PNX1300 Philips, PNX1300 Datasheet - Page 444

• Manufacturer Part Number: PNX1300
• Description: Media Processors
• Manufacturer: Philips

Philips Semiconductors
prefetch with 32-bit scaled index
SYNTAX
[ IF rguard ] pref32x rsrc1 rsrc2
FUNCTION
DESCRIPTION
x rscr2)) & cache_block_mask) and stores the data into the data cache. This operation is not guaranteed to be
executed. The prefetch unit will not execute this operation when the data to be prefetched is already in the data cache.
A pref32x operation will not be executed when the cache is already occupied with 2 cache misses, when the operation
is issued.
execution of the prefetch operation. If the LSB of rguard is 1, prefetch operation is executed; otherwise, it is not
executed..
EXAMPLES
NOTE: This operation may only be supported in TM-1000, TM-1100, TM-1300 and
PNX1300/01/02/11. It is not guaranteed to be available in future generations of Trimedia
products.
r10 = 0xabcd, r12 = 0xd
cache_block_size = 0x40
r10 = 0xabcd, r11 = 0, r12=0xd,
cache_block_size = 0x40
r10 = 0xabff, r11 = 1, r12 =0x1,
cache_block_size = 0x40
The pref32x operation loads the one full cache block size of memory value from the address computed by ((rsrc1+ (4
The pref32x operation optionally takes a guard, specified in rguard. If a guard is present, its LSB controls the
if rguard then {
}
cache_block_mask = ~(cache_block_size - 1)
data_cache <- mem[(rsrc1 + (4 x rscr2)) & cache_block_mask]
Initial Values
pref32x r10 r12
IF r11 pref32x r10 r12
IF r11 pref32x r10 r12
Operation
PRELIMINARY SPECIFICATION
Loads a cache line for the address space from
0xac00 to 0x0xac3f from the main memory. If the data
is already in the cache, the operation is not executed.
since guard is false, pref32x operation is not executed
Loads a cache line for the address space from
0xac00 to 0x0xac3f from the main memory. If the data
is already in the cache, the operation is not executed.
PNX1300/01/02/11 DSPCPU Operations
pref16x prefd prefr allocd
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
Result
allocr allocx
ATTRIBUTES
SEE ALSO
pref32x
dmemspec
212
No
2
5
-
-
A-146