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SYNTAX [<LABEL>] CNFP
OPERANDS None
EXECUTION (PC) + 1 . PC
1 . RAM configuration control (CNF) status bit
Affects CNF.
DESCRIPTION On-chip RAM block 0 is configured as program memory. The block
is mapped to locations 65280 to 65535 in program memory space.
This instruction is the complement of the CNFD instruction and
sets the CNF bit in status register ST1 to one. CNF is also
loaded by the CNFP and LST1 instructions.
Configuring this block as program memory allows the use of the
program counter as an address generator to access data from
on-chip RAM. Used in conjunction with the repeat instructions,
this allows two data memory locations to be addressed
simultaneously, one from the auxiliary registers and one from
the program counter. Instructions that take advantage of this
feature are the MAC, MACD, BLKD, and BLKP.
On the TMS32020, the instruction fetch immediately following
a CNFD or CNFP instruction uses the old CNF value, even if it
is the fetch of the second word of a two-word instruction.
On a TMS320C25, the next two instruction fetches immediately
following a CNFD or CNFP instruction use the old value of the
CNF.
WORDS 1
ENCODING 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
+-----------------------------------------------+
|1 1 0 0 1 1 1 0 0 0 0 0 0 1 0 1 |
+-----------------------------------------------+
CYCLES
+------------------------------------------------+
| Cycle Timings for a Single Instruction |
|------------------------------------------------|
| PI/DI | PI/DE | PE/DI | PE/DE | PR/DI | PR/DE |
|-------+-------+-------+--------+-------+-------|
'20 | 1 | 1 | 1+p | 1+p | - | - |
|-------+-------+-------+--------+-------+-------|
'C25 | 1 | 1 | 1+p | 1+p | 1 | 1 |
|------------------------------------------------|
| Cycle Timings for a Repeat Instruction |
|------------------------------------------------|
'20 | n | n | n+p | n+p | - | - |
|-------+-------+-------+--------+-------+-------|
'C25 | n | n | n+p | n+p | n | n |
+------------------------------------------------+
EXAMPLE CNFP The CNF bit is set to logic 1, thus configuring
block B0 as program memory (see memory maps).