pTAL Reference Manual (G06.24+, H06.09+, J06.03+)

NopTAL privileged procedure
YesCan be executed only by privileged procedures
NoSets condition code
YesSets $CARRY
NoSets $OVERFLOW
headersize
input
uINT:value
is the unsigned byte offset from the beginning of the SPT to the beginning of the header.
Because the SPT header always precedes the SPT, headersize is subtracted from the
address of the SPT to obtain the address of the start of the header.
virtaddr
input
EXTADDR:value
is the address of the SPT.
sptbase
output
EXTADDR:variable
is the address of the segment-page-table header associated with virtaddr.
$LOCATESPTHDR returns in sptbase the address of the segment-page table for the address in
virtaddr.
Example 276 $LOCATESPTHDR Routine
INT headersize;
EXTADDR addr;
EXTADDR seg_page_table_base;
$LOCATESPTHDR(headersize, addr, seg_page_table_base);
$LOCKPAGE
NOTE: The EpTAL compiler does not support this procedure.
$LOCKPAGE locks one page of memory.
YespTAL privileged procedure
YesCan be executed only by privileged procedures
Nonatomic Operations 325