The EDCX4KGT routine is called to get page-aligned storage from
the operating system. Its entry point must be
@@X4KGET.
It has the following parameter:
- R0
- The requested length, in bytes. If the high-order bit of this
register is zero or if the request was made in 24-bit addressing mode,
the storage is allocated below the 16M line. If the high-order bit
is on and the request is made in 31-bit addressing mode, storage
is allocated above the 16M line. If this space is not available, storage
is allocated elsewhere.
Upon return, the following values are set:
- R0
- The length of the storage block acquired, in bytes. This length
may be greater than the size requested.
- R1
- The address of the acquired area or NULL.
- R15
- A system-dependent return code, which must be zero on success
and nonzero otherwise.
This routine is not provided with a save
area. In addition to the linkage registers, this routine may freely
alter registers 2 and 4.