Guardian Procedure Calls Reference Manual (G06.25+)

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Guardian Procedure Calls (R)

Guardian Procedure Calls Reference Manual—522629-013

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REFPARAM_BOUNDSCHECK_ Procedure

start-address input

STRING .EXT:ref:*

identifies the start of the data area to be bounds checked.

When REFPARAM_BOUNDSCHECK_ is called from a native process,

start-

address cannot be a relative segment 1 or 2 address. Neither can it be an

absolute address unless

flags.<14> is set to allow this.

When REFPARAM_BOUNDSCHECK_ is called from a TNS process,

start-

address can be an absolute address that points to the TNS stack.

area-length input

INT(32):value

is the length of the area to be checked. It is a 31-bit value. On a native processor,

the area must not span separately allocated logical areas even if the areas are

contiguous in virtual memory.

area-length is zero (0D), start-address is not checked and

REFPARAM_BOUNDSCHECK_ returns without error.

framestart input

EXTADDR:value

excludes the stack area of the calling procedure from the area that

REFPARAM_BOUNDSCHECK_ accepts as valid.

framestart is zero, REFPARAM_BOUNDSCHECK_ verifies only that the

specified memory area is valid. It makes no attempt to verify that the specified

memory area does not overlap the part of the stack used by the calling process.

framestart is nonzero, it specifies one edge of a region to be excluded from

the valid area. For a TNS process, the excluded area begins at the address in

framestart and extends 600 bytes past the L-register setting of the procedure

that calls REFPARAM_BOUNDSCHECK_. For a native process, the excluded

area begins at the start of the stack area and extends to (but does not include) the

address specified by

framestart. Stack-frame overlap detection is possible only

for procedures running on the default stack of the process; it is not performed if

framestart designates an address on a user thread stack.

In pTAL, the correct value to pass in

framestart is obtained using the

$PARAMSTART function. In TAL, you use the $XADR function. A set of

DEFINEs are available to mask the differences between pTAL and TAL. See

“Considerations” for details.