PNX1300 Philips, PNX1300 Datasheet - Page 455

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

PNX1300/01/02/11 Data Book
readspc
SYNTAX
FUNCTION
DESCRIPTION
writes its target address to SPC. The value of SPC allows an exception-handling routine to determine the start
address of the block of scheduled code (called a decision tree) that was executing before the exception was
taken.This operation can be used to save state before idling a task in a multi-tasking environment.
modification of the destination register. If the LSB of rguard is 1, rdest is written; otherwise, rdest is unchanged.
EXAMPLES
A-157
SPC = 0xbeebee
r20 = 0, SPC = 0xabba
r21 = 1, SPC = 0xabba
The
An interruptible jump that is not interrupted (no NMI, INT, or EXC event was pending when the jump was executed)
The
[ IF rguard ] readspc
if rguard then {
}
rdest
readspc
readspc
Initial Values
SPC
writes the current value of the SPC (Source Program Counter) processor register to r dest.
operation optionally takes a guard, specified in rguard. If a guard is present, its LSB controls the
PRELIMINARY SPECIFICATION
readspc
IF r20 readspc
IF r21 readspc
rdest
Operation
r100
r101
r102
Read source program counter
r100
no change, since guard is false
r102
0xbeebee
0xabba
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
writespc readdpc ijmpf
Philips Semiconductors
Result
ijmpi ijmpt
ATTRIBUTES
SEE ALSO
fcomp
157
No
—
0
1
3