MRCNDD {CNDF}
Return Conditional Delayed
Operands
CNDF
optional condition.
Opcode
LSW: 0000 0000 0000 0000
MSW: 0111 1001 1010 cndf
Description
If the specified condition is true, then the RPC field of MSTF is loaded into MPC and
fetching continues from that location. Otherwise program fetches will continue without the
return.
Please refer to the pipeline section for important information regarding this instruction.
if (CNDF == TRUE) MPC = RPC;
CNDF is one of the following conditions:
Encode
CNDF
Description
MSTF Flags Tested
0000
NEQ
Not equal to zero
ZF == 0
0001
EQ
Equal to zero
ZF == 1
0010
GT
Greater than zero
ZF == 0 AND NF == 0
0011
GEQ
Greater than or equal
to zero
NF == 0
0100
LT
Less than zero
NF == 1
0101
LEQ
Less than or equal to
zero
ZF == 1 OR NF == 1
1010
TF
Test flag set
TF == 1
1011
NTF
Test flag not set
TF == 0
1100
LU
Latched underflow
LUF == 1
1101
LV
Latched overflow
LVF == 1
1110
UNC
Unconditional
None
1111
Unconditional with flag
modification
None
(1)
Values not shown are reserved.
(2)
This is the default operation if no CNDF field is specified. This condition will
allow the ZF and NF flags to be modified when a conditional operation is
executed. All other conditions will not modify these flags.
Flags
This instruction does not modify flags in the MSTF register.
Flag
TF
ZF
NF
LUF
LVF
Modified
No
No
No
No
No
Pipeline
The MRCNDD instruction by itself is a single-cycle instruction. As shown in
,
for each return 6 instruction slots are executed; three before the return instruction (d5-d7)
and three after the return instruction (d8-d10). The total number of cycles for a return
taken or not taken depends on the usage of these slots. That is, the number of cycles
depends on how many slots are filled with a MNOP as well as which slots are filled.
The effective number of cycles for a return can, therefore, range from 1 to 7 cycles. The
number of cycles for a return taken may not be the same as for a return not taken.
Control Law Accelerator (CLA)
688
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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