Texas Instruments TMS320C28x Reference Manual page 405

NEGTC ACC
NEGTC ACC
SYNTAX OPTIONS
NEGTC ACC
Operands ACC
Description
Flags and N
Modes
Z
C
V
TC
OVM
Repeat
6-248
0101 0110 0011 0010
Accumulator register
Based on the state of the test control (TC) bit, conditionally replace the
content of the ACC register with its negative:
if( TC = 1 )
{
if(ACC = 0x8000 0000)
{
V = 1;
if(OVM = 1)
ACC = 0x7FFF FFFF;
else
ACC = 0x8000 0000
}
else
ACC = −ACC;
if(ACC = 0x0000 0000)
C = 1;
else
C = 0;
}
After the operation, the N flag is set if bit 31 of the ACC is 1, else N is cleared.
After the operation, the Z flag is set if the ACC is zero, else Z is cleared.
If (TC = 1 AND ACC = 0) set C; if (TC = 1 AND ACC != 0) clear C; otherwise C
is not modified.
If (TC = 1 AND ACC = 0x8000 0000) at the start of the operation, this is
considered an overflow value and V is set. Otherwise, V is not affected.
The state of the TC bit is used as a test condition for the operation.
If at the start of the operation, ACC = 0x8000 0000, then this is considered an
overflow value and the ACC value after the operation depends on OVM. If
OVM is cleared and TC = 1, ACC will be filled with 0x8000 0000. If OVM is set
and TC = 1, ACC will be saturated to 0x7FFF FFFF.
This instruction is not repeatable. If this instruction follows the RPT
instruction, it resets the repeat counter (RPTC) and executes only once.
If TC is Equivalent to 1, Negate ACC
OPCODE OBJMODE RPT CYC
1 − 1