PNX1300 Datasheet, PDF (370/548 Pages) NXP Semiconductors – Media Processors

Philips Semiconductors
Hardware 8-bit store with displacement
PNX1300/01/02/11 DSPCPU Operations
h_st8d
SYNTAX
[ IF rguard ] h_st8d(d) rsrc1 rsrc2
FUNCTION
if rguard then
mem[rsrc2 + d] ← rsrc1<7:0>
ATTRIBUTES
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
dmem
29
2
7 bits
–64..63
n/a
4, 5
SEE ALSO
st8 st8d st16 st16d st32
st32d
DESCRIPTION
The h_st8d operation stores the least-significant 8-bit byte of rsrc1 into the memory location pointed to by the
address formed from the sum rsrc2 + d. The value of the opcode modifier d must be in the range -64 and 63 inclusive.
This operation does not depend on the bytesex bit in the PCSW since only a single byte is stored.
The h_st8d operation optionally takes a guard, specified in rguard. If a guard is present, its LSB controls the
modification of the addressed memory location (and the modification of cache if the location is cacheable). If the LSB
of rguard is 1, the store takes effect. If the LSB of rguard is 0, h_st8d has no side effects whatever; in particular, the
LRU and other status bits in the data cache are not affected.
EXAMPLES
Initial Values
r10 = 0xd00, r80 = 0x44332211
r50 = 0, r20 = 0xd01,
r70 = 0xaabbccdd
r60 = 1, r30 = 0xd02,
r70 = 0xaabbccdd
Operation
h_st8d(3) r80 r10
IF r50 h_st8d(-4) r70 r20
IF r60 h_st8d(-4) r70 r30
Result
[0xd03] ← 0x11
no change, since guard is false
[0xcfe] ← 0xdd
PRELIMINARY SPECIFICATION
A-72