
TM1300 Data Book
Philips Semiconductors
A-4
PRODUCT SPECIFICATION
allocd
Allocate a cache block with displacement
SYNTAX
[ IF r
guard ] allocd(d) rsrc1
FUNCTION
if r
guard then {
cache_block_mask = ~(cache_block_size -1)]
allocate adata cache block with [(rsrc1 + d) & cache_block_mask] address
}
ATTRIBUTES
Function unit
dmemspec
Operation code
213
Number of operands
1
Modier
7 bits
Modier range
-255..252 by 4
Latency
-
Issue slots
5
DESCRIPTION
The allocd operation allocate a cache block with the address computed from [(rsrc1 + d) & cache_block_mask] and
sets the status of this cache block as valid. No data is fetched from main memory for this operation. The allocated
cache block data is undened after this operation. It is the responsibility of the programmer to update the allocated
cache block by store operations.
Refer to the ‘cache architecture’ section for details on the cache block size.
The allocd
operation optionally takes a guard, specied in r
guard. If a guard is present, its LSB controls the
execution of the allocd operation. If the LSB of r
guard is 1, allocd operation is executed; otherwise, it is not executed.
EXAMPLES
Initial Values
Operation
Result
r10 = 0xabcd,
cache_block_size = 0x40
allocd(0x32) r10
Allocates a cache block for the address space from
0xabc0 to 0x0xabff without fetching the data from
main memory; The data in this address space is
undened.
r10 = 0xabcd, r11 = 0,
cache_block_size = 0x40
IF r11 allocd(0x32) r10
since guard is false, allocd operation is not executed
r10 = 0xabff, r11 = 1,
cache_block_size = 0x40
IF r11 allocd(0x4) r10
Allocates a cache block for the address space from
0xac00 to 0xac3f without fetching the data from main
memory; the data in this address space is undened.
SEE ALSO
allocr allocx