
# Add the pages to the lfile page table.
LF_NPAGES(lf) = l2
do i = l1, l2
Memi[pm+i-1] = p1 + i - l1
}
# Update the FTE for lfile zero (the page table file).
lf = FM_FTABLE(fm)
LF_FSIZE(lf) = FM_PTNPTE(fm) * SZ_SHORT * SZB_CHAR
FM_DHMODIFIED(fm) = YES
return (p1)
end
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